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Spinelli E, Damia A, Damarco F, Gregori B, Occhipinti F, Busani Z, Leali M, Battistin M, Lonati C, Zhao Z, Storaci AM, Lopez G, Vaira V, Ferrero S, Rosso L, Gatti S, Mauri T. Pathophysiological profile of non-ventilated lung injury in healthy female pigs undergoing mechanical ventilation. COMMUNICATIONS MEDICINE 2024; 4:18. [PMID: 38361130 PMCID: PMC10869686 DOI: 10.1038/s43856-024-00449-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 02/01/2024] [Indexed: 02/17/2024] Open
Abstract
BACKGROUND Lung regions excluded from mechanical insufflation are traditionally assumed to be spared from ventilation-associated lung injury. However, preliminary data showed activation of potential mechanisms of injury within these non-ventilated regions (e.g., hypoperfusion, inflammation). METHODS In the present study, we hypothesized that non-ventilated lung injury (NVLI) may develop within 24 h of unilateral mechanical ventilation in previously healthy pigs, and we performed extended pathophysiological measures to profile NVLI. We included two experimental groups undergoing exclusion of the left lung from the ventilation with two different tidal volumes (15 vs 7.5 ml/kg) and a control group on bilateral ventilation. Pathophysiological alteration including lung collapse, changes in lung perfusion, lung stress and inflammation were measured. Lung injury was quantified by histological score. RESULTS Histological injury score of the non-ventilated lung is significantly higher than normally expanded lung from control animals. The histological score showed lower intermediate values (but still higher than controls) when the tidal volume distending the ventilated lung was reduced by 50%. Main pathophysiological alterations associated with NVLI were: extensive lung collapse; very low pulmonary perfusion; high inspiratory airways pressure; and higher concentrations of acute-phase inflammatory cytokines IL-6, IL-1β and TNF-α and of Angiopoietin-2 (a marker of endothelial activation) in the broncho-alveolar lavage. Only the last two alterations were mitigated by reducing tidal volume, potentially explaining partial protection. CONCLUSIONS Non-ventilated lung injury develops within 24 h of controlled mechanical ventilation due to multiple pathophysiological alterations, which are only partially prevented by low tidal volume.
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Grants
- This study was supported, in part, by Current Research from the Italian Ministry of Health, Rome, Italy; by EuroELSO Research grant 2021; by the “Hub Life Science-Diagnostica Avanzata (HLS-DA), PNC-E3-2022-23683266-CUP: C43C22001630001/MI-0117” Project from the Italian Ministry of Health (Piano Nazionale Complementare Ecosistema Innovativo della Salute), Rome, Italy; by the “Dipartimenti di Eccellenza Program 2023–2027” to the Dept. of Pathophysiology and Transplantation, University of Milan, from The Italian Ministry of Education and Research (MUR), Rome, Italy.
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Affiliation(s)
- Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Anna Damia
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Francesco Damarco
- Division of Thoracic Surgery and Lung Transplantation, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Beatrice Gregori
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Federica Occhipinti
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Zara Busani
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Marco Leali
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Michele Battistin
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Caterina Lonati
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Zhanqi Zhao
- Furtwangen University, Institute of Technical Medicine, Villingen-Schwenningen, Germany
| | - Alessandra Maria Storaci
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Gianluca Lopez
- Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Valentina Vaira
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefano Ferrero
- Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Biomedical Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Lorenzo Rosso
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Division of Thoracic Surgery and Lung Transplantation, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefano Gatti
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy.
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy.
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Slobod D, Damia A, Leali M, Spinelli E, Mauri T. Pathophysiology and Clinical Meaning of Ventilation-Perfusion Mismatch in the Acute Respiratory Distress Syndrome. BIOLOGY 2022; 12:biology12010067. [PMID: 36671759 PMCID: PMC9855693 DOI: 10.3390/biology12010067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/20/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023]
Abstract
Acute respiratory distress syndrome (ARDS) remains an important clinical challenge with a mortality rate of 35-45%. It is being increasingly demonstrated that the improvement of outcomes requires a tailored, individualized approach to therapy, guided by a detailed understanding of each patient's pathophysiology. In patients with ARDS, disturbances in the physiological matching of alveolar ventilation (V) and pulmonary perfusion (Q) (V/Q mismatch) are a hallmark derangement. The perfusion of collapsed or consolidated lung units gives rise to intrapulmonary shunting and arterial hypoxemia, whereas the ventilation of non-perfused lung zones increases physiological dead-space, which potentially necessitates increased ventilation to avoid hypercapnia. Beyond its impact on gas exchange, V/Q mismatch is a predictor of adverse outcomes in patients with ARDS; more recently, its role in ventilation-induced lung injury and worsening lung edema has been described. Innovations in bedside imaging technologies such as electrical impedance tomography readily allow clinicians to determine the regional distributions of V and Q, as well as the adequacy of their matching, providing new insights into the phenotyping, prognostication, and clinical management of patients with ARDS. The purpose of this review is to discuss the pathophysiology, identification, consequences, and treatment of V/Q mismatch in the setting of ARDS, employing experimental data from clinical and preclinical studies as support.
