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Campaña-Duel E, Ceccato A, Morales-Quinteros L, Camprubí-Rimblas M, Artigas A. Hypercapnia and its relationship with respiratory infections. Expert Rev Respir Med 2024; 18:41-47. [PMID: 38489161 DOI: 10.1080/17476348.2024.2331767] [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: 11/13/2023] [Accepted: 03/13/2024] [Indexed: 03/17/2024]
Abstract
INTRODUCTION Hypercapnia is developed in patients with acute and/or chronic respiratory conditions. Clinical data concerning hypercapnia and respiratory infections interaction is limited. AREAS COVERED Currently, the relationship between hypercapnia and respiratory infections remains unclear. In this review, we summarize studies on the effects of hypercapnia on models of pulmonary infections to clarify the role of elevated CO2 in these pulmonary pathologies. Hypercapnia affects different cell types in the alveoli, leading to changes in the immune response. In vitro studies show that hypercapnia downregulates the NF-κβ pathway, reduces inflammation and impairs epithelial wound healing. While in vivo models show a dual role between short- and long-term effects of hypercapnia on lung infection. However, it is still controversial whether the effects observed under hypercapnia are pH dependent or not. EXPERT OPINION The role of hypercapnia is still a controversial debate. Hypercapnia could play a beneficial role in mechanically ventilated models, by lowering the inflammation produced by the stretch condition. But it could be detrimental in infectious scenarios, causing phagocyte dysfunction and lack of infection control. Further data concerning hypercapnia on respiratory infections is needed to elucidate this interaction.
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Affiliation(s)
- Elena Campaña-Duel
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| | - Adrian Ceccato
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
- Intensive care unit, Hospital Universitari Sagrat Cor, Grupo Quironsalud, Barcelona, Spain
| | - Luis Morales-Quinteros
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
- Servei de Medicina Intensiva, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Marta Camprubí-Rimblas
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| | - Antonio Artigas
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
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Vemuri SV, Rolfsen ML, Sykes AV, Takiar PG, Leonard AJ, Malhotra A, Spragg RG, Macedo E, Hepokoski ML. Association Between Acute Kidney Injury During Invasive Mechanical Ventilation and ICU Outcomes and Respiratory System Mechanics. Crit Care Explor 2022; 4:e0720. [PMID: 35782295 PMCID: PMC9246080 DOI: 10.1097/cce.0000000000000720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Compare ICU outcomes and respiratory system mechanics in patients with and without acute kidney injury during invasive mechanical ventilation.
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Almanza-Hurtado A, Polanco Guerra C, Martínez-Ávila MC, Borré-Naranjo D, Rodríguez-Yanez T, Dueñas-Castell C. Hypercapnia from Physiology to Practice. Int J Clin Pract 2022; 2022:2635616. [PMID: 36225533 PMCID: PMC9525762 DOI: 10.1155/2022/2635616] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/28/2022] [Accepted: 09/15/2022] [Indexed: 11/18/2022] Open
Abstract
Acute hypercapnic ventilatory failure is becoming more frequent in critically ill patients. Hypercapnia is the elevation in the partial pressure of carbon dioxide (PaCO2) above 45 mmHg in the bloodstream. The pathophysiological mechanisms of hypercapnia include the decrease in minute volume, an increase in dead space, or an increase in carbon dioxide (CO2) production per sec. They generate a compromise at the cardiovascular, cerebral, metabolic, and respiratory levels with a high burden of morbidity and mortality. It is essential to know the triggers to provide therapy directed at the primary cause and avoid possible complications.
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Terzi N, Guérin C. Optimizing Mechanical Ventilation in Refractory ARDS. ENCYCLOPEDIA OF RESPIRATORY MEDICINE 2022. [PMCID: PMC8740657 DOI: 10.1016/b978-0-12-801238-3.11480-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mechanical ventilation in patients with refractory acute respiratory distress syndrome (ARDS) must provide lung protection. This is achieved by limiting tidal volume (VT) and plateau pressure (Pplat). With the current evidence available VT should be initially set around 6 mL per kg predicted body weight and PPlat maintained below 30 cmH2O and monitored. Positive end-expiratory pressure (PEEP), which also contributes to lung protection, should be set > 12 cmH2O, provided oxygenation gets improved, with same Pplat target. Recruitment maneuvers should be used with caution avoiding higher PEEP. Neuromuscular blockade should be started and prone position performed for sessions longer than 16 h. High frequency oscillation ventilation should be used in expert centers only if previous management failed to improve oxygenation.
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Spinelli E, Mauri T. Reply to: Addition of 5% CO2 to Inspiratory Gas in Preventing Lung Injury Due to Pulmonary Artery Ligation. Am J Respir Crit Care Med 2021; 205:587-588. [PMID: 34890535 PMCID: PMC8906477 DOI: 10.1164/rccm.202111-2500le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
| | - Tommaso Mauri
- Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Department of Anesthesia, Critical Care and Emergency, Milano, Italy;
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Wang SY, Yuan WC, Wu EB. Airway management during left-sided gastrobronchial fistula repair after esophagectomy for esophageal carcinoma: A case report. Medicine (Baltimore) 2021; 100:e27133. [PMID: 34477161 PMCID: PMC8415952 DOI: 10.1097/md.0000000000027133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/31/2021] [Accepted: 08/18/2021] [Indexed: 02/05/2023] Open
Abstract
RATIONALE Gastrobronchial fistula (GBF) is a rare but life-threatening complication of esophagectomy with gastric conduit reconstruction, and airway management during fistula repair is challenging. Here, we describe airway management in a patient undergoing left-sided GBF repair using video-assisted thoracoscopic surgery. PATIENT CONCERNS A 63-year-old man diagnosed with esophageal carcinoma underwent esophagectomy with reconstruction by gastric pull-up and tabularization of the gastric conduit. Subsequently, about 8 weeks later, the patient presented with repeated pneumonia and a 1-week history of cough with significant sputum, dysphagia, and repeated fever. DIAGNOSIS GBF, a rare postoperative complication, was located on the left main bronchus at 2 cm below the carina and was diagnosed based on findings from gastroscopy, flexible bronchoscopy, and thoracic computed tomography scan with contrast. INTERVENTIONS We performed left-sided one-lung ventilation (OLV) under total intravenous anesthesia instead of inhalational anesthetics. The left-sided OLV, with positive end-expiratory pressure (PEEP) and nasogastric tube decompression, generated positive pressure across the fistula. It prevented backflow into the left main bronchus. Total intravenous anesthesia preserved hypoxic pulmonary vasoconstriction and prevented adverse effects associated with inhalational anesthetics. A right-sided, double-lumen endotracheal tube was inserted after anesthesia induction, and surgical repair was performed through a right-sided video-assisted thoracoscopic surgery. OUTCOMES Intraoperative hemodynamics remained relatively stable, except for brief tachycardia at 113 beats/min. Arterial blood gas analysis revealed pH 7.17 and PaO2 89.1 mmHg upon 100% oxygenation, along with hypercapnia (PaCO2 77.1 mmHg), indicating respiratory acidosis. During OLV, pulse oximetry remained higher than 92%. The defect in the left main bronchus was successfully sutured after dissecting the fistula between the left main bronchus and the gastric conduit, and subsequently, OLV resulted in ideal ventilation. LESSONS A left-sided GBF could lead to leakage from the OLV during surgery. Possible aspiration or alveolar hypoventilation due to this leakage is a major concern during airway management before surgical repair of the main bronchus.
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Masterson CH, O'Toole D, Laffey JG. Inhaled CO2 to Reduce Lung Ischemia and Reperfusion Injuries: Moving Towards Clinical Translation? Am J Respir Crit Care Med 2021; 204:878-879. [PMID: 34375575 PMCID: PMC8534625 DOI: 10.1164/rccm.202107-1665ed] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Claire H Masterson
- National University of Ireland Galway, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, Galway, Ireland
| | - Daniel O'Toole
- National University of Ireland Galway, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, Galway, Ireland
| | - John G Laffey
- National University of Ireland, Galway, Lung Biology Group, Galway, Ireland;
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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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Korang SK, Safi S, Feinberg J, Nielsen EE, Gluud C, Jakobsen JC. Bicarbonate for acute acidosis. Hippokratia 2021. [DOI: 10.1002/14651858.cd014371] [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)
- Steven Kwasi Korang
- Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
| | - Sanam Safi
- Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
| | - Joshua Feinberg
- Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
| | - Emil Eik Nielsen
- Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
| | - Christian Gluud
- Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
- Cochrane Hepato-Biliary Group, Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
- Department of Regional Health Research, The Faculty of Health Sciences; University of Southern Denmark; Odense Denmark
| | - Janus C Jakobsen
- Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
- Cochrane Hepato-Biliary Group, Copenhagen Trial Unit, Centre for Clinical Intervention Research; The Capital Region of Denmark, Rigshospitalet, Copenhagen University Hospital; Copenhagen Denmark
- Department of Regional Health Research, The Faculty of Health Sciences; University of Southern Denmark; Odense Denmark
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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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11
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Santini A, Fumagalli J, Merrino A, Protti I, Paleari MC, Montoli M, Dondossola D, Gori F, Righi I, Rosso L, Gatti S, Pesenti A, Grasselli G, Zanella A. Evidence of Air Trapping During Ex Vivo Lung Perfusion: A Swine Experimental Lung Imaging and Mechanics Study. Transplant Proc 2020; 53:457-465. [PMID: 33339649 DOI: 10.1016/j.transproceed.2020.10.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/21/2020] [Accepted: 10/19/2020] [Indexed: 11/17/2022]
Abstract
Ex vivo lung perfusion (EVLP) allows the ventilation and perfusion of lungs to evaluate their viability for transplantation. The aim of this study is to compare the mechanical, morphologic and functional properties of lungs during EVLP with values obtained in vivo to guide a safe mechanical ventilation strategy. Lungs from 5 healthy pigs were studied in vivo and during 4 hours of EVLP. Lung compliance, airway resistance, gas exchange, and hemodynamic parameters were collected at positive end-expiratory pressure (PEEP) of 5 cm H2O. Computed tomography was performed at PEEP 0, PEEP 5, and total lung capacity (TLC). Lung pressure-volume (PV) curves were performed from PEEP 0 to TLC. Lung compliance decreased during EVLP (53 ± 5 mL/cm H2O vs 29 ± 7 mL/cm H2O, P < .05), and the PV curve showed a lower inflection point. Gas content (528 ± 118 mL vs 892 ± 402 mL at PEEP 0) and airway resistance (25 ± 5 vs 44 ± 9 cmH2O/L∗s-1, P < .05) were higher during EVLP. Alveolar dead space (5% ± 2% vs 17% ± 6%, P < .05) and intrapulmonary shunt (9% ± 2% vs 28% ± 13%, P < .05) increased ex vivo compared to in vivo, while the partial pressure of oxygen to inspired oxygen fraction ratio (PO2/FiO2) did not differ (468 ± 52 mm Hg vs 536 ± 14 mm Hg). In conclusion, during EVLP lungs show signs of air trapping and bronchoconstriction, resulting in low compliance and increased alveolar dead space. Intrapulmonary shunt is high despite oxygenation levels acceptable for transplantation.
