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Peták F, Südy R, Diaper J, Fontao F, Bizzotto D, Dellacà RL, Habre W, Schranc Á. Benefits of intratracheal and extrathoracic high-frequency percussive ventilation in a model of capnoperitoneum. J Appl Physiol (1985) 2024; 136:928-937. [PMID: 38420682 DOI: 10.1152/japplphysiol.00881.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/29/2024] [Accepted: 02/20/2024] [Indexed: 03/02/2024] Open
Abstract
Abdominal inflation with CO2 is used to facilitate laparoscopic surgeries, however, providing adequate mechanical ventilation in this scenario is of major importance during anesthesia management. We characterized high-frequency percussive ventilation (HFPV) in protecting from the gas exchange and respiratory mechanical impairments during capnoperitoneum. In addition, we aimed to assess the difference between conventional pressure-controlled mechanical ventilation (CMV) and HFPV modalities generating the high-frequency signal intratracheally (HFPVi) or extrathoracally (HFPVe). Anesthetized rabbits (n = 16) were mechanically ventilated by random sequences of CMV, HFPVi, and HFPVe. The ventilator superimposed the conventional waveform with two high-frequency signals (5 Hz and 10 Hz) during intratracheal HFPV (HFPVi) and HFPV with extrathoracic application of oscillatory signals through a sealed chest cuirass (HFPVe). Lung oxygenation index ([Formula: see text]/[Formula: see text]), arterial partial pressure of carbon dioxide ([Formula: see text]), intrapulmonary shunt (Qs/Qt), and respiratory mechanics were assessed before abdominal inflation, during capnoperitoneum, and after abdominal deflation. Compared with CMV, HFPVi with additional 5-Hz oscillations during capnoperitoneum resulted in higher [Formula: see text]/[Formula: see text], lower [Formula: see text], and decreased Qs/Qt. These improvements were smaller but remained significant during HFPVi with 10 Hz and HFPVe with either 5 or 10 Hz. The ventilation modes did not protect against capnoperitoneum-induced deteriorations in respiratory tissue mechanics. These findings suggest that high-frequency oscillations combined with conventional pressure-controlled ventilation improved lung oxygenation and CO2 removal in a model of capnoperitoneum. Compared with extrathoracic pressure oscillations, intratracheal generation of oscillatory pressure bursts appeared more effective. These findings may contribute to the optimization of mechanical ventilation during laparoscopic surgery.NEW & NOTEWORTHY The present study examines an alternative and innovative mechanical ventilation modality in improving oxygen delivery, CO2 clearance, and respiratory mechanical abnormalities in a clinically relevant experimental model of capnoperitoneum. Our data reveal that high-frequency oscillations combined with conventional ventilation improve gas exchange, with intratracheal oscillations being more effective than extrathoracic oscillations in this clinically relevant translational model.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - John Diaper
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - Fabienne Fontao
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - Davide Bizzotto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
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Tolnai J, Ballók B, Südy R, Schranc Á, Varga G, Babik B, Fodor GH, Peták F. Changes in lung mechanics and ventilation-perfusion match: comparison of pulmonary air- and thromboembolism in rats. BMC Pulm Med 2024; 24:27. [PMID: 38200483 PMCID: PMC10782734 DOI: 10.1186/s12890-024-02842-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 01/03/2024] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND Pulmonary air embolism (AE) and thromboembolism lead to severe ventilation-perfusion defects. The spatial distribution of pulmonary perfusion dysfunctions differs substantially in the two pulmonary embolism pathologies, and the effects on respiratory mechanics, gas exchange, and ventilation-perfusion match have not been compared within a study. Therefore, we compared changes in indices reflecting airway and respiratory tissue mechanics, gas exchange, and capnography when pulmonary embolism was induced by venous injection of air as a model of gas embolism or by clamping the main pulmonary artery to mimic severe thromboembolism. METHODS Anesthetized and mechanically ventilated rats (n = 9) were measured under baseline conditions after inducing pulmonary AE by injecting 0.1 mL air into the femoral vein and after occluding the left pulmonary artery (LPAO). Changes in mechanical parameters were assessed by forced oscillations to measure airway resistance, lung tissue damping, and elastance. The arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were determined by blood gas analyses. Gas exchange indices were also assessed by measuring end-tidal CO2 concentration (ETCO2), shape factors, and dead space parameters by volumetric capnography. RESULTS In the presence of a uniform decrease in ETCO2 in the two embolism models, marked elevations in the bronchial tone and compromised lung tissue mechanics were noted after LPAO, whereas AE did not affect lung mechanics. Conversely, only AE deteriorated PaO2, and PaCO2, while LPAO did not affect these outcomes. Neither AE nor LPAO caused changes in the anatomical or physiological dead space, while both embolism models resulted in elevated alveolar dead space indices incorporating intrapulmonary shunting. CONCLUSIONS Our findings indicate that severe focal hypocapnia following LPAO triggers bronchoconstriction redirecting airflow to well-perfused lung areas, thereby maintaining normal oxygenation, and the CO2 elimination ability of the lungs. However, hypocapnia in diffuse pulmonary perfusion after AE may not reach the threshold level to induce lung mechanical changes; thus, the compensatory mechanisms to match ventilation to perfusion are activated less effectively.
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Affiliation(s)
- József Tolnai
- Department of Medical Physics and Informatics, University of Szeged, 9 Korányi fasor, Szeged, H-6720, Hungary
| | - Bence Ballók
- Department of Medical Physics and Informatics, University of Szeged, 9 Korányi fasor, Szeged, H-6720, Hungary
| | - Roberta Südy
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, 1 Rue Michel-Servet, 1206, Geneva, Switzerland
| | - Álmos Schranc
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, 1 Rue Michel-Servet, 1206, Geneva, Switzerland
| | - Gabriella Varga
- Institute of Surgical Research, University of Szeged, 1 Pulz utca, Szeged, H-6724, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis str., Szeged, H-6725, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, 9 Korányi fasor, Szeged, H-6720, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, 9 Korányi fasor, Szeged, H-6720, Hungary.
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Pálfi A, Balogh ÁL, Polónyi G, Schulcz D, Zöllei É, Bari G, Fodor GH, Baráth K, Somfay A, Peták F, Babik B. Post-COVID changes in lung function 6 months after veno-venous extracorporeal membrane oxygenation: a prospective observational clinical trial. Front Med (Lausanne) 2023; 10:1288679. [PMID: 38173937 PMCID: PMC10761408 DOI: 10.3389/fmed.2023.1288679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Background Severe coronavirus disease 2019 (COVID-19) may require veno-venous extracorporeal membrane oxygenation (V-V ECMO). While V-V ECMO is offered in severe lung injury to COVID-19, long-term respiratory follow-up in these patients is missing. Therefore, we aimed at providing comprehensive data on the long-term respiratory effects of COVID-19 requiring V-V ECMO support during the acute phase of infection. Methods In prospective observational cohort study design, patients with severe COVID-19 receiving invasive mechanical ventilation and V-V ECMO (COVID group, n = 9) and healthy matched controls (n = 9) were evaluated 6 months after hospital discharge. Respiratory system resistance at 5 and 19 Hz (R5, R19), and the area under the reactance curve (AX5) was evaluated using oscillometry characterizing total and central airway resistances, and tissue elasticity, respectively. R5 and R19 difference (R5-R19) reflecting small airway function was also calculated. Forced expired volume in seconds (FEV1), forced expiratory vital capacity (FVC), functional residual capacity (FRC), carbon monoxide diffusion capacity (DLCO) and transfer coefficient (KCO) were measured. Results The COVID group had a higher AX5 and R5-R19 than the healthy matched control group. However, there was no significant difference in terms of R5 or R19. The COVID group had a lower FEV1 and FVC on spirometry than the healthy matched control group. Further, the COVID group had a lower FRC on plethysmography than the healthy matched control group. Meanwhile, the COVID group had a lower DLCO than healthy matched control group. Nevertheless, its KCO was within the normal range. Conclusion Severe acute COVID-19 requiring V-V ECMO persistently impairs small airway function and reduces respiratory tissue elasticity, primarily attributed to lung restriction. These findings also suggest that even severe pulmonary pathologies of acute COVID-19 can manifest in a moderate but still persistent lung function impairment 6 months after hospital discharge. Trial registration NCT05812196.
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Affiliation(s)
- Alexandra Pálfi
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Ádám L. Balogh
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Gabriella Polónyi
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Domonkos Schulcz
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Éva Zöllei
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Gábor Bari
- Cardiac Surgery Unit, Department of Internal Medicine, University of Szeged, Szeged, Hungary
| | - Gergely H. Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Kristóf Baráth
- Department of Pulmonology, University of Szeged, Szeged, Hungary
| | - Attila Somfay
- Department of Pulmonology, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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Ballók B, Schranc Á, Tóth I, Somogyi P, Tolnai J, Peták F, Fodor GH. Comparison of the respiratory effects of commonly utilized general anaesthesia regimes in male Sprague-Dawley rats. Front Physiol 2023; 14:1249127. [PMID: 37791348 PMCID: PMC10544940 DOI: 10.3389/fphys.2023.1249127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 09/05/2023] [Indexed: 10/05/2023] Open
Abstract
Background: Respiratory parameters in experimental animals are often characterised under general anaesthesia. However, anaesthesia regimes may alter the functional and mechanical properties of the respiratory system. While most anaesthesia regimes have been shown to affect the respiratory system, the effects of general anaesthesia protocols commonly used in animal models on lung function have not been systematically compared. Methods: The present study comprised 40 male Sprague-Dawley rats divided into five groups (N = 8 in each) according to anaesthesia regime applied: intravenous (iv) Na-pentobarbital, intraperitoneal (ip) ketamine-xylazine, iv propofol-fentanyl, inhaled sevoflurane, and ip urethane. All drugs were administered at commonly used doses. End-expiratory lung volume (EELV), airway resistance (Raw) and tissue mechanics were measured in addition to arterial blood gas parameters during mechanical ventilation while maintaining positive end-expiratory pressure (PEEP) values of 0, 3, and 6 cm H2O. Respiratory mechanics were also measured during iv methacholine (MCh) challenges to assess bronchial responsiveness. Results: While PEEP influenced baseline respiratory mechanics, EELV and blood gas parameters (p < 0.001), no between-group differences were observed (p > 0.10). Conversely, significantly lower doses of MCh were required to achieve the same elevation in Raw under ketamine-xylazine anaesthesia compared to the other groups. Conclusion: In the most frequent rodent model of respiratory disorders, no differences in baseline respiratory mechanics or function were observed between commonly used anaesthesia regimes. Bronchial hyperresponsiveness in response to ketamine-xylazine anaesthesia should be considered when designing experiments using this regime. The findings of the present study indicate commonly used anaesthetic regimes allow fair comparison of respiratory mechanics in experimental animals undergoing any of the examined anaesthesia protocols.
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Affiliation(s)
- Bence Ballók
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- Unit for Anaesthesiological Investigations, Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Ibolya Tóth
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Petra Somogyi
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
- Department of Cell Biology and Molecular Medicine, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Gergely H. Fodor
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
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Schranc Á, Diaper J, Südy R, Peták F, Habre W, Albu G. Lung recruitment by continuous negative extra-thoracic pressure support following one-lung ventilation: an experimental study. Front Physiol 2023; 14:1160731. [PMID: 37256073 PMCID: PMC10225513 DOI: 10.3389/fphys.2023.1160731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/03/2023] [Indexed: 06/01/2023] Open
Abstract
Lung recruitment maneuvers following one-lung ventilation (OLV) increase the risk for the development of acute lung injury. The application of continuous negative extrathoracic pressure (CNEP) is gaining interest both in intubated and non-intubated patients. However, there is still a lack of knowledge on the ability of CNEP support to recruit whole lung atelectasis following OLV. We investigated the effects of CNEP following OLV on lung expansion, gas exchange, and hemodynamics. Ten pigs were anesthetized and mechanically ventilated with pressure-regulated volume control mode (PRVC; FiO2: 0.5, Fr: 30-35/min, VT: 7 mL/kg, PEEP: 5 cmH2O) for 1 hour, then baseline (BL) data for gas exchange (arterial partial pressure of oxygen, PaO2; and carbon dioxide, PaCO2), ventilation and hemodynamical parameters and lung aeration by electrical impedance tomography were recorded. Subsequently, an endobronchial blocker was inserted, and OLV was applied with a reduced VT of 5 mL/kg. Following a new set of measurements after 1 h of OLV, two-lung ventilation was re-established, combining PRVC (VT: 7 mL/kg) and CNEP (-15 cmH2O) without any hyperinflation maneuver and data collection was then repeated at 5 min and 1 h. Compared to OLV, significant increases in PaO2 (154.1 ± 13.3 vs. 173.8 ± 22.1) and decreases in PaCO2 (52.6 ± 11.7 vs. 40.3 ± 4.5 mmHg, p < 0.05 for both) were observed 5 minutes following initiation of CNEP, and these benefits in gas exchange remained after an hour of CNEP. Gradual improvements in lung aeration in the non-collapsed lung were also detected by electrical impedance tomography (p < 0.05) after 5 and 60 min of CNEP. Hemodynamics and ventilation parameters remained stable under CNEP. Application of CNEP in the presence of whole lung atelectasis proved to be efficient in improving gas exchange via recruiting the lung without excessive airway pressures. These benefits of combined CNEP and positive pressure ventilation may have particular value in relieving atelectasis in the postoperative period of surgical procedures requiring OLV.