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Affiliation(s)
- Douglas Slobod
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Critical Care Medicine, McGill University, Montreal, QC H3A 3R1, Canada
| | - Anna Damia
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Marco Leali
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
- Correspondence:
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Spinelli E, Pesenti A, Lopez G, Damia A, Damarco F, Garbelli E, Dal Santo G, Caccioppola A, Giudici G, Figgiaconi V, Biancolilli O, Battistin M, Lonati C, Vaira V, Rosso L, Ferrero S, Gatti S, Mauri T. Inhaled CO2 vs. Hypercapnia Obtained by Low Tidal Volume or Instrumental Dead Space in Unilateral Pulmonary Artery Ligation: Any Difference for Lung Protection? Front Med (Lausanne) 2022; 9:901809. [PMID: 35669918 PMCID: PMC9163369 DOI: 10.3389/fmed.2022.901809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/19/2022] [Indexed: 11/20/2022] Open
Abstract
Background Unilateral ligation of the pulmonary artery (UPAL) induces bilateral lung injury in pigs undergoing controlled mechanical ventilation. Possible mechanisms include redistribution of ventilation toward the non-ligated lung and hypoperfusion of the ligated lung. The addition of 5% CO2 to the inspiratory gas (FiCO2) prevents the injury, but it is not clear whether lung protection is a direct effect of CO2 inhalation or it is mediated by plasmatic hypercapnia. This study aims to compare the effects and mechanisms of FiCO2vs. hypercapnia induced by low tidal volume ventilation or instrumental dead space. Methods Healthy pigs underwent left UPAL and were allocated for 48 h to the following: Volume-controlled ventilation (VCV) with VT 10 ml/kg (injury, n = 6); VCV plus 5% FiCO2 (FiCO2, n = 7); VCV with VT 6 ml/kg (low VT, n = 6); VCV plus additional circuit dead space (instrumental VD, n = 6). Histological score, regional compliance, wet-to-dry ratio, and inflammatory infiltrate were assessed to evaluate lung injury at the end of the study. To investigate the mechanisms of protection, we quantified the redistribution of ventilation to the non-ligated lung, as the ratio between the percentage of tidal volume to the right and to the left lung (VTRIGHT/LEFT), and the hypoperfusion of the ligated lung as the percentage of blood flow reaching the left lung (PerfusionLEFT). Results In the left ligated lung, injury was prevented only in the FiCO2 group, as indicated by lower histological score, higher regional compliance, lower wet-to-dry ratio and lower density of inflammatory cells compared to other groups. For the right lung, the histological score was lower both in the FiCO2 and in the low VT groups, but the other measures of injury showed lower intensity only in the FiCO2 group. VTRIGHT/LEFT was lower and PerfusionLEFT was higher in the FiCO2 group compared to other groups. Conclusion In a model of UPAL, inhaled CO2 but not hypercapnia grants bilateral lung protection. Mechanisms of protection include reduced overdistension of the non-ligated and increased perfusion of the ligated lung.
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Affiliation(s)
- Elena Spinelli
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Antonio Pesenti
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Gianluca Lopez
- Department of Biomedical Surgical and Dental Sciences, University of Milan, Milan, Italy
| | - Anna Damia
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Francesco Damarco
- Division of Thoracic Surgery and Lung Transplantation, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Erica Garbelli
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Gaia Dal Santo
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Alessio Caccioppola
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Giorgio Giudici
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Virginia Figgiaconi
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
| | - Osvaldo Biancolilli
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Michele Battistin
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Caterina Lonati
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Valentina Vaira
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Lorenzo Rosso
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- Division of Thoracic Surgery and Lung Transplantation, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefano Ferrero
- Department of Biomedical Surgical and Dental Sciences, University of Milan, Milan, Italy
- Division of Pathology, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Stefano Gatti
- Center for Preclinical Research, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Tommaso Mauri
- Department of Anesthesia, Critical Care and Emergency, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
- *Correspondence: Tommaso Mauri
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Ismaiel N, Whynot S, Geldenhuys L, Xu Z, Slutsky AS, Chappe V, Henzler D. Lung-Protective Ventilation Attenuates Mechanical Injury While Hypercapnia Attenuates Biological Injury in a Rat Model of Ventilator-Associated Lung Injury. Front Physiol 2022; 13:814968. [PMID: 35530505 PMCID: PMC9068936 DOI: 10.3389/fphys.2022.814968] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 03/21/2022] [Indexed: 12/30/2022] Open
Abstract
Background and Objective: Lung-protective mechanical ventilation is known to attenuate ventilator-associated lung injury (VALI), but often at the expense of hypoventilation and hypercapnia. It remains unclear whether the main mechanism by which VALI is attenuated is a product of limiting mechanical forces to the lung during ventilation, or a direct biological effect of hypercapnia. Methods: Acute lung injury (ALI) was induced in 60 anesthetized rats by the instillation of 1.25 M HCl into the lungs via tracheostomy. Ten rats each were randomly assigned to one of six experimental groups and ventilated for 4 h with: 1) Conventional HighVENormocapnia (high VT, high minute ventilation, normocapnia), 2) Conventional Normocapnia (high VT, normocapnia), 3) Protective Normocapnia (VT 8 ml/kg, high RR), 4) Conventional iCO2Hypercapnia (high VT, low RR, inhaled CO2), 5) Protective iCO2Hypercapnia (VT 8 ml/kg, high RR, added CO2), 6) Protective endogenous Hypercapnia (VT 8 ml/kg, low RR). Blood gasses, broncho-alveolar lavage fluid (BALF), and tissue specimens were collected and analyzed for histologic and biologic lung injury assessment. Results: Mild ALI was achieved in all groups characterized by a decreased mean PaO2/FiO2 ratio from 428 to 242 mmHg (p < 0.05), and an increased mean elastance from 2.46 to 4.32 cmH2O/L (p < 0.0001). There were no differences in gas exchange among groups. Wet-to-dry ratios and formation of hyaline membranes were significantly lower in low VT groups compared to conventional tidal volumes. Hypercapnia reduced diffuse alveolar damage and IL-6 levels in the BALF, which was also true when CO2 was added to conventional VT. In low VT groups, hypercapnia did not induce any further protective effect except increasing pulmonary IL-10 in the BALF. No differences in lung injury were observed when hypercapnia was induced by adding CO2 or decreasing minute ventilation, although permissive hypercapnia decreased the pH significantly and decreased liver histologic injury. Conclusion: Our findings suggest that low tidal volume ventilation likely attenuates VALI by limiting mechanical damage to the lung, while hypercapnia attenuates VALI by limiting pro-inflammatory and biochemical mechanisms of injury. When combined, both lung-protective ventilation and hypercapnia have the potential to exert an synergistic effect for the prevention of VALI.
