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Sipmann FS, Giralt JAS, Tusman G. Monitoring CO2 kinetics as a marker of cardiopulmonary efficiency. Curr Opin Crit Care 2024; 30:251-259. [PMID: 38690954 DOI: 10.1097/mcc.0000000000001156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024]
Abstract
PURPOSE OF REVIEW To describe current and near future developments and applications of CO2 kinetics in clinical respiratory and cardiovascular monitoring. RECENT FINDINGS In the last years, we have witnessed a renewed interest in CO2 kinetics in relation with a better understanding of volumetric capnography and its derived parameters. This together with technological advances and improved measurement systems have expanded the monitoring potential of CO2 kinetics including breath by breath continuous end-expiratory lung volume and continuous noninvasive cardiac output. Dead space has slowly been gaining relevance in clinical monitoring and prognostic evaluation. Easy to measure dead space surrogates such as the ventilatory ratio have demonstrated a strong prognostic value in patients with acute respiratory failure. SUMMARY The kinetics of carbon dioxide describe many relevant physiological processes. The clinical introduction of new ways of assessing respiratory and circulatory efficiency based on advanced analysis of CO2 kinetics are paving the road to a long-desired goal in clinical monitoring of critically ill patients: the integration of respiratory and circulatory monitoring during mechanical ventilation.
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Affiliation(s)
- Fernando Suarez Sipmann
- Department of Intensive Care Medicine, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid
- Ciber de enfermedades respiratorias, Instituto Carlos III, Madrid, Spain
| | - Juan Antonio Sanchez Giralt
- Department of Intensive Care Medicine, Hospital Universitario de La Princesa, Universidad Autónoma de Madrid
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
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Sanchez Giralt JA, Tusman G, Wallin M, Hallback M, Perez Lucendo A, Sanchez Galindo M, Abad Santamaria B, Paz Calzada E, Garcia Garcia P, Rodriguez Huerta D, Canabal Berlanga A, Suarez-Sipmann F. Clinical validation of a capnodynamic method for measuring end-expiratory lung volume in critically ill patients. Crit Care 2024; 28:142. [PMID: 38689313 PMCID: PMC11059761 DOI: 10.1186/s13054-024-04928-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/21/2024] [Indexed: 05/02/2024] Open
Abstract
RATIONALE End-expiratory lung volume (EELV) is reduced in mechanically ventilated patients, especially in pathologic conditions. The resulting heterogeneous distribution of ventilation increases the risk for ventilation induced lung injury. Clinical measurement of EELV however, remains difficult. OBJECTIVE Validation of a novel continuous capnodynamic method based on expired carbon dioxide (CO2) kinetics for measuring EELV in mechanically ventilated critically-ill patients. METHODS Prospective study of mechanically ventilated patients scheduled for a diagnostic computed tomography exploration. Comparisons were made between absolute and corrected EELVCO2 values, the latter accounting for the amount of CO2 dissolved in lung tissue, with the reference EELV measured by computed tomography (EELVCT). Uncorrected and corrected EELVCO2 was compared with total CT volume (density compartments between - 1000 and 0 Hounsfield units (HU) and functional CT volume, including density compartments of - 1000 to - 200HU eliminating regions of increased shunt. We used comparative statistics including correlations and measurement of accuracy and precision by the Bland Altman method. MEASUREMENTS AND MAIN RESULTS Of the 46 patients included in the final analysis, 25 had a diagnosis of ARDS (24 of which COVID-19). Both EELVCT and EELVCO2 were significantly reduced (39 and 40% respectively) when compared with theoretical values of functional residual capacity (p < 0.0001). Uncorrected EELVCO2 tended to overestimate EELVCT with a correlation r2 0.58; Bias - 285 and limits of agreement (LoA) (+ 513 to - 1083; 95% CI) ml. Agreement improved for the corrected EELVCO2 to a Bias of - 23 and LoA of (+ 763 to - 716; 95% CI) ml. The best agreement of the method was obtained by comparison of corrected EELVCO2 with functional EELVCT with a r2 of 0.59; Bias - 2.75 (+ 755 to - 761; 95% CI) ml. We did not observe major differences in the performance of the method between ARDS (most of them COVID related) and non-ARDS patients. CONCLUSION In this first validation in critically ill patients, the capnodynamic method provided good estimates of both total and functional EELV. Bias improved after correcting EELVCO2 for extra-alveolar CO2 content when compared with CT estimated volume. If confirmed in further validations EELVCO2 may become an attractive monitoring option for continuously monitor EELV in critically ill mechanically ventilated patients. TRIAL REGISTRATION clinicaltrials.gov (NCT04045262).