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Affiliation(s)
- Álmos Schranc
- Unit for Anesthesiological Investigations, Department of Anesthesiology Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - John Diaper
- Unit for Anesthesiological Investigations, Department of Anesthesiology Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Roberta Südy
- Unit for Anesthesiological Investigations, Department of Anesthesiology Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, Albert Szent-Györgyi Medical School, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Anesthesiology Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Gergely Albu
- Unit for Anesthesiological Investigations, Department of Anesthesiology Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
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Peták F, Fodor GH, Schranc Á, Südy R, Balogh ÁL, Babik B, Dos Santos Rocha A, Bayat S, Bizzotto D, Dellacà RL, Habre W. Expiratory high-frequency percussive ventilation: a novel concept for improving gas exchange. Respir Res 2022; 23:283. [PMID: 36243752 PMCID: PMC9569091 DOI: 10.1186/s12931-022-02215-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 10/06/2022] [Indexed: 11/25/2022] Open
Abstract
Background Although high-frequency percussive ventilation (HFPV) improves gas exchange, concerns remain about tissue overdistension caused by the oscillations and consequent lung damage. We compared a modified percussive ventilation modality created by superimposing high-frequency oscillations to the conventional ventilation waveform during expiration only (eHFPV) with conventional mechanical ventilation (CMV) and standard HFPV. Methods Hypoxia and hypercapnia were induced by decreasing the frequency of CMV in New Zealand White rabbits (n = 10). Following steady-state CMV periods, percussive modalities with oscillations randomly introduced to the entire breathing cycle (HFPV) or to the expiratory phase alone (eHFPV) with varying amplitudes (2 or 4 cmH2O) and frequencies were used (5 or 10 Hz). The arterial partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) were determined. Volumetric capnography was used to evaluate the ventilation dead space fraction, phase 2 slope, and minute elimination of CO2. Respiratory mechanics were characterized by forced oscillations. Results The use of eHFPV with 5 Hz superimposed oscillation frequency and an amplitude of 4 cmH2O enhanced gas exchange similar to those observed after HFPV. These improvements in PaO2 (47.3 ± 5.5 vs. 58.6 ± 7.2 mmHg) and PaCO2 (54.7 ± 2.3 vs. 50.1 ± 2.9 mmHg) were associated with lower ventilation dead space and capnogram phase 2 slope, as well as enhanced minute CO2 elimination without altering respiratory mechanics. Conclusions These findings demonstrated improved gas exchange using eHFPV as a novel mechanical ventilation modality that combines the benefits of conventional and small-amplitude high-frequency oscillatory ventilation, owing to improved longitudinal gas transport rather than increased lung surface area available for gas exchange. Supplementary Information The online version contains supplementary material available at 10.1186/s12931-022-02215-2.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, 9, Korányi fasor, Szeged, 6720, Hungary.
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, 9, Korányi fasor, Szeged, 6720, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, 9, Korányi fasor, Szeged, 6720, Hungary
| | - Roberta Südy
- Department of Medical Physics and Informatics, University of Szeged, 9, Korányi fasor, Szeged, 6720, Hungary.,Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Ádám L Balogh
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - Barna Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - André Dos Santos Rocha
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - Sam Bayat
- Univ. Grenoble Alpes, Inserm UA07 STROBE Laboratory & Department of Pneumology and Clinical Physiology, Grenoble University Hospital, Grenoble, France
| | - Davide Bizzotto
- Dipartimento Di Elettronica, Informazione E Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Raffaele L Dellacà
- Dipartimento Di Elettronica, Informazione E Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Walid Habre
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland.,Paediatric Anaesthesia Unit, Department of Acute Medicine, University Hospitals of Geneva, Geneva, Switzerland
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Peták F, Kovács BN, Agócs S, Virág K, Nyári T, Molnár A, Südy R, Lengyel C, Babik B. Seasonal changes in proportion of cardiac surgeries associated with diabetes, smoking and elderly age. PLoS One 2022; 17:e0274105. [PMID: 36136994 PMCID: PMC9498963 DOI: 10.1371/journal.pone.0274105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 08/22/2022] [Indexed: 11/25/2022] Open
Abstract
Background Seasonal variations in the ambient temperature may affect the exacerbation of cardiovascular diseases. Our primary objective was to evaluate the seasonality of the monthly proportion of cardiac surgeries associated with diabetes, smoking and/or elderly age at a tertiary-care university hospital in East-Central Europe with a temperate climate zone. As a secondary objective, we also assessed whether additional factors affecting small blood vessels (smoking, aging, obesity) modulate the seasonal variability of diabetes. Methods Medical records were analyzed for 9838 consecutive adult patients who underwent cardiac surgery in 2007–2018. Individual seasonal variations of diabetes, smoking, and elderly patients were analyzed monthly, along with the potential risk factors for cardiovascular complication. We also characterized whether pairwise coexistence of diabetes, smoking, and elderly age augments or blunts the seasonal variations. Results Seasonal variations in the monthly proportion of cardiac surgeries associated with diabetes, smoking and/or elderly age were observed. The proportion of cardiac surgeries of non-elderly and smoking patients with diabetes peaked in winter (amplitude of change as [peak-nadir]/nadir: 19.2%, p<0.02), which was associated with increases in systolic (6.1%, p<0.001) and diastolic blood pressures (4.4%, p<0.05) and serum triglyceride levels (27.1%, p<0.005). However, heart surgery in elderly patients without diabetes and smoking was most frequently required in summer (52.1%, p<0.001). Concomitant occurrence of diabetes and smoking had an additive effect on the requirement for cardiac surgery (107%, p<0.001), while the simultaneous presence of older age and diabetes or smoking eliminated seasonal variations. Conclusions Scheduling regular cardiovascular control in accordance with periodicities in diabetes, elderly, and smoking patients more than once a year may improve patient health and social consequences. Trial registration NCT03967639.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- * E-mail:
| | - Barbara N. Kovács
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Szilvia Agócs
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
- Department of Internal Medicine and Cardiology Center, Cardiac Surgery Unit, University of Szeged, Szeged, Hungary
| | - Katalin Virág
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Tibor Nyári
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Andrea Molnár
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Csaba Lengyel
- Department of Internal Medicine, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
- Department of Internal Medicine and Cardiology Center, Cardiac Surgery Unit, University of Szeged, Szeged, Hungary
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Dos Santos Rocha A, Diaper J, Balogh AL, Marti C, Grosgurin O, Habre W, Peták F, Südy R. Effect of body position on the redistribution of regional lung aeration during invasive and non-invasive ventilation of COVID-19 patients. Sci Rep 2022; 12:11085. [PMID: 35773299 PMCID: PMC9245873 DOI: 10.1038/s41598-022-15122-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 06/20/2022] [Indexed: 11/09/2022] Open
Abstract
Severe COVID-19-related acute respiratory distress syndrome (C-ARDS) requires mechanical ventilation. While this intervention is often performed in the prone position to improve oxygenation, the underlying mechanisms responsible for the improvement in respiratory function during invasive ventilation and awake prone positioning in C-ARDS have not yet been elucidated. In this prospective observational trial, we evaluated the respiratory function of C-ARDS patients while in the supine and prone positions during invasive (n = 13) or non-invasive ventilation (n = 15). The primary endpoint was the positional change in lung regional aeration, assessed with electrical impedance tomography. Secondary endpoints included parameters of ventilation and oxygenation, volumetric capnography, respiratory system mechanics and intrapulmonary shunt fraction. In comparison to the supine position, the prone position significantly increased ventilation distribution in dorsal lung zones for patients under invasive ventilation (53.3 ± 18.3% vs. 43.8 ± 12.3%, percentage of dorsal lung aeration ± standard deviation in prone and supine positions, respectively; p = 0.014); whereas, regional aeration in both positions did not change during non-invasive ventilation (36.4 ± 11.4% vs. 33.7 ± 10.1%; p = 0.43). Prone positioning significantly improved the oxygenation both during invasive and non-invasive ventilation. For invasively ventilated patients reduced intrapulmonary shunt fraction, ventilation dead space and respiratory resistance were observed in the prone position. Oxygenation is improved during non-invasive and invasive ventilation with prone positioning in patients with C-ARDS. Different mechanisms may underly this benefit during these two ventilation modalities, driven by improved distribution of lung regional aeration, intrapulmonary shunt fraction and ventilation-perfusion matching. However, the differences in the severity of C-ARDS may have biased the sensitivity of electrical impedance tomography when comparing positional changes between the protocol groups.Trial registration: ClinicalTrials.gov (NCT04359407) and Registered 24 April 2020, https://clinicaltrials.gov/ct2/show/NCT04359407 .
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Affiliation(s)
- André Dos Santos Rocha
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland.
| | - John Diaper
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
| | - Adam L Balogh
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
| | - Christophe Marti
- Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | - Olivier Grosgurin
- Department of Internal Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | - Walid Habre
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Unit for Anaesthesiological Investigations, Division of Anaesthesiology, Department of Anaesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva and University of Geneva, Rue Willy Donzé 6, 1205, Geneva, Switzerland
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Schranc Á, Fodor GH, Südy R, Tolnai J, Babik B, Peták F. Exaggerated Ventilator-Induced Lung Injury in an Animal Model of Type 2 Diabetes Mellitus: A Randomized Experimental Study. Front Physiol 2022; 13:889032. [PMID: 35733997 PMCID: PMC9207264 DOI: 10.3389/fphys.2022.889032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Although ventilator-induced lung injury (VILI) often develops after prolonged mechanical ventilation in normal lungs, pulmonary disorders may aggravate the development of adverse symptoms. VILI exaggeration can be anticipated in type 2 diabetes mellitus (T2DM) due to its adverse pulmonary consequences. Therefore, we determined whether T2DM modulates VILI and evaluated how T2DM therapy affects adverse pulmonary changes. Rats were randomly assigned into the untreated T2DM group receiving low-dose streptozotocin with high-fat diet (T2DM, n = 8), T2DM group supplemented with metformin therapy (MET, n = 8), and control group (CTRL, n = 8). In each animal, VILI was induced by mechanical ventilation for 4 h with high tidal volume (23 ml/kg) and low positive end-expiratory pressure (0 cmH2O). Arterial and venous blood samples were analyzed to measure the arterial partial pressure of oxygen (PaO2), oxygen saturation (SaO2), and the intrapulmonary shunt fraction (Qs/Qt). Airway and respiratory tissue mechanics were evaluated by forced oscillations. Lung histology samples were analyzed to determine injury level. Significant worsening of VILI, in terms of PaO2, SaO2, and Qs/Qt, was observed in the T2DM group, without differences in the respiratory mechanics. These functional changes were also reflected in lung injury score. The MET group showed no difference compared with the CTRL group. Gas exchange impairment without significant mechanical changes suggests that untreated diabetes exaggerates VILI by augmenting the damage of the alveolar–capillary barrier. Controlled hyperglycemia with metformin may reduce the manifestations of respiratory defects during prolonged mechanical ventilation.
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Affiliation(s)
- Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Gergely H. Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva, Switzerland
| | - József Tolnai
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
- *Correspondence: Ferenc Peták,
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Kovács BN, Südy R, Peták F, Balogh ÁL, Fodor HG, Tolnai J, Korsós A, Schranc Á, Lengyel C, Babik B. Respiratory consequences of obesity and diabetes. Orv Hetil 2022; 163:63-73. [PMID: 34999572 DOI: 10.1556/650.2022.32335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/26/2021] [Indexed: 11/19/2022]
Abstract
Összefoglaló. Bevezetés: A cukorbetegségben nő a simaizmok tónusa, és megváltozik az elasztin és a kollagén szerkezete. Mivel a tüdőszövetben ezek a strukturális elemek meghatározóak, a cukorbetegség várhatóan módosítja a légutak és a tüdőszövet mechanikai és funkcionális viselkedését. Célkitűzés: Vizsgálatunk során diabetesben szenvedő, elhízott és nem elhízott betegeink körében tanulmányoztuk a légzésmechanikai elváltozásokat és a gázcserefunkciót. Módszer: Elektív szívsebészeti beavatkozásra kerülő, normál testalkatú betegeket diabetesben nem szenvedő (n = 80), illetve cukorbeteg (n = 35) csoportokra osztottuk. További két betegcsoportba elhízott és nem cukorbeteg (n = 47), valamint elhízott és diabetesben szenvedő (n = 33) betegek kerültek. A légzőrendszer mechanikai tulajdonságait kényszerített oszcillációs technikával határoztuk meg, mellyel a légúti ellenállás (Raw), valamint a szöveti csillapítás (G) és rugalmasság (H) tényezői jellemezhetők. Volumetriás kapnográfia segítségével a kapnogram 3. fázisának meredekségét és a légzési térfogat különböző ventilációs/perfúziós illeszkedési zavaraiból adódó holttérfrakciókat határoztuk meg. Az intrapulmonalis shuntfrakciót és az oxigenizációs indexet (PaO2/FiO2) artériás és centrális vénás vérgázmintákból határoztuk meg. Eredmények: A megfelelő kontrollcsoportokhoz hasonlítva a cukorbetegség önmagában is növelte az Raw (7,4 ± 5 vs. 3,0 ± 1,7 H2Ocm.s/l), a G (11,3 ± 4,9 vs. 6,2 ± 2,4 H2Ocm/l) és a H (32,3 ± 12,0 vs. 25,1± 6,9 H2Ocm/l) értékét (p<0,001 mindegyik betegcsoportnál), de ez nem járt együtt a gázcserefunckció romlásával. Hasonló patológiás elváltozásokat észleltünk elhízás során a légzésmechanikában és az alveolaris heterogenitásban, amelyek azonban a gázcsere hatékonyságát is rontották. Következtetés: Cukorbetegségben a légzésmechanika romlását a fokozott hypoxiás pulmonalis vasoconstrictio ellensúlyozni képes, ezzel kivédve az intrapulmonalis shunt növekedését és az oxigenizációs képesség romlását. Orv Hetil. 2022; 163(2): 63-73. SUMMARY INTRODUCTION While sustained hyperglicemia affects the smooth muscle tone and the elastin-collagen network, the effect of diabetes mellitus on the function and structure of the airways and the lung parenchyma has not been characterized, and the confounding influence of obesity has not been elucidated. OBJECTIVE To reveal the separate and additive roles of diabetes mellitus and obesity on the respiratory function. METHOD Non-obese mechanically ventilated patients were categorized as control non-diabetic (n = 80) and diabetic (n = 35) groups. Obese patients with (n = 33) or without (n = 47) associated diabetes were also enrolled. Forced oscillation technique was applied to measure airway resistance (Raw), tissue damping (G), and tissue elastance (H). Capnography was utilized to determine phase 3 slopes and ventilation dead space parameters. Arterial and central venous blood samples were analyzed to assess intrapulmonary shunt fraction (Qs/Qt) and the lung oxygenation index (PaO2/FiO2). RESULTS Diabetes without obesity increased the Raw (7.4 ± 5 cmH2O.s/l vs. 3.0 ± 1.7 cmH2O.s/l), G (11.3 ± 4.9 cmH2O/l vs. 6.2 ± 2.4 cmH2O/l), and H (32.3 ± 12.0 cmH2O/l vs. 25.1 ± 6.9 cmH2O/l, (p<0.001 for all), compared with the corresponding control groups. Capnographic phase 3 slope was increased in diabetes without significant changes in PaO2/FiO2 or Qs/Qt. While similar detrimental changes in respiratory mechanics and alveolar heterogeneity were observed in obese patients without diabetes, these alterations also compromised gas exchange. CONCLUSION The intrinsic mechanical abnormalities in the airways and lung tissue induced by diabetes are counterbalanced by hypoxic pulmonary vasoconstriction, thereby maintaining intrapulmonary shunt fraction and oxygenation ability of the lungs. Orv Hetil. 2022; 163(2): 63-73.