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Affiliation(s)
- Nada Ismaiel
- Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.,Department of Anesthesia, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Sara Whynot
- Department of Anesthesia, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Laurette Geldenhuys
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Zhaolin Xu
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | | | - Valerie Chappe
- Department of Physiology and Biophysics, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - Dietrich Henzler
- Department of Anesthesia, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.,Department of Anesthesiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
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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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Vishnupriya S, Priya Dharshini LC, Sakthivel KM, Rasmi RR. Autophagy markers as mediators of lung injury-implication for therapeutic intervention. Life Sci 2020; 260:118308. [PMID: 32828942 PMCID: PMC7442051 DOI: 10.1016/j.lfs.2020.118308] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022]
Abstract
Lung injury is characterized by inflammatory processes demonstrated as loss of function of the pulmonary capillary endothelial and alveolar epithelial cells. Autophagy is an intracellular digestion system that work as an inducible adaptive response to lung injury which is a resultant of exposure to various stress agents like hypoxia, ischemia-reperfusion and xenobiotics which may be manifested as acute lung injury (ALI), acute respiratory distress syndrome (ARDS), chronic lung injury (CLI), bronchopulmonary dysplasia (BPD), chronic obstructive pulmonary disease (COPD), asthma, ventilator-induced lung injury (VILI), ventilator-associated lung injury (VALI), pulmonary fibrosis (PF), cystic fibrosis (CF) and radiation-induced lung injury (RILI). Numerous regulators like LC3B-II, Beclin 1, p62, HIF1/BNIP3 and mTOR play pivotal role in autophagy induction during lung injury possibly for progression/inhibition of the disease state. The present review focuses on the critical autophagic mediators and their potential cross talk with the lung injury pathophysiology thereby bringing to limelight the possible therapeutic interventions.
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Affiliation(s)
- Selvaraj Vishnupriya
- Department of Biotechnology, PSG College of Arts and Science, Civil Aerodrome Post, Coimbatore 641 014, Tamil Nadu, India
| | | | - Kunnathur Murugesan Sakthivel
- Department of Biochemistry, PSG College of Arts and Science, Civil Aerodrome Post, Coimbatore 641 014, Tamil Nadu, India
| | - Rajan Radha Rasmi
- Department of Biotechnology, PSG College of Arts and Science, Civil Aerodrome Post, Coimbatore 641 014, Tamil Nadu, India.
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Haywood N, Byler MR, Zhang A, Roeser ME, Kron IL, Laubach VE. Isolated Lung Perfusion in the Management of Acute Respiratory Distress Syndrome. Int J Mol Sci 2020; 21:ijms21186820. [PMID: 32957547 PMCID: PMC7555278 DOI: 10.3390/ijms21186820] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/08/2020] [Accepted: 09/15/2020] [Indexed: 01/08/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is associated with high morbidity and mortality, and current management has a dramatic impact on healthcare resource utilization. While our understanding of this disease has improved, the majority of treatment strategies remain supportive in nature and are associated with continued poor outcomes. There is a dramatic need for the development and breakthrough of new methods for the treatment of ARDS. Isolated machine lung perfusion is a promising surgical platform that has been associated with the rehabilitation of injured lungs and the induction of molecular and cellular changes in the lung, including upregulation of anti-inflammatory and regenerative pathways. Initially implemented in an ex vivo fashion to evaluate marginal donor lungs prior to transplantation, recent investigations of isolated lung perfusion have shifted in vivo and are focused on the management of ARDS. This review presents current tenants of ARDS management and isolated lung perfusion, with a focus on how ex vivo lung perfusion (EVLP) has paved the way for current investigations utilizing in vivo lung perfusion (IVLP) in the treatment of severe ARDS.