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Affiliation(s)
- J A Sanchez Giralt
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain
| | - G Tusman
- Department of Anesthesia, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - M Wallin
- Department of Physiology and Pharmacology (FYFA), C3, Eriksson Lars Group, Karolinska Institute, Stockholm, Sweden
| | | | - A Perez Lucendo
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain
| | - M Sanchez Galindo
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain
| | - B Abad Santamaria
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain
| | - E Paz Calzada
- Deparment of Radiology, Hospital Universitario de la Princesa, Madrid, España
| | - P Garcia Garcia
- Deparment of Radiology, Hospital Universitario de la Princesa, Madrid, España
| | - D Rodriguez Huerta
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain
| | - A Canabal Berlanga
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain
| | - Fernando Suarez-Sipmann
- Department of Intensive Care, Hospital Universitario de La Princesa, Diego de León 62, 28006, Madrid, Spain.
- CIBER Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.
- Hedenstierna Laboratory, Uppsala University, Uppsala, Sweden.
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Lundquist J, Shams N, Wallin M, Hallbäck M, Lönnqvist PA, Karlsson J. Capnodynamic end-expiratory lung volume assessment in anesthetized healthy children. Paediatr Anaesth 2024; 34:251-258. [PMID: 38055609 DOI: 10.1111/pan.14804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 10/18/2023] [Accepted: 11/21/2023] [Indexed: 12/08/2023]
Abstract
BACKGROUND Capnodynamic lung function monitoring generates variables that may be useful for pediatric perioperative ventilation. AIMS Establish normal values for end-expiratory lung volume CO2 in healthy children undergoing anesthesia and to compare these values to previously published values obtained with alternative end-expiratory lung volume methods. The secondary aim was to investigate the ability of end-expiratory lung volume CO2 to react to positive end-expiratory pressure-induced changes in end-expiratory lung volume. In addition, normal values for associated volumetric capnography lung function variables were examined. METHODS Fifteen pediatric patients with healthy lungs (median age 8 months, range 1-36 months) undergoing general anesthesia were examined before start of surgery. Tested variables were recorded at baseline positive end-expiratory pressure 3 cmH2 O, 1 and 3 min after positive end-expiratory pressure 10 cmH2 O and 3 min after returning to baseline positive end-expiratory pressure 3 cmH2 O. RESULTS Baseline end-expiratory lung volume CO2 was 32 mL kg-1 (95% CI 29-34 mL kg-1 ) which increased to 39 mL kg-1 (95% CI 35-43 mL kg-1 , p < .0001) and 37 mL kg-1 (95% CI 34-41 mL kg-1 , p = .0003) 1 and 3 min after positive end-expiratory pressure 10 cmH2 O, respectively. End-expiratory lung volume CO2 returned to baseline, 33 mL kg-1 (95% CI 29-37 mL kg-1 , p = .72) 3 min after re-establishing positive end-expiratory pressure 3 cmH2 O. Airway dead space increased from 1.1 mL kg-1 (95% CI 0.9-1.4 mL kg-1 ) to 1.4 (95% CI 1.1-1.8 mL kg-1 , p = .003) and 1.5 (95% CI 1.1-1.8 mL kg-1 , p < .0001) 1 and 3 min after positive end-expiratory pressure 10 cmH2 O, respectively, and 1.2 mL kg-1 (95% CI 0.9-1.4 mL kg-1 , p = .08) after 3 min of positive end-expiratory pressure 3 cmH2 O. Additional volumetric capnography and lung function variables showed no major changes in response to positive end-expiratory pressure variations. CONCLUSIONS Capnodynamic noninvasive and continuous end-expiratory lung volume CO2 values assessed during anesthesia in children were in close agreement with previously reported end-expiratory lung volume values generated by alternative methods. Furthermore, positive end-expiratory pressure changes resulted in physiologically expected end-expiratory lung volume CO2 responses in a timely manner, suggesting that it can be used to trend end-expiratory lung volume changes during anesthesia.