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Affiliation(s)
- Barbara Nóra Kovács
- 1 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Aneszteziológiai és Intenzív Terápiás Intézet Szeged, Semmelweis u. 6., 6720.,2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - Roberta Südy
- 1 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Aneszteziológiai és Intenzív Terápiás Intézet Szeged, Semmelweis u. 6., 6720.,2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - Ferenc Peták
- 2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - Ádám László Balogh
- 1 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Aneszteziológiai és Intenzív Terápiás Intézet Szeged, Semmelweis u. 6., 6720.,2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - H Gergely Fodor
- 2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - József Tolnai
- 2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - Anita Korsós
- 1 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Aneszteziológiai és Intenzív Terápiás Intézet Szeged, Semmelweis u. 6., 6720
| | - Álmos Schranc
- 2 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Orvosi Fizikai és Orvosi Informatikai Intézet Szeged
| | - Csaba Lengyel
- 3 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Belgyógyászati Klinika Szeged
| | - Barna Babik
- 1 Szegedi Tudományegyetem, Általános Orvostudományi Kar, Aneszteziológiai és Intenzív Terápiás Intézet Szeged, Semmelweis u. 6., 6720
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Schranc Á, Balogh ÁL, Diaper J, Südy R, Peták F, Habre W, Albu G. Flow-controlled ventilation maintains gas exchange and lung aeration in a pediatric model of healthy and injured lungs: A randomized cross-over experimental study. Front Pediatr 2022; 10:1005135. [PMID: 36160799 PMCID: PMC9500311 DOI: 10.3389/fped.2022.1005135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/24/2022] [Indexed: 11/30/2022] Open
Abstract
Flow-controlled ventilation (FCV) is characterized by a constant flow to generate active inspiration and expiration. While the benefit of FCV on gas exchange has been demonstrated in preclinical and clinical studies with adults, the value of this modality for a pediatric population remains unknown. Thus, we aimed at observing the effects of FCV as compared to pressure-regulated volume control (PRVC) ventilation on lung mechanics, gas exchange and lung aeration before and after surfactant depletion in a pediatric model. Ten anesthetized piglets (10.4 ± 0.2 kg) were randomly assigned to start 1-h ventilation with FCV or PRVC before switching the ventilation modes for another hour. This sequence was repeated after inducing lung injury by bronchoalveolar lavage and injurious ventilation. The primary outcome was respiratory tissue elastance. Secondary outcomes included oxygenation index (PaO2/FiO2), PaCO2, intrapulmonary shunt (Qs/Qt), airway resistance, respiratory tissue damping, end-expiratory lung volume, lung clearance index and lung aeration by chest electrical impedance tomography. Measurements were performed at the end of each protocol stage. Ventilation modality had no effect on any respiratory mechanical parameter. Adequate gas exchange was provided by FCV, similar to PRVC, with sufficient CO2 elimination both in healthy and surfactant-depleted lungs (39.46 ± 7.2 mmHg and 46.2 ± 11.4 mmHg for FCV; 36.0 ± 4.1 and 39.5 ± 4.9 mmHg, for PRVC, respectively). Somewhat lower PaO2/FiO2 and higher Qs/Qt were observed in healthy and surfactant depleted lungs during FCV compared to PRVC (p < 0.05, for all). Compared to PRVC, lung aeration was significantly elevated, particularly in the ventral dependent zones during FCV (p < 0.05), but this difference was not evidenced in injured lungs. Somewhat lower oxygenation and higher shunt ratio was observed during FCV, nevertheless lung aeration improved and adequate gas exchange was ensured. Therefore, in the absence of major differences in respiratory mechanics and lung volumes, FCV may be considered as an alternative in ventilation therapy of pediatric patients with healthy and injured lungs.
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Affiliation(s)
- Álmos Schranc
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Ádám L Balogh
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - John Diaper
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Roberta Südy
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland.,Pediatric Anesthesia Unit, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | - Gergely Albu
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland.,Division of Anesthesiology, Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine, University Hospitals of Geneva, Geneva, Switzerland
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Peták F, Balogh ÁL, Hankovszky P, Fodor GH, Tolnai J, Südy R, Kovács BN, Molnár A, Babik B. Dopamine Reverses Lung Function Deterioration After Cardiopulmonary Bypass Without Affecting Gas Exchange. J Cardiothorac Vasc Anesth 2021; 36:1047-1055. [PMID: 34404593 DOI: 10.1053/j.jvca.2021.07.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To investigate the effects of dopamine on the adverse pulmonary changes after cardiopulmonary bypass. DESIGN A prospective, nonrandomized clinical investigation. SETTING A university hospital. PARTICIPANTS One hundred fifty-seven patients who underwent elective cardiac surgery that required cardiopulmonary bypass. INTERVENTIONS Fifty-two patients were administered intravenous infusion of dopamine (3 µg/kg/min) for five minutes after weaning from cardiopulmonary bypass; no intervention was applied in the other 105 patients. MEASUREMENTS AND MAIN RESULTS Measurements were performed under general anesthesia and mechanical ventilation before cardiopulmonary bypass, after cardiopulmonary bypass, and after the intervention. In each protocol stage, forced oscillatory lung impedance was measured to assess airway and tissue mechanical changes. Mainstream capnography was performed to assess ventilation- and/or perfusion-matching by calculating the normalized phase-3 slopes of the time and volumetric capnograms and the physiologic deadspace. Arterial and central venous blood samples were analyzed to characterize lung oxygenation and intrapulmonary shunt. After cardiopulmonary bypass, dopamineinduced marked improvements in airway resistance and tissue damping, with relatively small decreases in lung tissue elastance. These changes were associated with decreases in the normalized phase-3 slopes of the time and volumetric capnograms. The inotrope had no effect on physiologic deadspace, intrapulmonary shunt, or lung oxygenation. CONCLUSION Dopamine reversed the complex detrimental lung mechanical changes induced by cardiopulmonary bypass and alleviated ventilation heterogeneities without affecting the physiologic deadspace or intrapulmonary shunt. Therefore, dopamine has a potential benefit on the gas exchange abnormalities after weaning from cardiopulmonary bypass.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
| | - Ádám L Balogh
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Péter Hankovszky
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Südy
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Barbara N Kovács
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Andrea Molnár
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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Dos Santos Rocha A, Südy R, Peták F, Habre W. Physiologically variable ventilation and severe asthma. Response to Br J Anaesth 2020; 125: 1107-16. Br J Anaesth 2021; 127:e93-e94. [PMID: 34217467 DOI: 10.1016/j.bja.2021.05.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 11/28/2022] Open
Affiliation(s)
- André Dos Santos Rocha
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva and University of Geneva, Geneva, Switzerland.
| | - Roberta Südy
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva and University of Geneva, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva and University of Geneva, Geneva, Switzerland
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Korsós A, Peták F, Südy R, Schranc Á, Fodor GH, Babik B. Use of capnography to verify emergency ventilator sharing in the COVID-19 era. Respir Physiol Neurobiol 2021; 285:103611. [PMID: 33359758 PMCID: PMC7832691 DOI: 10.1016/j.resp.2020.103611] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/10/2020] [Accepted: 12/21/2020] [Indexed: 01/29/2023]
Abstract
Exacerbation of COVID-19 pandemic may lead to acute shortage of ventilators, which may require shared use of ventilator as a lifesaving concept. Two model lungs were ventilated with one ventilator to i) test the adequacy of individual tidal volumes via capnography, ii) assess cross-breathing between lungs, and iii) offer a simulation-based algorithm for ensuring equal tidal volumes. Ventilation asymmetry was induced by placing rubber band around one model lung, and the uneven distribution of tidal volumes (VT) was counterbalanced by elevating airflow resistance (HR) contralaterally. VT, end-tidal CO2 concentration (ETCO2), and peak inspiratory pressure (Ppi) were measured. Unilateral LC reduced VT and elevated ETCO2 on the affected side. Under HR, VT and ETCO2 were re-equilibrated. In conclusion, capnography serves as simple, bedside method for controlling the adequacy of split ventilation in each patient. No collateral gas flow was observed between the two lungs with different time constants. Ventilator sharing may play a role in emergency situations.
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Affiliation(s)
- Anita Korsós
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis Street, H 6725, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi Fasor, H 6720, Szeged, Hungary.
| | - Roberta Südy
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis Street, H 6725, Szeged, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi Fasor, H 6720, Szeged, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi Fasor, H 6720, Szeged, Hungary
| | - Barna Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis Street, H 6725, Szeged, Hungary
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Dos Santos Rocha A, Südy R, Bizzotto D, Kassai M, Carvalho T, Dellacà RL, Peták F, Habre W. Benefit of Physiologically Variable Over Pressure-Controlled Ventilation in a Model of Chronic Obstructive Pulmonary Disease: A Randomized Study. Front Physiol 2021; 11:625777. [PMID: 33519528 PMCID: PMC7839245 DOI: 10.3389/fphys.2020.625777] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/15/2020] [Indexed: 11/25/2022] Open
Abstract
Introduction The advantages of physiologically variable ventilation (PVV) based on a spontaneous breathing pattern have been demonstrated in several respiratory conditions. However, its potential benefits in chronic obstructive pulmonary disease (COPD) have not yet been characterized. We used an experimental model of COPD to compare respiratory function outcomes after 6 h of PVV versus conventional pressure-controlled ventilation (PCV). Materials and Methods Rabbits received nebulized elastase and lipopolysaccharide throughout 4 weeks. After 30 days, animals were anesthetized, tracheotomized, and randomized to receive 6 h of physiologically variable (n = 8) or conventional PCV (n = 7). Blood gases, respiratory mechanics, and chest fluoroscopy were assessed hourly. Results After 6 h of ventilation, animals receiving variable ventilation demonstrated significantly higher oxygenation index (PaO2/FiO2 441 ± 37 (mean ± standard deviation) versus 354 ± 61 mmHg, p < 0.001) and lower respiratory elastance (359 ± 36 versus 463 ± 81 cmH2O/L, p < 0.01) than animals receiving PCV. Animals ventilated with the variable mode also presented less lung derecruitment (decrease in lung aerated area, –3.4 ± 9.9 versus –17.9 ± 6.7%, p < 0.01) and intrapulmonary shunt fraction (9.6 ± 4.1 versus 17.0 ± 5.8%, p < 0.01). Conclusion PVV applied to a model of COPD improved oxygenation, respiratory mechanics, lung aeration, and intrapulmonary shunt fraction compared to conventional ventilation. A reduction in alveolar derecruitment and lung tissue stress leading to better aeration and gas exchange may explain the benefits of PVV.
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Affiliation(s)
- Andre Dos Santos Rocha
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Roberta Südy
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Davide Bizzotto
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Miklos Kassai
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
| | - Tania Carvalho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Raffaele L Dellacà
- Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Milan, Italy
| | - Ferenc Peták
- Department of Medical Physics and Informatics, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University Hospitals of Geneva, University of Geneva, Geneva, Switzerland
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Südy R, Peták F, Kiss L, Balogh ÁL, Fodor GH, Korsós A, Schranc Á, Babik B. Obesity and diabetes: similar respiratory mechanical but different gas exchange defects. Am J Physiol Lung Cell Mol Physiol 2020; 320:L368-L376. [PMID: 33264577 DOI: 10.1152/ajplung.00439.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Diabetes mellitus increases smooth muscle tone and causes tissue remodeling, affecting elastin and collagen. Although the lung is dominated by these elements, diabetes is expected to modify the airway function and respiratory tissue mechanics. Therefore, we characterized the respiratory function in patients with diabetes with and without associated obesity. Mechanically ventilated patients with normal body shapes were divided into the control nondiabetic (n = 73) and diabetic (n = 31) groups. The other two groups included obese patients without diabetes (n = 43) or with diabetes (n = 30). The mechanical properties of the respiratory system were determined by forced oscillation technique. Airway resistance (Raw), tissue damping (G), and tissue elastance (H) were assessed by forced oscillation. Capnography was applied to determine phase 3 slopes and dead space indices. The intrapulmonary shunt fraction (Qs/Qt) and the lung oxygenation index (PaO2/FIO2) were estimated from arterial and central venous blood samples. Compared with the corresponding control groups, diabetes alone increased the Raw (7.6 ± 6 cmH2O.s/l vs. 3.1 ± 1.9 cmH2O.s/l), G (11.7 ± 5.5 cmH2O/l vs. 6.5 ± 2.8 cmH2O/l), and H (31.5 ± 11.8 cmH2O/l vs. 24.2 ± 7.2 cmH2O/l (P < 0.001 for all). Diabetes increased the capnographic phase 3 slope, whereas PaO2/FIO2 or Qs/Qt was not affected. Obesity alone caused similar detrimental changes in respiratory mechanics and alveolar heterogeneity, but these alterations also compromised gas exchange. We conclude that diabetes-induced intrinsic mechanical abnormalities are counterbalanced by hypoxic pulmonary vasoconstriction, which maintained intrapulmonary shunt fraction and oxygenation ability of the lungs.
