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Melberg MB, Flaa A, Andersen GØ, Sunde K, Bellomo R, Eastwood G, Olasveengen TM, Qvigstad E. Effects of mild hypercapnia on myocardial injury after out-of-hospital cardiac arrest. A sub-study of the TAME trial. Resuscitation 2024; 201:110295. [PMID: 38936652 DOI: 10.1016/j.resuscitation.2024.110295] [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: 05/06/2024] [Revised: 06/21/2024] [Accepted: 06/21/2024] [Indexed: 06/29/2024]
Abstract
PURPOSE Mild hypercapnia did not improve neurological outcomes for resuscitated out-of-hospital cardiac arrest (OHCA) patients in the Targeted Therapeutic Mild Hypercapnia After Resuscitated Cardiac Arrest (TAME) trial. However, the effects of hypercapnic acidosis on myocardial injury in patients with cardiac arrest is unexplored. We investigated whether mild hypercapnia compared to normocapnia, following emergency coronary intervention, increased myocardial injury in comatose OHCA-patients with AMI. METHODS Single-centre, prospective, pre-planned sub-study of the TAME trial. Patients were randomised to targeted mild hypercapnia (PaCO2 = 6.7-7.3 kPa) or normocapnia (PaCO2 = 4.7-6.0 kPa) for 24 h. Myocardial injury was assessed with high-sensitive cardiac troponin T (hs-cTnT) measured at baseline, 24, 48 and 72 h. Haemodynamics were assessed with right heart catheterisation and blood-gas analyses every 4th hour for 48 h. RESULTS We included 125 OHCA-patients. 57 (46%) had an AMI, with 31 and 26 patients randomised to hypercapnia and normocapnia, respectively. Median peak hs-cTnT in AMI-patients was 58% lower in the hypercapnia-group: 2136 (IQR: 861-4462) versus 5165 ng/L (IQR: 2773-7519), p = 0.007. Lower average area under the hs-cTnT curve was observed in the hypercapnia-group: 2353 (95% CI 1388-3319) versus 4953 ng/L (95% CI 3566-6341), P-group = 0.002. Hypercapnia was associated with increased cardiac power output (CPO) and lower lactate levels in patients with AMI (P-group < 0.05). hs-cTnT, lactate and CPO were not significantly different between intervention groups in OHCA-patients without AMI (p > 0.05). CONCLUSIONS Mild hypercapnia was not associated with increased myocardial injury in resuscitated OHCA-patients. In AMI-patients, mild hypercapnia was associated with lower hs-cTnT and lactate, and improved cardiac performance. TRIAL REGISTRATION NUMBER NCT03114033.
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Affiliation(s)
- Mathias Baumann Melberg
- Department of Research and Development, Division of Emergencies and Critical Care, Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Norway.
| | - Arnljot Flaa
- Department of Research and Development, Division of Emergencies and Critical Care, Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway
| | - Geir Øystein Andersen
- Department of Research and Development, Division of Emergencies and Critical Care, Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway
| | - Kjetil Sunde
- Department of Anaesthesiology and Intensive Care, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway and Institute of Clinical Medicine, University of Oslo, Norway
| | - Rinaldo Bellomo
- Department of Intensive Care, Austin Hospital, Heidelberg, Victoria, Australia; Australian and New Zealand Intensive Care Research Centre, Monash University, Victoria, Melbourne, Australia; Department of Critical Care, Melbourne University, Melbourne, Australia; Department of Intensive Care, Royal Melbourne Hospital, Melbourne, Australia
| | - Glenn Eastwood
- Department of Intensive Care, Austin Hospital, Heidelberg, Victoria, Australia; Australian and New Zealand Intensive Care Research Centre, Monash University, Victoria, Melbourne, Australia
| | - Theresa Mariero Olasveengen
- Department of Anaesthesiology and Intensive Care, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway and Institute of Clinical Medicine, University of Oslo, Norway
| | - Eirik Qvigstad
- Department of Research and Development, Division of Emergencies and Critical Care, Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway
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Melberg MB, Flaa A, Andersen GØ, Sunde K, Bellomo R, Eastwood G, Olasveengen TM, Qvigstad E. Cardiovascular changes induced by targeted mild hypercapnia after out of hospital cardiac arrest. A sub-study of the TAME cardiac arrest trial. Resuscitation 2023; 193:109970. [PMID: 37716401 DOI: 10.1016/j.resuscitation.2023.109970] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/08/2023] [Accepted: 09/09/2023] [Indexed: 09/18/2023]
Abstract
AIM Hypercapnia may elicit detrimental haemodynamic effects in critically ill patients. We aimed to investigate the consequences of targeted mild hypercapnia versus targeted normocapnia on pulmonary vascular resistance and right ventricular function in patients resuscitated from out-of-hospital cardiac arrest (OHCA). METHODS Pre-planned, single-centre, prospective, sub-study of the Targeted Therapeutic Mild Hypercapnia After Resuscitated Cardiac Arrest (TAME) trial. Patients were randomised to mild hypercapnia (PaCO2 = 6.7-7.3 kPa) or normocapnia (PaCO2 = 4.7-6.0 kPa) for 24 hours. Haemodynamic assessment was performed with right heart catheterisation and serial blood-gas analyses every4th hour for 48 hours. RESULTS We studied 84 patients. Mean pH was 7.24 (95% CI 7.22-7.30) and 7.32 (95% CI 7.31-7.34) with hypercapnia and normocapnia, respectively (P-group < 0.001). Pulmonary vascular resistance index (PVRI), pulmonary artery pulsatility index, and right atrial pressure did not differ between groups (P-group > 0.05). Mean cardiac index was higher with mild hypercapnia (P-group < 0.001): 2.0 (95% CI 1.85-2.1) vs 1.6 (95% CI 1.52-1.76) L/min/m2. Systemic vascular resistance index was 2579 dyne-sec/cm-5/ m2 (95% CI 2356-2830) with hypercapnia, and 3249 dyne-sec/cm-5/ m2 (95% CI 2930-3368) with normocapnia (P-group < 0.001). Stroke volumes (P-group = 0.013) and mixed venous oxygen saturation (P-group < 0.001) were higher in the hypercapnic group. CONCLUSION In resuscitated OHCA patients, targeting mild hypercapnia did not increase PVRI or worsen right ventricular function compared to normocapnia. Mild hypercapnia comparatively improved cardiac performance and mixed venous oxygen saturation.
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Affiliation(s)
- Mathias Baumann Melberg
- Department of Research and Development, Division of Emergencies and Critical Care, Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Norway.
| | - Arnljot Flaa
- Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway
| | - Geir Øystein Andersen
- Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway
| | - Kjetil Sunde
- Department of Anaesthesiology and Intensive Care, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Norway
| | - Rinaldo Bellomo
- Department of Intensive Care, Austin Hospital, Heidelberg, Victoria, Australia; Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria, Australia; Department of Critical Care, Melbourne University, Melbourne, Australia; Department of Intensive Care, Royal Melbourne Hospital, Melbourne, Australia
| | - Glenn Eastwood
- Department of Intensive Care, Austin Hospital, Heidelberg, Victoria, Australia; Australian and New Zealand Intensive Care Research Centre, Monash University, Melbourne, Victoria, Australia
| | - Theresa Mariero Olasveengen
- Department of Anaesthesiology and Intensive Care, Division of Emergencies and Critical Care, Oslo University Hospital, Oslo, Norway; Institute of Clinical Medicine, University of Oslo, Norway
| | - Eirik Qvigstad
- Department of Cardiology, Division of Medicine, Oslo University Hospital, Oslo, Norway
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Agrawal V, Zhong XZ, Chen JJ. Generating dynamic carbon-dioxide traces from respiration-belt recordings: Feasibility using neural networks and application in functional magnetic resonance imaging. FRONTIERS IN NEUROIMAGING 2023; 2:1119539. [PMID: 37554640 PMCID: PMC10406216 DOI: 10.3389/fnimg.2023.1119539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 01/20/2023] [Indexed: 08/10/2023]
Abstract
INTRODUCTION In the context of functional magnetic resonance imaging (fMRI), carbon dioxide (CO2) is a well-known vasodilator that has been widely used to monitor and interrogate vascular physiology. Moreover, spontaneous fluctuations in end-tidal carbon dioxide (PETCO2) reflects changes in arterial CO2 and has been demonstrated as the largest physiological noise source for denoising the low-frequency range of the resting-state fMRI (rs-fMRI) signal. However, the majority of rs-fMRI studies do not involve CO2 recordings, and most often only heart rate and respiration are recorded. While the intrinsic link between these latter metrics and CO2 led to suggested possible analytical models, they have not been widely applied. METHODS In this proof-of-concept study, we propose a deep-learning (DL) approach to reconstruct CO2 and PETCO2 data from respiration waveforms in the resting state. RESULTS We demonstrate that the one-to-one mapping between respiration and CO2 recordings can be well predicted using fully convolutional networks (FCNs), achieving a Pearson correlation coefficient (r) of 0.946 ± 0.056 with the ground truth CO2. Moreover, dynamic PETCO2 can be successfully derived from the predicted CO2, achieving r of 0.512 ± 0.269 with the ground truth. Importantly, the FCN-based methods outperform previously proposed analytical methods. In addition, we provide guidelines for quality assurance of respiration recordings for the purposes of CO2 prediction. DISCUSSION Our results demonstrate that dynamic CO2 can be obtained from respiration-volume using neural networks, complementing the still few reports in DL of physiological fMRI signals, and paving the way for further research in DL based bio-signal processing.