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Affiliation(s)
- A Santini
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Anestesia e Terapie Intensive, Humanitas Clinical and Research Center, IRCCS, Rozzano, Milan, Italy
| | - J Fumagalli
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Merrino
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - I Protti
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - M C Paleari
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - M Montoli
- Dipartimento di Chirurgia Toracica, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - D Dondossola
- Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy; Dipartimento di Chirurgia Generale e dei Trapianti di Fegato, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - F Gori
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - I Righi
- Dipartimento di Chirurgia Toracica, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - L Rosso
- Dipartimento di Chirurgia Toracica, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - S Gatti
- Centro di Ricerche Precliniche, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - A Pesenti
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - G Grasselli
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy
| | - A Zanella
- Dipartimento di Anestesia, Rianimazione ed Emergenza, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy; Dipartimento di Fisiopatologia Medico-Chirurgica e dei Trapianti, Università degli Studi di Milano, Milan, Italy.
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12
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Madotto F, Rezoagli E, McNicholas BA, Pham T, Slutsky AS, Bellani G, Laffey JG. Patterns and Impact of Arterial CO 2 Management in Patients With Acute Respiratory Distress Syndrome: Insights From the LUNG SAFE Study. Chest 2020; 158:1967-1982. [PMID: 32589951 DOI: 10.1016/j.chest.2020.05.605] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/08/2020] [Accepted: 05/29/2020] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Considerable variability exists regarding CO2 management in early ARDS, with the impact of arterial CO2 tension on management and outcomes poorly understood. RESEARCH QUESTION To determine the prevalence and impact of hypocapnia and hypercapnia on the management and outcomes of patients with early ARDS enrolled in the Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure (LUNG SAFE) study, an international multicenter observational study. STUDY DESIGN AND METHODS Our primary objective was to examine the prevalence of day 1 and sustained (day 1 and 2) hypocapnia (Paco2 < 35 mm Hg), normocapnia (Paco2 35-45 mm Hg), and hypercapnia (Paco2 > 45 mm Hg) in patients with ARDS. Secondary objectives included elucidating the effect of CO2 tension on ventilatory management and examining the relationship with ARDS outcome. RESULTS Of 2,813 patients analyzed, 551 (19.6%; 95%CI, 18.1-21.1) were hypocapnic, 1,018 (36.2%; 95% CI, 34.4-38.0) were normocapnic, and 1,214 (43.2%; 95% CI, 41.3-45.0) were hypercapnic, on day 1. Sustained hypocapnia was seen in 252 (9.3%; 95% CI, 8.2-10.4), sustained normocapnia in 544 (19.3%; 95% CI, 17.9-20.8), and sustained hypercapnia in 654 (24.1%; 95% CI, 22.5-25.7) patients. Hypocapnia was more frequent and severe in patients receiving noninvasive ventilation but also was observed in patients on controlled mechanical ventilation. Sustained hypocapnia was more frequent in middle-income countries, whereas sustained hypercapnia was more frequent in Europe. ARDS severity profile was highest in sustained hypercapnia, and these patients received more protective ventilation. No independent association was seen between arterial CO2 and outcome. In propensity-matched analyses, the hospital mortality rate was 36% in both sustained normocapnic and hypercapnic patients (P = 1.0). ICU mortality was higher in patients with mild to moderate ARDS receiving sustained hypocapnia (38.1%) compared with normocapnia (27.1%). INTERPRETATION No evidence was found for benefit or harm with hypercapnia. Of concern, ICU mortality was higher with sustained hypocapnia in mild to moderate ARDS.
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Affiliation(s)
- Fabiana Madotto
- IRCCS MultiMedica, Value-based healthcare unit, Sesto San Giovanni (Milan), Italy
| | - Emanuele Rezoagli
- School of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy; Department of Emergency and Intensive Care, San Gerardo Hospital, Monza, Italy
| | - Bairbre A McNicholas
- School of Medicine, National University of Ireland Galway, Galway, Ireland; Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Galway, Ireland
| | - Tài Pham
- Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada; Service de médecine intensive-réanimation, AP-HP, Hôpital de Bicêtre, Hôpitaux Universitaires Paris-Saclay, Le Kremlin-Bicêtre, France; Keenan Research Center at the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada
| | - Arthur S Slutsky
- Keenan Research Center at the Li Ka Shing Knowledge Institute of St. Michael's Hospital, Toronto, ON, Canada; Interdepartmental Division of Critical Care Medicine, and the Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Giacomo Bellani
- School of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy; Department of Emergency and Intensive Care, San Gerardo Hospital, Monza, Italy
| | - John G Laffey
- School of Medicine, National University of Ireland Galway, Galway, Ireland; Department of Anaesthesia and Intensive Care Medicine, Galway University Hospitals, Galway, Ireland; Lung Biology Group, Regenerative Medicine Institute (REMEDI) at CÚRAM Centre for Research in Medical Devices, Biomedical Sciences Building, National University of Ireland Galway, Galway, Ireland.
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13
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Morales-Quinteros L, Camprubí-Rimblas M, Bringué J, Bos LD, Schultz MJ, Artigas A. The role of hypercapnia in acute respiratory failure. Intensive Care Med Exp 2019; 7:39. [PMID: 31346806 PMCID: PMC6658637 DOI: 10.1186/s40635-019-0239-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 03/07/2019] [Indexed: 12/16/2022] Open
Abstract
The biological effects and physiological consequences of hypercapnia are increasingly understood. The literature on hypercapnia is confusing, and at times contradictory. On the one hand, it may have protective effects through attenuation of pulmonary inflammation and oxidative stress. On the other hand, it may also have deleterious effects through inhibition of alveolar wound repair, reabsorption of alveolar fluid, and alveolar cell proliferation. Besides, hypercapnia has meaningful effects on lung physiology such as airway resistance, lung oxygenation, diaphragm function, and pulmonary vascular tree. In acute respiratory distress syndrome, lung-protective ventilation strategies using low tidal volume and low airway pressure are strongly advocated as these have strong potential to improve outcome. These strategies may come at a price of hypercapnia and hypercapnic acidosis. One approach is to accept it (permissive hypercapnia); another approach is to treat it through extracorporeal means. At present, it remains uncertain what the best approach is.
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Affiliation(s)
- Luis Morales-Quinteros
- Intensive Care Unit, Hospital Universitario Sagrado Corazón, Carrer de Viladomat, 288, 08029, Barcelona, Spain.
| | - Marta Camprubí-Rimblas
- Department of Medicine, Universitat Autònoma de Barcelona, Bellatera, Spain.,Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain
| | - Josep Bringué
- Department of Medicine, Universitat Autònoma de Barcelona, Bellatera, Spain.,Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Lieuwe D Bos
- Department of Intensive Care, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.,Respiratory Medicine, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory of Experimental Intensive Care and Anesthesiology (L·E·I·C·A), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Marcus J Schultz
- Department of Intensive Care, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.,Laboratory of Experimental Intensive Care and Anesthesiology (L·E·I·C·A), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands.,Mahidol Oxford Tropical Medicine Research Unit (MORU), Mahidol University, Bangkok, Thailand
| | - Antonio Artigas
- Intensive Care Unit, Hospital Universitario Sagrado Corazón, Carrer de Viladomat, 288, 08029, Barcelona, Spain.,Department of Medicine, Universitat Autònoma de Barcelona, Bellatera, Spain.,Critical Care Center, Corporació Sanitària I Universitària Parc Taulí, Sabadell, Spain.,Institut d'Investigació i Innovació Parc Taulí (I3PT), Sabadell, Spain.,Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), Madrid, Spain
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Protection of Myocardial Ischemia-Reperfusion by Therapeutic Hypercapnia: a Mechanism Involving Improvements in Mitochondrial Biogenesis and Function. J Cardiovasc Transl Res 2019; 12:467-477. [PMID: 30980235 DOI: 10.1007/s12265-019-09886-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 03/26/2019] [Indexed: 12/14/2022]
Abstract
Previous studies proposed that acidic reperfusion may be a protective strategy for myocardial ischemia-reperfusion therapy with potential of clinical transformation. In this study, we investigated whether therapeutic hypercapnia could mimic acidosis postconditioning in isolated hearts with a 30-min left coronary artery ligation-reperfusion model in rats. Therapeutic hypercapnia (inhalation 20% CO2 for 10 min) is cardioprotective with a strict therapeutic time window and acidity: it reduced the infarct ratio and serum myocardial enzyme and increased the myocardial ATP content. Furthermore, mitochondrial morphology damage, the loss of mitochondrial membrane potential, and the formation of mitochondrial permeability transition pore were effectively inhibited, indicating the improvements in mitochondrial function. The expression of the mitochondrial biogenesis regulators was upregulated simultaneously. These findings indicated therapeutic hypercapnia in animals can mimic ex vivo acidosis postconditioning to alleviate myocardial ischemia-reperfusion injury. The effect is related to improvement in mitochondrial function and regulation of the mitochondrial biogenesis pathway.