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Affiliation(s)
- Johanna Lundquist
- Pediatric perioperative medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
| | - Niki Shams
- Pediatric perioperative medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
| | - Mats Wallin
- Department of Physiology and Pharmacology (FYFA), C3, Eriksson I Lars, PA Lönnqvist group, Section of Anesthesiology and Intensive Care, Anestesi- och Intensivvårdsavdelningen, Karolinska Institute, Stockholm, Sweden
| | | | - Per-Arne Lönnqvist
- Pediatric perioperative medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
- Department of Physiology and Pharmacology (FYFA), C3, Eriksson I Lars, PA Lönnqvist group, Section of Anesthesiology and Intensive Care, Anestesi- och Intensivvårdsavdelningen, Karolinska Institute, Stockholm, Sweden
| | - Jacob Karlsson
- Pediatric perioperative medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
- Department of Physiology and Pharmacology (FYFA), C3, Eriksson I Lars, PA Lönnqvist group, Section of Anesthesiology and Intensive Care, Anestesi- och Intensivvårdsavdelningen, Karolinska Institute, Stockholm, Sweden
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4
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Acosta CM, Poliotto S, Abrego D, Bradley D, de Esteban S, Mir F, Ricci L, Natal M, Wallin M, Hallbäck M, Sipmann FS, Tusman G. Effect of an Individualized Lung Protective Ventilation on Lung Strain and Stress in Children Undergoing Laparoscopy: An Observational Cohort Study. Anesthesiology 2024; 140:430-441. [PMID: 38064715 DOI: 10.1097/aln.0000000000004856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
BACKGROUND Exaggerated lung strain and stress could damage lungs in anesthetized children. The authors hypothesized that the association of capnoperitoneum and lung collapse in anesthetized children increases lung strain-stress. Their primary aim was to describe the impact of capnoperitoneum on lung strain-stress and the effects of an individualized protective ventilation during laparoscopic surgery in children. METHODS The authors performed an observational cohort study in healthy children aged 3 to 7 yr scheduled for laparoscopic surgery in a community hospital. All received standard protective ventilation with 5 cm H2O of positive end-expiratory pressure (PEEP). Children were evaluated before capnoperitoneum, during capnoperitoneum before and after lung recruitment and optimized PEEP (PEEP adjusted to get end-expiratory transpulmonary pressure of 0), and after capnoperitoneum with optimized PEEP. The presence of lung collapse was evaluated by lung ultrasound, positive Air-Test (oxygen saturation measured by pulse oximetry 96% or less breathing 21% O2 for 5 min), and negative end-expiratory transpulmonary pressure. Lung strain was calculated as tidal volume/end-expiratory lung volume measured by capnodynamics, and lung stress as the end-inspiratory transpulmonary pressure. RESULTS The authors studied 20 children. Before capnoperitoneum, mean lung strain was 0.20 ± 0.07 (95% CI, 0.17 to 0.23), and stress was 5.68 ± 2.83 (95% CI, 4.44 to 6.92) cm H2O. During capnoperitoneum, 18 patients presented lung collapse and strain (0.29 ± 0.13; 95% CI, 0.23 to 0.35; P < 0.001) and stress (5.92 ± 3.18; 95% CI, 4.53 to 7.31 cm H2O; P = 0.374) increased compared to before capnoperitoneum. During capnoperitoneum and optimized PEEP, children presenting lung collapse were recruited and optimized PEEP was 8.3 ± 2.2 (95% CI, 7.3 to 9.3) cm H2O. Strain returned to values before capnoperitoneum (0.20 ± 0.07; 95% CI, 0.17 to 0.22; P = 0.318), but lung stress increased (7.29 ± 2.67; 95% CI, 6.12 to 8.46 cm H2O; P = 0.020). After capnoperitoneum, strain decreased (0.18 ± 0.04; 95% CI, 0.16 to 0.20; P = 0.090), but stress remained higher (7.25 ± 3.01; 95% CI, 5.92 to 8.57 cm H2O; P = 0.024) compared to before capnoperitoneum. CONCLUSIONS Capnoperitoneum increased lung strain in healthy children undergoing laparoscopy. Lung recruitment and optimized PEEP during capnoperitoneum decreased lung strain but slightly increased lung stress. This little rise in pulmonary stress was maintained within safe, lung-protective, and clinically acceptable limits. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Cecilia M Acosta
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - Sergio Poliotto
- Department of Pediatric Surgery, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - Diego Abrego
- Department of Pediatric Surgery, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - Dolores Bradley