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Affiliation(s)
- Vismay Agrawal
- Baycrest Centre for Geriatric Care, Rotman Research Institute, Toronto, ON, Canada
| | - Xiaole Z. Zhong
- Baycrest Centre for Geriatric Care, Rotman Research Institute, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - J. Jean Chen
- Baycrest Centre for Geriatric Care, Rotman Research Institute, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Department of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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Chalkias A, Xenos M. Relationship of Effective Circulating Volume with Sublingual Red Blood Cell Velocity and Microvessel Pressure Difference: A Clinical Investigation and Computational Fluid Dynamics Modeling. J Clin Med 2022; 11:jcm11164885. [PMID: 36013124 PMCID: PMC9410298 DOI: 10.3390/jcm11164885] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/12/2022] [Accepted: 08/18/2022] [Indexed: 11/18/2022] Open
Abstract
The characteristics of physiologic hemodynamic coherence are not well-investigated. We examined the physiological relationship between circulating blood volume, sublingual microcirculatory perfusion, and tissue oxygenation in anesthetized individuals with steady-state physiology. We assessed the correlation of mean circulatory filling pressure analogue (Pmca) with sublingual microcirculatory perfusion and red blood cell (RBC) velocity using SDF+ imaging and a modified optical flow-based algorithm. We also reconstructed the 2D microvessels and applied computational fluid dynamics (CFD) to evaluate the correlation of Pmca and RBC velocity with the obtained pressure and velocity fields in microvessels from CFD (pressure difference, (Δp)). Twenty adults with a median age of 39.5 years (IQR 35.5−44.5) were included in the study. Sublingual velocity distributions were similar and followed a log-normal distribution. A constant Pmca value of 14 mmHg was observed in all individuals with sublingual RBC velocity 6−24 μm s−1, while a Pmca < 14 mmHg was observed in those with RBC velocity > 24 μm s−1. When Pmca ranged between 11 mmHg and 15 mmHg, Δp fluctuated between 0.02 Pa and 0.1 Pa. In conclusion, the intact regulatory mechanisms maintain a physiological coupling between systemic hemodynamics, sublingual microcirculatory perfusion, and tissue oxygenation when Pmca is 14 mmHg.
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Affiliation(s)
- Athanasios Chalkias
- Department of Anesthesiology, Faculty of Medicine, University of Thessaly, 41500 Larisa, Greece
- Outcomes Research Consortium, Cleveland, OH 44195, USA
- Committee on Shock, Hellenic Society of Cardiopulmonary Resuscitation, 10434 Athens, Greece
- Correspondence:
| | - Michalis Xenos
- Section of Applied and Computational Mathematics, Department of Mathematics, University of Ioannina, 45110 Ioannina, Greece
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Jones H, Robson K. Hyperthermia in a Chow Chow under general anaesthesia for magnetic resonance imaging. VETERINARY RECORD CASE REPORTS 2022. [DOI: 10.1002/vrc2.423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Heather Jones
- Department of Small Animal Anaesthesia School of Veterinary Science University of Liverpool Wirral UK
| | - Katherine Robson
- Department of Small Animal Anaesthesia School of Veterinary Science University of Liverpool Wirral UK
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Zhou Y, He H, Cui N, Wang H, Zhou X, Long Y. Acute hyperventilation increases oxygen consumption and decreases peripheral tissue perfusion in critically ill patients. J Crit Care 2021; 66:148-153. [PMID: 34364716 DOI: 10.1016/j.jcrc.2021.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 05/07/2021] [Accepted: 05/15/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE This study aimed to evaluate the effects of acute hyperventilation on central venous-to-arterial carbon dioxide tension difference (Pv-aCO2), central venous oxygen saturation (ScvO2), central venous-to-arterial CO2 difference/arterial-central venous O2 difference ratio (CO2GAP-Ratio), and peripheral perfusion index (PI) in hemodynamically stable critically ill patients. METHODS Fifty-four mechanically ventilated patients were evaluated. The cardiac index, Pv-aCO2, ScvO2, CO2GAP-Ratio, PI, and arterial and venous blood gas parameters were measured in the first set of measurements. Then, alveolar ventilation was increased by raising the respiratory rate (10 breaths/min). After a 30 min hyperventilation period, the second set of measurements was recorded. RESULTS Acute hyperventilation induces an increase in Pv-aCO2 (from 3.87 ± 1.31 to 8.44 ± 1.81 mmHg, P < 0.001) and a decrease in ScvO2(from 71.78 ± 4.82 to 66.47 ± 5.74%, P < 0.001). The CO2GAP-Ratio was significantly increased(from 0.97 ± 0.40 to 1.74 ± 0.46, P < 0.001), and the PI showed a remarkable decrease caused by acute hyperventilation(from 1.82 ± 1.14 to 1.40 ± 0.99,P = 0.04). Hyperventilation-induced ∆_Pv-aCO2 was negatively correlated with ∆PaCO2(r = -0.572, P<0.001). The change in ∆_PaCO2 was correlated with ∆_ScvO2(r = 0.450, P<0.001). However, the left ventricular outflow tract velocity time integral (LVOT-VTI) remained unchanged during hyperventilation. CONCLUSIONS Acute hyperventilation induced an increase in oxygen consumption and decreased peripheral tissue perfusion in patients. For critical care patients, it is necessary to pay attention to the influence of hyperventilation on peripheral tissue perfusion indices and oxygen consumption indices.
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Affiliation(s)
- Yuankai Zhou
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Huaiwu He
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Na Cui
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Hao Wang
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Xiang Zhou
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China
| | - Yun Long
- Department of Critical Care Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing 100730, China.
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Masterson C, Horie S, McCarthy SD, Gonzalez H, Byrnes D, Brady J, Fandiño J, Laffey JG, O'Toole D. Hypercapnia in the critically ill: insights from the bench to the bedside. Interface Focus 2021; 11:20200032. [PMID: 33628425 PMCID: PMC7898152 DOI: 10.1098/rsfs.2020.0032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2020] [Indexed: 01/16/2023] Open
Abstract
Carbon dioxide (CO2) has long been considered, at best, a waste by-product of metabolism, and at worst, a toxic molecule with serious health consequences if physiological concentration is dysregulated. However, clinical observations have revealed that 'permissive' hypercapnia, the deliberate allowance of respiratory produced CO2 to remain in the patient, can have anti-inflammatory effects that may be beneficial in certain circumstances. In parallel, studies at the cell level have demonstrated the profound effect of CO2 on multiple diverse signalling pathways, be it the effect from CO2 itself specifically or from the associated acidosis it generates. At the whole organism level, it now appears likely that there are many biological sensing systems designed to respond to CO2 concentration and tailor respiratory and other responses to atmospheric or local levels. Animal models have been widely employed to study the changes in CO2 levels in various disease states and also to what extent permissive or even directly delivered CO2 can affect patient outcome. These findings have been advanced to the bedside at the same time that further clinical observations have been elucidated at the cell and animal level. Here we present a synopsis of the current understanding of how CO2 affects mammalian biological systems, with a particular emphasis on inflammatory pathways and diseases such as lung specific or systemic sepsis. We also explore some future directions and possibilities, such as direct control of blood CO2 levels, that could lead to improved clinical care in the future.