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Gavra P, Denault AY, Théoret Y, Perrault LP, Varin F. Pharmacokinetics and Pharmacodynamics of Nebulized and Intratracheal Milrinone in a Swine Model of Hypercapnia Pulmonary Hypertension. J Cardiothorac Vasc Anesth 2018. [DOI: 10.1053/j.jvca.2018.01.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Driving-pressure-independent protective effects of open lung approach against experimental acute respiratory distress syndrome. Crit Care 2018; 22:228. [PMID: 30243301 PMCID: PMC6151188 DOI: 10.1186/s13054-018-2154-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 08/08/2018] [Indexed: 12/16/2022] Open
Abstract
Background The open lung approach (OLA) reportedly has lung-protective effects against acute respiratory distress syndrome (ARDS). Recently, lowering of the driving pressure (ΔP), rather than improvement in lung aeration per se, has come to be considered as the primary lung-protective mechanism of OLA. However, the driving pressure-independent protective effects of OLA have never been evaluated in experimental studies. We here evaluated whether OLA shows protective effects against experimental ARDS even when the ΔP is not lowered. Methods Lipopolysaccharide was intratracheally administered to rats to establish experimental ARDS. After 24 h, rats were mechanically ventilated and randomly allocated to the OLA or control group. In the OLA group, 5 cmH2O positive end-expiratory pressure (PEEP) and recruitment maneuver (RM) were applied. Neither PEEP nor RM was applied to the rats in the control group. Dynamic ΔP was kept at 15 cmH2O in both groups. After 6 h of mechanical ventilation, rats in both groups received RM to inflate reversible atelectasis of the lungs. Arterial blood gas analysis, lung computed tomography, histological evaluation, and comprehensive biochemical analysis were performed. Results OLA significantly improved lung aeration, arterial oxygenation, and gas exchange. Even after RM in both groups, the differences in these parameters between the two groups persisted, indicating that the atelectasis-induced respiratory dysfunction observed in the control group is not an easily reversible functional problem. Lung histological damage was severe in the dorsal dependent area in both groups, but was attenuated by OLA. White blood cell counts, protein concentrations, and tissue injury markers in the broncho-alveolar lavage fluid (BALF) were higher in the control than in the OLA group. Furthermore, levels of CXCL-7, a platelet-derived chemokine, were higher in the BALF from the control group, indicating that OLA protects the lungs by suppressing platelet activation. Conclusions OLA shows protective effects against experimental ARDS, even when the ΔP is not decreased. In addition to reducing ΔP, maintaining lung aeration seems to be important for lung protection in ARDS. Electronic supplementary material The online version of this article (10.1186/s13054-018-2154-2) contains supplementary material, which is available to authorized users.
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Preemptive Mechanical Ventilation Based on Dynamic Physiology in the Alveolar Microenvironment: Novel Considerations of Time-Dependent Properties of the Respiratory System. J Trauma Acute Care Surg 2018; 85:1081-1091. [PMID: 30124627 DOI: 10.1097/ta.0000000000002050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The acute respiratory distress syndrome (ARDS) remains a serious clinical problem with the current treatment being supportive in the form of mechanical ventilation. However, mechanical ventilation can be a double-edged sword; if set properly, it can significantly reduce ARDS associated mortality but if set improperly it can have unintended consequences causing a secondary ventilator induced lung injury (VILI). The hallmark of ARDS pathology is a heterogeneous lung injury, which predisposes the lung to a secondary VILI. The current standard of care approach is to wait until ARDS is well established and then apply a low tidal volume (LVt) strategy to avoid over-distending the remaining normal lung. However, even with the use of LVt strategy, the mortality of ARDS remains unacceptably high at ~40%. In this review, we analyze the lung pathophysiology associated with ARDS that renders the lung highly vulnerable to a secondary VILI. The current standard of care LVt strategy is critiqued as well as new strategies used in combination with LVt to protect the lung. Using the current understanding of alveolar mechanics (i.e. the dynamic change in alveolar size and shape with tidal ventilation) we provide a rationale for why the current protective ventilation strategies have not further reduced ARDS mortality. New strategies of protective ventilation based on dynamic physiology in the micro-environment (i.e. alveoli and alveolar ducts) are discussed. Current evidence suggests that alveolar inflation and deflation is viscoelastic in nature, with a fast and slow phase in both alveolar recruitment and collapse. Using this knowledge, a ventilation strategy with a prolonged time at inspiration would recruit alveoli and a brief release time at expiration would prevent alveolar collapse, converting heterogeneous to homogeneous lung inflation significantly reducing ARDS incidence and mortality.
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18
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Morales Quinteros L, Bringué Roque J, Kaufman D, Artigas Raventós A. Importance of carbon dioxide in the critical patient: Implications at the cellular and clinical levels. Med Intensiva 2018; 43:234-242. [PMID: 29486904 DOI: 10.1016/j.medin.2018.01.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/10/2018] [Accepted: 01/10/2018] [Indexed: 01/22/2023]
Abstract
Important recent insights have emerged regarding the cellular and molecular role of carbon dioxide (CO2) and the effects of hypercapnia. The latter may have beneficial effects in patients with acute lung injury, affording reductions in pulmonary inflammation, lessened oxidative alveolar damage, and the regulation of innate immunity and host defenses by inhibiting the expression of inflammatory cytokines. However, other studies suggest that CO2 can have deleterious effects upon the lung, reducing alveolar wound repair in lung injury, decreasing the rate of reabsorption of alveolar fluid, and inhibiting alveolar cell proliferation. Clearly, hypercapnia has both beneficial and harmful consequences, and it is important to determine the net effect under specific conditions. The purpose of this review is to describe the immunological and physiological effects of carbon dioxide, considering their potential consequences in patients with acute respiratory failure.
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Affiliation(s)
| | | | - David Kaufman
- Division of Pulmonary, Critical Care & Sleep, NYU School of Medicine, New York, NY, Estados Unidos
| | - Antonio Artigas Raventós
- Servicio de Medicina Intensiva, Hospital Universitario Sagrat Cor, Barcelona, España; Universidad Autónoma de Barcelona, Sabadell, Barcelona, España; Centro de Investigación Biomédica en Red de Enfermedades Respiratorias, España
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19
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Effects of Hypercapnia on Acute Cellular Rejection after Lung Transplantation in Rats. Anesthesiology 2017; 128:130-139. [PMID: 29023354 DOI: 10.1097/aln.0000000000001908] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Hypercapnia alleviates pulmonary ischemia-reperfusion injury, regulates T lymphocytes, and inhibits immune reaction. This study aimed to evaluate the effect of hypercapnia on acute cellular rejection in a rat lung transplantation model. METHODS Recipient rats in sham-operated (Wistar), isograft (Wistar to Wistar), and allograft (Sprague-Dawley to Wistar) groups were ventilated with 50% oxygen, whereas rats in the hypercapnia (Sprague-Dawley to Wistar) group were administered 50% oxygen and 8% carbon dioxide for 90 min during reperfusion (n = 8). Recipients were euthanized 7 days after transplantation. RESULTS The hypercapnia group showed a higher oxygenation index (413 ± 78 vs. 223 ± 24), lower wet weight-to-dry weight ratio (4.23 ± 0.54 vs. 7.04 ± 0.80), lower rejection scores (2 ± 1 vs. 4 ± 1), and lower apoptosis index (31 ± 6 vs. 57 ± 4) as compared with the allograft group. The hypercapnia group showed lower CD8 (17 ± 4 vs. 31 ± 3) and CD68 (24 ± 3 vs. 43 ± 2), lower CD8 T cells (12 ± 2 vs. 35 ± 6), and higher CD4/CD8 ratio (2.2 ± 0.6 vs. 1.1 ± 0.4) compared to the allograft group. Tumor necrosis factor-α (208 ± 40 vs. 292 ± 49), interleukin-2 (30.6 ± 6.7 vs. 52.7 ± 8.3), and interferon-γ (28.1 ± 4.9 vs. 62.7 ± 10.1) levels in the hypercapnia group were lower than those in allograft group. CD4, CD4 T cells, and interleukin-10 levels were similar between groups. CONCLUSIONS Hypercapnia ameliorated acute cellular rejection in a rat lung transplantation model.
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20
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Tiruvoipati R, Pilcher D, Buscher H, Botha J, Bailey M. Effects of Hypercapnia and Hypercapnic Acidosis on Hospital Mortality in Mechanically Ventilated Patients. Crit Care Med 2017; 45:e649-e656. [PMID: 28406813 DOI: 10.1097/ccm.0000000000002332] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVES Lung-protective ventilation is used to prevent further lung injury in patients on invasive mechanical ventilation. However, lung-protective ventilation can cause hypercapnia and hypercapnic acidosis. There are no large clinical studies evaluating the effects of hypercapnia and hypercapnic acidosis in patients requiring mechanical ventilation. DESIGN Multicenter, binational, retrospective study aimed to assess the impact of compensated hypercapnia and hypercapnic acidosis in patients receiving mechanical ventilation. SETTINGS Data were extracted from the Australian and New Zealand Intensive Care Society Centre for Outcome and Resource Evaluation Adult Patient Database over a 14-year period where 171 ICUs contributed deidentified data. PATIENTS Patients were classified into three groups based on a combination of pH and carbon dioxide levels (normocapnia and normal pH, compensated hypercapnia [normal pH with elevated carbon dioxide], and hypercapnic acidosis) during the first 24 hours of ICU stay. Logistic regression analysis was used to identify the independent association of hypercapnia and hypercapnic acidosis with hospital mortality. INTERVENTIONS Nil. MEASUREMENTS AND MAIN RESULTS A total of 252,812 patients (normocapnia and normal pH, 110,104; compensated hypercapnia, 20,463; and hypercapnic acidosis, 122,245) were included in analysis. Patients with compensated hypercapnia and hypercapnic acidosis had higher Acute Physiology and Chronic Health Evaluation III scores (49.2 vs 53.2 vs 68.6; p < 0.01). The mortality was higher in hypercapnic acidosis patients when compared with other groups, with the lowest mortality in patients with normocapnia and normal pH. After adjusting for severity of illness, the adjusted odds ratio for hospital mortality was higher in hypercapnic acidosis patients (odds ratio, 1.74; 95% CI, 1.62-1.88) and compensated hypercapnia (odds ratio, 1.18; 95% CI, 1.10-1.26) when compared with patients with normocapnia and normal pH (p < 0.001). In patients with hypercapnic acidosis, the mortality increased with increasing PCO2 until 65 mm Hg after which the mortality plateaued. CONCLUSIONS Hypercapnic acidosis during the first 24 hours of intensive care admission is more strongly associated with increased hospital mortality than compensated hypercapnia or normocapnia.