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - Santiago de Esteban
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - Francisco Mir
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
| | - Lila Ricci
- Department of Mathematics, Facultad de Ciencias Exactas, Universidad Nacional de Mar del Plata, Argentina
| | - Marcela Natal
- Department of Mathematics, Facultad de Ciencias Exactas, Universidad Nacional de Mar del Plata, Argentina
| | - Mats Wallin
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden; Getinge Critical Care AB, Solna, Sweden
| | | | - Fernando Suarez Sipmann
- Hedenstierna Laboratory, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden; CIBERES (Network Biomedical Research Center), Madrid, Spain; Department of Critical Care, Hospital Universitario de La Princesa, Universidad Autonoma de Madrid, Madrid, Spain
| | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
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Keleher E, Iftikhar H, Schulz LF, McCanny P, Austin D, Stewart A, O'Regan W, Hallbäck M, Wallin M, Aneman A. Capnodynamic monitoring of lung volume and pulmonary blood flow during alveolar recruitment: a prospective observational study in postoperative cardiac patients. J Clin Monit Comput 2023; 37:1463-1472. [PMID: 37243954 DOI: 10.1007/s10877-023-01033-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/08/2023] [Indexed: 05/29/2023]
Abstract
Alveolar recruitment manoeuvres may mitigate ventilation and perfusion mismatch after cardiac surgery. Monitoring the efficacy of recruitment manoeuvres should provide concurrent information on pulmonary and cardiac changes. This study in postoperative cardiac patients applied capnodynamic monitoring of changes in end-expiratory lung volume and effective pulmonary blood flow. Alveolar recruitment was performed by incremental increases in positive end-expiratory pressure (PEEP) to a maximum of 15 cmH2O from a baseline of 5 cmH2O over 30 min. The change in systemic oxygen delivery index after the recruitment manoeuvre was used to identify responders (> 10% increase) with all other changes (≤ 10%) denoting non-responders. Mixed factor ANOVA using Bonferroni correction for multiple comparisons was used to denote significant changes (p < 0.05) reported as mean differences and 95% CI. Changes in end-expiratory lung volume and effective pulmonary blood flow were correlated using Pearson's regression. Twenty-seven (42%) of 64 patients were responders increasing oxygen delivery index by 172 (95% CI 61-2984) mL min-1 m-2 (p < 0.001). End-expiratory lung volume increased by 549 (95% CI 220-1116) mL (p = 0.042) in responders associated with an increase in effective pulmonary blood flow of 1140 (95% CI 435-2146) mL min-1 (p = 0.012) compared to non-responders. A positive correlation (r = 0.79, 95% CI 0.5-0.90, p < 0.001) between increased end-expiratory lung volume and effective pulmonary blood flow was only observed in responders. Changes in oxygen delivery index after lung recruitment were correlated to changes in end-expiratory lung volume (r = 0.39, 95% CI 0.16-0.59, p = 0.002) and effective pulmonary blood flow (r = 0.60, 95% CI 0.41-0.74, p < 0.001). Capnodynamic monitoring of end-expiratory lung volume and effective pulmonary blood flow early in postoperative cardiac patients identified a characteristic parallel increase in both lung volume and perfusion after the recruitment manoeuvre in patients with a significant increase in oxygen delivery.Trial registration This study was registered on ClinicalTrials.gov (NCT05082168, 18th of October 2021).
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Affiliation(s)
- E Keleher
- Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - H Iftikhar
- Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - L F Schulz
- Intensive Care Unit, Liverpool Hospital, South Western Sydney Local Health District, Sydney, NSW, Australia
| | - P McCanny
- Intensive Care Unit, Liverpool Hospital, South Western Sydney Local Health District, Sydney, NSW, Australia
| | - D Austin
- Intensive Care Unit, Liverpool Hospital, South Western Sydney Local Health District, Sydney, NSW, Australia
| | - A Stewart
- Intensive Care Unit, Liverpool Hospital, South Western Sydney Local Health District, Sydney, NSW, Australia
| | - W O'Regan
- Intensive Care Unit, Liverpool Hospital, South Western Sydney Local Health District, Sydney, NSW, Australia
| | | | - M Wallin
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - A Aneman
- Intensive Care Unit, Liverpool Hospital, South Western Sydney Local Health District, Sydney, NSW, Australia.