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Affiliation(s)
- Roberta Südy
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Liliána Kiss
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ádám L Balogh
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary.,Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Anita Korsós
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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Karlsson J, Fodor GH, Santos Rocha A, Lin N, Habre W, Wallin M, Hallbäck M, Peták F, Lönnqvist P. End-expiratory lung volume assessment using helium and carbon dioxide in an experimental model of pediatric capnoperitoneum. Acta Anaesthesiol Scand 2020; 64:1106-1113. [PMID: 32314349 DOI: 10.1111/aas.13607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 02/08/2020] [Accepted: 04/08/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND Capnoperitoneum during laparoscopy leads to cranial shift of the diaphragm, loss in lung volume, and risk of impaired gas exchange. Infants are susceptible to these changes and bedside assessment of lung volume during laparoscopy might assist with optimizing the ventilation. Thus, the primary aim was to investigate the monitoring value of a continuous end-expiratory lung volume (EELV) assessment method based on CO2 dynamics ( EELV CO 2 ) in a pediatric capnoperitoneum model by evaluating the correlation and trending ability against helium washout (EELVHe ). METHODS Intra-abdominal pressure (IAP) was randomly varied between 0, 6, and 12 mm Hg with CO2 insufflation, while positive end-expiratory pressure (PEEP) levels of 3, 6, and 9 cm H2 O were randomly applied in eight anesthetized and mechanically ventilated chinchilla rabbits. Concomitant EELV CO 2 and EELVHe and lung clearance index (LCI) were obtained under each experimental condition. RESULTS Significant correlations were found between EELV CO 2 and EELVHe before capnoperitoneum (r = .85, P < .001), although increased IAP distorted this relationship. The negative influence of IAP was counteracted by the application of PEEP 9, which restored the correlation between EELV CO 2 and EELVHe and resulted in 100% concordance rate between the methods regarding changes in lung volume. EELVHe and LCI showed a curvilinear relationship, and an EELVHe of approximately 20 mL kg-1 , determined with a receiver operating characteristic curve, was associated with near-normal LCI values. CONCLUSION In this animal model of pediatric capnoperitoneum, reliable assessment of changes in EELV based on EELV CO 2 requires an open lung strategy, defined as EELV above approximately 20 mL kg-1 .
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Affiliation(s)
- Jacob Karlsson
- Department of Physiology and Pharmacology (FYFA) Eriksson I Lars group‐Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Pediatric Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
| | - Gergely H. Fodor
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Andre Santos Rocha
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Na Lin
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Walid Habre
- Unit for Anaesthesiological Investigations Department of Anesthesiology, Pharmacology, Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
- Pediatric Anesthesia Unit Geneva Children's Hospital Geneva Switzerland
| | - Mats Wallin
- Department of Physiology and Pharmacology (FYFA) Eriksson I Lars group‐Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Maquet Critical Care AB Solna Sweden
| | | | - Ferenc Peták
- Departmenet of Medical Physics and Informatics University of Szeged Szeged Hungary
| | - Per‐Arne Lönnqvist
- Department of Physiology and Pharmacology (FYFA) Eriksson I Lars group‐Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Pediatric Perioperative Medicine and Intensive Care Karolinska University Hospital Stockholm Sweden
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Karlsson J, Fodor GH, dos Santos Rocha A, Lin N, Habre W, Wallin M, Hallbäck M, Peták F, Lönnqvist P. Determination of adequate positive end-expiratory pressure level required for carbon dioxide homeostasis in an animal model of infant laparoscopy. Acta Anaesthesiol Scand 2020; 64:1114-1119. [PMID: 32386340 DOI: 10.1111/aas.13617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 04/22/2020] [Accepted: 04/22/2020] [Indexed: 01/02/2023]
Abstract
BACKGROUND Capnoperitoneum provides a ventilatory challenge due to reduction in end-expiratory lung volume and peritoneal carbon dioxide absorption in both children and adults. The primary aim of this controlled interventional trial was to determine the positive end-expiratory pressure (PEEP) level needed to ensure for adequate carbon dioxide clearance and preservation of carbon dioxide homeostasis in an experimental model of infant laparoscopy. The secondary aim was to evaluate potential effects on cardiac output of PEEP and abdominal pressure level variations in the same setting. METHODS Eight chinchilla bastard rabbits were anesthetized and mechanically ventilated. Intra-abdominal pressures were randomly set to 0, 6, and 12 mm Hg by carbon dioxide insufflation. Carbon dioxide clearance using volumetric capnography, arterial blood gas data, and cardiac output was recorded, while PEEP 3, 6, and 9 cmH2 O were applied in a random order. RESULTS A PEEP of 9 cmH2 O showed restoration of carbon dioxide clearance without causing changes in arterial partial pressure of carbon dioxide and bicarbonate and with no associated deterioration in cardiac output. CONCLUSION The results promote a PEEP level of 9 cmH2 O in this model of infant capnoperitoneum to allow for adequate carbon dioxide removal with subsequent preservation of carbon dioxide homeostasis. The use of high PEEP was not associated with any decrease in cardiac output.
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Affiliation(s)
- Jacob Karlsson
- Anestesi‐ochIntensivvårdsavdelningen Department of Physiology and Pharmacology (FYFA) C3, Eiksson I Lars Group – Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Pediatric Perioperative Medicine and Intensive Care Karolinska University Hospital Eugenivägen 23 Stockholm Sweden
| | - Gergely H. Fodor
- Unit for Anaesthesiological Investigations Department of Anesthesiology Pharmacology Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Andre dos Santos Rocha
- Unit for Anaesthesiological Investigations Department of Anesthesiology Pharmacology Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Na Lin
- Unit for Anaesthesiological Investigations Department of Anesthesiology Pharmacology Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
| | - Walid Habre
- Unit for Anaesthesiological Investigations Department of Anesthesiology Pharmacology Intensive Care and Emergency Medicine University of Geneva Geneva Switzerland
- Pediatric Anesthesia Unit Geneva Children’s Hospital Geneva Switzerland
| | - Mats Wallin
- Anestesi‐ochIntensivvårdsavdelningen Department of Physiology and Pharmacology (FYFA) C3, Eiksson I Lars Group – Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Maquet Critical Care AB Solna Sweden
| | | | - Ferenc Peták
- Departmenet of Medical Physics and Informatics University of Szeged Szeged Hungary
| | - Per‐Arne Lönnqvist
- Anestesi‐ochIntensivvårdsavdelningen Department of Physiology and Pharmacology (FYFA) C3, Eiksson I Lars Group – Section of Anesthesiology and Intensive Care Karolinska Institute Stockholm Sweden
- Pediatric Perioperative Medicine and Intensive Care Karolinska University Hospital Eugenivägen 23 Stockholm Sweden
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Südy R, Schranc Á, Fodor GH, Tolnai J, Babik B, Peták F. Lung volume dependence of respiratory function in rodent models of diabetes mellitus. Respir Res 2020; 21:82. [PMID: 32272932 PMCID: PMC7146915 DOI: 10.1186/s12931-020-01334-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 03/09/2020] [Indexed: 12/16/2022] Open
Abstract
Background Diabetes mellitus causes the deterioration of smooth muscle cells and interstitial matrix proteins, including collagen. Collagen and smooth muscle cells are abundant in the lungs, but the effect of diabetes on airway function and viscoelastic respiratory tissue mechanics has not been characterized. This study investigated the impact of diabetes on respiratory function, bronchial responsiveness, and gas exchange parameters. Methods Rats were allocated randomly to three groups: a model of type 1 diabetes that received a high dose of streptozotocin (DM1, n = 13); a model of type 2 diabetes that received a low dose of streptozotocin with a high-fat diet (DM2, n = 14); and a control group with no treatment (C, n = 14). Forced oscillations were applied to assess airway resistance (Raw), respiratory tissue damping (G), and elastance (H). The arterial partial pressure of oxygen to the inspired oxygen fraction (PaO2/FiO2) and intrapulmonary shunt fraction (Qs/Qt) were determined from blood gas samples at positive end-expiratory pressures (PEEPs) of 0, 3, and 6 cmH2O. Lung responsiveness to methacholine was also assessed. Collagen fibers in lung tissue were quantified by histology. Results The rats in groups DM1 and DM2 exhibited elevated Raw, G, H, and Qs/Qt, compromised PaO2/FiO2, and diminished airway responsiveness. The severity of adverse tissue mechanical change correlated with excessive lung collagen expression. Increased PEEP normalized the respiratory mechanics, but the gas exchange abnormalities remained. Conclusions These findings indicate that diabetes reduces airway and lung tissue viscoelasticity, resulting in alveolar collapsibility that can be compensated by increasing PEEP. Diabetes also induces persistent alveolo-capillary dysfunction and abnormal adaptation ability of the airways to exogenous constrictor stimuli.
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Affiliation(s)
- Roberta Südy
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720, Hungary.,Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis Street, Szeged, H 6725, Hungary
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720, Hungary.,Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis Street, Szeged, H 6725, Hungary
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720, Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720, Hungary
| | - Barna Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, 6 Semmelweis Street, Szeged, H 6725, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720, Hungary.
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Fodor GH, Bayat S, Babik B, Habre W, Peták F. Reversing Cholinergic Bronchoconstriction by Common Inotropic Agents: A Randomized Experimental Trial on Isolated Perfused Rat Lungs. Anesth Analg 2019; 129:745-752. [PMID: 31425216 DOI: 10.1213/ane.0000000000003502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The ability of inotropic agents to alter airway reactivity and lung tissue mechanics has not been compared in a well-controlled experimental model. Therefore, we compared the potential to alter lung tissue viscoelasticity and bronchodilator effects of commonly used inotropic agents in an isolated perfused rat lung model. METHODS After achieving steady state lung perfusion, sustained bronchoconstriction was induced by acetylcholine (ACh). Isolated rat lungs were then randomly allocated to 6 groups treated with either saline vehicle (n = 8) or incremental concentrations of inotropes (adrenaline, n = 8; dopamine, n = 7; dobutamine, n = 7; milrinone, n = 8; or levosimendan, n = 6) added to the whole-blood perfusate. Airway resistance (Raw), lung tissue damping (G), and elastance were measured under baseline conditions, during steady-state ACh-induced constriction and for each inotrope dose. RESULTS No change in Raw was observed after addition of the saline vehicle. Raw was significantly lower after addition of dopamine (maximum difference [95% CI] of 29 [12-46]% relative to the saline control, P = .004), levosimendan (58 [39-77]%, P < .001), and adrenaline (37 [21-53]%, P < .001), whereas no significant differences were observed at any dose of milrinone (5 [-12 to 22]%) and dobutamine (4 [-13 to 21]%). Lung tissue damping (G) was lower in animals receiving the highest doses of adrenaline (difference: 22 [7-37]%, P = .015), dobutamine (20 [5-35]%, P = .024), milrinone (20 [6-34]%, P = .026), and levosimendan (36 [19-53]%, P < .001) than in controls. CONCLUSIONS Although dobutamine and milrinone did not reduce cholinergic bronchoconstriction, they reversed the ACh-induced elevations in lung tissue resistance. In contrast, adrenaline, dopamine, and levosimendan exhibited both potent bronchodilatory action against ACh and diminished lung tissue damping. Further work is needed to determine whether these effects are clinically relevant in humans.
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Affiliation(s)
- Gergely H Fodor
- From the Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Sam Bayat
- From the Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Barna Babik
- Department of Anesthesiology and Intensive Care, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva and Pediatric Anesthesia Unit, Geneva Children's Hospital, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
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Dos Santos Rocha A, Südy R, Fodor GH, Habre W, Peták F. Feasibility of forced oscillatory assessment of respiratory mechanics across a laryngeal mask airway in rabbits. Physiol Meas 2019; 40:065001. [PMID: 31051489 DOI: 10.1088/1361-6579/ab1f13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVES The forced oscillation technique (FOT) is the method of choice for assessment of respiratory tissue mechanics. A laryngeal mask airway (LMA) is increasingly used to secure the airways in subjects under sedation or general anesthesia. While FOT is routinely performed using an endotracheal tube (ETT), the accuracy of information about airway and tissue mechanics obtained with FOT using a LMA has not been characterized. Therefore, we compared the mechanical parameters obtained with FOT using LMA and ETT in rabbits. APPROACH FOT was performed through a LMA at normal and reduced oscillatory amplitudes in anesthetized and mechanically ventilated rabbits (n = 9) at positive end-expiratory pressures (PEEP) of 3 and 6 cmH2O. These measurements were repeated at normal amplitude for the same animal using an ETT. Airway resistance, inertance, respiratory tissue damping (G) and elastance (H) were measured under each condition by FOT. The potential bias of the distensible upper airways when FOT was applied using LMA was assessed with a simulation study. MAIN RESULTS Values of parameters reflecting airway mechanics were significantly higher when measured using LMA at both PEEPs and oscillatory amplitudes than with ETT. Conversely, regardless of the condition, there was a correlation (r = 0.89 both at normal and reduced amplitudes; p < 0.0001) with good agreement (mean bias of 8.8 cmH2O/l and 11.3 cmH2O/l) in H, whereas G was systematically lower when obtained with LMA than with ETT at PEEP 3 (21.1% ± 7.2% and 9.6% ± 6.9% at normal and reduced oscillatory amplitudes, respectively) and 6 cmH2O (15.1% ± 8.2%, 1.6% ± 9.4%, p < 0.05 for all). SIGNIFICANCE Mechanical properties of the airways and the respiratory tissues, particularly for respiratory tissue stiffness, can be reliably assessed using LMA. However, the involvement of a longer laryngo-tracheo-bronchial pathway when using LMA should be considered for airway resistance and inertance, whereas upper airway shunting may affect the assessment of respiratory tissue damping.