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Cao J, Gao X, Zhang X, Li J, Zhang J. Feasibility of laryngeal mask anesthesia combined with nerve block in adult patients undergoing internal fixation of rib fractures: a prospective observational study. BMC Anesthesiol 2020; 20:170. [PMID: 32669087 PMCID: PMC7362641 DOI: 10.1186/s12871-020-01082-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Accepted: 07/01/2020] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The laryngeal mask airway (LMA) is occasionally used in internal fixation of rib fractures. We evaluated the feasibility of general anesthesia with an LMA associated to a thoracic paravertebral block (TPB) and/or an erector spinae plane block (ESPB) for internal fixation of rib fractures. METHODS Twenty patients undergoing unilateral rib fracture fixation surgery were enrolled. Each patient received general anesthesia with an LMA combined with TPB and/or ESPB, which provided a successful blocking effect. All patients received postoperative continuous analgesia (PCA) with 500 mg of tramadol and 16 mg of lornoxicam, and intravenous injection of 50 mg of flurbiprofen twice a day. Our primary outcomes including the partial pressure of arterial oxygen (PaO2) and arterial carbon dioxide (PaCO2) were measured preoperatively and on the first day after surgery. Secondary outcomes including the vital signs, ventilation parameters, postoperative numerical rating scale (NRS) pain scores, the incidence of postoperative nausea and vomiting (PONV), perioperative reflux and aspiration, and nerve block-related complications were also evaluated. RESULTS Thirteen men and seven women (age 35-70 years) were enrolled. Six (30%) had a flail chest, nine (45%) had hemothorax and/or pneumothorax, and two (10%) had pulmonary contusions. The postoperative PaO2 was higher than the preoperative value (91.2 ± 16.0 vs. 83.7 ± 15.9 mmHg, p = 0.004). The preoperative and postoperative PaCO2 were 42.1 ± 3.7 and 43.2 ± 3.7 mmHg (p = 0.165), respectively. Vital signs and spontaneous breathing were stable during the surgery. The end-tidal carbon dioxide concentrations (EtCO2) remained within an acceptable range (≤ 63 mmHg in all cases). NRS at T1, T2, and T3 were 3(2,4), 1(1,3), and 0(0,1), respectively. None had PONV, regurgitation, aspiration, and nerve block-related complications. CONCLUSIONS The technique of laryngeal mask anesthesia combined with a nerve block was feasible for internal fixation of rib fractures. TRIAL REGISTRATION Current Controlled Trials ChiCTR1900023763 . Registrated on June 11, 2019.
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Affiliation(s)
- Jun Cao
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Rd., Shanghai, China
| | - Xiaoyun Gao
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Rd., Shanghai, China
| | - Xiaoli Zhang
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Rd., Shanghai, China
| | - Jing Li
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Rd., Shanghai, China
| | - Junfeng Zhang
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600, Yishan Rd., Shanghai, China.
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Lee JH, Kim Y, Mun J, Lee J, Ko S. Effects of hypercarbia on arterial oxygenation during one-lung ventilation: prospective randomized crossover study. Korean J Anesthesiol 2020; 73:534-541. [PMID: 32460465 PMCID: PMC7714622 DOI: 10.4097/kja.19445] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 05/27/2020] [Indexed: 11/12/2022] Open
Abstract
Background This study aimed to evaluate the effects of hypercarbia on arterial oxygenation during one-lung ventilation (OLV). Methods Fifty adult patients undergoing elective video-assisted thoracoscopic lobectomy or pneumonectomy were enrolled. Group I patients (n = 25) were first maintained at normocarbia (PaCO2: 38–42 mmHg) for 30 min and then at hypercarbia (45–50 mmHg). In Group II patients (n = 25), PaCO2 was maintained in the reverse order. Arterial oxygen partial pressure (PaO2), respiratory variables, hemodynamic variables, and hemoglobin concentration were compared during normocarbia and hypercarbia. Arterial O2 content and O2 delivery were calculated. Results PaO2 values during normocarbia and hypercarbia were 66.5 ± 10.6 and 79.7 ± 17.3 mmHg, respectively (mean difference: 13.2 mmHg, 95% CI for difference of means: 17.0 to 9.3, P < 0.001). SaO2 values during normocarbia and hypercarbia were 92.5 ± 4.8% and 94.3 ± 3.1% (P = 0.009), respectively. Static compliance of the lung (33.0 ± 5.4 vs. 30.4 ± 5.3 ml/cmH2O, P < 0.001), arterial O2 content (15.4 ± 1.4 vs. 14.9 ± 1.5 ml/dl, P < 0.001) and O2 delivery (69.9 ± 18.4 vs. 65.1 ± 18.1 ml/min, P < 0.001) were significantly higher during hypercarbia than during normocarbia. Conclusions Hypercarbia increases PaO2 and O2 carrying capacity and improves pulmonary mechanics during OLV, suggesting that it may help manage oxygenation during OLV. Therefore, permissive hypercarbia may be a simple and valuable modality to manage arterial oxygenation during OLV.