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Chen JJ, Gauthier CJ. The Role of Cerebrovascular-Reactivity Mapping in Functional MRI: Calibrated fMRI and Resting-State fMRI. Front Physiol 2021; 12:657362. [PMID: 33841190 PMCID: PMC8027080 DOI: 10.3389/fphys.2021.657362] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/02/2021] [Indexed: 12/14/2022] Open
Abstract
Task and resting-state functional MRI (fMRI) is primarily based on the same blood-oxygenation level-dependent (BOLD) phenomenon that MRI-based cerebrovascular reactivity (CVR) mapping has most commonly relied upon. This technique is finding an ever-increasing role in neuroscience and clinical research as well as treatment planning. The estimation of CVR has unique applications in and associations with fMRI. In particular, CVR estimation is part of a family of techniques called calibrated BOLD fMRI, the purpose of which is to allow the mapping of cerebral oxidative metabolism (CMRO2) using a combination of BOLD and cerebral-blood flow (CBF) measurements. Moreover, CVR has recently been shown to be a major source of vascular bias in computing resting-state functional connectivity, in much the same way that it is used to neutralize the vascular contribution in calibrated fMRI. Furthermore, due to the obvious challenges in estimating CVR using gas challenges, a rapidly growing field of study is the estimation of CVR without any form of challenge, including the use of resting-state fMRI for that purpose. This review addresses all of these aspects in which CVR interacts with fMRI and the role of CVR in calibrated fMRI, provides an overview of the physiological biases and assumptions underlying hypercapnia-based CVR and calibrated fMRI, and provides a view into the future of non-invasive CVR measurement.
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Affiliation(s)
- J Jean Chen
- Baycrest Centre for Geriatric Care, Rotman Research Institute, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Claudine J Gauthier
- Department of Physics, Concordia University, Montreal, QC, Canada.,Montreal Heart Institute, Montreal, QC, Canada
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Chand R, Swenson ER, Goldfarb DS. Sodium bicarbonate therapy for acute respiratory acidosis. Curr Opin Nephrol Hypertens 2021; 30:223-230. [PMID: 33395037 DOI: 10.1097/mnh.0000000000000687] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW Respiratory acidosis is commonly present in patients with respiratory failure. The usual treatment of hypercapnia is to increase ventilation. During the recent surge of COVID-19, respiratory acidosis unresponsive to increased mechanical ventilatory support was common. Increasing mechanical ventilation comes at the expense of barotrauma and hemodynamic compromise from increasing positive end-expiratory pressures or minute ventilation. Treating acute respiratory acidemia with sodium bicarbonate remains controversial. RECENT FINDINGS There are no randomized controlled trials of administration of sodium bicarbonate for respiratory acidemia. A recent review concluded that alkali therapy for mixed respiratory and metabolic acidosis might be useful but was based on the conflicting and not conclusive literature regarding metabolic acidosis. This strategy should not be extrapolated to treatment of respiratory acidemia. Low tidal volume ventilation in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) has beneficial effects associated with permissive hypercapnia. Whether the putative benefits will be negated by administration of alkali is not known. Hypercapnic acidosis is well tolerated, with few adverse effects as long as tissue perfusion and oxygenation are maintained. SUMMARY There is a lack of clinical evidence that administration of sodium bicarbonate for respiratory acidosis has a net benefit; in fact, there are potential risks associated with it.
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Affiliation(s)
- Ranjeeta Chand
- Nephrology Division, New York University Langone Health and Nephrology Section, NY Harbor VA Healthcare System
| | - Erik R Swenson
- Pulmonary, Critical Care and Sleep Medicine Division, University of Washington, and VA Puget Sound Healthcare System, Seattle, Washington, USA
| | - David S Goldfarb
- Nephrology Division, New York University Langone Health and Nephrology Section, NY Harbor VA Healthcare System
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Lung-Protective Mechanical Ventilation Strategies in Pediatric Acute Respiratory Distress Syndrome. Pediatr Crit Care Med 2020; 21:720-728. [PMID: 32205663 DOI: 10.1097/pcc.0000000000002324] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
OBJECTIVES Reduced morbidity and mortality associated with lung-protective mechanical ventilation is not proven in pediatric acute respiratory distress syndrome. This study aims to determine if a lung-protective mechanical ventilation protocol in pediatric acute respiratory distress syndrome is associated with improved clinical outcomes. DESIGN This pilot study over April 2016 to September 2019 adopts a before-and-after comparison design of a lung-protective mechanical ventilation protocol. All admissions to the PICU were screened daily for fulfillment of the Pediatric Acute Lung Injury Consensus Conference criteria and included. SETTING Multidisciplinary PICU. PATIENTS Patients with pediatric acute respiratory distress syndrome. INTERVENTIONS Lung-protective mechanical ventilation protocol with elements on peak pressures, tidal volumes, end-expiratory pressure to FIO2 combinations, permissive hypercapnia, and permissive hypoxemia. MEASUREMENTS AND MAIN RESULTS Ventilator and blood gas data were collected for the first 7 days of pediatric acute respiratory distress syndrome and compared between the protocol (n = 63) and nonprotocol groups (n = 69). After implementation of the protocol, median tidal volume (6.4 mL/kg [5.4-7.8 mL/kg] vs 6.0 mL/kg [4.8-7.3 mL/kg]; p = 0.005), PaO2 (78.1 mm Hg [67.0-94.6 mm Hg] vs 74.5 mm Hg [59.2-91.1 mm Hg]; p = 0.001), and oxygen saturation (97% [95-99%] vs 96% [94-98%]; p = 0.007) were lower, and end-expiratory pressure (8 cm H2O [7-9 cm H2O] vs 8 cm H2O [8-10 cm H2O]; p = 0.002] and PaCO2 (44.9 mm Hg [38.8-53.1 mm Hg] vs 46.4 mm Hg [39.4-56.7 mm Hg]; p = 0.033) were higher, in keeping with lung protective measures. There was no difference in mortality (10/63 [15.9%] vs 18/69 [26.1%]; p = 0.152), ventilator-free days (16.0 [2.0-23.0] vs 19.0 [0.0-23.0]; p = 0.697), and PICU-free days (13.0 [0.0-21.0] vs 16.0 [0.0-22.0]; p = 0.233) between the protocol and nonprotocol groups. After adjusting for severity of illness, organ dysfunction and oxygenation index, the lung-protective mechanical ventilation protocol was associated with decreased mortality (adjusted hazard ratio, 0.37; 95% CI, 0.16-0.88). CONCLUSIONS In pediatric acute respiratory distress syndrome, a lung-protective mechanical ventilation protocol improved adherence to lung-protective mechanical ventilation strategies and potentially mortality.
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The Organ-Protective Effect of Higher Partial Pressure of Arterial Carbon Dioxide in the Normal Range for Infant Patients Undergoing Ventricular Septal Defect Repair. Pediatr Cardiol 2020; 41:372-381. [PMID: 31844927 DOI: 10.1007/s00246-019-02269-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 12/07/2019] [Indexed: 10/25/2022]
Abstract
Hypercapnia has been reported to play an active role in protection against organ injury. The aim of this study was to determine whether a higher level of partial pressure of arterial carbon dioxide (PaCO2) within the normal range in pediatric patients undergoing cardiac surgery had a similar organ-protective effect. From May 2017 to May 2018, 83 consecutive infant patients undergoing ventricular septal defect (VSD) repair with cardiopulmonary bypass were retrospectively enrolled. We recorded the end-expiratory tidal partial pressure of carbon dioxide (Pet-CO2) as an indirect and continuous way to reflect the PaCO2. The patients were divided into a low PaCO2 group (LPG; 30 mmHg < Pet-CO2 < 40 mmHg) and a high PaCO2 group (HPG; 40 mmHg < Pet-CO2 < 50 mmHg). The regional cerebral oxygen saturation (rScO2), cerebral blood flow velocity (CBFV), and hemodynamics at five time points throughout the operation, and perioperative data were recorded and analyzed for the two groups. In total, 34 LPG and 49 HPG patients were included. Demographics and perioperative clinical data showed no significant difference between the groups. Compared with LPG, the HPG produced lower postoperative creatine kinase isoenzyme-MB (40.88 versus 50.34 ng/mL, P = 0.038). The postoperative C-reactive protein of HPG trended lower than in LPG (61.09 versus 73.4 mg/L, P = 0.056). The rScO2 and mean CBFV of HPG were significantly higher compared with LPG (P < 0.05) except at the end of cardiopulmonary bypass. Hemodynamic data showed no significant difference between the groups. As a convenient and safe approach, higher-normal PaCO2 could attenuate brain injury, heart injury, and inflammatory response in infant patients undergoing VSD repair.