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Affiliation(s)
- Ravindranath Tiruvoipati
- 1Department of Intensive Care Medicine, Frankston Hospital, Frankston, VIC, Australia.2Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia.3ANZIC-RC, Department of Epidemiology & Preventive Medicine, School of Public Health and Preventive Medicine, Monash University, The Alfred Centre, Melbourne, VIC, Australia.4Department of Intensive Care Medicine, St Vincent's Hospital, Sydney, NSW, Australia.5University of New South Wales, Kensington, NSW, Australia
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Abstract
Critical care medicine is a young specialty that has experienced an expansion of research efforts in the last decade. Many physiologic and therapeutic principles or “dogmas” have been challenged, resulting in major “shifts” and minor “drifts” in thinking. This article reviews the available literature about some of these important and sometimes controversial changes, with emphasis on the practical implications of the concepts. Specific areas discussed include supply-dependent oxygen consumption in critical illness, manipulation of the cytokine cascade in sepsis, ventilation in the acute respiratory distress syndrome (ARDS), blood transfusion in the critically ill, the concept of the multiple organ dysfunction syndrome (MODS), the need for nutritional support in the critically ill, and others. Many of the changes discussed involve the recognition that the host response to a severe insult is exceedingly complex, and the understanding of this response and the effects of it at a tissue and cellular level are incomplete. As a result, the ability to impact the outcome of sepsis and MODS has thus far been disappointing, with the possible exception of “lung-protective” ventilation. The final challenge in critical care medicine is to gain information that will allow the practitioner to better understand, prevent, and treat the complex events that result in organ and cellular dysfunction. Future changes in dogma are welcome if they help achieve these goals.
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Affiliation(s)
- Ari Robin Joffe
- Department of Pediatrics, University of Alberta Hospital, University of Alberta, Edmonton, Alberta, Canada.
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22
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Aguirre-Bermeo H, Morán I, Bottiroli M, Italiano S, Parrilla FJ, Plazolles E, Roche-Campo F, Mancebo J. End-inspiratory pause prolongation in acute respiratory distress syndrome patients: effects on gas exchange and mechanics. Ann Intensive Care 2016; 6:81. [PMID: 27558174 PMCID: PMC4996808 DOI: 10.1186/s13613-016-0183-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/11/2016] [Indexed: 11/19/2022] Open
Abstract
Background End-inspiratory pause (EIP) prolongation decreases dead space-to-tidal volume ratio (Vd/Vt) and PaCO2. We do not know the physiological benefits of this approach to improve respiratory system mechanics in acute respiratory distress syndrome (ARDS) patients when mild hypercapnia is of no concern. Methods The investigation was conducted in an intensive care unit of a university hospital, and 13 ARDS patients were included. The study was designed in three phases. First phase, baseline measurements were taken. Second phase, the EIP was prolonged until one of the following was achieved: (1) EIP of 0.7 s; (2) intrinsic positive end-expiratory pressure ≥1 cmH2O; or (3) inspiratory–expiratory ratio 1:1. Third phase, the Vt was decreased (30 mL every 30 min) until PaCO2 equal to baseline was reached. FiO2, PEEP, airflow and respiratory rate were kept constant. Results EIP was prolonged from 0.12 ± 0.04 to 0.7 s in all patients. This decreased the Vd/Vt and PaCO2 (0.70 ± 0.07 to 0.64 ± 0.08, p < 0.001 and 54 ± 9 to 50 ± 8 mmHg, p = 0.001, respectively). In the third phase, the decrease in Vt (from 6.3 ± 0.8 to 5.6 ± 0.8 mL/Kg PBW, p < 0.001) allowed to decrease plateau pressure and driving pressure (24 ± 3 to 22 ± 3 cmH2O, p < 0.001 and 13.4 ± 3.6 to 10.9 ± 3.1 cmH2O, p < 0.001, respectively) and increased respiratory system compliance from 29 ± 9 to 32 ± 11 mL/cmH2O (p = 0.001). PaO2 did not significantly change. Conclusions Prolonging EIP allowed a significant decrease in Vt without changes in PaCO2 in passively ventilated ARDS patients. This produced a significant decrease in plateau pressure and driving pressure and significantly increased respiratory system compliance, which suggests less overdistension and less dynamic strain.
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Affiliation(s)
- Hernan Aguirre-Bermeo
- Servei de Medicina Intensiva, Hospital de la Santa Creu i Sant Pau, Universidad Autònoma de Barcelona (UAB), Sant Quintí, 89, 08041, Barcelona, Spain
| | - Indalecio Morán
- Servei de Medicina Intensiva, Hospital de la Santa Creu i Sant Pau, Universidad Autònoma de Barcelona (UAB), Sant Quintí, 89, 08041, Barcelona, Spain
| | | | - Stefano Italiano
- Servei de Medicina Intensiva, Hospital de la Santa Creu i Sant Pau, Universidad Autònoma de Barcelona (UAB), Sant Quintí, 89, 08041, Barcelona, Spain
| | - Francisco José Parrilla
- Servei de Medicina Intensiva, Hospital de la Santa Creu i Sant Pau, Universidad Autònoma de Barcelona (UAB), Sant Quintí, 89, 08041, Barcelona, Spain
| | - Eugenia Plazolles
- Servei de Medicina Intensiva, Hospital de la Santa Creu i Sant Pau, Universidad Autònoma de Barcelona (UAB), Sant Quintí, 89, 08041, Barcelona, Spain
| | - Ferran Roche-Campo
- Servei de Medicina Intensiva, Hospital Verge de la Cinta, Tortosa, Spain
| | - Jordi Mancebo
- Servei de Medicina Intensiva, Hospital de la Santa Creu i Sant Pau, Universidad Autònoma de Barcelona (UAB), Sant Quintí, 89, 08041, Barcelona, Spain.
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The Goldilocks Principle, Carbon Dioxide, and Acute Respiratory Distress Syndrome: Too Much, Too Little, or Just Right? Anesthesiology 2016; 124:532-4. [PMID: 26709573 DOI: 10.1097/aln.0000000000000996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Horie S, Ansari B, Masterson C, Devaney J, Scully M, O'Toole D, Laffey JG. Hypercapnic acidosis attenuates pulmonary epithelial stretch-induced injury via inhibition of the canonical NF-κB pathway. Intensive Care Med Exp 2016; 4:8. [PMID: 27001525 PMCID: PMC4801837 DOI: 10.1186/s40635-016-0081-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 03/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypercapnia, with its associated acidosis (HCA), is a consequence of respiratory failure and is also seen in critically ill patients managed with conventional "protective" ventilation strategies. Nuclear factor kappa-B (NF-κB), a pivotal transcription factor, is activated in the setting of injury and repair and is central to innate immunity. We have previously established that HCA protects against ventilation-induced lung injury in vivo, potentially via a mechanism involving inhibition of NF-κB signaling. We wished to further elucidate the role and mechanism of HCA-mediated inhibition of the NF-κB pathway in attenuating stretch-induced injury in vitro. METHODS Initial experiments examined the effect of HCA on cyclic stretch-induced inflammation and injury in human bronchial and alveolar epithelial cells. Subsequent experiments examined the role of the canonical NF-κB pathway in mediating stretch-induced injury and the mechanism of action of HCA. The contribution of pH versus CO2 in mediating this effect of HCA was also examined. RESULTS Pulmonary epithelial high cyclic stretch (22 % equibiaxial strain) activated NF-κB, enhanced interleukin-8 (IL-8) production, caused cell injury, and reduced cell survival. In contrast, physiologic stretch (10 % strain) did not activate inflammation or cause cell injury. HCA reduced cyclic mechanical stretch-induced NF-κB activation, attenuated IL-8 production, reduced injury, and enhanced survival, in bronchial and alveolar epithelial cells, following shorter (24 h) and longer (120 h) cyclic mechanical stretch. Pre-conditioning with HCA was less effective than when HCA was applied after commencement of cell stretch. HCA prevented the stretch-induced breakdown of the NF-κB cytosolic inhibitor IκBα, while IκBα overexpression "occluded" the effect of HCA. These effects were mediated by a pH-dependent mechanism rather than via CO2 per se. CONCLUSIONS HCA attenuates adverse mechanical stretch-induced epithelial injury and death, via a pH-dependent mechanism that inhibits the canonical NF-κB activation by preventing IκBα breakdown.
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Affiliation(s)
- Shahd Horie
- Discipline of Anaesthesia, School of Medicine, Clinical Sciences Institute, National University of Ireland, Galway, Ireland.,Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
| | - Bilal Ansari
- Discipline of Anaesthesia, School of Medicine, Clinical Sciences Institute, National University of Ireland, Galway, Ireland.,Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
| | - Claire Masterson
- Regenerative Medicine Institute, National University of Ireland, Galway, Ireland.,Department of Anesthesia, Critical Illness and Injury Research Centre, Keenan Research Centre for Biomedical Science, St Michael's Hospital, University of Toronto, Toronto, Canada
| | - James Devaney
- Discipline of Anaesthesia, School of Medicine, Clinical Sciences Institute, National University of Ireland, Galway, Ireland.,Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
| | - Michael Scully
- Discipline of Anaesthesia, School of Medicine, Clinical Sciences Institute, National University of Ireland, Galway, Ireland.,Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
| | - Daniel O'Toole
- Discipline of Anaesthesia, School of Medicine, Clinical Sciences Institute, National University of Ireland, Galway, Ireland.,Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
| | - John G Laffey
- Regenerative Medicine Institute, National University of Ireland, Galway, Ireland. .,Department of Anesthesia, Critical Illness and Injury Research Centre, Keenan Research Centre for Biomedical Science, St Michael's Hospital, University of Toronto, Toronto, Canada.
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Effect of Therapeutic Hypercapnia on Inflammatory Responses to One-lung Ventilation in Lobectomy Patients. Anesthesiology 2015; 122:1235-52. [PMID: 25751232 DOI: 10.1097/aln.0000000000000627] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND One-lung ventilation (OLV) can result in local and systemic inflammation. This prospective, randomized trial was to evaluate the effect of therapeutic hypercapnia on lung injury after OLV. METHOD Fifty patients aged 20 to 60 yr undergoing lobectomy were randomly provided with air or carbon dioxide (partial pressure of carbon dioxide: 35 to 45 mmHg or 60 to 70 mmHg). Peak pressure, plateau pressure, and lung compliance were recorded. Bronchoalveolar lavage fluid (BALF) and blood samples were collected. Adverse events were monitored. The primary outcome was the concentration of BALF tumor necrosis factor, and the secondary outcomes were serum cytokine concentrations. RESULTS The BALF tumor necrosis factor was lower in the carbon dioxide group than in the air group (median [range], 51.1 [42.8 to 76.6] vs. 71.2 [44.8 to 92.7]; P = 0.034). Patients in the carbon dioxide group had lower concentrations of serum and BALF interleukin (IL)-1, IL-6, and IL-8, but higher serum concentrations of IL-10, accompanied by reduced numbers of cells and neutrophils as well as lower concentrations of protein in the BALF. Also, patients in the carbon dioxide group had lower peak (mean ± SD, 22.2 ± 2.9 vs. 29.8 ± 4.6) and plateau pressures (20.5 ± 2.4 vs. 27.1 ± 2.9), but higher dynamic compliance (46.6 ± 5.8 vs. 38.9 ± 6.5). Furthermore, patients in the carbon dioxide group had higher postoperation oxygenation index values. Ten patients experienced slightly increased blood pressure and heart rate during OLV in the carbon dioxide group. CONCLUSION Under intravenous anesthesia, therapeutic hypercapnia inhibits local and systematic inflammation and improves respiratory function after OLV in lobectomy patients without severe complications.