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Affiliation(s)
- Andre Dos Santos Rocha
- Unit for Anaesthesiological Investigations, Department of Acute Medicine, University of Geneva, Geneva,Switzerland
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Fodor GH, Bayat S, Albu G, Lin N, Baudat A, Danis J, Peták F, Habre W. Variable Ventilation Is Equally Effective as Conventional Pressure Control Ventilation for Optimizing Lung Function in a Rabbit Model of ARDS. Front Physiol 2019; 10:803. [PMID: 31297064 PMCID: PMC6607923 DOI: 10.3389/fphys.2019.00803] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 06/06/2019] [Indexed: 11/24/2022] Open
Abstract
Background Introducing mathematically derived variability (MVV) into the otherwise monotonous conventional mechanical ventilation has been suggested to improve lung recruitment and gas exchange. Although the application of a ventilation pattern based on variations in physiological breathing (PVV) is beneficial for healthy lungs, its value in the presence of acute respiratory distress syndrome (ARDS) has not been characterized. We therefore aimed at comparing conventional pressure-controlled ventilation with (PCS) or without regular sighs (PCV) to MVV and PVV at two levels of positive end-expiratory pressure (PEEP) in a model of severe ARDS. Methods Anesthetised rabbits (n = 54) were mechanically ventilated and severe ARDS (PaO2/FiO2 ≤ 150 mmHg) was induced by combining whole lung lavage, i.v. endotoxin and injurious ventilation. Rabbits were then randomly assigned to be ventilated with PVV, MVV, PCV, or PCS for 5 h while maintaining either 6 or 9 cmH2O PEEP. Ventilation parameters, blood gas indices and respiratory mechanics (tissue damping, G, and elastance, H) were recorded hourly. Serum cytokine levels were assessed with ELISA and lung histology was analyzed. Results Although no progression of lung injury was observed after 5 h of ventilation at PEEP 6 cmH2O with PVV and PCV, values for G (58.8 ± 71.1[half-width of 95% CI]% and 40.8 ± 39.0%, respectively), H (54.5 ± 57.2%, 50.7 ± 28.3%), partial pressure of carbon-dioxide (PaCO2, 43.9 ± 23.8%, 46.2 ± 35.4%) and pH (−4.6 ± 3.3%, −4.6 ± 2.2%) worsened with PCS and MVV. Regardless of ventilation pattern, application of a higher PEEP improved lung function and precluded progression of lung injury and inflammation. Histology lung injury scores were elevated in all groups with no difference between groups at either PEEP level. Conclusion At moderate PEEP, variable ventilation based on a pre-recorded physiological breathing pattern protected against progression of lung injury equally to the conventional pressure-controlled mode, whereas mathematical variability or application of regular sighs caused worsening in lung mechanics. This outcome may be related to the excessive increases in peak inspiratory pressure with the latter ventilation modes. However, a greater benefit on respiratory mechanics and gas exchange could be obtained by elevating PEEP, compared to the ventilation mode in severe ARDS.
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Affiliation(s)
- Gergely H Fodor
- Unit for Anesthesiological Investigations, Geneva University Hospitals - University of Geneva, Geneva, Switzerland
| | - Sam Bayat
- Unit for Anesthesiological Investigations, Geneva University Hospitals - University of Geneva, Geneva, Switzerland.,Inserm UA7 STROBE Laboratory, Department of Clinical Physiology, Sleep and Exercise, Grenoble University Hospital, Grenoble, France
| | - Gergely Albu
- Unit for Anesthesiological Investigations, Geneva University Hospitals - University of Geneva, Geneva, Switzerland
| | - Na Lin
- Unit for Anesthesiological Investigations, Geneva University Hospitals - University of Geneva, Geneva, Switzerland.,Department of Anesthesiology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Aurélie Baudat
- Unit for Anesthesiological Investigations, Geneva University Hospitals - University of Geneva, Geneva, Switzerland
| | - Judit Danis
- MTA-SZTE Dermatological Research Group, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Geneva University Hospitals - University of Geneva, Geneva, Switzerland
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Lovisari F, Fodor GH, Peták F, Habre W, Bayat S. Effect of PEEP and I:E ratio on cerebral oxygenation in ARDS: an experimental study in anesthetized rabbit. BMC Anesthesiol 2019; 19:110. [PMID: 31216981 PMCID: PMC6582519 DOI: 10.1186/s12871-019-0782-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 06/09/2019] [Indexed: 12/03/2022] Open
Abstract
Background Although PEEP and inversed I:E ratio have been shown to improve gas exchange in ARDS, both can adversely affect systemic hemodynamics and cerebral perfusion. The goal of this study was to assess how changes in PEEP and I:E ratio affect systemic and cerebral oxygenation and perfusion in normal and injured lung. Methods Eight anesthetized Chinchilla-Bastard rabbits were ventilated at baseline with pressure-regulated volume control mode, VT = 6 ml/kg, PEEP = 6 cmH2O, FIO2 = 0.4; respiratory rate set for ETCO2 = 5.5%, and I:E = 1:2, 1:1 or 2:1 in random order. Ultrasonic carotid artery flow (CF), arterial (PaO2), jugular venous blood gases and near infrared spectroscopic cerebral oxygenation (∆HBO2) were recorded for each experimental condition. After induced lung injury, the animals were ventilated with PEEP = 9 followed by 6 cmH2O. Results At baseline, inverse-ratio ventilation (IRV) significantly reduced cerebral oxygenation (∆O2HB; − 27 at 1:2; − 15 at 1:1 vs. 0.27 μmol/L at 2:1; p < 0.05), due to a significant reduction in mean arterial pressure and CF without modifying gas exchange. In injured lung, IRV improved gas exchange but decreased cerebral perfusion without affecting brain oxygenation. The higher PEEP level, however, improved PaO2 (67.5 ± 19.3 vs. 42.2 ± 8.4, p < 0.05), resulting in an improved ∆HBO2 (− 13.8 ± 14.7 vs. –43.5 ± 21.3, p < 0.05), despite a drop in CF. Conclusions Our data suggest that unlike moderate PEEP, IRV is not effective in improving brain oxygenation in ARDS. In normal lung, IRV had a deleterious effect on brain oxygenation, which is relevant in anesthetized patients. Electronic supplementary material The online version of this article (10.1186/s12871-019-0782-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Federica Lovisari
- Unit for Anesthesiological Investigations Department of Anesthesiology Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland.,University of Milano-Bicocca, Milan, Italy
| | - Gergely H Fodor
- Unit for Anesthesiological Investigations Department of Anesthesiology Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations Department of Anesthesiology Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland.,Pediatric Anesthesia Unit, Geneva Children's Hospital, Geneva, Switzerland
| | - Sam Bayat
- Unit for Anesthesiological Investigations Department of Anesthesiology Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland. .,Inserm UA7 STROBE Laboratory, University of Grenoble, Grenoble, France. .,Department of Clinical Physiology, Sleep and Exercise, Grenoble University Hospital, Grenoble, France.
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Südy R, Fodor GH, Dos Santos Rocha A, Schranc Á, Tolnai J, Habre W, Peták F. Different contributions from lungs and chest wall to respiratory mechanics in mice, rats, and rabbits. J Appl Physiol (1985) 2019; 127:198-204. [PMID: 31161880 DOI: 10.1152/japplphysiol.00048.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Changes in lung mechanics are frequently inferred from intact-chest measures of total respiratory system mechanics without consideration of the chest wall contribution. The participation of lungs and chest wall in respiratory mechanics has not been evaluated systematically in small animals commonly used in respiratory research. Thus, we compared these contributions in intact-chest mice, rats, and rabbits and further characterized the influence of positive end-expiratory pressure (PEEP). Forced oscillation technique was applied to anesthetized mechanically ventilated healthy animals to obtain total respiratory system impedance (Zrs) at 0, 3, and 6 cmH2O PEEP levels. Esophageal pressure was measured by a catheter-tip micromanometer to separate Zrs into pulmonary (ZL) and chest wall (Zcw) components. A model containing a frequency-independent Newtonian resistance (RN), inertance, and a constant-phase tissue damping (G) and elastance (H) was fitted to Zrs, ZL, and Zcw spectra. The contribution of Zcw to RN was negligible in all species and PEEP levels studied. However, the participation of Zcw in G and H was significant in all species and increased significantly with increasing PEEP and animal size (rabbit > rat > mice). Even in mice, the chest wall contribution to G and H was still considerable, reaching 47.0 ± 4.0(SE)% and 32.9 ± 5.9% for G and H, respectively. These findings demonstrate that airway parameters can be assessed from respiratory system mechanical measurements. However, the contribution from the chest wall should be considered when intact-chest measurements are used to estimate lung parenchymal mechanics in small laboratory models (even in mice), particularly at elevated PEEP levels. NEW & NOTEWORTHY In species commonly used in respiratory research (rabbits, rats, mice), esophageal pressure-based estimates revealed negligible contribution from the chest wall to the Newtonian resistance. Conversely, chest wall participation in the viscoelastic tissue mechanical parameters increased with body size (rabbit > rat > mice) and positive end-expiratory pressure, with contribution varying between 30 and 50%, even in mice. These findings demonstrate the potential biasing effects of the chest wall when lung tissue mechanics are inferred from intact-chest measurements in small laboratory animals.
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Affiliation(s)
- Roberta Südy
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland.,Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
| | - Gergely H Fodor
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland
| | - André Dos Santos Rocha
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland
| | - Álmos Schranc
- Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
| | - József Tolnai
- Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Acute Medicine, University of Geneva , Geneva , Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged , Szeged , Hungary
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Fodor GH, Habre W, Balogh AL, Südy R, Babik B, Peták F. Optimal crystalloid volume ratio for blood replacement for maintaining hemodynamic stability and lung function: an experimental randomized controlled study. BMC Anesthesiol 2019; 19:21. [PMID: 30760207 PMCID: PMC6375132 DOI: 10.1186/s12871-019-0691-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 02/04/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Crystalloids are first line in fluid resuscitation therapy, however there is a lack of evidence-based recommendations on the volume to be administered. Therefore, we aimed at comparing the systemic hemodynamic and respiratory effects of volume replacement therapy with a 1:1 ratio to the historical 1:3 ratio. METHODS Anesthetized, ventilated rats randomly included in 3 groups: blood withdrawal and replacement with crystalloid in 1:1 ratio (Group 1, n = 11), traditional 1:3 ratio (Group 3, n = 12) and a control group with no interventions (Group C, n = 9). Arterial blood of 5% of the total blood volume was withdrawn 7 times, and replaced stepwise with different volume rations of Ringer's acetate, according to group assignments. Airway resistance (Raw), respiratory tissue damping (G) and tissue elastance (H), mean arterial pressure (MAP) and heart rate (HR) were assessed following each step of fluid replacement with a crystalloid (CR1-CR6). Lung edema index was measured from histological samples. RESULTS Raw decreased in Groups 1 and 3 following CR3 (p < 0.02) without differences between the groups. H elevated in all groups (p < 0.02), with significantly higher changes in Group 3 compared to Groups C and 1 (both p = 0.03). No differences in MAP or HR were present between Groups 1 and 3. Lung edema was noted in Group 3 (p < 0.05). CONCLUSIONS Fluid resuscitation therapy by administering a 1:1 blood replacement ratio revealed adequate compensation capacity and physiological homeostasis similar with no lung stiffening and pulmonary edema. Therefore, considering this ratio promotes the restrictive fluid administration in the presence of continuous and occult bleeding.
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Affiliation(s)
- Gergely H. Fodor
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720 Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University Hospitals of Geneva, University of Geneva, 1 Rue Michel Servet, CH-1205 Geneva, Switzerland
| | - Adam L. Balogh
- Department of Anesthesiology and Intensive Therapy, University of Szeged, 8 Semmelweis str, Szeged, H-6725 Hungary
| | - Roberta Südy
- Department of Anesthesiology and Intensive Therapy, University of Szeged, 8 Semmelweis str, Szeged, H-6725 Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, 8 Semmelweis str, Szeged, H-6725 Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, 9 Koranyi fasor, Szeged, H-6720 Hungary
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Tolnai J, Fodor GH, Babik B, Dos Santos Rocha A, Bayat S, Peták F, Habre W. Volumetric but Not Time Capnography Detects Ventilation/Perfusion Mismatch in Injured Rabbit Lung. Front Physiol 2018; 9:1805. [PMID: 30618817 PMCID: PMC6299046 DOI: 10.3389/fphys.2018.01805] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 11/29/2018] [Indexed: 12/31/2022] Open
Abstract
Whereas time capnography (Tcap) is routinely displayed during mechanical ventilation, the volumetric representation (Vcap) is seldom used. We compared the diagnostic value of indices derived from Tcap and Vcap following ventilation to perfusion ratio ( ) mismatch subsequent to experimentally induced acute respiratory distress syndrome (ARDS), and alveolar recruitment by elevating the positive end-expiratory pressure (PEEP). Lung injury was induced by iv lipopolysaccharide, whole lung lavage and injurious ventilation in anesthetized, mechanically ventilated rabbits (n = 26). Mainstream Tcap and Vcap were performed to assess normalized phase 2 (Sn2T, Sn2V) and phase 3 slopes (Sn3T, Sn3V) in the time and volumetric domains. Vcap was also used to estimate Enghoff’s physiological dead space (VDE). Lung oxygenation index (PaO2/FiO2) and intrapulmonary shunt (Qs/Qt) were derived from arterial and central venous blood gas samples. All measurements were made under baseline conditions, and, following lung injury, under moderate (6 cmH2O) and high PEEP levels (9 cmH2O). Lung injury deteriorated the PaO2/FiO2 (baseline vs. injured 466 ± 10.2 [95% confidence interval] vs. 77.3 ± 17.1 mmHg, p < 0.05) and compromised all mechanical parameters significantly, whereas Tcap parameters exhibited contradictory or inconsistent changes. Conversely, Vcap indices exhibited consistent changes and provided excellent diagnostic value in detecting lung-function deterioration subsequent to lung injury [area under the receiver operating characteristic (ROC) curve of 1.0 ± 0.0, 0.87 ± 0.22 and 0.86 ± 0.22 for VDE, Sn3V and Sn3V/Sn2V, respectively]. Elevated PEEP increased PaO2/FiO2 and decreased Qs/Qt, which was reflected only in the Vcap slope ratio (Sn3V/Sn2V, p < 0.05). Our findings demonstrate the limited value of Tcap to detect ventilation to perfusion ratio ( ) mismatch, following severe lung injury. Conversely, indices derived from Vcap proved to be sensitive for detecting lung volume loss and alveolar recruitment. Therefore, promotion of Vcap is of paramount importance as a real-time, non-invasive, bedside monitoring modality to detect the development of and to follow-up the progression of lung injury in a model of ARDS.