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Affiliation(s)
- Jun Ho Lee
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea
| | - Yesull Kim
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea
| | - Juhan Mun
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea
| | - Joseph Lee
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea
| | - Seonghoon Ko
- Department of Anesthesiology and Pain Medicine, Jeonbuk National University Medical School and Hospital, Jeonju, Korea
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10
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Ding H, Liu X, Li X, Wen M, Li Y, Han Y, Huang L, Liu M, Zeng H. Hypercapnia exacerbates the disruption of the blood‑brain barrier by inducing interleukin‑1β overproduction in the blood of hypoxemic adult rats. Int J Mol Med 2020; 46:762-772. [PMID: 32626911 PMCID: PMC7307827 DOI: 10.3892/ijmm.2020.4604] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 04/27/2020] [Indexed: 12/28/2022] Open
Abstract
Refractory hypoxemia is the main symptom of acute respiratory distress syndrome (ARDS). Low tidal volume ventilation is routinely applied in clinical practice to correct hypoxemia, which aims to prevent ventilator‑induced lung injury. However, this ventilation strategy inevitably leads to hypercapnia. Our previous study demonstrated that hypercapnia aggravated cognitive impairment in hypoxemic rats; however, the underlying mechanism remains unclear. The aim of the present study was to investigate whether hypercapnia exacerbates the blood‑brain barrier (BBB) disruption through inducing interleukin (IL)‑1β overproduction in the blood of hypoxemic rats. The BBB permeability in a rat model of hypercapnia/hypoxemia was evaluated. The levels of IL‑1β in the blood of rats and human whole‑blood cultures were assessed. The expression of IL‑1 receptor 1 (IL‑1R1), phosphorylated IL‑1R1‑associated kinase (p‑IRAK‑1) and tight junctional proteins in cerebral vascular endothelial cells was examined in vitro and in vivo. In addition, IL‑1Ra, an IL‑1 receptor antagonist, was used to determine whether hypercapnia affects tight junctional protein expression in hypoxic cerebral vascular endothelial cells through inducing IL‑1β overproduction. It was observed that hypercapnia alone did not disrupt the BBB, but aggravated the damage to the BBB integrity in hypoxemic rats. Hypercapnia increased IL‑1β expression in the blood of hypoxemic rats as well as in hypoxic human whole‑blood cultures. IL‑1R1 and p‑IRAK‑1 expression was increased, while that of tight junctional proteins was reduced by hypercapnia in hypoxemic cerebral vascular endothelial cells in vitro and in vivo. Additionally, the expression of tight junctional proteins was markedly increased following treatment with IL‑1Ra. These results suggest that hypercapnia‑induced IL‑1β overproduction in the hypoxemic blood may decrease tight junctional protein expression in cerebrovascular endothelial cells via the IL‑1R1/p‑IRAK‑1 pathway, further disrupting BBB integrity, and eventually resulting in increased BBB permeability.
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Affiliation(s)
- Hongguang Ding
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Xinqiang Liu
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Xusheng Li
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Miaoyun Wen
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Ya Li
- School of Medicine, South China University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Yongli Han
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Linqiang Huang
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
| | - Mengting Liu
- School of Medicine, South China University of Technology, Guangzhou, Guangdong 510006, P.R. China
| | - Hongke Zeng
- Department of Emergency and Critical Care Medicine, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510080, P.R. China
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11
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Pan P, Su L, Zhang Q, Long Y, Wang X, Liu D. Effects of Quality Control Targets (SpO2≠100%, PaCO2/<40 mmHg, Pmean/>10 cmH2O) on Outcomes in Patients in the ICU. Front Med (Lausanne) 2020; 7:111. [PMID: 32351963 PMCID: PMC7174732 DOI: 10.3389/fmed.2020.00111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 03/10/2020] [Indexed: 11/13/2022] Open
Abstract
Objectives: A series of quality control (QC) targets (SpO2≠100%, PaCO2≮40 mmHg, Pmean≯10 cmH2O) was put forward and widely used in a single intensive care unit (ICU) setting. The aim of this study was to assess whether these QC targets could improve the outcomes of critically ill patients. Methods: The real-time clinical data of patients undergoing mechanical ventilation at ICU admission between May 2013 and May 2017 in the Department of Critical Care Medicine of Peking Union Medical College Hospital were collected and analyzed. Results: A total of 7,670 patients [mean age, 58 years; 3,943 (51.5%) male] were divided into the before QC (n = 3,936) and after QC (n = 3,734) groups. QC targets (SpO2, PaCO2, and Pmean) and respiratory parameters (FiO2%, PaO2, PEEP, tidal volume, and respiratory rate) within 72 h of ICU admission, primary outcomes (ICU mortality, 28-, 60-, and 90-day mortality) and secondary outcomes (discharge against medical advice, ICU admission days, mechanical ventilation times, and central venous pressure) were measured and compared between the before and after QC groups. The 72 h average of the Pmean, FiO2%, PaO2, and VT were significantly lower and PaCO2 was higher in the after QC than in the before QC group (P < 0.05). A lower 90-day mortality rate, less discharge against medical advice, fewer ICU admission days, and reduced mechanical ventilation times were found in the after QC group compared with the before QC group (P < 0.05). Interestingly, CVP was significantly lower in the after QC group than in the before QC group (P < 0.05). Conclusions: The QC targets (SpO2≠100%, PaCO2≮40 mmHg, Pmean≯10 cmH2O) contributed to avoiding high oxygen level hazards, protecting against lung injury, and improving circulatory function, which resulted in a better prognosis of critically ill patients.