- Southwestern Clinical School, University of New South Wales, Sydney, NSW, Australia.
- Ingham Institute for Applied Medical Research, Sydney, NSW, Australia.
- Intensive Care Unit, Liverpool Hospital, Locked Bag 7103, Liverpool BC, NSW, 1871, Australia.
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Campos MD, Palazzi LH, Böhm SH, Tusman G. Effects of apparatus dead space on volumetric capnograms in neonates with healthy lungs: a simulation study. Paediatr Anaesth 2023; 33:973-982. [PMID: 37403466 DOI: 10.1111/pan.14724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 06/19/2023] [Accepted: 06/22/2023] [Indexed: 07/06/2023]
Abstract
BACKGROUND Volumetric capnography in healthy ventilated neonates showed deformed waveforms, which are supposedly due to technological limitations of flow and carbon dioxide sensors. AIMS This bench study analyzed the role of apparatus dead space on the shape of capnograms in simulated neonates with healthy lungs. METHODS We simulated mechanical breaths in neonates of 2, 2.5, and 3 kg of body weight using a neonatal volumetric capnography simulator. The simulator was fed by a fixed amount of carbon dioxide of 6 mL/kg/min. Such simulator was ventilated in a volume control mode using fixed ventilatory settings with a tidal volume of 8 mL/kg and respiratory rates of 40, 35, and 30 breaths per minute for the 2, 2.5 and 3 kg neonates, respectively. We tested the above baseline ventilation with and without an additional apparatus dead space of 4 mL. RESULTS Simulations showed that adding the apparatus dead space to baseline ventilation increased the amount of re-inhaled carbon dioxide in all neonates: 0.16 ± 0.01 to 0.32 ± 0.03 mL (2 kg), 0.14 ± 0.02 to 0.39 ± 0.05 mL (2.5 kg), and 0.13 ± 0.01 to 0.36 ± 0.05 mL (3 kg); (p < .001). Apparatus dead space was computed as part of the airway dead space, and therefore, the ratio of airway dead space to tidal volume increased from 0.51 ± 0.04 to 0.68 ± 0.06, from 0.43 ± 0.04 to 0.62 ± 0.01 and from 0.38 ± 0.01 to 0.60 ± 0.02 in the 2, 2.5 and 3 kg simulated neonates, respectively (p < .001). Compared to baseline ventilation, adding apparatus dead space decreased the ratio of the volume of phase III to VT size from 31% to 11% (2 kg), from 40% to 16% (2.5 kg) and from 50% to 18% (3 kg); (p < .001). CONCLUSIONS The addition of a small apparatus dead space artificially deformed the volumetric capnograms in simulated neonates with healthy lungs.