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Thome UH, Genzel-Boroviczeny O, Bohnhorst B, Schmid M, Fuchs H, Rohde O, Avenarius S, Topf HG, Zimmermann A, Faas D, Timme K, Kleinlein B, Buxmann H, Schenk W, Segerer H, Teig N, Gebauer C, Hentschel R, Heckmann M, Schlösser R, Peters J, Rossi R, Rascher W, Böttger R, Seidenberg J, Hansen G, Zernickel M, Alzen G, Dreyhaupt J, Muche R, Hummler HD. Permissive hypercapnia in extremely low birthweight infants (PHELBI): a randomised controlled multicentre trial. THE LANCET RESPIRATORY MEDICINE 2015; 3:534-43. [PMID: 26088180 DOI: 10.1016/s2213-2600(15)00204-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/08/2015] [Accepted: 05/14/2015] [Indexed: 02/02/2023]
Abstract
BACKGROUND Tolerating higher partial pressure of carbon dioxide (pCO2) in mechanically ventilated, extremely low birthweight infants might reduce ventilator-induced lung injury and bronchopulmonary dysplasia. We aimed to test the hypothesis that higher target ranges for pCO2 decrease the rate of bronchopulmonary dysplasia or death. METHODS In this randomised multicentre trial, we recruited infants from 16 tertiary care perinatal centres in Germany with birthweight between 400 g and 1000 g and gestational age 23-28 weeks plus 6 days, who needed endotracheal intubation and mechanical ventilation within 24 h of birth. Infants were randomly assigned to either a high target or control group. The high target group aimed at pCO2 values of 55-65 mm Hg on postnatal days 1-3, 60-70 mm Hg on days 4-6, and 65-75 mm Hg on days 7-14, and the control target at pCO2 40-50 mmHg on days 1-3, 45-55 mm Hg on days 4-6, and 50-60 mm Hg on days 7-14. The primary outcome was death or moderate to severe bronchopulmonary dysplasia, defined as need for mechanical pressure support or supplemental oxygen at 36 weeks postmenstrual age. Cranial ultrasonograms were assessed centrally by a masked paediatric radiologist. This trial is registered with the ISRCTN registry, number ISRCTN56143743. RESULTS Between March 1, 2008, and July 31, 2012, we recruited 362 patients of whom three dropped out, leaving 179 patients in the high target and 180 in the control group. The trial was stopped after an interim analysis (n=359). The rate of bronchopulmonary dysplasia or death in the high target group (65/179 [36%]) did not differ significantly from the control group (54/180 [30%]; p=0·18). Mortality was 25 (14%) in the high target group and 19 (11%; p=0·32) in the control group, grade 3-4 intraventricular haemorrhage was 26 (15%) and 21 (12%; p=0·30), and the rate of severe retinopathy recorded was 20 (11%) and 26 (14%; p=0·36). INTERPRETATION Targeting a higher pCO2 did not decrease the rate of bronchopulmonary dysplasia or death in ventilated preterm infants. The rates of mortality, intraventricular haemorrhage, and retinopathy did not differ between groups. These results suggest that higher pCO2 targets than in the slightly hypercapnic control group do not confer increased benefits such as lung protection. FUNDING Deutsche Forschungsgemeinschaft.
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Affiliation(s)
- Ulrich H Thome
- Division of Neonatology, University Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany.
| | - Orsolya Genzel-Boroviczeny
- Division of Neonatology, Dr. von Hauner University Children's Hospital, Ludwig Maximilian University of Munich, Munich, Germany
| | - Bettina Bohnhorst
- Division of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Manuel Schmid
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, University of Ulm, Ulm, Germany
| | - Hans Fuchs
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Oliver Rohde
- Division of Neonatology and Pediatric Critical Care, Elisabeth Children's Hospital, Klinikum Oldenburg, Medical Campus, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Stefan Avenarius
- Hospital for General Pediatrics and Neonatology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Hans-Georg Topf
- Division of Neonatology, University Hospital for Children and Adolescents, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Andrea Zimmermann
- Mutter-Kind-Zentrum, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Dirk Faas
- University Hospital for General Pediatrics and Neonatology, Justus Liebig University Giessen, Giessen, Germany
| | - Katharina Timme
- Division of Neonatology, Hospital for Children and Adolescents, Vivantes-Hospital Neukölln, Berlin, Berlin, Germany
| | - Barbara Kleinlein
- Hospital for Children and Adolescents, Children's Hospital of the Third Order, Munich, Germany
| | - Horst Buxmann
- Division of Neonatology, University Hospital for Children and Adolescents of the J.W. Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Wilfried Schenk
- Hospital for Children and Adolescents, Central Hospital Augsburg, Augsburg, Germany
| | - Hugo Segerer
- St. Hedwig Hospital, University of Regensburg, Regensburg, Germany
| | - Norbert Teig
- Department of Neonatology and Pediatric Intensive Care, Katholisches Klinikum, Ruhr University Bochum, Bochum, Germany
| | - Corinna Gebauer
- Division of Neonatology, University Hospital for Children and Adolescents, University of Leipzig, Leipzig, Germany
| | - Roland Hentschel
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, Albert Ludwigs University Freiburg, Freiburg, Germany
| | - Matthias Heckmann
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, Ernst Moritz Arndt University Greifswald, Greifswald, Germany
| | - Rolf Schlösser
- Division of Neonatology, University Hospital for Children and Adolescents of the J.W. Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Jochen Peters
- Hospital for Children and Adolescents, Children's Hospital of the Third Order, Munich, Germany
| | - Rainer Rossi
- Division of Neonatology, Hospital for Children and Adolescents, Vivantes-Hospital Neukölln, Berlin, Berlin, Germany
| | - Wolfgang Rascher
- Division of Neonatology, University Hospital for Children and Adolescents, Friedrich-Alexander University Erlangen, Erlangen, Germany
| | - Ralf Böttger
- Hospital for General Pediatrics and Neonatology, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Jürgen Seidenberg
- Division of Neonatology and Pediatric Critical Care, Elisabeth Children's Hospital, Klinikum Oldenburg, Medical Campus, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Gesine Hansen
- Division of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Maria Zernickel
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, University of Ulm, Ulm, Germany
| | - Gerhard Alzen
- Division of Pediatric Radiology, University Hospital of the Justus Liebig University Giessen, Giessen, Germany
| | - Jens Dreyhaupt
- Institute of Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany
| | - Rainer Muche
- Institute of Epidemiology and Medical Biometry, University of Ulm, Ulm, Germany
| | - Helmut D Hummler
- Division of Neonatology and Pediatric Critical Care, University Hospital for Children and Adolescents, University of Ulm, Ulm, Germany
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Ventilatory support in children with pediatric acute respiratory distress syndrome: proceedings from the Pediatric Acute Lung Injury Consensus Conference. Pediatr Crit Care Med 2015; 16:S51-60. [PMID: 26035364 DOI: 10.1097/pcc.0000000000000433] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE To describe the recommendations of the Pediatric Acute Lung Injury Consensus Conference for mechanical ventilation management of pediatric patients with acute respiratory distress syndrome. DESIGN Consensus Conference of experts in pediatric acute lung injury. METHODS The Pediatric Acute Lung Injury Consensus Conference experts developed and voted on a total of 27 recommendations focused on the optimal mechanical ventilation approach of the patient with pediatric acute respiratory distress syndrome. Topics included ventilator mode, tidal volume delivery, inspiratory plateau pressure, high-frequency ventilation, cuffed endotracheal tubes, and gas exchange goals. When experimental data were lacking, a modified Delphi approach emphasizing the strong professional agreement was used. RESULTS There were 17 recommendations with strong agreement and 10 recommendations with weak agreement. There were no recommendations with equipoise or disagreement. There was weak agreement on recommendations concerning approach to tidal volume and inspiratory pressure limitation (88% to 72% agreement, respectively), whereas strong agreement could be achieved for accepting permissive hypercapnia. Using positive end-expiratory pressure levels greater than 15 cm H2O in severe pediatric acute respiratory distress syndrome, under the condition that the markers of oxygen delivery, respiratory system compliance, and hemodynamics are closely monitored as positive end-expiratory pressure is increased, is strongly recommended. The concept of exploring the effects of careful recruitment maneuvers during conventional ventilation met an agreement level of 88%, whereas the use of recruitment maneuvers during rescue high-frequency oscillatory ventilation is highly recommended (strong agreement). CONCLUSIONS The Consensus Conference developed pediatric-specific recommendations regarding mechanical ventilation of the patient with pediatric acute respiratory distress syndrome as well as future research priorities. These recommendations are intended to initiate discussion regarding optimal mechanical ventilation management for children with pediatric acute respiratory distress syndrome and identify areas of controversy requiring further investigation.
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MORIMONT P, GUIOT J, DESAIVE T, TCHANA-SATO V, JANSSEN N, CAGNINA A, HELLA D, BLAFFART F, DEFRAIGNE JO, LAMBERMONT B. Veno-venous extracorporeal CO2 removal improves pulmonary hemodynamics in a porcine ARDS model. Acta Anaesthesiol Scand 2015; 59:448-56. [PMID: 25736472 DOI: 10.1111/aas.12497] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 12/16/2022]
Abstract
BACKGROUND Protective lung ventilation is recommended in patients with acute respiratory distress syndrome (ARDS) to minimize additional injuries to the lung. However, hypercapnic acidosis resulting from ventilation at lower tidal volume enhances pulmonary hypertension and might induce right ventricular (RV) failure. We investigated if extracorporeal veno-venous CO2 removal therapy could have beneficial effects on pulmonary circulation and RV function. METHODS This study was performed on an experimental model of ARDS obtained in eight anaesthetized pigs connected to a volume-cycled ventilator. A micromanometer-tipped catheter was inserted into the main pulmonary artery and an admittance micromanometer-tipped catheter was inserted into the right ventricle. RV-arterial coupling was derived from RV pressure-volume loops. ARDS was obtained by repeated bronchoalveolar lavage. Protective ventilation was then achieved, and the pigs were connected to a pump-driven extracorporeal membrane oxygenator (PALP, Maquet, Germany) in order to achieve CO2 removal. RESULTS ARDS induced severe hypercapnic acidosis. Systolic pulmonary artery pressure significantly increased from 29.6±1.8 to 43.9±2.0 mmHg (P<0.001). After the PALP was started, acidosis was corrected and normocarbia was maintained despite protective ventilation. Pulmonary artery pressure significantly decreased to 31.6±3.2 mmHg (P<0.001) and RV-arterial coupling significantly improved (RV-arterial coupling index=1.03±0.33 vs. 0.55±0.41, P<0.05). CONCLUSION Veno-venous CO2 removal therapy enabled protective ventilation while maintaining normocarbia during ARDS. CO2 removal decreased pulmonary hypertension and improved RV function. This technique may be an effective lung- and RV-protective adjunct to mechanical ventilation.