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Affiliation(s)
- József Tolnai
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Gergely H Fodor
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - André Dos Santos Rocha
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
| | - Sam Bayat
- EA-7442 RSRM Laboratory, Department of Clinical Physiology, Sleep and Exercise, Grenoble University Hospital, University of Grenoble, Grenoble, France
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Unit for Anesthesiological Investigations, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland
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Abstract
Abstract: Diabetes mellitus involves a group of chronic metabolic disorders with elevated blood glucose concentrations. Since this disease needs lifelong treatment and care, the medical and social aspects present major public health concerns and pose a global challenge for health care providers. The number of aged patients with degenerative diseases undergoing surgical procedures is continuously increasing, resulting in an overwhelming dominance of diabetes in the perioperative care. There is a particular need for an increased awareness of diabetic patients in cardiovascular units, where the incidence of this disease reaches as high as 30–40%. The main hallmarks of the pathologic metabolic milieu of diabetes are hyperglycaemia, insulin resistance and pathologic lipid metabolism. The biochemical, cellular and organ-level pathophysiological changes lead to endothelial dysfunction including a low-grade prothrombotic balance, inflammatory state and, as a consequence, impaired micro- and macrocirculation. Diabetes is also followed by platelet dysfunction resulting from intracellular hyperglycaemia, because thrombocytes have insulin-independent glucose transporters in their cell membrane. The levels of the coagulation factors of the plasma are increased, and these factors are also modified by oxidation and glycation. Diabetes mellitus is a prothrombotic condition resulting from direct and indirect tendencies of the endothelial platelet and the plasma coagulation factors. The basic “bench to clinical basics” knowledge of the endothelial dysfunction and prothrombotic balance in diabetes may contribute to the better understanding of the clinical focuses in the perioperative care of patients with diabetes mellitus. Orv Hetil. 2018; 159(33): 1335–1345.
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Affiliation(s)
- Barna Babik
- Aneszteziológiai és Intenzív Terápiás Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged, Semmelweis u. 6., 6720
| | - Ferenc Peták
- Orvosi Fizikai és Orvosi Informatikai Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged
| | - Szilvia Agócs
- Aneszteziológiai és Intenzív Terápiás Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged, Semmelweis u. 6., 6720
| | - Ivett Blaskovics
- Aneszteziológiai és Intenzív Terápiás Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged, Semmelweis u. 6., 6720
| | - Endre Alács
- Aneszteziológiai és Intenzív Terápiás Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged, Semmelweis u. 6., 6720
| | - Kinga Bodó
- Aneszteziológiai és Intenzív Terápiás Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged, Semmelweis u. 6., 6720
| | - Roberta Südy
- Aneszteziológiai és Intenzív Terápiás Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged, Semmelweis u. 6., 6720
- Orvosi Fizikai és Orvosi Informatikai Intézet, Szegedi Tudományegyetem, Általános Orvostudományi Kar Szeged
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Albu G, Sottas C, Dolci M, Walesa M, Peták F, Habre W. Cardiorespiratory Alterations Following Acute Normovolemic Hemodilution in a Pediatric and an Adult Porcine Model. Anesth Analg 2018; 126:995-1003. [DOI: 10.1213/ane.0000000000002175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Porra L, Dégrugilliers L, Broche L, Albu G, Strengell S, Suhonen H, Fodor GH, Peták F, Suortti P, Habre W, Sovijärvi ARA, Bayat S. Quantitative Imaging of Regional Aerosol Deposition, Lung Ventilation and Morphology by Synchrotron Radiation CT. Sci Rep 2018; 8:3519. [PMID: 29476086 PMCID: PMC5824954 DOI: 10.1038/s41598-018-20986-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 01/29/2018] [Indexed: 01/02/2023] Open
Abstract
To understand the determinants of inhaled aerosol particle distribution and targeting in the lung, knowledge of regional deposition, lung morphology and regional ventilation, is crucial. No single imaging modality allows the acquisition of all such data together. Here we assessed the feasibility of dual-energy synchrotron radiation imaging to this end in anesthetized rabbits; both in normal lung (n = 6) and following methacholine (MCH)-induced bronchoconstriction (n = 6), a model of asthma. We used K-edge subtraction CT (KES) imaging to quantitatively map the regional deposition of iodine-containing aerosol particles. Morphological and regional ventilation images were obtained, followed by quantitative regional iodine deposition maps, after 5 and 10 minutes of aerosol administration. Iodine deposition was markedly inhomogeneous both in normal lung and after induced bronchoconstrition. Deposition was significantly reduced in the MCH group at both time points, with a strong dependency on inspiratory flow in both conditions (R2 = 0.71; p < 0.0001). We demonstrate for the first time, the feasibility of KES CT for quantitative imaging of lung deposition of aerosol particles, regional ventilation and morphology. Since these are among the main factors determining lung aerosol deposition, we expect this imaging approach to bring new contributions to the understanding of lung aerosol delivery, targeting, and ultimately biological efficacy.
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Affiliation(s)
- L Porra
- Department of Physics, University of Helsinki, Helsinki, Finland.,Helsinki University Central Hospital Medical Imaging Center, Helsinki, Finland
| | - L Dégrugilliers
- Department of Pediatric Intensive Care, Amiens University Hospital, Amiens, France
| | - L Broche
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - G Albu
- Anesthesiological Investigations Unit, University Hospitals of Geneva, Geneva, Switzerland
| | - S Strengell
- Department of Physics, University of Helsinki, Helsinki, Finland.,Helsinki University Central Hospital Medical Imaging Center, Helsinki, Finland
| | - H Suhonen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - G H Fodor
- Anesthesiological Investigations Unit, University Hospitals of Geneva, Geneva, Switzerland
| | - F Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - P Suortti
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - W Habre
- Anesthesiological Investigations Unit, University Hospitals of Geneva, Geneva, Switzerland
| | - A R A Sovijärvi
- Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - S Bayat
- University of Grenoble EA-7442 RSRM Laboratory and Department of Clinical Physiology, Sleep and Exercise, Grenoble University Hospital, Grenoble, France.
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Abstract
OBJECTIVE To investigate sevoflurane's potential to alleviate the detrimental pulmonary changes after cardiopulmonary bypass (CPB). DESIGN Prospective, randomized clinical investigation. SETTING University hospital. PARTICIPANTS One hundred ninety patients undergoing elective cardiac surgery. INTERVENTIONS Ninety-nine patients under intravenous anesthesia were administered 1 minimal alveolar concentration of sevoflurane for 5 minutes after being weaned from CPB (group SEV); intravenous anesthesia was maintained in the other 91 patients (group CTRL). MEASUREMENTS AND MAIN RESULTS Measurements were performed with open chest: before CPB, after CPB, and after intervention. The lungs' mechanical impedance and capnogram traces were recorded, arterial and central venous blood samples were analyzed, and lung compliance was documented. Airway resistance, tissue damping, and elastance were obtained from the impedance spectra. The capnogram phase III slope was determined using linear regression. The partial pressure of oxygen in the arterial blood/fraction of inspired oxygen ratio and shunt fraction were calculated from blood gas parameters. After CPB, sevoflurane induced bronchodilation, reflected in marked drops in airway resistance and smaller improvements in lung tissue viscoelasticity indicated by decreases in tissue damping and elastance. These changes were reflected in a decreased capnogram phase III slope and shunt fraction and increased partial pressure of oxygen in the arterial blood/fraction of inspired oxygen ratio and lung compliance. The more severe deteriorations that occurred after CPB, the greater improvements by sevoflurane were observed. CONCLUSIONS Sevoflurane can alleviate CPB-induced bronchoconstriction, compromised lung tissue mechanics, and enhanced intrapulmonary shunt. This benefit has particular importance in patients with severe CPB-induced lung function deterioration.
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Affiliation(s)
- Adam L Balogh
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary; Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Roberta Sudy
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary; Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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Peták F, Fodor GH, Babik B, Habre W. Airway mechanics and lung tissue viscoelasticity: effects of altered blood hematocrit in the pulmonary circulation. J Appl Physiol (1985) 2016; 121:261-7. [PMID: 27283919 DOI: 10.1152/japplphysiol.01103.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 06/08/2016] [Indexed: 11/22/2022] Open
Abstract
The contribution of the hematocrit (Hct) of the blood in the pulmonary vasculature to the overall lung mechanics has not been characterized. We therefore set out to establish how changes of the Hct level in the pulmonary circulation affect the airway and lung tissue viscoelastic properties. The Hct level of the blood in an isolated perfused rat lung model was randomly altered. Intermediate (26.5%), followed by low (6.6%) or normal (43.7%), Hct was set in two consecutive sequences. The pulmonary capillary pressure was maintained constant throughout the experiment, and the pulmonary hemodynamic parameters were monitored continuously. The airway resistance (Raw), the viscous (G) and elastic (H) parameters, and the hysteresivity (η = G/H) of the lung tissues were obtained from measurements of forced oscillatory input impedance data. Raw was not affected by the alterations of the Hct levels. As concerns the lung tissues, the decrease of Hct to intermediate or low levels resulted in close to proportional decreases in the viscoelastic parameters G [16.5 ± 7.7% (SD), 12.1 ± 9.5%, P < 0.005] and H (13.2 ± 8.6%, 10.8 ± 4.7%, P < 0.001). No significant changes in η were detected in a wide range of Hct, which indicates that coupled processes cause alterations in the resistive and elastic properties of the lungs following Hct changes in the pulmonary circulation. The diminishment of the viscous and elastic parameters of the pulmonary parenchyma following a reduction of blood Hct demonstrates the significant contribution of the red blood cells to the overall lung viscoelasticity.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary;
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Walid Habre
- Pathophysiological Experimental Platform, Department of Anesthesiology, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland; and Pediatric Anesthesia Unit, Geneva Children's Hospital, Geneva, Switzerland
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Filep Á, Fodor GH, Kun-Szabó F, Tiszlavicz L, Rázga Z, Bozsó G, Bozóki Z, Szabó G, Peták F. Exposure to urban PM1 in rats: development of bronchial inflammation and airway hyperresponsiveness. Respir Res 2016; 17:26. [PMID: 26966003 PMCID: PMC4785744 DOI: 10.1186/s12931-016-0332-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/09/2016] [Indexed: 11/10/2022] Open
Abstract
Background Several epidemiological and laboratory studies have evidenced the fact that atmospheric particulate matter (PM) increases the risk of respiratory morbidity. It is well known that the smallest fraction of PM (PM1 - particulate matter having a diameter below 1 μm) penetrates the deepest into the airways. The ratio of the different size fractions in PM is highly variable, but in industrial areas PM1 can be significant. Despite these facts, the health effects of PM1 have been poorly investigated and air quality standards are based on PM10 and PM2.5 (PM having diameters below 10 μm and 2.5 μm, respectively) concentrations. Therefore, this study aimed at determining whether exposure to ambient PM1 at a near alert threshold level for PM10 has respiratory consequences in rats. Methods Rats were either exposed for 6 weeks to 100 μg/m3 (alert threshold level for PM10 in Hungary) urban submicron aerosol, or were kept in room air. End-expiratory lung volume, airway resistance (Raw) and respiratory tissue mechanics were measured. Respiratory mechanics were measured under baseline conditions and following intravenous methacholine challenges to characterize the development of airway hyperresponsiveness (AH). Bronchoalveolar lavage fluid (BALF) was analyzed and lung histology was performed. Results No significant differences were detected in lung volume and mechanical parameters at baseline. However, the exposed rats exhibited significantly greater MCh-induced responses in Raw, demonstrating the progression of AH. The associated bronchial inflammation was evidenced by the accumulation of inflammatory cells in BALF and by lung histology. Conclusions Our findings suggest that exposure to concentrated ambient PM1 (mass concentration at the threshold level for PM10) leads to the development of mild respiratory symptoms in healthy adult rats, which may suggest a need for the reconsideration of threshold limits for airborne PM1.
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Affiliation(s)
- Ágnes Filep
- Department: MTA-SZTE Research Group on Photoacoustic Spectroscopy, H-6720, Szeged, Dóm tér 9, Hungary. .,Department of Optics and Quantum Electronics, University of Szeged, H-6720, Szeged, Dóm tér 9, Hungary.
| | - Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, H-6720, Szeged, Korányi fasor 9, Hungary
| | - Fruzsina Kun-Szabó
- Institute for Environmental Sciences, University of Szeged, H-6720, Szeged, Dóm tér 9, Hungary
| | - László Tiszlavicz
- Department of Pathology, University of Szeged, H-6720, Szeged, Állomás u. 2, Hungary
| | - Zsolt Rázga
- Department of Pathology, University of Szeged, H-6720, Szeged, Állomás u. 2, Hungary
| | - Gábor Bozsó
- Department of Mineralogy, Geochemistry and Petrology, University of Szeged, H-6722, Szeged, Egyetem u. 2, Hungary
| | - Zoltán Bozóki
- Department: MTA-SZTE Research Group on Photoacoustic Spectroscopy, H-6720, Szeged, Dóm tér 9, Hungary.,Department of Optics and Quantum Electronics, University of Szeged, H-6720, Szeged, Dóm tér 9, Hungary
| | - Gábor Szabó
- Department: MTA-SZTE Research Group on Photoacoustic Spectroscopy, H-6720, Szeged, Dóm tér 9, Hungary.,Department of Optics and Quantum Electronics, University of Szeged, H-6720, Szeged, Dóm tér 9, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, H-6720, Szeged, Korányi fasor 9, Hungary
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Bayat S, Porra L, Broche L, Albu G, Malaspinas I, Doras C, Strengell S, Peták F, Habre W. Effect of surfactant on regional lung function in an experimental model of respiratory distress syndrome in rabbit. J Appl Physiol (1985) 2015; 119:290-8. [DOI: 10.1152/japplphysiol.00047.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 05/14/2015] [Indexed: 11/22/2022] Open
Abstract
We assessed the changes in regional lung function following instillation of surfactant in a model of respiratory distress syndrome (RDS) induced by whole lung lavage and mechanical ventilation in eight anaesthetized, paralyzed, and mechanically ventilated New Zealand White rabbits. Regional specific ventilation (sV̇) was measured by K-edge subtraction synchrotron computed tomography during xenon washin. Lung regions were classified as poorly aerated (PA), normally aerated (NA), or hyperinflated (HI) based on regional density. A functional category was defined within each class based on sV̇ distribution (High, Normal, and Low). Airway resistance (Raw), respiratory tissue damping (G), and elastance (H) were measured by forced oscillation technique at low frequencies before and after whole lung saline lavage-induced (100 ml/kg) RDS, and 5 and 45 min after intratracheal instillation of beractant (75 mg/kg). Surfactant instillation improved Raw, G, and H ( P < 0.05 each), and gas exchange and decreased atelectasis ( P < 0.001). It also significantly improved lung aeration and ventilation in atelectatic lung regions. However, in regions that had remained normally aerated after lavage, it decreased regional aeration and increased sV̇ ( P < 0.001) and sV̇ heterogeneity. Although surfactant treatment improved both central airway and tissue mechanics and improved regional lung function of initially poorly aerated and atelectatic lung, it deteriorated regional lung function when local aeration was normal prior to administration. Local mechanical and functional heterogeneity can potentially contribute to the worsening of RDS and gas exchange. These data underscore the need for reassessing the benefits of routine prophylactic vs. continuous positive airway pressure and early “rescue” surfactant therapy in very immature infants.