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Affiliation(s)
- Marcelo D Campos
- Department of Anesthesiology, Sanatorio Finochietto, Buenos Aires, Argentina
| | - Lucio H Palazzi
- Department of Anesthesiology, Children Hospital Dr. Orlando Alassia, Santa Fe, Argentina
| | - Stephan H Böhm
- Clinic of Anesthesiology, Intensive Care Medicine and Pain Therapy, Rostock University Medical Center, Rostock, Germany
| | - Gerardo Tusman
- Department of Anesthesia, Hospital Privado de Comunidad, Mar del Plata, Argentina
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Öhman T, Jalde FC, Fredby M, Björne H, Karlsson J. Effect of external dead space removal on CO 2 homeostasis in mechanically ventilated adult Covid-19 patients. Acta Anaesthesiol Scand 2023. [PMID: 37354078 DOI: 10.1111/aas.14252] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 12/29/2022] [Accepted: 03/29/2023] [Indexed: 06/26/2023]
Abstract
BACKGROUND Patients with Covid-19 respiratory failure present with hypoxemia, often in combination with hypercapnia. In this prospective, observational study we examined the effect of removing external dead space (DS) on CO2 -homeostasis in mechanically ventilated Covid-19 patients. In addition, volumetric capnography was validated for its ability to estimate external DS volume using in vitro measured DS volumes as reference. METHODS In total, 10 patients with acute respiratory distress syndrome from Covid-19 were included. Volumetric capnography, mechanical ventilation, and arterial blood gas data were analyzed before and after removal of external DS and analyzed for potentially significant changes in response to DS removal. Measurements of external DS were obtained in circuit using volumetric capnography and compared to actual measured DS volumes off the circuit. RESULTS After the removal of external DS, the alveolar minute ventilation and CO2 elimination improved, notwithstanding unchanged respiratory rate and tidal volumes. The increase in CO2 elimination was associated with a decrease in arterial CO2 partial pressure (PaCO2 ). The volumetric capnography method for assessment of external DS showed a low bias of -9 mL (lower limit of agreement -40, 95% CI -60 to -20 mL, upper limit of agreement 21 mL, 95% CI: 1-40 mL) and a percentage error of 48% compared to absolute values measured in vitro. CONCLUSION Removal of external DS increased alveolar minute ventilation and CO2 elimination in Covid-19 patients with respiratory failure in the current study. This was associated with a decrease in PaCO2 . This may indicate a decreased CO2 production due to decreased work of breathing and more effective gas-exchange in response to DS removal. In addition, volumetric capnography appears to be a clinically feasible method for continuous measurement of external DS in the current study and may be of value in optimizing ventilator treatment.
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Affiliation(s)
- Tomas Öhman
- Department of Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Francesca Campoccia Jalde
- Department of Thoracic Anesthesiology, Surgical Services and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
- Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Magnus Fredby
- Department of Thoracic Anesthesiology, Surgical Services and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
| | - Håkan Björne
- Department of Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jacob Karlsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department of Pediatric Perioperative Medicine and Intensive Care, Karolinska University Hospital, Stockholm, Sweden
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Karlsson J, Lönnqvist PA. Capnodynamics - noninvasive cardiac output and mixed venous oxygen saturation monitoring in children. Front Pediatr 2023; 11:1111270. [PMID: 36816378 PMCID: PMC9936087 DOI: 10.3389/fped.2023.1111270] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023] Open
Abstract
Hemodynamic monitoring in children is challenging for many reasons. Technical limitations in combination with insufficient validation against reference methods, makes reliable monitoring systems difficult to establish. Since recent studies have highlighted perioperative cardiovascular stability as an important factor for patient outcome in pediatrics, the need for accurate hemodynamic monitoring methods in children is obvious. The development of mathematical processing of fast response mainstream capnography signals, has allowed for the development of capnodynamic hemodynamic monitoring. By inducing small changes in ventilation in intubated and mechanically ventilated patients, fluctuations in alveolar carbon dioxide are created. The subsequent changes in carbon dioxide elimination can be used to calculate the blood flow participating in gas exchange, i.e., effective pulmonary blood flow which equals the non-shunted pulmonary blood flow. Cardiac output can then be estimated and continuously monitored in a breath-by-breath fashion without the need for additional equipment, training, or calibration. In addition, the method allows for mixed venous oxygen saturation (SvO2) monitoring, without pulmonary artery catheterization. The current review will discuss the capnodyamic method and its application and limitation as well as future potential development and functions in pediatric patients.