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Affiliation(s)
- P. MORIMONT
- Medical Intensive Care Unit; University Hospital of Liege; Liege Belgium
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
| | - J. GUIOT
- Medical Intensive Care Unit; University Hospital of Liege; Liege Belgium
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
| | - T. DESAIVE
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
| | - V. TCHANA-SATO
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
| | - N. JANSSEN
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
| | - A. CAGNINA
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
| | - D. HELLA
- School of Perfusion; University of Liege; Liege Belgium
| | - F. BLAFFART
- School of Perfusion; University of Liege; Liege Belgium
| | - J.-O. DEFRAIGNE
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
- Department of Cardiothoracic Surgery; University Hospital of Liege; Liege Belgium
| | - B. LAMBERMONT
- Medical Intensive Care Unit; University Hospital of Liege; Liege Belgium
- GIGA-Research; Cardiovascular Sciences; University of Liege; Liege Belgium
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Nardelli L, Rzezinski A, Silva J, Maron-Gutierrez T, Ornellas D, Henriques I, Capelozzi V, Teodoro W, Morales M, Silva P, Pelosi P, Garcia C, Rocco P. Effects of acute hypercapnia with and without acidosis on lung inflammation and apoptosis in experimental acute lung injury. Respir Physiol Neurobiol 2015; 205:1-6. [DOI: 10.1016/j.resp.2014.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/04/2014] [Accepted: 09/14/2014] [Indexed: 12/24/2022]
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Tao T, Zhao M, Yang W, Bo Y, Li W. Neuroprotective effects of therapeutic hypercapnia on spatial memory and sensorimotor impairment via anti-apoptotic mechanisms after focal cerebral ischemia/reperfusion. Neurosci Lett 2014; 573:1-6. [PMID: 24813106 DOI: 10.1016/j.neulet.2014.04.051] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 04/10/2014] [Accepted: 04/30/2014] [Indexed: 01/23/2023]
Abstract
A number of studies have demonstrated that therapeutic hypercapnia ameliorates neurological deficits and attenuates the histological damage of cerebral ischemia-reperfusion injury. However, the effects of therapeutic hypercapnia on impaired spatial memory have not been reported. Here we aimed to investigate the effects and mechanisms of therapeutic hypercapnia on spatial memory in a rat model of focal cerebral ischemia induced by middle cerebral artery occlusion/reperfusion (MCAO/R). Adult male rats were randomly assigned into three experimental groups: sham (sham operation), IR (MCAO/R), and hypercapnia [arterial blood CO2 tension (PaCO2) 80-100 mmHg+IR] groups. Sensorimotor deficits and spatial memory testing were evaluated by an 18-point scoring system and an 8-arm radial maze task, respectively. The hippocampal histological damage and the percentage of apoptotic neurons were evaluated by hematoxylin and eosin (HE) staining as well as flow cytometry. Western blotting was used to investigate the changes of the apoptosis-related Bcl-2 and Bax proteins. The results indicated that hypercapnia treatment significantly improved the abilities of impaired sensorimotor and spatial memory after MCAO/R. Moreover, hypercapnia treatment significantly increased the percentage of surviving neurons and decreased the percentage of apoptotic neurons in the hippocampus after MCAO/R damage. The expressions of anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax were significantly increased and decreased in the hypercapnia treated rats, respectively. These findings suggest that therapeutic hypercapnia can attenuate neuronal apoptosis and improve impaired spatial memory and sensorimotor after MCAO/R, which may be attributable to its anti-apoptotic effects through modulation of apoptosis-related protein.
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Affiliation(s)
- Tao Tao
- Department of Anesthesiology, the Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China; Hei Long Jiang Province key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China.
| | - Meng Zhao
- Department of Anesthesiology, the Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China; Hei Long Jiang Province key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China.
| | - Wanchao Yang
- Department of Anesthesiology, the Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China; Hei Long Jiang Province key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China.
| | - Yulong Bo
- Department of Anesthesiology, the Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China; Hei Long Jiang Province key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China.
| | - Wenzhi Li
- Department of Anesthesiology, the Second Affiliated Hospital of Harbin Medical University, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China; Hei Long Jiang Province key Lab of Research on Anesthesiology and Critical Care Medicine, Harbin Medical University, 246 Xuefu Road, Nangang District, Heilongjiang Province, Harbin 150081, China.
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Dunlop K, Gosal K, Kantores C, Ivanovska J, Dhaliwal R, Desjardins JF, Connelly KA, Jain A, McNamara PJ, Jankov RP. Therapeutic hypercapnia prevents inhaled nitric oxide-induced right-ventricular systolic dysfunction in juvenile rats. Free Radic Biol Med 2014; 69:35-49. [PMID: 24423485 DOI: 10.1016/j.freeradbiomed.2014.01.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/31/2013] [Accepted: 01/04/2014] [Indexed: 10/25/2022]
Abstract
Chronic pulmonary hypertension in the neonate and infant frequently presents with right-ventricular (RV) failure. Current clinical management may include protracted treatment with inhaled nitric oxide (iNO), with the goal of reducing RV afterload. We have previously reported that prolonged exposure to iNO causes RV systolic dysfunction in the chronic hypoxia-exposed juvenile rat, which was prevented by a peroxynitrite decomposition catalyst. Given that inhalation of CO2 (therapeutic hypercapnia) may limit oxidative stress and upregulated cytokine expression in the lung and other organs, we hypothesized that therapeutic hypercapnia would attenuate cytokine-mediated nitric oxide synthase (NOS) upregulation, thus limiting peroxynitrite generation. Sprague-Dawley rat pups were exposed to chronic hypoxia (13% O2) from postnatal day 1 to 21, while receiving iNO (20 ppm) from day 14 to 21, with or without therapeutic hypercapnia (10% CO2). Therapeutic hypercapnia completely normalized RV systolic function, RV hypertrophy, and remodeling of pulmonary resistance arteries in animals exposed to iNO. Inhaled nitric oxide-mediated increases in RV peroxynitrite, apoptosis, and contents of tumor necrosis factor (TNF)-α, interleukin (IL)-1α, and NOS-2 were all attenuated by therapeutic hypercapnia. Inhibition of NOS-2 activity with 1400 W (1 mg/kg/day) prevented iNO-mediated upregulation of peroxynitrite and led to improved RV systolic function. Blockade of IL-1 receptor signaling with anakinra (500 mg/kg/day) decreased NOS-2 content and had similar effects compared to NOS-2 inhibition on iNO-mediated effects, whereas blockade of TNF-α signaling with etanercept (0.4 mg/kg on alternate days) had no effects on these parameters. We conclude that therapeutic hypercapnia prevents the adverse effects of sustained exposure to iNO on RV systolic function by limiting IL-1-mediated NOS-2 upregulation and consequent nitration. Therapeutic hypercapnia also acts synergistically with iNO in normalizing RV hypertrophy, vascular remodeling, and raised pulmonary vascular resistance secondary to chronic hypoxia.
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Affiliation(s)
- Kristyn Dunlop
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8
| | - Kiranjot Gosal
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8; Department of Physiology, Faculty of Medicine, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Crystal Kantores
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8
| | - Julijana Ivanovska
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8
| | - Rupinder Dhaliwal
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8
| | - Jean-François Desjardins
- Keenan Research Center, Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, ON, Canada
| | - Kim A Connelly
- Keenan Research Center, Li Ka Shing Knowledge Institute, St Michael's Hospital, Toronto, ON, Canada; Heart and Stroke Richard Lewar Centre of Excellence in Cardiovascular Research, and Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Amish Jain
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8; Department of Physiology, Faculty of Medicine, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8; Division of Neonatology, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Patrick J McNamara
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8; Department of Physiology, Faculty of Medicine, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8; Division of Neonatology, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8
| | - Robert P Jankov
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, ON, Canada M5G 1X8; Department of Physiology, Faculty of Medicine, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8; Heart and Stroke Richard Lewar Centre of Excellence in Cardiovascular Research, and Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8; Division of Neonatology, Department of Paediatrics, Faculty of Medicine, University of Toronto, Toronto, ON, Canada M5S 1A8.