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Affiliation(s)
- Sam Bayat
- Université de Picardie Jules Verne, Inserm U1105 and Pediatric Lung Function Laboratory, Amiens University Hospital, Amiens, France
| | - Liisa Porra
- Department of Physics, University of Helsinki, and Helsinki University Central Hospital, Helsinki, Finland
| | - Ludovic Broche
- Université de Picardie Jules Verne, Inserm U1105 and Pediatric Lung Function Laboratory, Amiens University Hospital, Amiens, France
- European Synchrotron Radiation Facility, Biomedical Beamline-ID17, Grenoble, France
| | - Gergely Albu
- Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland
| | - Iliona Malaspinas
- Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland
| | - Camille Doras
- Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland
| | - Satu Strengell
- Department of Physics, University of Helsinki, and Helsinki University Central Hospital, Helsinki, Finland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; and
| | - Walid Habre
- Anesthesiological Investigation Unit, University of Geneva, Geneva, Switzerland
- Geneva Children's Hospital, University Hospitals of Geneva and Geneva University, Geneva, Switzerland
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Doras C, Le Guen M, Peták F, Habre W. Cardiorespiratory effects of recruitment maneuvers and positive end expiratory pressure in an experimental context of acute lung injury and pulmonary hypertension. BMC Pulm Med 2015; 15:82. [PMID: 26228052 PMCID: PMC4521467 DOI: 10.1186/s12890-015-0079-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 07/20/2015] [Indexed: 01/17/2023] Open
Abstract
Background Recruitment maneuvers (RM) and positive end expiratory pressure (PEEP) are the cornerstone of the open lung strategy during ventilation, particularly during acute lung injury (ALI). However, these interventions may impact the pulmonary circulation and induce hemodynamic and respiratory effects, which in turn may be critical in case of pulmonary hypertension (PHT). We aimed to establish how ALI and PHT influence the cardiorespiratory effects of RM and PEEP. Methods Rabbits control or with monocrotaline-induced PHT were used. Forced oscillatory airway and tissue mechanics, effective lung volume (ELV), systemic and right ventricular hemodynamics and blood gas were assessed before and after RM, during baseline and following surfactant depletion by whole lung lavage. Results RM was more efficient in improving respiratory elastance and ELV in the surfactant-depleted lungs when PHT was concomitantly present. Moreover, the adverse changes in respiratory mechanics and ELV following ALI were lessened in the animals suffering from PHT. Conclusions During ventilation with open lung strategy, the role of PHT in conferring protection from the adverse respiratory consequences of ALI was evidenced. This finding advocates the safety of RM and PEEP in improving elastance and advancing lung reopening in the simultaneous presence of PHT and ALI.
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Affiliation(s)
- Camille Doras
- Anesthesiological Investigation, University Medical Centre, University of Geneva, Geneva, Switzerland.
| | - Morgan Le Guen
- Department of Anesthesiology, Hospital Foch, University Versailles Saint-Quentin en Yvelines, Suresnes, France.
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
| | - Walid Habre
- Anesthesiological Investigation, University Medical Centre, University of Geneva, Geneva, Switzerland. .,Pediatric Anesthesia Unit, Geneva Children's Hospital, Rue Willy Donzé 6, 1205, Geneva, Switzerland.
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Czövek D, Peták F, Donati Y, Belin X, Pache JC, Barazzone Argiroffo C, Habre W. Prevention of hyperoxia-induced bronchial hyperreactivity by sildenafil and vasoactive intestinal peptide: impact of preserved lung function and structure. Respir Res 2014; 15:81. [PMID: 25117627 PMCID: PMC4261898 DOI: 10.1186/1465-9921-15-81] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 07/02/2014] [Indexed: 01/10/2023] Open
Abstract
Objective Hyperoxia exposure leads to the development of lung injury and bronchial hyperreactivity (BHR) via involvement of nitric oxide (NO) pathway. We aimed at characterizing whether the stimulation of the NO pathway by sildenafil or vasoactive intestinal peptide (VIP) is able to prevent the hyperoxia-induced development of BHR. The respective roles of the preserved lung volume and alveolar architecture, the anti-inflammatory and anti-apoptotic potentials of these treatments in the diminished lung responsiveness were also characterized. Materials and methods Immature (28-day-old) rats were exposed for 72 hours to room air (Group C), hyperoxia (>95%, Group HC), or hyperoxia with the concomitant administration of vasoactive intestinal peptide (VIP, Group HV) or sildenafil (Group HS). Following exposure, the end-expiratory lung volume (EELV) was assessed plethysmographically. Airway and respiratory tissue mechanics were measured under baseline conditions and following incremental doses of methacholine to assess BHR. Inflammation was assessed by analyzing the bronchoalveolar lavage fluid (BALF), while biochemical and histological analyses were used to characterize the apoptotic and structural changes in the lungs. Results The BHR, the increased EELV, the aberrant alveolarization, and the infiltration of inflammatory cells into the BALF that developed in Group HC were all suppressed significantly by VIP or sildenafil treatment. The number of apoptotic cells increased significantly in Group HC, with no evidence of statistically significant effects on this adverse change in Groups HS and HV. Conclusions These findings suggest that stimulating the NO pathway by sildenafil and VIP exert their beneficial effect against hyperoxia-induced BHR via preserving normal EELV, inhibiting airway inflammation and preserving the physiological lung structure, whereas the antiapoptotic potential of these treatments were not apparent in this process.
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Affiliation(s)
| | | | | | | | | | | | - Walid Habre
- Department of Anesthesiology, Anesthesiological Investigation Unit, Pharmacology and Intensive Care, University of Geneva, Geneva, Switzerland.
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Fodor GH, Peták F, Erces D, Balogh AL, Babik B. Lung mechanical changes following bronchoaspiration in a porcine model: differentiation of direct and indirect mechanisms. Respir Physiol Neurobiol 2014; 199:41-9. [PMID: 24814560 DOI: 10.1016/j.resp.2014.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 04/01/2014] [Accepted: 05/02/2014] [Indexed: 01/13/2023]
Abstract
Bronchoaspiration results in local deterioration of lung function through direct damage and/or indirect systemic effects related to neurohumoral pathways. We distinguished these effects by selectively intubating the two main bronchi in pigs while a PEEP of 4 or 10cm H2O was maintained. Gastric juice was instilled only into the right lung. Lung mechanical and ventilation defects were assessed by measuring unilateral pulmonary input impedance (ZL,s) and the third phase slope of the capnogram (SIII) for each lung side separately before the aspiration and for 120min thereafter. Marked transient elevations in ZL,s parameters and SIII were observed in the affected lung after aspiration. Elevating PEEP did not affect these responses in the ZL,s parameters, whereas it prevented the SIII increases. None of these indices changed in the intact left lung. These findings furnish evidence of the predominance of the local direct damage over the indirect systemic effects in the development of the deterioration of lung function, and demonstrate the benefit of an initially elevated PEEP following aspiration.
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Affiliation(s)
- Gergely H Fodor
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary.
| | - Dániel Erces
- Institute of Surgical Research, University of Szeged, Szeged, Hungary
| | - Adám L Balogh
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
| | - Barna Babik
- Department of Anaesthesiology and Intensive Therapy, University of Szeged, Szeged, Hungary
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Bayat S, Porra L, Albu G, Suhonen H, Strengell S, Suortti P, Sovijärvi A, Peták F, Habre W. Effect of positive end-expiratory pressure on regional ventilation distribution during mechanical ventilation after surfactant depletion. Anesthesiology 2013; 119:89-100. [PMID: 23559029 DOI: 10.1097/aln.0b013e318291c165] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Ventilator-induced lung injury occurs due to exaggerated local stresses, repeated collapse, and opening of terminal air spaces in poorly aerated dependent lung, and increased stretch in nondependent lung. The aim of this study was to quantify the functional behavior of peripheral lung units in whole-lung lavage-induced surfactant depletion, and to assess the effect of positive end-expiratory pressure. METHODS The authors used synchrotron imaging to measure lung aeration and regional specific ventilation at positive end-expiratory pressure of 3 and 9 cm H2O, before and after whole-lung lavage in rabbits. Respiratory mechanical parameters were measured, and helium-washout was used to assess end-expiratory lung volume. RESULTS Atelectatic, poorly, normally aerated, hyperinflated, and trapped regions could be identified using the imaging technique used in this study. Surfactant depletion significantly increased atelectasis (6.3±3.3 [mean±SEM]% total lung area; P=0.04 vs. control) and poor aeration in dependent lung. Regional ventilation was distributed to poorly aerated regions with high (16.4±4.4%; P<0.001), normal (20.7±5.9%; P<0.001 vs. control), and low (5.7±1.2%; P<0.05 vs. control) specific ventilation. Significant redistribution of ventilation to normally aerated nondependent lung regions occurred (41.0±9.6%; P=0.03 vs. control). Increasing positive end-expiratory pressure level to 9 cm H2O significantly reduced poor aeration and recruited atelectasis, but ventilation redistribution persisted (39.2±9.5%; P<0.001 vs. control). CONCLUSIONS Ventilation of poorly aerated dependent lung regions, which can promote the local concentration of mechanical stresses, was the predominant functional behavior in surfactant-depleted lung. Potential tidal recruitment of atelectatic lung regions involved a smaller fraction of the imaged lung. Significant ventilation redistribution to aerated lung regions places these at risk of increased stretch injury.
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Affiliation(s)
- Sam Bayat
- Université de Picardie Jules Verne, EA4285 Péritox-INERIS and Pediatric Lung Function Laboratory, CHU Amiens, Amiens, France
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Layachi S, Porra L, Albu G, Trouillet N, Suhonen H, Peták F, Sevestre H, Suortti P, Sovijärvi A, Habre W, Bayat S. Role of cellular effectors in the emergence of ventilation defects during allergic bronchoconstriction. J Appl Physiol (1985) 2013; 115:1057-64. [PMID: 23887899 DOI: 10.1152/japplphysiol.00844.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is not known whether local factors within the airway wall or parenchyma may influence the emergence and spatial distribution of ventilation defects (VDs), thereby modulating the dynamic system behavior of the lung during bronchoconstriction. We assessed the relationship between the distribution of cellular effectors and the emergence of defects in regional ventilation distribution following allergen challenge. We performed high-resolution K-edge subtraction (KES) synchrotron imaging during xenon inhalation and measured the forced oscillatory input impedance in ovalbumin (OVA)-sensitized Brown-Norway rats (n = 12) at baseline and repeatedly following OVA challenge. Histological slices with best anatomic matching to the computed tomographic images were stained with a modified May-Grunwald Giemsa and immunohistochemical staining with monoclonal anti-rat CD68, in six rats. Slides were digitized and total cells and eosinophils were counted in the walls of bronchi and vessels randomly selected within and outside of VDs on the basis of xenon-KES images. Ventilated alveolar area decreased and ventilation heterogeneity, Newtonian resistance, tissue damping, and elastance increased following OVA challenge. Eosinophil, total cell, and CD68+ counts were significantly higher in the bronchial and vascular walls within vs. outside of the VDs. The minimal central airway diameters during OVA-induced bronchoconstriction were correlated with eosinophil (R = -0.85; P = 0.031) and total cell densities (R = -0.82; P = 0.046) in the airway walls within the poorly ventilated zones. Our findings suggest that allergic airway inflammation is locally heterogeneous and is topographically associated with the local emergence of VDs following allergen challenge.
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Affiliation(s)
- Skander Layachi
- Université de Picardie Jules Verne and Amiens University Hospital, Amiens, France
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Babik B, Csorba Z, Czövek D, Mayr PN, Bogáts G, Peták F. Effects of respiratory mechanics on the capnogram phases: importance of dynamic compliance of the respiratory system. Crit Care 2012; 16:R177. [PMID: 23031408 PMCID: PMC3682277 DOI: 10.1186/cc11659] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Accepted: 10/02/2012] [Indexed: 11/10/2022]
Abstract
INTRODUCTION The slope of phase III of the capnogram (SIII) relates to progressive emptying of the alveoli, a ventilation/perfusion mismatch, and ventilation inhomogeneity. S(III) depends not only on the airway geometry, but also on the dynamic respiratory compliance (Crs); this latter effect has not been evaluated. Accordingly, we established the value of SIII for monitoring airway resistance during mechanical ventilation. METHODS Sidestream capnography was performed during mechanical ventilation in patients undergoing elective cardiac surgery (n = 144). The airway resistance (Raw), total respiratory resistance and Crs displayed by the ventilator, the partial pressure of arterial oxygen (PaO2) and S(III) were measured in time domain (S(T-III)) and in a smaller cohort (n = 68) by volumetry (S(V-III)) with and without normalization to the average CO2 phase III concentration. Measurements were performed at positive end-expiratory pressure (PEEP) levels of 3, 6 and 9 cmH2O in patients with healthy lungs (Group HL), and in patients with respiratory symptoms involving low (Group LC), medium (Group MC) or high Crs (Group HC). RESULTS S(T-III) and S(V-III) exhibited similar PEEP dependencies and distribution between the protocol groups formed on the basis of Crs. A wide interindividual scatter was observed in the overall Raw-S(T-III) relationship, which was primarily affected by Crs. Decreases in Raw with increasing PEEP were reflected in sharp falls in S(III) in Group HC, and in moderate decreases in S(III) in Group MC, whereas S(T-III) was insensitive to changes in airway caliber in Groups LC and HL. CONCLUSIONS SIII assessed in the time domain and by volumetry provide meaningful information about alterations in airway caliber, but only within an individual patient. Although S(T-III) may be of value for bedside monitoring of the airway properties, its sensitivity depends on Crs. Thus, assessment of the capnogram shape should always be coupled with Crs when the airway resistance or oxygenation are evaluated.