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Affiliation(s)
- Jacob Karlsson
- Dept of Physiology & Pharmacology, Section of Anaesthesiology and Intensive Care, Karolinska University Hospital, Stockholm, Sweden.,Paediatric Perioperative Medicine & Intensive Care, Karolinska University Hospital, Stockholm, Sweden
| | - Per-Arne Lönnqvist
- Dept of Physiology & Pharmacology, Section of Anaesthesiology and Intensive Care, Karolinska University Hospital, Stockholm, Sweden.,Paediatric Perioperative Medicine & Intensive Care, Karolinska University Hospital, Stockholm, Sweden
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Schulz L, Stewart A, O’Regan W, McCanny P, Austin D, Hallback M, Wallin M, Aneman A. Capnodynamic monitoring of lung volume and blood flow in response to increased positive end-expiratory pressure in moderate to severe COVID-19 pneumonia: an observational study. Crit Care 2022; 26:232. [PMID: 35909174 PMCID: PMC9340710 DOI: 10.1186/s13054-022-04110-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/20/2022] [Indexed: 11/18/2022] Open
Abstract
Background The optimal level of positive end-expiratory pressure (PEEP) during mechanical ventilation for COVID-19 pneumonia remains debated and should ideally be guided by responses in both lung volume and perfusion. Capnodynamic monitoring allows both end-expiratory lung volume (\documentclass[12pt]{minimal}
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\begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 and EPBF during a step increase in PEEP by 50% above the baseline (PEEPlow to PEEPhigh). The primary outcome was a > 20 mm Hg increase in arterial oxygen tension to inspired fraction of oxygen (P/F) ratio to define responders versus non-responders. Secondary outcomes included changes in physiological dead space and correlations with independently determined recruited lung volume and the recruitment-to-inflation ratio at an instantaneous, single breath decrease in PEEP. Mixed factor ANOVA for group mean differences and correlations by Pearson’s correlation coefficient are reported including their 95% confidence intervals. Results Of 27 patients studied, 15 responders increased the P/F ratio by 55 [24–86] mm Hg compared to 12 non-responders (p < 0.01) as PEEPlow (11 ± 2.7 cm H2O) was increased to PEEPhigh (18 ± 3.0 cm H2O). The \documentclass[12pt]{minimal}
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\begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 was 461 [82–839] ml less in responders at PEEPlow (p = 0.02) but not statistically different between groups at PEEPhigh. Responders increased both \documentclass[12pt]{minimal}
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\begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 and EPBF at PEEPhigh (r = 0.56 [0.18–0.83], p = 0.03). In contrast, non-responders demonstrated a negative correlation (r = − 0.65 [− 0.12 to − 0.89], p = 0.02) with increased lung volume associated with decreased pulmonary perfusion. Decreased (− 0.06 [− 0.02 to − 0.09] %, p < 0.01) dead space was observed in responders. The change in \documentclass[12pt]{minimal}
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\begin{document}$${\text{EELV}}_{{{\text{CO}}_{2} }}$$\end{document}EELVCO2 correlated with both the recruited lung volume (r = 0.85 [0.69–0.93], p < 0.01) and the recruitment-to-inflation ratio (r = 0.87 [0.74–0.94], p < 0.01). Conclusions In mechanically ventilated patients with moderate to severe COVID-19 respiratory failure, improved oxygenation in response to increased PEEP was associated with increased end-expiratory lung volume and pulmonary perfusion. The change in end-expiratory lung volume was positively correlated with the lung volume recruited and the recruitment-to-inflation ratio. This study demonstrates the feasibility of capnodynamic monitoring to assess physiological responses to PEEP at the bedside to facilitate an individualised setting of PEEP. Trial registration: NCT05082168 (18th October 2021). Supplementary Information The online version contains supplementary material available at 10.1186/s13054-022-04110-0.
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Suárez-Sipmann F, Villar J, Ferrando C, Sánchez-Giralt JA, Tusman G. Monitoring Expired CO 2 Kinetics to Individualize Lung-Protective Ventilation in Patients With the Acute Respiratory Distress Syndrome. Front Physiol 2022; 12:785014. [PMID: 34992549 PMCID: PMC8724128 DOI: 10.3389/fphys.2021.785014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Mechanical ventilation (MV) is a lifesaving supportive intervention in the management of acute respiratory distress syndrome (ARDS), buying time while the primary precipitating cause is being corrected. However, MV can contribute to a worsening of the primary lung injury, known as ventilation-induced lung injury (VILI), which could have an important impact on outcome. The ARDS lung is characterized by diffuse and heterogeneous lung damage and is particularly prone to suffer the consequences of an excessive mechanical stress imposed by higher airway pressures and volumes during MV. Of major concern is cyclic overdistension, affecting those lung segments receiving a proportionally higher tidal volume in an overall reduced lung volume. Theoretically, healthier lung regions are submitted to a larger stress and cyclic deformation and thus at high risk for developing VILI. Clinicians have difficulties in detecting VILI, particularly cyclic overdistension at the bedside, since routine monitoring of gas exchange and lung mechanics are relatively insensitive to this mechanism of VILI. Expired CO2 kinetics integrates relevant pathophysiological information of high interest for monitoring. CO2 is produced by cell metabolism in large daily quantities. After diffusing to tissue capillaries, CO2 is transported first by the venous and then by pulmonary circulation to the lung. Thereafter diffusing from capillaries to lung alveoli, it is finally convectively transported by lung ventilation for its elimination to the atmosphere. Modern readily clinically available sensor technology integrates information related to pulmonary ventilation, perfusion, and gas exchange from the single analysis of expired CO2 kinetics measured at the airway opening. Current volumetric capnography (VCap), the representation of the volume of expired CO2 in one single breath, informs about pulmonary perfusion, end-expiratory lung volume, dead space, and pulmonary ventilation inhomogeneities, all intimately related to cyclic overdistension during MV. Additionally, the recently described capnodynamic method provides the possibility to continuously measure the end-expiratory lung volume and effective pulmonary blood flow. All this information is accessed non-invasively and breath-by-breath helping clinicians to personalize ventilatory settings at the bedside and minimize overdistension and cyclic deformation of lung tissue.