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Affiliation(s)
- Pan Pan
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
- Center of Respiratory and Critical Care Medicine, Chinese PLA General Hospital, Beijing, China
| | - Longxiang Su
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Qing Zhang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Yun Long
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Xiaoting Wang
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
| | - Dawei Liu
- Department of Critical Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College & Chinese Academy of Medical Sciences, Beijing, China
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12
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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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13
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Hypercapnia Alters Alveolar Epithelial Repair by a pH-Dependent and Adenylate Cyclase-Mediated Mechanism. Sci Rep 2019; 9:349. [PMID: 30674971 PMCID: PMC6344503 DOI: 10.1038/s41598-018-36951-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 11/23/2018] [Indexed: 12/16/2022] Open
Abstract
Lung cell injury and repair is a hallmark of the acute respiratory distress syndrome (ARDS). Lung protective mechanical ventilation strategies in these patients may lead to hypercapnia (HC). Although HC has been explored in the clinical context of ARDS, its effect upon alveolar epithelial cell (AEC) wounding and repair remains poorly understood. We have previously reported that HC alters the likelihood of AEC repair by a pH-sensitive but otherwise unknown mechanism. Adenylate cyclase (AC) is an attractive candidate as a putative AEC CO2 sensor and effector as it is bicarbonate sensitive and controls key mediators of AEC repair. The effect of HC on AC activity and plasma membrane (PM) wound repair was measured in AEC type 1 exposed to normocapnia (NC, 40 Torr) or HC (80 Torr), ± tromethamine (THAM) or sodium bicarbonate (HCO3) ± AC probes in a micropuncture model of AEC injury relevant to ARDS. Intracellular pH and AC activity were measured and correlated with repair. HC decreased intracellular pH 0.56, cAMP by 37%, and absolute PM repair rate by 26%. Buffering or pharmacologic manipulation of AC reduced or reversed the effects of HC on AC activity (THAM 103%, HCO3 113% of NC cAMP, ns; Forskolin 168%, p < 0.05) and PM repair (THAM 87%, HCO3 108% of NC likelihood to repair, ns; Forskolin 160%, p < 0.01). These findings suggest AC to be a putative AEC CO2 sensor and modulator of AEC repair, and may have implications for future pharmacologic targeting of downstream messengers of the AC-cAMP axis in experimental models of ARDS.
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14
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Effects of hypercapnia in sepsis: protocol for a systematic review of clinical and preclinical data. Syst Rev 2018; 7:171. [PMID: 30348218 PMCID: PMC6198495 DOI: 10.1186/s13643-018-0840-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 10/09/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Respiratory failure requiring mechanical ventilation is a common manifestation of end-organ damage among patients with sepsis and has a high morbidity and mortality rate, as well as substantial associated treatment costs. Considering the burden of this condition, there is great need to identify novel, pragmatic therapies to improve outcomes in this population. Hypercapnia has shown benefits in several different ex vivo and in vivo models of lung injury. However, it is currently unclear if hypercapnia can confer clinical benefit among patients with sepsis. The objective of this systematic review is to collate the biomedical literature of preclinical and clinical studies testing the effects of higher PaCO2 levels in the setting of sepsis. METHODS We will perform a qualitative systematic review of preclinical and clinical studies evaluating the effects of hypercapnia in sepsis. We will search CENTRAL, PubMed, CINAHL, and EMBASE using a comprehensive strategy. We will screen the reference lists of the articles we select for inclusion to identify additional studies for potential inclusion. Two independent reviewers will review all search results. Upon inclusion of articles, we will extract data using a standardized form. We will use tables to describe the study type, population included, exposure and control groups, outcome measures, and effects of exposure on outcome measures compared to controls. DISCUSSION This systematic review aims to synthesize the world's literature on the effects of hypercapnia in the setting of sepsis. We expect this systematic review will find that majority of the studies will demonstrate a potential benefit of higher PaCO2 levels in sepsis. The results of this systematic review will contribute to the understanding of the effects of hypercapnia in the setting of sepsis and promote future research of PaCO2 management in mechanically ventilated patients with sepsis. SYSTEMATIC REVIEW REGISTRATION The systematic review is registered in the PROSPERO international prospective register of systematic review (PROSPERO # CRD42018086703 ).
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15
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Regunath H, Moulton N, Woolery D, Alnijoumi M, Whitacre T, Collins J. Ultra-protective mechanical ventilation without extra-corporeal carbon dioxide removal for acute respiratory distress syndrome. J Intensive Care Soc 2018; 20:40-45. [PMID: 30792761 DOI: 10.1177/1751143718774712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background Tidal hyperinflation can still occur with mechanical ventilation using low tidal volume (LVT) (6 mL/kg predicted body weight (PBW)) in acute respiratory distress syndrome (ARDS), despite a well-demonstrated reduction in mortality. Methods Retrospective chart review from August 2012 to October 2014. Inclusion: Age >18years, PaO2/FiO2<200 with bilateral pulmonary infiltrates, absent heart failure, and ultra-protective mechanical ventilation (UPMV) defined as tidal volume (VT) <6 mL/kg PBW. Exclusion: UPMV use for <24 h. Demographics, admission Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, arterial blood gas, serum bicarbonate, ventilator parameters for pre-, during, and post-UPMV periods including modes, VT, peak inspiratory pressure (PIP), plateau pressure (Pplat), driving pressure, etc. were gathered. We compared lab and ventilator data for pre-, during, and post-UPMV periods. Results Fifteen patients (male:female = 7:8, age 42.13 ± 11.29 years) satisfied criteria, APACHEII 20.6 ± 7.1, mean days in intensive care unit and hospitalization were 18.5 ± 8.85 and 20.81 ± 9.78 days, 9 (60%) received paralysis and 7 (46.67%) required inotropes. Eleven patients had echocardiogram, 7 (63.64%) demonstrated right ventricular volume or pressure overload. Eleven patients (73.33%) survived. During-UPMV, VT ranged 2-5 mL/kg PBW(3.99 ± 0.73), the arterial partial pressure of carbon dioxide (PaCO2) was higher than pre-UPMV values (84.81 ± 18.95 cmH2O vs. 69.16 ± 33.09 cmH2O), but pH was comparable and none received extracorporeal carbon dioxide removal (ECCO2-R). The positive end-expiratory pressure (14.18 ± 7.56 vs. 12.31 ± 6.84 cmH2O), PIP (38.21 ± 12.89 vs. 32.59 ± 9.88), and mean airway pressures (19.98 ± 7.61 vs. 17.48 ± 6.7 cm H2O) were higher during UPMV, but Pplat and PaO2/FiO2 were comparable during- and pre-UPMV. Driving pressure was observed to be higher in those who died than who survived (24.18 ± 12.36 vs. 13.42 ± 3.25). Conclusion UPMV alone may be a safe alternative option for ARDS patients in centers without ECCO2-R.