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Effects of crystalloids and colloids on microcirculation, central venous oxygen saturation, and central venous-to-arterial carbon dioxide gap in a rabbit model of hemorrhagic shock. J Anesth 2018; 33:108-117. [DOI: 10.1007/s00540-018-2594-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2018] [Accepted: 11/30/2018] [Indexed: 10/27/2022]
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Bellini L, De Benedictis GM. Neuromuscular blockade of atracurium in permissive hypercapnic versus normocapnic swine undergoing laparoscopy. PLoS One 2018; 13:e0200439. [PMID: 29979782 PMCID: PMC6034893 DOI: 10.1371/journal.pone.0200439] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 06/26/2018] [Indexed: 11/25/2022] Open
Abstract
Neuromuscular blocking agents (NMBAs) are commonly used in experimental laparoscopy in swine undergoing carbon dioxide pneumoperitoneum. Hypercapnia may be present and may prolong NMBAs’ pharmacologic activity. The aim of this study is to evaluate the effect of permissive hypercapnia on the neuromuscular blockade of atracurium in swine. Six Large White swine weighing 30.5 ± 1.6 kg were sedated with intramuscular ketamine and medetomidine, after which anaesthesia was induced with propofol and maintained with sevoflurane. Atracurium 0.4 mg/kg was administered intravenously and the neuromuscular block monitored by acceleromyography during normocapnic and hypercapnic conditions (PaCO2 range 35–45 mmHg and 60–70 mmHg, respectively). Onset time and time to reach a train of four ratio (TOFR) of 0.7 and 0.9 were recorded. Cardiorespiratory parameters, electrolytes and acid-base status were measured under both conditions. Onset time was similar between the two conditions. Time to reach a TOFR of 0.7 and 0.9 (duration of the neuromuscular block) was longer in hypercapnic compared to normocapnic animals being 1325 ± 300 vs 855 ±111 (p = 0.002) and 1823 ± 434 vs 1218 ± 210 seconds (p = 0.005), respectively. Three hypercapnic swine had a TOF count of 2 and 1 instead of a count of 4 with fade. Permissive hypercapnia was associated with a decrease in pH from 7.444 ± 0.039 to 7.257 ± 0.025 (p < 0.001). No differences were observed for heart rate, end-tidal concentration of sevoflurane, body temperature and arterial haemoglobin saturation. Nonetheless, hypercapnic swine had a statistically significant increase in mean arterial pressure (p = 0.020) and plasma potassium concentration (p = 0.003). The values of PaCO2 achieved during hypercapnia were well tolerated in swine undergoing CO2 pneumoperitoneum for laparoscopy. Permissive hypercapnia increased the duration of the atracurium effect and caused an increase in the intensity of the neuromuscular block in few swine.
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Affiliation(s)
- Luca Bellini
- Department of Animal Medicine, Production and Health, University of Padua, Legnaro, Italy
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Pulmonary hemodynamics responses to hypoxia and/or CO 2 inhalation during moderate exercise in humans. Pflugers Arch 2018; 470:1035-1045. [PMID: 29502264 DOI: 10.1007/s00424-018-2127-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 02/07/2018] [Accepted: 02/19/2018] [Indexed: 02/06/2023]
Abstract
In this study, we hypothesized that adding CO2 to an inhaled hypoxic gas mixture will limit the rise of pulmonary artery pressure (PAP) induced by a moderate exercise. Eight 20-year-old males performed four constant-load exercise tests on cycle at 40% of maximal oxygen consumption in four conditions: ambient air, normobaric hypoxia (12.5% O2), inhaled CO2 (4.5% CO2), and combination of hypoxia and inhaled CO2. Doppler echocardiography was used to measure systolic (s)PAP, cardiac output (CO). Total pulmonary resistance (TPR) was calculated. Arterialized blood pH was 7.40 at exercise in ambient and hypoxia conditions, whereas CO2 inhalation and combined conditions showed acidosis. sPAP increases from rest in ambient air to exercise ranged as follows: ambient + 110%, CO2 inhalation + 135%, combined + 184%, hypoxia + 217% (p < 0.001). CO was higher when inhaling O2-poor gas mixtures with or without CO2 (~ 17 L min-1) than in the other conditions (~ 14 L min-1, p < 0.001). Exercise induced a significant decrease in TPR in the four conditions (p < 0.05) but less marked in hypoxia (- 19% of the resting value in ambient air) than in ambient (- 33%) and in both CO2 inhalation and combined condition (- 29%). We conclude that (1) acute CO2 inhalation did not significantly modify pulmonary hemodynamics during moderate exercise. (2) CO2 adjunction to hypoxic gas mixture did not modify CO, despite a higher CaO2 in combined condition than in hypoxia. (3) TPR was lower in combined than in hypoxia condition, limiting sPAP increase in combined condition.
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Puchwein-Schwepcke AF, Schottmayer K, Mormanová Z, Dreyhaupt J, Genzel-Boroviczeny O, Thome UH. Permissive Hypercapnia Results in Decreased Functional Vessel Density in the Skin of Extremely Low Birth Weight Infants. Front Pediatr 2018; 6:52. [PMID: 29662873 PMCID: PMC5890181 DOI: 10.3389/fped.2018.00052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 02/23/2018] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Ventilator-induced lung injury with subsequent bronchopulmonary dysplasia remains an important issue in the care of extremely low-birth-weight infants. Permissive hypercapnia has been proposed to reduce lung injury. Hypercapnia changes cerebral perfusion, but its influence on the peripheral microcirculation is unknown. METHODS Data were collected from 12 infants, who were randomized to a permissive high PCO2 target group (HTG) or a control group (CG). Inclusion criteria were birth weight between 400 and 1,000 g, gestational age from 23 to 28 6/7 weeks, intubation during the first 24 h of life, and no malformations. The PCO2 target range was increased stepwise in both groups for weaning and was always 15 mmHg higher in the HTG than in the CG. Skin microvascular parameters were assessed non-invasively with sidestream dark field imaging on the inner side of the right arm every 24 h during the first week of life and on the 14th day of life. RESULTS Infants in the HTG had significantly higher max. PCO2 exposure, which was associated with a significantly and progressively reduced functional vessel density (FVD, p < 0.01). Moreover, there were significant differences in the diameter distribution over time, with HTG subjects having fewer small vessels but more large vessels. CONCLUSION High PCO2 levels significantly impaired peripheral microcirculation in preterm infants, as shown by a decreased FVD, presumably secondary to peripheral vasoconstriction. ISRCTN 56143743.
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Affiliation(s)
| | - Kristina Schottmayer
- Divsion of Neonatology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Zuzana Mormanová
- Divsion of Neonatology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Jens Dreyhaupt
- Institute for Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany
| | - Orsolya Genzel-Boroviczeny
- Divsion of Neonatology, Dr. von Hauner Children's Hospital, Ludwig-Maximilians-University, Munich, Germany
| | - Ulrich H Thome
- Divsion of Neonatology, University Hospital of Leipzig, Leipzig, Germany
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Westermaier T, Stetter C, Kunze E, Willner N, Holzmeier J, Weiland J, Koehler S, Lotz C, Kilgenstein C, Ernestus RI, Roewer N, Muellenbach RM. Controlled Hypercapnia Enhances Cerebral Blood Flow and Brain Tissue Oxygenation After Aneurysmal Subarachnoid Hemorrhage: Results of a Phase 1 Study. Neurocrit Care 2017; 25:205-14. [PMID: 26886010 DOI: 10.1007/s12028-016-0246-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND This study investigated if cerebral blood flow (CBF) regulation by changes of the arterial partial pressure of carbon dioxide (PaCO2) can be used therapeutically to increase CBF and improve neurological outcome after subarachnoid hemorrhage (SAH). METHODS In 12 mechanically ventilated poor-grade SAH-patients, a daily trial intervention was performed between day 4 and 14. During this intervention, PaCO2 was decreased to 30 mmHg and then gradually increased to 40, 50, and 60 mmHg in 15-min intervals by modifications of the respiratory minute volume. CBF and brain tissue oxygen saturation (StiO2) were the primary and secondary endpoints. Intracranial pressure was controlled by an external ventricular drainage. RESULTS CBF reproducibly decreased during hyperventilation and increased to a maximum of 141 ± 53 % of baseline during hypercapnia (PaCO2 60 mmHg) on all days between day 4 and 14 after SAH. Similarly, StiO2 increased during hypercapnia. CBF remained elevated within the first hour after resetting ventilation to baseline parameters and no rebound effect was observed within this time-span. PaCO2-reactivities of CBF and StiO2 were highest between 30 and 50 mmHg and slightly decreased at higher levels. CONCLUSION CBF and StiO2 reproducibly increased by controlled hypercapnia of up to 60 mmHg even during the period of the maximum expected vasospasm. The absence of a rebound effect within the first hour after hypercapnia indicates that an improvement of the protocol is possible. The intervention may yield a therapeutic potential to prevent ischemic deficits after aneurysmal SAH.