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Peták F, Czövek D, Novák Z. Spirometry and forced oscillations in the detection of airway hyperreactivity in asthmatic children. Pediatr Pulmonol 2012; 47:956-65. [PMID: 22451241 DOI: 10.1002/ppul.22551] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 12/29/2011] [Indexed: 12/18/2022]
Abstract
BACKGROUND Provocation tests are routinely used to detect airway hyperreactivity (AH) in the diagnosis of asthma. We compared the sensitivities of the forced oscillation technique (FOT) and spirometry in the detection of AH in asthmatic children. METHODS FOT and spirometry were performed in 20 asthmatic children (aged 5-18 years) following aerosolized histamine and methacholine at an interval of 2 weeks. The respiratory system input impedance was measured by FOT; the resistance at 6 Hz (R(6) ), the average resistance between 4 and 24 Hz, the area under the reactance curve (AX) and the resonant frequency were extracted from these recordings. Spirometry was used to obtain forced expiratory volumes and flow parameters. RESULTS Following provocation with the two agonists, the FOT detected the airway response as early as spirometry. When the greater variability of the impedance parameters was taken into account, the two methods were observed to have similar sensitivities. Among the lung function parameters studied, AX and R(6) were the most sensitive for the demonstration of AH. CONCLUSIONS Our findings demonstrate that FOT is as suitable as spirometry for the measurement of bronchoconstriction and thus it may be considered for the detection of AH in asthmatic children. Since its application requires minimal cooperation, this approach imposes less stress and may be particularly favorable in the diagnosis of asthma at a young age.
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Affiliation(s)
- Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Hungary.
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Czövek D, Novák Z, Somlai C, Asztalos T, Tiszlavicz L, Bozóki Z, Ajtai T, Utry N, Filep A, Bari F, Peták F. Respiratory consequences of red sludge dust inhalation in rats. Toxicol Lett 2011; 209:113-20. [PMID: 22209771 DOI: 10.1016/j.toxlet.2011.12.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 10/24/2011] [Accepted: 12/14/2011] [Indexed: 11/27/2022]
Abstract
The environmental disaster following flooding by red sludge in the Ajka region in Hungary poses a serious public health threat with particular concern regarding the potentially adverse respiratory effects of the inhalation of red sludge dust (RSD). The respiratory consequences of the inhalation of RSD obtained from field samples were investigated in rats. Rats were either exposed to RSD at a high concentration (2 weeks, 8h/day), or kept in room air. After the exposures, the airway resistance (R(aw)) and the respiratory tissues mechanics were measured under baseline condition, and following methacholine (MCh) challenges with the aim of establishing airway hyper-responsiveness (AH). Histopathology was performed to assess lung morphologic alterations. The physical properties and the chemical composition of the RSD were also characterized. The size distribution, chemical composition and topology of the RSD particles applied in our experiments were similar to those observed at the site of the disaster. The inhalation of RSD did not alter the basal respiratory mechanics, whereas it led to greater MCh-induced responses in R(aw), demonstrating the progression of mild AH. Histopathological investigations revealed fine, granular particles in the alveolar macrophages, as evidence that RSD had reached the lower respiratory tract and induced mild inflammation around the alveoli and the pulmonary vasculature. The mild respiratory symptoms that developed following short-term exposure of healthy individuals to high concentrations of airborne RSD do not appear to pose a greater respiratory hazard than the inhalation of urban dust at a comparable concentration.
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Affiliation(s)
- Dorottya Czövek
- Department of Medical Physics and Informatics, University of Szeged, H-6720 Szeged, Korányi fasor 9, Hungary
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Bayat S, Albu G, Layachi S, Portier F, Fathi M, Peták F, Habre W. Acute hemorrhagic shock decreases airway resistance in anesthetized rat. J Appl Physiol (1985) 2011; 111:458-64. [PMID: 21596916 DOI: 10.1152/japplphysiol.00024.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We studied the relation between changes in pulmonary and systemic hemodynamics to those in the airway resistance, respiratory tissue mechanics, and thoracic gas volume (TGV) following acute hemorrhage and blood reinfusion in rats. Forced oscillation technique was used to measure airway resistance (Raw), respiratory tissue damping, and elastance at baseline and after stepwise 1-ml blood withdrawals up to 5 ml total, followed by stepwise reinfusion up to full restoration. Mean systemic (Pam) and pulmonary arterial pressures and suprarenal aortic blood flow were measured at each step. In supplemental animals, plethysmographic TGV, Pam, and respiratory mechanics measurements were performed. Blood volume loss (BVL) led to proportional decreases in Raw (66.5 ± 8.8 vs. 44.8 ± 9.0 cmH2O·s·l−1 with 5 ml, P < 0.001), Pam, and aortic blood flow. In contrast, tissue damping increased significantly (1,070 ± 91 vs. 1,235 ± 105 cmH2O/l, P = 0.009 with 5 ml BVL), whereas tissue elastance did not change significantly. TGV significantly increased with acute BVL (3.7 ± 0.2 vs. 4.2 ± 0.2 ml, P = 0.01). Stepwise reinfusions produced opposite changes in the above parameters, with Raw reaching a higher value than baseline ( P = 0.001) upon full volume restoration. Both adrenalin ( P = 0.015) and noradrenalin levels were elevated ( P = 0.010) after 5-ml blood withdrawal. Our data suggest that the decreases in Raw following BVL may be attributed to the following: 1) an increased TGV enhancing airway parenchymal tethering forces; and 2) an increase in circulating catecholamines. The apparent beneficial effect of a reduction in Raw in acute hemorrhagic shock is counteracted by an increase in dead space and the appearance of peripheral mechanical heterogeneities due to de-recruitment of the pulmonary vasculature.
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Affiliation(s)
- Sam Bayat
- Université de 1Picardie Jules Verne, EA4285 Péritox UMI01 Institut National de l'Environnement Industriel et des Risques and Centre Hospitalier Universitaire d'Amiens, Amiens, France
| | - Gergely Albu
- Anesthesiological Investigations Unit, University of Geneva, and
| | - Skander Layachi
- Université de 1Picardie Jules Verne, EA4285 Péritox UMI01 Institut National de l'Environnement Industriel et des Risques and Centre Hospitalier Universitaire d'Amiens, Amiens, France
| | - Flore Portier
- Université de 1Picardie Jules Verne, EA4285 Péritox UMI01 Institut National de l'Environnement Industriel et des Risques and Centre Hospitalier Universitaire d'Amiens, Amiens, France
| | - Marc Fathi
- Laboratory of Toxicology and Immunology, University Hospitals of Geneva, Geneva, Switzerland
| | - Ferenc Peták
- Department of Medical Physics and Informatics, University of Szeged, Szeged, Hungary; and
| | - Walid Habre
- Anesthesiological Investigations Unit, University of Geneva, and
- Pediatric Anesthesia Unit, Geneva Children's Hospital, Geneva, Switzerland
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Babik B, Csorba Z, Czövek D, Mayr PN, Bogáts G, Peták F. O-67 Potential of dopamine to treat respiratory adverse events after cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2011. [DOI: 10.1053/j.jvca.2011.03.080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Csorba Z, Czövek D, Bogáts G, Peták F, Babik B. O-48 The open chest condition provides improved gas exchange and respiratory mechanics in cardiac surgery patients. J Cardiothorac Vasc Anesth 2011. [DOI: 10.1053/j.jvca.2011.03.061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Csorba Z, Czövek D, Bogáts G, Peták F, Babik B. O-63 Sevoflurane diminishes lung function deterioration caused by cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2011. [DOI: 10.1053/j.jvca.2011.03.076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Lele EE, Hantos Z, Bitay M, Szívós B, Bogáts G, Peták F, Babik B. Bronchoconstriction during alveolar hypocapnia and systemic hypercapnia in dogs with a cardiopulmonary bypass. Respir Physiol Neurobiol 2011; 175:140-5. [DOI: 10.1016/j.resp.2010.10.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 10/19/2010] [Accepted: 10/20/2010] [Indexed: 11/30/2022]
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Porra L, Peták F, Strengell S, Neitola K, Janosi TZ, Suhonen H, Suortti P, Sovijärvi ARA, Habre W, Bayat S. Acute cigarette smoke inhalation blunts lung responsiveness to methacholine and allergen in rabbit: differentiation of central and peripheral effects. Am J Physiol Lung Cell Mol Physiol 2010; 299:L242-51. [DOI: 10.1152/ajplung.00033.2010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite the prevalence of active smoking in asthmatics, data on the short-term effect of acute mainstream tobacco smoke exposure on airway responsiveness are very scarce. The aim of this study was to assess the immediate effect of acute exposure to mainstream cigarette smoke on airway reactivity to subsequent nonspecific and allergenic challenges in healthy control ( n = 5) and ovalbumin-sensitized rabbits ( n = 6). We combined low-frequency forced oscillations and synchrotron radiation CT imaging to differentiate central airway and peripheral airway and lung parenchymal components of the response to airway provocation. Acute exposure to smoke generated by four successive cigarettes (CS) strongly inhibited the central airway response to subsequent IV methacholine (MCh) challenge. In the sensitized animals, although the response to ovalbumin was also inhibited in the central airways, mainstream CS did not blunt the peripheral airway response in this group. In additional groups of experiments, exposure to HEPA-filtered CS ( n = 6) similarly inhibited the MCh response, whereas CO (10,000 ppm for 4 min, n = 6) or nitric oxide inhalation instead of CS (240 ppm, 4 × 7 min, n = 5) failed to blunt nonspecific airway responsiveness. Pretreatment with α-chymotrypsin to inhibit endogenous VIP before CS exposure had no effect ( n = 4). Based on these observations, the gas phase of mainstream cigarette smoke may contain one or more short-term inhibitory components acting primarily on central airways and inhibiting the response to both specific and nonspecific airway provocation, but not on the lung periphery where both lung mechanical parameters, and synchrotron-imaging derived parameters, showed large changes in response to allergen challenge in sensitized animals.
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Affiliation(s)
- Liisa Porra
- European Synchrotron Radiation Facility, Grenoble, France
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Ferenc Peták
- Department of Medical Informatics and Engineering, University of Szeged, Szeged, Hungary
| | - Satu Strengell
- Department of Physics, University of Helsinki, Helsinki, Finland
- Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Kimmo Neitola
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Tibor Z. Janosi
- Department of Medical Informatics and Engineering, University of Szeged, Szeged, Hungary
| | - Heikki Suhonen
- European Synchrotron Radiation Facility, Grenoble, France
| | - Pekka Suortti
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Anssi R. A. Sovijärvi
- Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, Helsinki, Finland
| | - Walid Habre
- Geneva Children's Hospital, University Hospitals of Geneva and Geneva University, Geneva, Switzerland; and
| | - Sam Bayat
- Université de Picardie Jules Verne, EA4285 Péritox UMI01 INERIS and Department of Pediatric Cardiology and Pulomonary Medicine, CHU Amiens, Amiens, France
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von Ungern-Sternberg BS, Habre W, Regli A, Pache JC, Fontao F, Janosi TZ, Beghetti M, Peták F. Precapillary pulmonary hypertension leads to reversible bronchial hyperreactivity in rats. Exp Lung Res 2010; 36:129-39. [PMID: 20334605 DOI: 10.3109/01902140903214667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Congenital heart disease with left-to-right shunt may lead to precapillary pulmonary hypertension (PREPHT) with potential lung function impairment. The authors investigated the effects of PREPHT on lung responsiveness in a rat model of PREPHT by creating and repairing an abdominal aortocaval shunt (ACS). Rats were studied 4 weeks after the induction of ACS, and 4 weeks after its surgical repair. Control rats underwent sham surgery. To assess bronchial hyperreactivity, airway resistance (Raw) was measured at baseline and after increasing doses of methacholine. Raw was estimated by model fitting of the mechanical impedance of the respiratory system generated by forced oscillation technique. Lung morphological changes were assessed by histology. The prolonged presence of the ACS led to only minor changes in the basal respiratory mechanics, whereas it induced marked bronchial hyperreactivity, the methacholine-induced elevations in Raw being 49% +/- 5% before and 232% +/- 32% (P <.001) after ACS. These alterations were not associated with any changes in lung histology and were completely reversible on closure of the shunt. These results suggest that the induction of chronic increases in pulmonary blood flow and pressure causes reversible bronchial hyperreactivity. This may be consequent to the altered mechanical interdependence between the pulmonary vasculature and the respiratory tract.
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Albu G, Babik B, Késmárky K, Balázs M, Hantos Z, Peták F. Changes in airway and respiratory tissue mechanics after cardiac surgery. Ann Thorac Surg 2010; 89:1218-26. [PMID: 20338338 DOI: 10.1016/j.athoracsur.2009.12.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 12/22/2009] [Accepted: 12/23/2009] [Indexed: 11/25/2022]
Abstract
BACKGROUND Because of the critical importance of the first postoperative week in the development of respiratory complications after cardiac surgery, the mechanical properties of the respiratory system in this period were followed up systematically. METHODS The input impedance of the respiratory system (Zrs) was measured during spontaneous breathing in patients (n=35) undergoing cardiac surgery on the day before surgery to establish the baseline, and for six days thereafter. The airway resistance was inferred from the average of the resistive component of Zrs, while the changes in respiratory elastance were assessed from the imaginary part of Zrs by model fitting. An assessment was made of the impact on the postoperative changes of factors characteristic of the patients (gender, age, smoking, and obesity) or the surgery duration and the need or not for a cardiopulmonary bypass. RESULTS Airway resistance increased immediately after extubation (peak rise on day 1, evening: 48+/-10%) and subsequently gradually decreased to the initial level, the recovery proving prolonged in obese patients. Postoperative elevation in elastance peaked later (day 2, evening: 83+/-14%), lasted longer, and was affected by both cardiopulmonary bypass (p<0.05) and obesity (p<0.005). CONCLUSIONS These findings demonstrate the need for particular attention in the postoperative management of patients after cardiac surgery in order to reduce the immediate airway symptoms, and to take steps to maintain the lungs open during the critical postoperative days 2 and 3, especially in obese patients and (or) if the surgery involves the use of cardiopulmonary bypass.
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Affiliation(s)
- Gergely Albu
- Department of Medical Informatics and Engineering, University of Szeged, Szeged, Hungary
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