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Curley GF, Laffey JG, Kavanagh BP. Rebuttal from Gerard F. Curley, John G. Laffey and Brian P. Kavanagh. J Physiol 2013; 591:2771-2. [PMID: 23729792 DOI: 10.1113/jphysiol.2013.255638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] 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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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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Stengl M, Ledvinova L, Chvojka J, Benes J, Jarkovska D, Holas J, Soukup P, Sviglerová J, Matejovic M. Effects of clinically relevant acute hypercapnic and metabolic acidosis on the cardiovascular system: an experimental porcine study. Crit Care 2013; 17:R303. [PMID: 24377654 PMCID: PMC4056780 DOI: 10.1186/cc13173] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 12/11/2013] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Hypercapnic acidosis (HCA) that accompanies lung-protective ventilation may be considered permissive (a tolerable side effect), or it may be therapeutic by itself. Cardiovascular effects may contribute to, or limit, the potential therapeutic impact of HCA; therefore, a complex physiological study was performed in healthy pigs to evaluate the systemic and organ-specific circulatory effects of HCA, and to compare them with those of metabolic (eucapnic) acidosis (MAC). METHODS In anesthetized, mechanically ventilated and instrumented pigs, HCA was induced by increasing the inspired fraction of CO2 (n = 8) and MAC (n = 8) by the infusion of HCl, to reach an arterial plasma pH of 7.1. In the control group (n = 8), the normal plasma pH was maintained throughout the experiment. Hemodynamic parameters, including regional organ hemodynamics, blood gases, and electrocardiograms, were measured in vivo. Subsequently, isometric contractions and membrane potentials were recorded in vitro in the right ventricular trabeculae. RESULTS HCA affected both the pulmonary (increase in mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR)) and systemic (increase in mean arterial pressure (MAP), decrease in systemic vascular resistance (SVR)) circulations. Although the renal perfusion remained unaffected by any type of acidosis, HCA increased carotid, portal, and, hence, total liver blood flow. MAC influenced the pulmonary circulation only (increase in MPAP and PVR). Both MAC and HCA reduced the stroke volume, which was compensated for by an increase in heart rate to maintain (MAC), or even increase (HCA), the cardiac output. The right ventricular stroke work per minute was increased by both MAC and HCA; however, the left ventricular stroke work was increased by HCA only. In vitro, the trabeculae from the control pigs and pigs with acidosis showed similar contraction force and action-potential duration (APD). Perfusion with an acidic solution decreased the contraction force, whereas APD was not influenced. CONCLUSIONS MAC preferentially affects the pulmonary circulation, whereas HCA affects the pulmonary, systemic, and regional circulations. The cardiac contractile function was reduced, but the cardiac output was maintained (MAC), or even increased (HCA). The increased ventricular stroke work per minute revealed an increased work demand placed by acidosis on the heart.
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From the Journal archives: Understanding the mechanism(s) regulating hypoxic pulmonary vasoconstriction: how an early study has led to novel translational approaches. Can J Anaesth 2013; 61:195-9. [DOI: 10.1007/s12630-013-0086-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 11/15/2013] [Indexed: 10/26/2022] Open
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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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Abstract
OBJECTIVES Accidental hypothermia increases mortality and morbidity after hemorrhage, but controversial data are available on the effects of therapeutic hypothermia. Therefore, we tested the hypothesis whether moderate pretreatment hypothermia would beneficially influence organ dysfunction during long-term, porcine hemorrhage and resuscitation. DESIGN Prospective, controlled, randomized study. SETTING University animal research laboratory. SUBJECTS Twenty domestic pigs of either gender. INTERVENTIONS Using an extracorporeal heat exchanger, anesthetized and instrumented animals were maintained at 38°C, 35°C, or 32°C core temperature and underwent 4 hours of hemorrhage (removal of 40% of the blood volume and subsequent blood removal/retransfusion to maintain mean arterial pressure at 30 mm Hg). Resuscitation comprised of hydroxyethyl starch and norepinephrine infusion titrated to maintain mean arterial pressure at preshock values. MEASUREMENTS AND MAIN RESULTS Before, immediately at the end of, and 12 and 22 hours after hemorrhage, we measured systemic and regional hemodynamics (portal vein, hepatic and right kidney artery ultrasound flow probes) and oxygen transport, and nitric oxide and cytokine production. Hemostasis was assessed by rotation thromboelastometry. Postmortem biopsies were analyzed for histomorphology (hematoxylin and eosin staining) and markers of apoptosis (kidney Bcl-xL and caspase-3 expression). Hypothermia at 32°C attenuated the shock-related lactic acidosis but caused metabolic acidosis, most likely resulting from reduced carbohydrate oxidation. Although hypothermia did not further aggravate shock-related coagulopathy, it caused a transitory attenuation of kidney and liver dysfunction, which was ultimately associated with reduced histological damage and more pronounced apoptosis. CONCLUSIONS During long-term porcine hemorrhage and resuscitation, moderate pretreatment hypothermia was associated with a transitory attenuation of organ dysfunction and less severe histological tissue damage despite more pronounced metabolic acidosis. This effect is possibly due to a switch from necrotic to apoptotic cell death, ultimately resulting from reduced tissue energy deprivation during the shock phase.
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Obiako B, Calchary W, Xu N, Kunstadt R, Richardson B, Nix J, Sayner SL. Bicarbonate disruption of the pulmonary endothelial barrier via activation of endogenous soluble adenylyl cyclase, isoform 10. Am J Physiol Lung Cell Mol Physiol 2013; 305:L185-92. [PMID: 23686854 PMCID: PMC3726949 DOI: 10.1152/ajplung.00392.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Accepted: 05/14/2013] [Indexed: 01/23/2023] Open
Abstract
It is becoming increasingly apparent that cAMP signals within the pulmonary endothelium are highly compartmentalized, and this compartmentalization is critical to maintaining endothelial barrier integrity. Studies demonstrate that the exogenous soluble bacterial toxin, ExoY, and heterologous expression of the forskolin-stimulated soluble mammalian adenylyl cyclase (AC) chimera, sACI/II, elevate cytosolic cAMP and disrupt the pulmonary microvascular endothelial barrier. The barrier-disruptive effects of cytosolic cAMP generated by exogenous soluble ACs are in contrast to the barrier-protective effects of subplasma membrane cAMP generated by transmembrane AC, which strengthens endothelial barrier integrity. Endogenous soluble AC isoform 10 (AC10 or commonly known as sAC) lacks transmembrane domains and localizes within the cytosolic compartment. AC10 is uniquely activated by bicarbonate to generate cytosolic cAMP, yet its role in regulation of endothelial barrier integrity has not been addressed. Here we demonstrate that, within the pulmonary circulation, AC10 is expressed in pulmonary microvascular endothelial cells (PMVECs) and pulmonary artery endothelial cells (PAECs), yet expression in PAECs is lower. Furthermore, pulmonary endothelial cells selectively express bicarbonate cotransporters. While extracellular bicarbonate generates a phosphodiesterase 4-sensitive cAMP pool in PMVECs, no such cAMP response is detected in PAECs. Finally, addition of extracellular bicarbonate decreases resistance across the PMVEC monolayer and increases the filtration coefficient in the isolated perfused lung above osmolality controls. Collectively, these findings suggest that PMVECs have a bicarbonate-sensitive cytosolic cAMP pool that disrupts endothelial barrier integrity. These studies could provide an alternative mechanism for the controversial effects of bicarbonate correction of acidosis of acute respiratory distress syndrome patients.
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Affiliation(s)
- Boniface Obiako
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, AL 36688, USA
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Abstract
This article focuses on the respiratory management and monitoring of pediatric acute lung injury (ALI) as a specific cause for respiratory failure. Definitive, randomized, controlled trials in pediatrics to guide optimal ventilatory management are few. The only adjunct therapy that has been proved to improve clinical outcome is low tidal volume ventilation, but only in adult patients. Careful monitoring of the patient's respiratory status with airway graphic analysis and capnography can be helpful. Definitive data are needed in the pediatric population to assist in the care of infants, children, and adolescents with ALI to improve survival and functional outcome.
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Tiruvoipati R, Botha JA, Pilcher D, Bailey M. Carbon dioxide clearance in critical care. Anaesth Intensive Care 2013; 41:157-62. [PMID: 23530782 DOI: 10.1177/0310057x1304100129] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Lung protective ventilation limiting tidal volumes and airway pressures were proven to reduce mortality in patients with acute severe respiratory failure. Hypercapnia and hypercapnic acidosis is often noted with lung protective ventilation. While the protective effects of lung protective ventilation are well recognised, the role of hypercapnia and hypercapnic acidosis remains debatable. Some clinicians argue that hypercapnia and hypercapnic acidosis protect the lungs and may be associated with improved outcomes. To the contrary, some clinicians do not tolerate hypercapnic acidosis and use various techniques including extracorporeal carbon dioxide elimination to treat hypercapnia and acidosis. This review aims at defining the effects of hypercapnia and hypercapnic acidosis with a focus on the pros and cons of clearing carbon dioxide and the modalities that may enhance carbon dioxide clearance.
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Affiliation(s)
- R Tiruvoipati
- Department of Intensive Care Medicine, Frankston Hospital, Frankston, Victoria, Australia.
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HÖSTMAN S, ENGSTRÖM J, HEDENSTIERNA G, LARSSON A. Intensive buffering can keep pH above 7.2 for over 4 h during apnea: an experimental porcine study. Acta Anaesthesiol Scand 2013; 57:63-70. [PMID: 23167283 DOI: 10.1111/aas.12012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/21/2012] [Indexed: 11/29/2022]
Abstract
BACKGROUND Ventilation with low tidal volumes reduces mortality in acute respiratory distress syndrome. A further reduction of tidal volumes might be beneficial, and it is known that apneic oxygenation (no tidal volumes) with arteriovenous CO(2) removal can keep acid-base balance and oxygenation normal for at least 7 h in an acute lung injury model. We hypothesized that adequate buffering might be another approach and tested whether tris-hydroxymethyl aminomethane (THAM) alone could keep pH at a physiological level during apneic oxygenation for 4 h. METHODS Six pigs were anesthetized, muscle relaxed, and normoventilated. The lungs were recruited, and apneic oxygenation as well as administration of THAM, 20 mmol/kg/h, was initiated. The experiment ended after 270 min, except one that was studied for 6 h. RESULTS Two animals died before the end of the experiment. Arterial pH and arterial carbon dioxide tension (PaCO(2) ) changed from 7.5 (7.5, 7.5) to 7.3 (7.2, 7.3) kPa, P < 0.001 at 270 min, and from 4.5 (4.3, 4.7) to 25 (22, 28) kPa, P < 0.001, respectively. Base excess increased from 5 (3, 6) to 54 (51, 57) mM, P < 0.001. Cardiac output and arterial pressure were well maintained. The pig, which was studied for 6 h, had pH 7.27 and PaCO(2) 27 kPa at that time. CONCLUSION With intensive buffering using THAM, pH can be kept in a physiologically acceptable range for 4 h during apnea.