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Affiliation(s)
- Thomas Westermaier
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany.
| | - Christian Stetter
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Ekkehard Kunze
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Nadine Willner
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Judith Holzmeier
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Judith Weiland
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Stefan Koehler
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Christopher Lotz
- Department of Anesthesia and Critical Care, University Hospital Wuerzburg, 97080, Würzburg, Germany
| | - Christian Kilgenstein
- Department of Anesthesia and Critical Care, University Hospital Wuerzburg, 97080, Würzburg, Germany
| | - Ralf-Ingo Ernestus
- Department of Neurosurgery, University Hospital Wuerzburg, Josef-Schneider-Str. 11, 97080, Würzburg, Germany
| | - Norbert Roewer
- Department of Anesthesia and Critical Care, University Hospital Wuerzburg, 97080, Würzburg, Germany
| | - Ralf Michael Muellenbach
- Department of Anesthesia and Critical Care, University Hospital Wuerzburg, 97080, Würzburg, Germany
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Radermacher P, Maggiore SM, Mercat A. FiftyYears ofResearch inARDS.Gas Exchange in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2017; 196:964-984. [DOI: 10.1164/rccm.201610-2156so] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Peter Radermacher
- Institute of Anaesthesiological Pathophysiology and Process Engineering, University Medical School, Ulm, Germany
| | - Salvatore Maurizio Maggiore
- Section of Anesthesia, Analgesia, Perioperative, and Intensive Care, Department of Medical, Oral, and Biotechnological Sciences, School of Medicine and Health Sciences, “SS. Annunziata” Hospital, “Gabriele d’Annunzio” University of Chieti-Pescara, Chieti, Italy; and
| | - Alain Mercat
- Department of Medical Intensive Care and Hyperbaric Medicine, Angers University Hospital, Angers, France
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Fuchs H, Rossmann N, Schmid MB, Hoenig M, Thome U, Mayer B, Klotz D, Hummler HD. Permissive hypercapnia for severe acute respiratory distress syndrome in immunocompromised children: A single center experience. PLoS One 2017. [PMID: 28632754 PMCID: PMC5478142 DOI: 10.1371/journal.pone.0179974] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Controlled hypoventilation while accepting hypercapnia has been advocated to reduce ventilator-induced lung injury. The aim of the study was to analyze outcomes of a cohort of immunocompromised children with acute respiratory distress syndrome (ARDS) ventilated with a strategy of stepwise increasing PCO2 targets up to 140 mm Hg. METHODS Retrospective analysis of outcomes of a cohort of children with oncologic disease or after stem cell transplantation and severe respiratory failure in comparison with a historical control cohort. RESULTS Out of 150 episodes of admission to the PICU 88 children underwent invasive mechanical ventilation for >24h (overall survival 75%). In a subgroup of 38 children with high ventilator requirements the PCO2 target ranges were increased stepwise. Fifteen children survived and were discharged from the PICU. Severe pulmonary hypertension was seen in two patients and no case of cerebral edema was observed. Long term outcome was available in 15 patients and 10 of these patients survived without adverse neurological sequelae. With introduction of this strategy survival of immunocompromised children undergoing mechanical ventilation for >24h increased to 48% compared to 32% prior to introduction (historical cohort). CONCLUSIONS A ventilation strategy incorporating very high carbon dioxide levels to allow for low tidal volumes and limited inspiratory pressures is feasible in children. Even severe hypercapnia may be well tolerated. No severe side effects associated with hypercapnia were observed. This strategy could potentially increase survival in immunocompromised children with severe ARDS.
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Affiliation(s)
- Hans Fuchs
- Center for Pediatrics, Department of Neonatology and Pediatric Intensive Care, Medical Center – Albert Ludwig University of Freiburg, Faculty of Medicine, Freiburg, Germany
- * E-mail:
| | - Nicola Rossmann
- Division of Neonatology and Pediatric Critical Care, Department for Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany
| | - Manuel B. Schmid
- Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Manfred Hoenig
- Oncology and stem cell transplantation, Department for Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany
| | - Ulrich Thome
- Division of Neonatology, University Hospital of Leipzig, Leipzig, Germany
| | - Benjamin Mayer
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | - Daniel Klotz
- Center for Pediatrics, Department of Neonatology and Pediatric Intensive Care, Medical Center – Albert Ludwig University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Helmut D. Hummler
- Division of Neonatology and Pediatric Critical Care, Department for Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany
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Zhu YF, Meng FM. Effect of Retroperitoneal Lavage with Normal Saline Containing Adrenaline on Carbon Dioxide Absorption in Patients Undergoing Retroperitoneal Laparoscopic Surgery. J Laparoendosc Adv Surg Tech A 2016; 25:903-7. [PMID: 26575248 DOI: 10.1089/lap.2015.0215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVE To determine the effect of lavage with adrenaline solution on CO2 absorption during retroperitoneal laparoscopic surgery. MATERIALS AND METHODS Sixty patients scheduled to undergo retroperitoneal laparoscopic surgery were divided into an AD group (lavage with normal saline containing adrenaline [1:500,000], n = 30) and an NS group (lavage with normal saline only, n = 30). After the establishment of artificial pneumoperitoneum and before the start of the operation, the retroperitoneal space was irrigated with 300 mL of normal saline with or without adrenaline, depending on the group. The lavage fluid was aspirated after 3 minutes. Heart rate (HR), mean arterial pressure (MAP), blood oxygen saturation (SpO2), partial pressure of O2 (PaO2), partial pressure of CO2 (PaCO2), and end-tidal CO2 partial pressure (PETCO2) were recorded before the lavage (T0) and at 10, 30, 60, 90, and 120 minutes (T1-T5, respectively) after the lavage. The CO2 output (VCO2) was calculated, and the incidence of intraoperative arrhythmia and postoperative complications (e.g., headache, palpitations, irritation) was determined. RESULTS HR, MAP, SpO2, PaO2, PaCO2, PETCO2, and VCO2 at T0 did not significantly differ between the groups (P > .05). HR, PaCO2, PETCO2, and VCO2 at T1-T5 were lower in the AD group than in the NS group (P < .05). The incidence of intraoperative arrhythmia and postoperative complications was lower in the AD group than in the NS group (P < .05). CONCLUSIONS Lavage with normal saline containing adrenaline (1:500,000) reduced CO2 absorption during retroperitoneal laparoscopic surgery, prevented hypercapnia, and decreased intra- and postoperative complications.
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Affiliation(s)
- Yong-Feng Zhu
- Department of Anesthesiology, People's Hospital of Zhengzhou University , Zhengzhou, People's Republic of China
| | - Fan-Min Meng
- Department of Anesthesiology, People's Hospital of Zhengzhou University , Zhengzhou, People's Republic of China
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Morel J, Gergelé L, Dominé A, Molliex S, Perrot JL, Labeille B, Costes F. The venous–arterial difference in CO2 should be interpreted with caution in case of respiratory alkalosis in healthy volunteers. J Clin Monit Comput 2016; 31:701-707. [DOI: 10.1007/s10877-016-9897-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 06/06/2016] [Indexed: 11/24/2022]
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21
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Swenson ER. Hypoxia and Its Acid-Base Consequences: From Mountains to Malignancy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:301-23. [PMID: 27343105 DOI: 10.1007/978-1-4899-7678-9_21] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hypoxia, depending upon its magnitude and circumstances, evokes a spectrum of mild to severe acid-base changes ranging from alkalosis to acidosis, which can alter many responses to hypoxia at both non-genomic and genomic levels, in part via altered hypoxia-inducible factor (HIF) metabolism. Healthy people at high altitude and persons hyperventilating to non-hypoxic stimuli can become alkalotic and alkalemic with arterial pH acutely rising as high as 7.7. Hypoxia-mediated respiratory alkalosis reduces sympathetic tone, blunts hypoxic pulmonary vasoconstriction and hypoxic cerebral vasodilation, and increases hemoglobin oxygen affinity. These effects and others can be salutary or counterproductive to tissue oxygen delivery and utilization, based upon magnitude of each effect and summation. With severe hypoxia either in the setting of profound arterial hemoglobin desaturation and reduced O2 content or poor perfusion (ischemia) at the global or local level, metabolic and hypercapnic acidosis develop along with considerable lactate formation and pH falling to below 6.8. Although conventionally considered to be injurious and deleterious to cell function and survival, both acidoses may be cytoprotective by various anti-inflammatory, antioxidant, and anti-apoptotic mechanisms which limit total hypoxic or ischemic-reperfusion injury. Attempts to correct acidosis by giving bicarbonate or other alkaline agents under these circumstances ahead of or concurrent with reoxygenation efforts may be ill advised. Better understanding of this so-called "pH paradox" or permissive acidosis may offer therapeutic possibilities. Rapidly growing cancers often outstrip their vascular supply compromising both oxygen and nutrient delivery and metabolic waste disposal, thus limiting their growth and metastatic potential. However, their excessive glycolysis and lactate formation may not necessarily represent oxygen insufficiency, but rather the Warburg effect-an attempt to provide a large amount of small carbon intermediates to supply the many synthetic pathways of proliferative cell growth. In either case, there is expression and upregulation of many genes involved in acid-base homeostasis, in part by HIF-1 signaling. These include a unique isoform of carbonic anhydrase (CA-IX) and numerous membrane acid-base transporters engaged to maintain an optimal intracellular and extracellular pH for maximal growth. Inhibition of these proteins or gene suppression may have important therapeutic application in cancer chemotherapy.