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Affiliation(s)
- Hariharan Regunath
- Department of Medicine, Division of Pulmonary, Critical Care and Environmental Medicine, University of Missouri, Columbia, MO, USA.,Department of Medicine, Division of Infectious Diseases, University of Missouri, Columbia, MO, USA
| | - Nathanial Moulton
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Daniel Woolery
- Department of Medicine, Division of Pulmonary, Critical Care and Environmental Medicine, University of Missouri, Columbia, MO, USA
| | - Mohammed Alnijoumi
- Department of Medicine, Division of Pulmonary, Critical Care and Environmental Medicine, University of Missouri, Columbia, MO, USA
| | - Troy Whitacre
- Respiratory Therapy Services, University of Missouri Hospital and Clinics, Columbia, MO, USA
| | - Jonathan Collins
- Department of Medicine, Division of Pulmonary, Critical Care and Environmental Medicine, University of Missouri, Columbia, MO, USA.,Department of Medicine, Division of Infectious Diseases, University of Missouri, Columbia, MO, USA
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16
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Roberts BW, Mohr NM, Ablordeppey E, Drewry AM, Ferguson IT, Trzeciak S, Kollef MH, Fuller BM. Association Between Partial Pressure of Arterial Carbon Dioxide and Survival to Hospital Discharge Among Patients Diagnosed With Sepsis in the Emergency Department. Crit Care Med 2018; 46:e213-e220. [PMID: 29261567 PMCID: PMC5825256 DOI: 10.1097/ccm.0000000000002918] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE The objective of this study was to test the association between the partial pressure of arterial carbon dioxide and survival to hospital discharge among mechanically ventilated patients diagnosed with sepsis in the emergency department. DESIGN Retrospective cohort study of a single center trial registry. SETTING Academic medical center. PATIENTS Mechanically ventilated emergency department patients. INCLUSION CRITERIA age 18 years and older, diagnosed with sepsis in the emergency department, and mechanical ventilation initiated in the emergency department. INTERVENTIONS Arterial blood gases obtained after initiation of mechanical ventilation were analyzed. The primary outcome was survival to hospital discharge. We tested the association between partial pressure of arterial carbon dioxide and survival using multivariable logistic regression adjusting for potential confounders. Sensitivity analyses, including propensity score matching were also performed. MEASUREMENTS AND MAIN RESULTS Six hundred subjects were included, and 429 (72%) survived to hospital discharge. The median (interquartile range) partial pressure of arterial carbon dioxide was 42 (34-53) mm Hg for the entire cohort and 44 (35-57) and 39 (31-45) mm Hg among survivors and nonsurvivors, respectively (p < 0.0001 Wilcox rank-sum test). On multivariable analysis, a 1 mm Hg rise in partial pressure of arterial carbon dioxide was associated with a 3% increase in odds of survival (adjusted odds ratio, 1.03; 95% CI, 1.01-1.04) after adjusting for tidal volume and other potential confounders. These results remained significant on all sensitivity analyses. CONCLUSION In this sample of mechanically ventilated sepsis patients, we found an association between increasing levels of partial pressure of arterial carbon dioxide and survival to hospital discharge. These findings justify future studies to determine the optimal target partial pressure of arterial carbon dioxide range for mechanically ventilated sepsis patients.
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Affiliation(s)
- Brian W. Roberts
- The Department of Emergency Medicine, Cooper University Hospital, Cooper Medical School of Rowan University, Camden, New Jersey
| | - Nicholas M. Mohr
- Departments of Emergency Medicine and Anesthesiology, Division of Critical Care Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Enyo Ablordeppey
- Department of Emergency Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
- Department of Anesthesiology, Division of Critical Care, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Anne M. Drewry
- Department of Emergency Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Ian T. Ferguson
- School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Stephen Trzeciak
- The Department of Emergency Medicine, Cooper University Hospital, Cooper Medical School of Rowan University, Camden, New Jersey
- The Department of Medicine, Division of Critical Care Medicine, Cooper University Hospital, Cooper Medical School of Rowan University, Camden, New Jersey
| | - Marin H. Kollef
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
| | - Brian M. Fuller
- Department of Emergency Medicine, Washington University School of Medicine in St. Louis, St. Louis, Missouri
- Department of Anesthesiology, Division of Critical Care, Washington University School of Medicine in St. Louis, St. Louis, Missouri
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17
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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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18
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Nin N, Angulo M, Briva A. Effects of hypercapnia in acute respiratory distress syndrome. ANNALS OF TRANSLATIONAL MEDICINE 2018; 6:37. [PMID: 29430454 PMCID: PMC5799147 DOI: 10.21037/atm.2018.01.09] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 01/11/2018] [Indexed: 01/11/2023]
Abstract
In patients with acute respiratory distress syndrome (ARDS) hypercapnia is a marker of poor prognosis, however there is controversial information regarding the effect of hypercapnia on outcomes. Recently two studies in a large population of mechanical ventilation patients showed higher mortality associated independently to hypercapnia. Key roles responsible for the poor clinical outcomes observed in critically ill patients exposed to hypercapnia are not well known, two possible mechanisms involved are the effect of CO2 on the muscle and the alveolar epithelium. Hypercapnia frequently coexists with muscle atrophy and dysfunction, moreover patients surviving ARDS present reduced muscle strength and decreased physical quality of life. One of the possible mechanisms responsible for these abnormalities could be the effects of hypercapnia during the course of ARDS. More over controversy persists about the hypercapnia role in the alveolar space, in the last years there is abundant experimental information on its deleterious effects on essential functions of the alveolar epithelium.