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Affiliation(s)
- S. HÖSTMAN
- Hedenstierna laboratory, Anesthesia and Intensive Care; Department of Surgical Sciences; Uppsala University; Uppsala; Sweden
| | - J. ENGSTRÖM
- Hedenstierna laboratory, Anesthesia and Intensive Care; Department of Surgical Sciences; Uppsala University; Uppsala; Sweden
| | - G. HEDENSTIERNA
- Department of Medical Sciences, Clinical Physiology; Uppsala University; Uppsala; Sweden
| | - A. LARSSON
- Hedenstierna laboratory, Anesthesia and Intensive Care; Department of Surgical Sciences; Uppsala University; Uppsala; Sweden
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Hypercapnic acidosis attenuates ventilation-induced lung injury by a nuclear factor-κB–dependent mechanism. Crit Care Med 2012; 40:2622-30. [DOI: 10.1097/ccm.0b013e318258f8b4] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
PURPOSE OF REVIEW Mechanical ventilation is essential for the support of critically ill patients, but may aggravate lung damage, leading to ventilator-associated lung injury (VALI). VALI results from a succession of events beginning with mechanical alteration of lung parenchyma, because of disproportionate stress and strain. The resulting structural tension initiates a biological inflammatory cascade; however, tension can reach the limits of stress, triggering the destruction of structures. This article reviews and discusses the ongoing research into the mechanisms of VALI and their implications for the management of ventilated patients. RECENT FINDINGS Several experimental and clinical studies have been performed to evaluate the contribution of pathogenic mechanical forces to organ and cellular deformation and the implications for guiding ventilator management in patients at risk for VALI. VALI may be attenuated by reducing tidal volume, but the key variable in determining pulmonary overdistension is transpulmonary pressure. Other parameters associated with the induction of VALI include positive end-expiratory pressure, inspiratory airflow and time, and respiratory frequency. SUMMARY How ventilation strategy, specific mechanisms of mechanotransduction, and their individual threshold values impact on VALI remains to be elucidated. In addition, clinical studies are required to evaluate the usefulness of individualized ventilator strategies based on lung mechanics.
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Sewing ACP, Kantores C, Ivanovska J, Lee AH, Masood A, Jain A, McNamara PJ, Tanswell AK, Jankov RP. Therapeutic hypercapnia prevents bleomycin-induced pulmonary hypertension in neonatal rats by limiting macrophage-derived tumor necrosis factor-α. Am J Physiol Lung Cell Mol Physiol 2012; 303:L75-87. [DOI: 10.1152/ajplung.00072.2012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Bleomycin-induced lung injury is characterized in the neonatal rat by inflammation, arrested lung growth, and pulmonary hypertension (PHT), as observed in human infants with severe bronchopulmonary dysplasia. Inhalation of CO2 (therapeutic hypercapnia) has been described to limit cytokine production and to have anti-inflammatory effects on the injured lung; we therefore hypothesized that therapeutic hypercapnia would prevent bleomycin-induced lung injury. Spontaneously breathing rat pups were treated with bleomycin (1 mg/kg/d ip) or saline vehicle from postnatal days 1–14 while being continuously exposed to 5% CO2 (PaCO2 elevated by 15–20 mmHg), 7% CO2 (PaCO2 elevated by 35 mmHg), or normocapnia. Bleomycin-treated animals exposed to 7%, but not 5%, CO2, had significantly attenuated lung tissue macrophage influx and PHT, as evidenced by normalized pulmonary vascular resistance and right ventricular systolic function, decreased right ventricular hypertrophy, and attenuated remodeling of pulmonary resistance arteries. The level of CO2 neither prevented increased tissue neutrophil influx nor led to improvements in decreased lung weight, septal thinning, impaired alveolarization, or decreased numbers of peripheral arteries. Bleomycin led to increased expression and content of lung tumor necrosis factor (TNF)-α, which was found to colocalize with tissue macrophages and to be attenuated by exposure to 7% CO2. Inhibition of TNF-α signaling with the soluble TNF-2 receptor etanercept (0.4 mg/kg ip from days 1–14 on alternate days) prevented bleomycin-induced PHT without decreasing tissue macrophages and, similar to CO2, had no effect on arrested alveolar development. Our findings are consistent with a preventive effect of therapeutic hypercapnia with 7% CO2 on bleomycin-induced PHT via attenuation of macrophage-derived TNF-α. Neither tissue macrophages nor TNF-α appeared to contribute to arrested lung development induced by bleomycin. That 7% CO2 normalized pulmonary vascular resistance and right ventricular function without improving inhibited airway and vascular development suggests that vascular hypoplasia does not contribute significantly to functional changes of PHT in this model.
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Affiliation(s)
- A. Charlotte P. Sewing
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Crystal Kantores
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Julijana Ivanovska
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Alvin H. Lee
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Azhar Masood
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Amish Jain
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Patrick J. McNamara
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - A. Keith Tanswell
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
| | - Robert P. Jankov
- Physiology and Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada
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Peng G, Ivanovska J, Kantores C, Van Vliet T, Engelberts D, Kavanagh BP, Enomoto M, Belik J, Jain A, McNamara PJ, Jankov RP. Sustained therapeutic hypercapnia attenuates pulmonary arterial Rho-kinase activity and ameliorates chronic hypoxic pulmonary hypertension in juvenile rats. Am J Physiol Heart Circ Physiol 2012; 302:H2599-611. [DOI: 10.1152/ajpheart.01180.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sustained therapeutic hypercapnia prevents pulmonary hypertension in experimental animals, but its rescue effects on established disease have not been studied. Therapies that inhibit Rho-kinase (ROCK) and/or augment nitric oxide (NO)-cyclic guanosine monophosphate (cGMP) signaling can reverse or prevent progression of chronic pulmonary hypertension. Our objective in the present study was to determine whether sustained rescue treatment with inhaled CO2 (therapeutic hypercapnia) would improve structural and functional changes of chronic hypoxic pulmonary hypertension. Spontaneously breathing pups were exposed to normoxia (21% O2) or hypoxia (13% O2) from postnatal days 1–21 with or without 7% CO2 (PaCO2 elevated by ∼25 mmHg) or 10% CO2 (PaCO2 elevated by ∼40 mmHg) from days 14 to 21. Compared with hypoxia alone, animals exposed to hypoxia and 10% CO2 had significantly ( P < 0.05) decreased pulmonary vascular resistance, right-ventricular systolic pressure, right-ventricular hypertrophy, and medial wall thickness of pulmonary resistance arteries as well as decreased lung phosphodiesterase (PDE) V, RhoA, and ROCK activity. Rescue treatment with 10% CO2, or treatment with a ROCK inhibitor (15 mg/kg ip Y-27632 twice daily from days 14 to 21), also increased pulmonary arterial endothelial nitric oxide synthase and lung NO content. In contrast, cGMP content and cGMP-dependent protein kinase (PKG) activity were increased by exposure to 10% CO2, but not by ROCK inhibition with Y-27632. In vitro exposure of pulmonary artery smooth muscle cells to hypercapnia suppressed serum-induced ROCK activity, which was prevented by inhibition of PKG with Rp-8-Br-PET-cGMPS. We conclude that sustained hypercapnia dose-dependently inhibited ROCK activity, augmented NO-cGMP-PKG signaling, and led to partial improvements in the hemodynamic and structural abnormalities of chronic hypoxic PHT in juvenile rats. Increased PKG content and activity appears to play a major upstream role in CO2-induced suppression of ROCK activity in pulmonary arterial smooth muscle.
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Affiliation(s)
- Gary Peng
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Julijana Ivanovska
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Crystal Kantores
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Todd Van Vliet
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada; and
| | - Doreen Engelberts
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Brian P. Kavanagh
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- the 4Department of Anaesthesia, University of Toronto, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Masahiro Enomoto
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
| | - Jaques Belik
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Amish Jain
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada; and
| | - Patrick J. McNamara
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Robert P. Jankov
- Physiology & Experimental Medicine Program, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada
- Heart and Stroke Richard Lewar Centre of Excellence, University of Toronto, Toronto, Ontario, Canada
- Division of Neonatology, Department of Paediatrics, University of Toronto, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Ketabchi F, Ghofrani HA, Schermuly RT, Seeger W, Grimminger F, Egemnazarov B, Shid-Moosavi SM, Dehghani GA, Weissmann N, Sommer N. Effects of hypercapnia and NO synthase inhibition in sustained hypoxic pulmonary vasoconstriction. Respir Res 2012; 13:7. [PMID: 22292558 PMCID: PMC3306743 DOI: 10.1186/1465-9921-13-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 01/31/2012] [Indexed: 01/11/2023] Open
Abstract
Background Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. Hypoxic pulmonary vasoconstriction (HPV) optimizes gas exchange during local acute (0-30 min), as well as sustained (> 30 min) hypoxia by matching blood perfusion to alveolar ventilation. Hypercapnia with acidosis improves pulmonary gas exchange in repetitive conditions of acute hypoxia by potentiating HPV and preventing pulmonary endothelial dysfunction. This study investigated, if the beneficial effects of hypercapnia with acidosis are preserved during sustained hypoxia as it occurs, e.g in permissive hypercapnic ventilation in intensive care units. Furthermore, the effects of NO synthase inhibitors under such conditions were examined. Method We employed isolated perfused and ventilated rabbit lungs to determine the influence of hypercapnia with or without acidosis (pH corrected with sodium bicarbonate), and inhibitors of endothelial as well as inducible NO synthase on acute or sustained HPV (180 min) and endothelial permeability. Results In hypercapnic acidosis, HPV was intensified in sustained hypoxia, in contrast to hypercapnia without acidosis when HPV was amplified during both phases. L-NG-Nitroarginine (L-NNA), a non-selective NO synthase inhibitor, enhanced acute as well as sustained HPV under all conditions, however, the amplification of sustained HPV induced by hypercapnia with or without acidosis compared to normocapnia disappeared. In contrast 1400 W, a selective inhibitor of inducible NO synthase (iNOS), decreased HPV in normocapnia and hypercapnia without acidosis at late time points of sustained HPV and selectively reversed the amplification of sustained HPV during hypercapnia without acidosis. Hypoxic hypercapnia without acidosis increased capillary filtration coefficient (Kfc). This increase disappeared after administration of 1400 W. Conclusion Hypercapnia with and without acidosis increased HPV during conditions of sustained hypoxia. The increase of sustained HPV and endothelial permeability in hypoxic hypercapnia without acidosis was iNOS dependent.
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Affiliation(s)
- Farzaneh Ketabchi
- Justus-Liebig-University Giessen, University of Giessen & Marburg Lung Center (UGMLC), Excellence Cluster Cardio-Pulmonary System (ECCPS), Medical Clinic II/IV/V, Aulweg 130, 35392 Giessen, Germany
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Otulakowski G, Kavanagh BP. Hypercapnia in acute illness: sometimes good, sometimes not. Crit Care Med 2011; 39:1581-2. [PMID: 21610635 DOI: 10.1097/ccm.0b013e318215bb0a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Therapeutic hypercapnia enhances the inflammatory response to endotoxin in the lung of spontaneously breathing rats*. Crit Care Med 2011; 39:1400-6. [DOI: 10.1097/ccm.0b013e31820ee1f2] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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