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Affiliation(s)
- Erik R Swenson
- Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington, Seattle, WA, USA. .,Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA. .,VA Puget Sound Health Care System, University of Washington, Seattle, WA, USA.
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22
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Yang H, Xiang P, Zhang E, Guo W, Shi Y, Zhang S, Tong Z. Is hypercapnia associated with poor prognosis in chronic obstructive pulmonary disease? A long-term follow-up cohort study. BMJ Open 2015; 5:e008909. [PMID: 26671953 PMCID: PMC4679936 DOI: 10.1136/bmjopen-2015-008909] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To assess whether hypercapnia may predict the prognosis in chronic obstructive pulmonary disease (COPD). DESIGN Prospective cohort study comparing the survival of patients with COPD and normocapnia to those with chronic hypercapnia. SETTING Patients with consecutive COPD were enrolled between 1 May 1993 and 31 October 2006 at two medical centres. Follow-up was censored on 31 October 2011. PARTICIPANTS A total of 275 patients with stable COPD and aged 40-85 years were enrolled. Diagnosis of hypercapnia was confirmed by blood gas analysis. Patients with near-terminal illness or comorbidities that affect PaCO2 (obstructive sleep apnoea, obesity-related hypoventilation, or neuromuscular disease) were excluded. The outcome of 98 patients with normocapnia and 177 with chronic hypercapnia was analysed. OUTCOME MEASURES Overall survival. RESULTS Median survival was longer in patients with normocapnia than in those with hypercapnia (6.5 vs 5.0 years, p=0.016). Multivariate COX regression analysis indicated that age (HR=1.043, 95% CI 1.012 to 1.076), Charlson Index, which is a measure of comorbidity (HR=1.172, 95% CI 1.067 to 1.288), use of medication (HR=0.565, 95% CI 0.379 to 0.842), body mass index (BMI) (HR=0.922, 95% CI 0.883 to 0.963), PaCO2 (HR=1.026, 95% CI 1.011 to 1.042), Cor pulmonale (HR=2.164, 95% CI 1.557 to 3.006), non-invasive positive-pressure ventilation (NPPV) (HR=0.615, 95% CI 0.429 to 0.881) and per cent of forced expiratory volume in 1 s (FEV1%) (HR=0.979, 95% CI 0.967 to 0.991), were independent risk factors for mortality. CONCLUSIONS Increased age, Charlson Index, chronic hypercapnia and Cor pulmonale, and decreased FEV1%, use of medication, BMI and NPPV, were associated with a poor prognosis in patients with COPD.
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Affiliation(s)
- Hui Yang
- Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital Beijing, Capital Medical University, Beijing, China
- Department of Respiratory and Critical Care Medicine, Shou-Gang Hospital Affiliated to Peking University, Beijing, China
| | - Pingchao Xiang
- Department of Respiratory and Critical Care Medicine, Shou-Gang Hospital Affiliated to Peking University, Beijing, China
| | - Erming Zhang
- Department of Respiratory and Critical Care Medicine, Shou-Gang Hospital Affiliated to Peking University, Beijing, China
| | - Weian Guo
- Department of Respiratory and Critical Care Medicine, Shou-Gang Hospital Affiliated to Peking University, Beijing, China
| | - Yanwei Shi
- Department of Respiratory and Critical Care Medicine, Shou-Gang Hospital Affiliated to Peking University, Beijing, China
| | - Shuo Zhang
- Department of Respiratory and Critical Care Medicine, Shou-Gang Hospital Affiliated to Peking University, Beijing, China
| | - Zhaohui Tong
- Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital Beijing, Capital Medical University, Beijing, China
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In reply. Anesthesiology 2015; 122:1179-80. [PMID: 25985027 DOI: 10.1097/aln.0000000000000623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Beck C, Barthel F, Hahn AM, Vollmer C, Herminghaus A, Schäfer S, Bauer I, Picker O. The beneficial effects of acute hypercapnia on microcirculatory oxygenation in an animal model of sepsis are independent of K(+)ATP channels. Microvasc Res 2015; 99:78-85. [PMID: 25758765 DOI: 10.1016/j.mvr.2015.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 02/13/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Acute hypercapnia maintains the microcirculatory oxygenation of the splanchnic region during sepsis. The first aim of this study was to characterize the role of K(+)ATP channels on the microcirculatory flow and oxygenation during acute moderate hypercapnia. The second aim was to investigate whether a short period of hypercapnia induces detrimental effects in an otherwise undamaged rodent lung. METHODS Experiments were performed on 60 male Wistar rats. A moderate polymicrobial sepsis was induced by colon ascendens stent peritonitis (CASP) surgery. 24h after induction of sepsis volume-controlled and pressure-limited ventilation was established for 120 min, with either normocapnic (pCO2 35-45 mmHg) or moderate hypercapnic ventilation targets (pCO2 65-75 mmHg) and with or without non-selective K(+)ATP channel blockade with glibenclamide. Microcirculatory blood flow of the colonic wall as well as oxygen delivery and consumption were assessed with tissue laser Doppler and reflectance spectrophotometry. Hemodynamic variables were recorded and plasma cytokine levels and myeloperoxidase levels of the lungs were analyzed. RESULTS In septic animals microcirculatory oxygenation deteriorated progressively with normocapnia (-11.7 ± 11.8%) but was maintained (-2.9 ± 5.6%) with hypercapnia. This effect was associated with an increased microcirculatory oxygen consumption in septic animals with normocapnia (+25.7 ± 37.1%) that was decreased in the hypercapnia groups (-7.2 ± 28.1%). The effect of hypercapnia in septic animals was not altered by additional K(+)ATP channel blockade (-5.7 ± 32.7%). Hypercapnia neither induced an inflammatory response in lungs nor altered the systemic cytokine response. CONCLUSIONS The observed beneficial effect of hypercapnia on microvascular oxygenation of the colon in sepsis does not seem to be mediated via K(+)ATP channels.
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Affiliation(s)
- Christopher Beck
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Franziska Barthel
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Anna-Maria Hahn
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Christian Vollmer
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Anna Herminghaus
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Sabrina Schäfer
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Inge Bauer
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany
| | - Olaf Picker
- Department of Anaesthesiology, University Hospital Duesseldorf, Germany.
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Navarrete-Calvo R, Gómez-Villamandos RJ, Morgaz J, Manuel Domínguez J, Fernández-Sarmiento A, Muñoz-Rascón P, López Villalba I, Del Mar Granados M. Cardiorespiratory, anaesthetic and recovery effects of morphine combined with medetomidine and alfaxalone in rabbits. Vet Rec 2014; 174:95. [DOI: 10.1136/vr.101293] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- R. Navarrete-Calvo
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - R. J. Gómez-Villamandos
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - J. Morgaz
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - J. Manuel Domínguez
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - A. Fernández-Sarmiento
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - P. Muñoz-Rascón
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - I. López Villalba
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
| | - M. Del Mar Granados
- Department of Animal Medicine and Surgery; Scholl of Veterinary Medicine; University of Córdoba; Córdoba Spain
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Hwang JH. Optimal Ventilatory Strategies in Preterm Infants: Permissive Hypercapnia. NEONATAL MEDICINE 2014. [DOI: 10.5385/nm.2014.21.2.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Jong Hee Hwang
- Department of Pediatrics, Ilsan Paik Hospital, Inje University College of Medicine, Goyang, Korea
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Curley GF, Laffey JG, Kavanagh BP. CrossTalk proposal: there is added benefit to providing permissive hypercapnia in the treatment of ARDS. J Physiol 2013; 591:2763-5. [PMID: 23729790 DOI: 10.1113/jphysiol.2013.252601] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Gerard F Curley
- Department of Anesthesia, Keenan Research Centre in the Li Ka Shing Knowledge Institute, St Michael’s Hospital, Toronto, Ontario, Canada
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28
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Stübs CC, Picker O, Schulz J, Obermiller K, Barthel F, Hahn AM, Bauer I, Beck C. Acute, short-term hypercapnia improves microvascular oxygenation of the colon in an animal model of sepsis. Microvasc Res 2013; 90:180-6. [DOI: 10.1016/j.mvr.2013.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 06/25/2013] [Accepted: 07/22/2013] [Indexed: 12/13/2022]
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Fuchs H, Mendler MR, Scharnbeck D, Ebsen M, Hummler HD. Very low tidal volume ventilation with associated hypercapnia--effects on lung injury in a model for acute respiratory distress syndrome. PLoS One 2011; 6:e23816. [PMID: 21886825 PMCID: PMC3158784 DOI: 10.1371/journal.pone.0023816] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 07/27/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Ventilation using low tidal volumes with permission of hypercapnia is recommended to protect the lung in acute respiratory distress syndrome. However, the most lung protective tidal volume in association with hypercapnia is unknown. The aim of this study was to assess the effects of different tidal volumes with associated hypercapnia on lung injury and gas exchange in a model for acute respiratory distress syndrome. METHODOLOGY/PRINCIPAL FINDINGS In this randomized controlled experiment sixty-four surfactant-depleted rabbits were exposed to 6 hours of mechanical ventilation with the following targets: Group 1: tidal volume = 8-10 ml/kg/PaCO(2) = 40 mm Hg; Group 2: tidal volume = 4-5 ml/kg/PaCO(2) = 80 mm Hg; Group 3: tidal volume = 3-4 ml/kg/PaCO(2) = 120 mm Hg; Group 4: tidal volume = 2-3 ml/kg/PaCO(2) = 160 mm Hg. Decreased wet-dry weight ratios of the lungs, lower histological lung injury scores and higher PaO(2) were found in all low tidal volume/hypercapnia groups (group 2, 3, 4) as compared to the group with conventional tidal volume/normocapnia (group 1). The reduction of the tidal volume below 4-5 ml/kg did not enhance lung protection. However, oxygenation and lung protection were maintained at extremely low tidal volumes in association with very severe hypercapnia and no adverse hemodynamic effects were observed with this strategy. CONCLUSION Ventilation with low tidal volumes and associated hypercapnia was lung protective. A tidal volume below 4-5 ml/kg/PaCO(2) 80 mm Hg with concomitant more severe hypercapnic acidosis did not increase lung protection in this surfactant deficiency model. However, even at extremely low tidal volumes in association with severe hypercapnia lung protection and oxygenation were maintained.