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Affiliation(s)
- Fernando Suárez-Sipmann
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Intensive Care Unit, Hospital Universitario La Princesa, Madrid, Spain.,Department of Surgical Sciences, Anesthesiology & Critical Care, Hedenstierna Laboratory, Uppsala University Hospital, Uppsala, Sweden
| | - Jesús Villar
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Multidisciplinary Organ Dysfunction Evaluation Research Network (MODERN), Research Unit, Hospital Universitario Dr. Negrín, Las Palmas de Gran Canaria, Spain.,Keenan Research Center at the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - Carlos Ferrando
- CIBER de Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain.,Department of Anesthesiology and Critical Care, Hospital Clinic, Barcelona, Spain.,Hospital Clinic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Gerardo Tusman
- Department of Anesthesiology, Hospital Privado de Comunidad, Mar del Plata, Argentina
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Positive end-expiratory pressure individualization guided by continuous end-expiratory lung volume monitoring during laparoscopic surgery. J Clin Monit Comput 2021; 36:1557-1567. [PMID: 34966951 DOI: 10.1007/s10877-021-00800-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/24/2021] [Indexed: 10/19/2022]
Abstract
To determine whether end-expiratory lung volume measured with volumetric capnography (EELVCO2) can individualize positive end-expiratory pressure (PEEP) setting during laparoscopic surgery. We studied patients undergoing laparoscopic surgery subjected to Fowler (F-group; n = 20) or Trendelenburg (T-group; n = 20) positions. EELVCO2 was measured at 0° supine (baseline), during capnoperitoneum (CP) at 0° supine, during CP with Fowler (head up + 20°) or Trendelenburg (head down - 30°) positions and after CP back to 0° supine. PEEP was adjusted to preserve baseline EELVCO2 during and after CP. Baseline EELVCO2 was statistically similar to predicted FRC in both groups. At supine and CP, EELVCO2 decreased from baseline values in F-group [median and IQR 2079 (768) to 1545 (725) mL; p = 0.0001] and in T-group [2164 (789) to 1870 (940) mL; p = 0.0001]. Change in body position maintained EELVCO2 unchanged in both groups. PEEP adjustments from 5.6 (1.1) to 10.0 (2.5) cmH2O in the F-group (p = 0.0001) and from 5.6 (0.9) to 10.0 (2.6) cmH2O in T-group (p = 0.0001) were necessary to reach baseline EELVCO2 values. EELVCO2 increased close to baseline with PEEP in the F-group [1984 (600) mL; p = 0.073] and in the T-group [2175 (703) mL; p = 0.167]. After capnoperitoneum and back to 0° supine, PEEP needed to maintain EELVCO2 was similar to baseline PEEP in F-group [5.9 (1.8) cmH2O; p = 0.179] but slightly higher in the T-group [6.5 (2.2) cmH2O; p = 0.006]. Those new PEEP values gave EELVCO2 similar to baseline in the F-group [2039 (980) mL; p = 0.370] and in the T-group [2150 (715) mL; p = 0.881]. Breath-by-breath noninvasive EELVCO2 detected changes in lung volume induced by capnoperitoneum and body position and was useful to individualize the level of PEEP during laparoscopy.Trial registry: Clinicaltrials.gov NCT03693352. Protocol started 1st October 2018.
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