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Affiliation(s)
- Hans Fuchs
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany.
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30
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Manzanares W, Cancela M, Berrutti D. Shock and Pulmonary Edema Secondary to Severe Acute Hypercapnic Acidosis. Am J Respir Crit Care Med 2010; 182:1455. [DOI: 10.1164/ajrccm.182.11.1455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Hypercapnic Acidosis Preserves Gastric Mucosal Microvascular Oxygen Saturation in a Canine Model of Hemorrhage. Shock 2010; 34:636-42. [DOI: 10.1097/shk.0b013e3181e68422] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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32
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Bench-to-bedside review: hypercapnic acidosis in lung injury--from 'permissive' to 'therapeutic'. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:237. [PMID: 21067531 PMCID: PMC3220022 DOI: 10.1186/cc9238] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modern ventilation strategies for patients with acute lung injury and acute respiratory distress syndrome frequently result in hypercapnic acidosis (HCA), which is regarded as an acceptable side effect ('permissive hypercapnia'). Multiple experimental studies have demonstrated advantageous effects of HCA in several lung injury models. To date, however, human trials studying the effect of carbon dioxide per se on outcome in patients with lung injury have not been performed. While significant concerns regarding HCA remain, in particular the possible unfavorable effects on bacterial killing and the inhibition of pulmonary epithelial wound repair, the potential for HCA in attenuating lung injury is promising. The underlying mechanisms by which HCA exerts its protective effects are complex, but dampening of the inflammatory response seems to play a pivotal role. After briefly summarizing the physiological effects of HCA, a critical analysis of the available evidence on the potential beneficial effects of therapeutic HCA from in vitro, ex vivo and in vivo lung injury models and from human studies will be reviewed. In addition, the potential concerns in the clinical setting will be outlined.
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Chin LMK, Heigenhauser GJF, Paterson DH, Kowalchuk JM. Pulmonary O2 uptake and leg blood flow kinetics during moderate exercise are slowed by hyperventilation-induced hypocapnic alkalosis. J Appl Physiol (1985) 2010; 108:1641-50. [PMID: 20339012 PMCID: PMC2886676 DOI: 10.1152/japplphysiol.01346.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 03/23/2010] [Indexed: 11/22/2022] Open
Abstract
The effect of hyperventilation-induced hypocapnic alkalosis (Hypo) on the adjustment of pulmonary O2 uptake (VO2p) and leg femoral conduit artery ("bulk") blood flow (LBF) during moderate-intensity exercise (Mod) was examined in eight young male adults. Subjects completed four to six repetitions of alternate-leg knee-extension exercise during normal breathing [Con; end-tidal partial pressure of CO2 (PetCO2) approximately 40 mmHg] and sustained hyperventilation (Hypo; PetCO2 approximately 20 mmHg). Increases in work rate were made instantaneously from baseline (3 W) to Mod (80% estimated lactate threshold). VO2p was measured breath by breath by mass spectrometry and volume turbine, and LBF (calculated from mean femoral artery blood velocity and femoral artery diameter) was measured simultaneously by Doppler ultrasound. Concentration changes of deoxy (Delta[HHb])-, oxy (Delta[O2Hb])-, and total hemoglobin-myoglobin (Delta[HbTot]) of the vastus lateralis muscle were measured continuously by near-infrared spectroscopy (NIRS). The kinetics of VO2p, LBF, and Delta[HHb] were modeled using a monoexponential equation by nonlinear regression. The time constants for the phase 2 VO2p (Hypo, 49+/-26 s; Con, 28+/-8 s) and LBF (Hypo, 46+/-16 s; Con, 23+/-6 s) were greater (P<0.05) in Hypo compared with Con. However, the mean response time for the overall Delta[HHb] response was not different between conditions (Hypo, 23+/-5 s; Con, 24+/-3 s), whereas the Delta[HHb] amplitude was greater (P<0.05) in Hypo (8.05+/-7.47 a.u.) compared with Con (6.69+/-6.31 a.u.). Combined, these results suggest that hyperventilation-induced hypocapnic alkalosis is associated with slower convective (i.e., slowed femoral artery and microvascular blood flow) and diffusive (i.e., greater fractional O2 extraction for a given DeltaVO2p) O2 delivery, which may contribute to the hyperventilation-induced slowing of VO2p (and muscle O2 utilization) kinetics.
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Affiliation(s)
- Lisa M K Chin
- Canadian Centre for Activity and Aging, School of Kinesiology, Department of Physiology and Pharmacology, Arthur and Sonia Labatt Health Sciences Bldg., Rm. 411C, The University of Western Ontario, London, ON, Canada N6A 5B9
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Abstract
Carbon dioxide is a waste product of aerobic cellular respiration in all aerobic life forms. PaCO2 represents the balance between the carbon dioxide produced and that eliminated. Hypocapnia remains a common - and generally underappreciated - component of many disease states, including early asthma, high-altitude pulmonary edema, and acute lung injury. Induction of hypocapnia remains a common, if controversial, practice in both adults and children with acute brain injury. In contrast, hypercapnia has traditionally been avoided in order to keep parameters normal. More recently, advances in our understanding of the role of excessive tidal volume has prompted clinicians to use ventilation strategies that result in hypercapnia. Consequently, hypercapnia has become increasingly prevalent in the critically ill patient. Hypercapnia may play a beneficial role in the pathogenesis of inflammation and tissue injury, but may hinder the host response to sepsis and reduce repair. In contrast, hypocapnia may be a pathogenic entity in the setting of critical illness. The present paper reviews the current clinical status of low and high PaCO2 in the critically ill patient, discusses the insights gained to date from studies of carbon dioxide, identifies key concerns regarding hypocapnia and hypercapnia, and considers the potential clinical implications for the management of patients with acute lung injury.
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Affiliation(s)
- Gerard Curley
- Department of Anaesthesia, Clinical Sciences Institute, National University of Ireland, Galway, Ireland
- Lung Biology Group, National Centre of Biomedical Engineering Sciences, National University of Ireland, Galway, Ireland
| | - John G Laffey
- Department of Anaesthesia, Clinical Sciences Institute, National University of Ireland, Galway, Ireland
- Lung Biology Group, National Centre of Biomedical Engineering Sciences, National University of Ireland, Galway, Ireland
| | - Brian P Kavanagh
- Departments of Critical Care Medicine and Anesthesia and the Program in Physiology and Experimental Medicine, The Hospital for Sick Children, University of Toronto, 555 university Avenue, Toronto, ON M5G 1X8, Canada
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Hughes EL, Gavins FN. Troubleshooting methods: Using intravital microscopy in drug research. J Pharmacol Toxicol Methods 2010; 61:102-12. [DOI: 10.1016/j.vascn.2010.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2009] [Revised: 01/12/2010] [Accepted: 01/14/2010] [Indexed: 12/30/2022]
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[Microcirculatory alterations in critically ill patients: pathophysiology, monitoring and treatments]. ACTA ACUST UNITED AC 2010; 29:135-44. [PMID: 20116198 DOI: 10.1016/j.annfar.2009.10.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2008] [Accepted: 10/28/2009] [Indexed: 01/18/2023]
Abstract
Microcirculation represents a complex system devoted to provide optimal tissue substrates and oxygen. Therefore, pathophysiological and technological knowledge developments tailored for capillary circulation analysis should generate major advances for critically ill patients' management. In the future, microcirculatory monitoring in several critical care situations will allow recognition of macro-microcirculatory decoupling, and, hopefully, it will promote the use of treatments aimed at preserving tissue oxygenation and substrate delivery.
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Haemodynamic effects during endoscopic vein harvest of the saphenous vein for off-pump coronary artery bypass grafting surgery. Eur J Anaesthesiol 2009; 26:969-73. [PMID: 19842243 DOI: 10.1097/eja.0b013e32832eb508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Endoscopic vein harvest (EVH) for coronary artery bypass grafting surgery is performed with carbon dioxide (CO2) insufflation for visualization and dissection. The insufflated CO2 is rapidly absorbed into the body and may influence haemodynamics. However, the haemodynamic changes during EVH have not been clearly defined. This study evaluated the haemodynamic effects during EVH of the saphenous vein for off-pump coronary artery bypass grafting surgery (OPCAB). METHODS After fixing the position for harvesting of the left internal mammary artery, EVH of the saphenous vein was performed at a maximum CO2 pressure of 12 mmHg and a flow of 3 l/min. The haemodynamic parameters were measured before and just after the end of endoscopic vein harvest. RESULTS One hundred patients were studied. The end-tidal CO2 pressure (P(ET)CO2, 35.0 +/- 2.7 vs. 52.0 +/- 6.2 mmHg), partial pressure of arterial CO2 (PaCO2, 35.1 +/- 3.1 vs. 52.5 +/- 4.3 mmHg), mixed venous oxygen saturation (SvO2, 75.6 +/- 4.1 vs. 82.0 +/- 1.6%), cardiac index (2.7 +/- 0.6 vs. 3.3 +/- 0.6 l/min/m2), and cerebral oxygen saturation (ScO2, left: 63.5 +/- 7.9 vs. 73.3 +/- 8.4; right: 62.2 +/- 8.0 vs. 72.3 +/- 6.3%) differed significantly between before and after CO2 insufflation, whereas mean systemic blood pressure, mean pulmonary artery blood pressure, central venous pressure, heart rate, partial pressure of arterial oxygen, and peak inspiratory pressure did not differ significantly between before and after CO2 insufflation. CONCLUSIONS EVH, at a maximum CO2 pressure of 12 mmHg and a flow of 3 l/min, of the saphenous vein for OPCAB was associated with hypercarbia and a tolerable range of hypercarbia (PaCO2 < 60 mmHg) increased the cardiac index and ScO2 without any complications.
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Manca T, Welch LC, Sznajder JI. The Cardiopulmonary Effects of Hypercapnia. Intensive Care Med 2009. [DOI: 10.1007/978-0-387-77383-4_26] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Komori M, Takada K, Tomizawa Y, Nishiyama K, Kondo I, Kawamata M, Ozaki M. Microcirculatory Responses to Acupuncture Stimulation and Phototherapy. Anesth Analg 2009; 108:635-40. [DOI: 10.1213/ane.0b013e31819317bc] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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40
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Thome UH, Ambalavanan N. Permissive hypercapnia to decrease lung injury in ventilated preterm neonates. Semin Fetal Neonatal Med 2009; 14:21-7. [PMID: 18974027 DOI: 10.1016/j.siny.2008.08.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Lung injury in ventilated premature infants occurs primarily through the mechanism of volutrauma, often due to the combination of high tidal volumes in association with a high end-inspiratory volume and occasionally end-expiratory alveolar collapse. Tolerating a higher level of arterial partial pressure of carbon dioxide (PaCO2) is considered as 'permissive hypercapnia' and when combined with the use of low tidal volumes may reduce volutrauma and lead to improved pulmonary outcomes. Permissive hypercapnia may also protect against hypocapnia-induced brain hypoperfusion and subsequent periventricular leukomalacia. However, extreme hypercapnia may be associated with an increased risk of intracranial hemorrhage. It may therefore be important to avoid large fluctuations in PaCO2 values. Recent randomized clinical trials in preterm infants have demonstrated that mild permissive hypercapnia is safe, but clinical benefits are modest. The optimal PaCO2 goal in clinical practice has not been determined, and the available evidence does not currently support a general recommendation for permissive hypercapnia in preterm infants.
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Affiliation(s)
- Ulrich H Thome
- Division of Neonatology, University Hospital for Children and Adolescents, 04103 Leipzig, Germany.
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Abstract
Mechanical ventilation using high tidal volume (VT) and transpulmonary pressure can damage the lung, causing ventilator-induced lung injury. Permissive hypercapnia, a ventilatory strategy for acute respiratory failure in which the lungs are ventilated with a low inspiratory volume and pressure, has been accepted progressively in critical care for adult, pediatric, and neonatal patients requiring mechanical ventilation and is one of the central components of current protective ventilatory strategies.
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Affiliation(s)
- Alex Rogovik
- Pediatric Research in Emergency Therapeutics (PRETx) Program, Division of Pediatric Emergency Medicine, Ambulatory Care Building, BC Children's Hospital, 4480 Oak Street, Vancouver, BC, Canada
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Abstract
UNLABELLED 'Permissive hypercapnia' is a familiar term in neonatal intensive care, given the widespread adoption of low-tidal-volume ventilation strategies applied with the goal of decreasing respiratory morbidity. Recent evidence suggesting that hypercapnic acidosis may itself have protective effects on the lung and other organs has led to the coining of a new phrase, 'therapeutic hypercapnia', which also encompasses the use of supplemental inspired CO(2). CONCLUSION Experimental evidence suggests that mild-moderate hypercapnia can improve tissue oxygenation and perfusion, which may ameliorate injury to the immature lung and brain. However, hypercapnia may also be associated with adverse outcomes, and the range of PaCO(2) levels that are both safe and effective for specific subsets of neonates has yet to be determined.
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Affiliation(s)
- Robert P Jankov
- Department of Paediatric, University of Toronto, Toronto, Ontario Canada.
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Abstract
OBJECTIVES Hypercapnia is known to modulate inflammation in lungs. However, the effect of hypocapnia and hypercapnia on blood cytokine production during sepsis is not well understood. We hypothesized that CO2 modulates ex vivo inflammatory cytokine production during endotoxin stimulation. To test this hypothesis, we measured the production of pro- and anti-inflammatory cytokines in endotoxin-stimulated human whole blood cultures under hypercapnic, normocapnic, and hypocapnic conditions. DESIGN Prospective randomized study. SETTING Basic research laboratory. SUBJECTS Ten male and 10 female volunteers. INTERVENTIONS Venous blood samples, taken from volunteers were cultured at 37 degrees C, under hypocapnic (2% CO2), normocapnic (5% CO2), and hypercapnic (7% CO2) conditions, with and without endotoxin stimulation. After 24 hrs of incubation, each culture's supernatant was analyzed for tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, interleukin-10, and interferon-gamma concentrations by enzyme-linked immunosorbent assay. Data were analyzed using nonparametric repeated measures of analysis of variance followed by Dunn's multiple comparisons test. Analysis of variance with Bonferroni correction was used to compare gender differences in cytokine concentrations. The Pearson test was used to estimate correlation between hydrogen ion and individual cytokine concentrations. MEASUREMENTS AND MAIN RESULTS Concentrations of the proinflammatory cytokines tumor necrosis factor-alpha, interleukin-1beta and of the anti-inflammatory cytokine interleukin-10 under hypercapnic condition were significantly decreased (p < 0.05, 0.01, and 0.001, respectively) for both genders when compared with either normocapnic or hypocapnic conditions. Concentrations of tumor necrosis factor-alpha and interleukin-1beta were significantly higher in men. In women, concentrations of interleukin-6 were significantly decreased under hypercapnic condition when compared with hypocapnic condition. An inverse relationship was found between hydrogen ion concentration and concentrations of tumor necrosis factor-alpha and interleukin-10. CONCLUSIONS Our results are consistent with the hypothesis that CO2 can affect the production of pro- and anti-inflammatory cytokines after ex vivo stimulation with endotoxin.
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Hypercapnia induces a concentration-dependent increase in gastric mucosal oxygenation in dogs. Intensive Care Med 2008; 34:1898-906. [DOI: 10.1007/s00134-008-1183-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 03/02/2008] [Indexed: 11/30/2022]
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Hassett P, Laffey JG. Permissive hypercapnia: Balancing risks and benefits in the peripheral microcirculation*. Crit Care Med 2007; 35:2229-31. [PMID: 17713380 DOI: 10.1097/01.ccm.0000281462.98740.c5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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