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Affiliation(s)
- Nicolás Nin
- Unidad de Cuidados Intensivos, Hospital Español, Montevideo, Uruguay
| | - Martín Angulo
- Unidad de Cuidados Intensivos, Hospital de Clínicas, Montevideo, Uruguay
| | - Arturo Briva
- Unidad de Cuidados Intensivos, Hospital Español, Montevideo, Uruguay
- Unidad de Cuidados Intensivos, Hospital de Clínicas, Montevideo, Uruguay
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19
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Barnes T, Zochios V, Parhar K. Re-examining Permissive Hypercapnia in ARDS: A Narrative Review. Chest 2017; 154:185-195. [PMID: 29175086 DOI: 10.1016/j.chest.2017.11.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/20/2017] [Accepted: 11/13/2017] [Indexed: 12/16/2022] Open
Abstract
Lung-protective ventilation (LPV) has become the cornerstone of management in patients with ARDS. A subset of patients is unable to tolerate LPV without significant CO2 elevation. In these patients, permissive hypercapnia is used. Although thought to be benign, it is becoming increasingly evident that elevated CO2 levels have significant physiological effects. In this narrative review, we highlight clinically relevant end-organ effects in both animal models and clinical studies. We also explore the association between elevated CO2, acute cor pulmonale, and ICU mortality. We conclude with a brief review of alternative therapies for CO2 management currently under investigation in patients with moderate to severe ARDS.
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Affiliation(s)
- Tavish Barnes
- Department of Critical Care Medicine, University of Calgary, Calgary, AB, Canada
| | - Vasileios Zochios
- Department of Critical Care Medicine, University Hospitals Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, College of Medical and Dental Sciences, University of Birmingham, Birmingham, England
| | - Ken Parhar
- Department of Critical Care Medicine, University of Calgary, Calgary, AB, Canada.
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20
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Fuchs H, Rossmann N, Schmid MB, Hoenig M, Thome U, Mayer B, Klotz D, Hummler HD. Permissive hypercapnia for severe acute respiratory distress syndrome in immunocompromised children: A single center experience. PLoS One 2017. [PMID: 28632754 PMCID: PMC5478142 DOI: 10.1371/journal.pone.0179974] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Controlled hypoventilation while accepting hypercapnia has been advocated to reduce ventilator-induced lung injury. The aim of the study was to analyze outcomes of a cohort of immunocompromised children with acute respiratory distress syndrome (ARDS) ventilated with a strategy of stepwise increasing PCO2 targets up to 140 mm Hg. METHODS Retrospective analysis of outcomes of a cohort of children with oncologic disease or after stem cell transplantation and severe respiratory failure in comparison with a historical control cohort. RESULTS Out of 150 episodes of admission to the PICU 88 children underwent invasive mechanical ventilation for >24h (overall survival 75%). In a subgroup of 38 children with high ventilator requirements the PCO2 target ranges were increased stepwise. Fifteen children survived and were discharged from the PICU. Severe pulmonary hypertension was seen in two patients and no case of cerebral edema was observed. Long term outcome was available in 15 patients and 10 of these patients survived without adverse neurological sequelae. With introduction of this strategy survival of immunocompromised children undergoing mechanical ventilation for >24h increased to 48% compared to 32% prior to introduction (historical cohort). CONCLUSIONS A ventilation strategy incorporating very high carbon dioxide levels to allow for low tidal volumes and limited inspiratory pressures is feasible in children. Even severe hypercapnia may be well tolerated. No severe side effects associated with hypercapnia were observed. This strategy could potentially increase survival in immunocompromised children with severe ARDS.
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Affiliation(s)
- Hans Fuchs
- Center for Pediatrics, Department of Neonatology and Pediatric Intensive Care, Medical Center – Albert Ludwig University of Freiburg, Faculty of Medicine, Freiburg, Germany
- * E-mail:
| | - Nicola Rossmann
- Division of Neonatology and Pediatric Critical Care, Department for Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany
| | - Manuel B. Schmid
- Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Manfred Hoenig
- Oncology and stem cell transplantation, Department for Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany
| | - Ulrich Thome
- Division of Neonatology, University Hospital of Leipzig, Leipzig, Germany
| | - Benjamin Mayer
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | - Daniel Klotz
- Center for Pediatrics, Department of Neonatology and Pediatric Intensive Care, Medical Center – Albert Ludwig University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Helmut D. Hummler
- Division of Neonatology and Pediatric Critical Care, Department for Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany
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Repessé X, Vieillard-Baron A. Hypercapnia during acute respiratory distress syndrome: the tree that hides the forest! J Thorac Dis 2017; 9:1420-1425. [PMID: 28740647 DOI: 10.21037/jtd.2017.05.69] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Xavier Repessé
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, University Hospital Ambroise Paré, Boulogne-Billancourt, France
| | - Antoine Vieillard-Baron
- Intensive Care Unit, Section Thorax-Vascular Disease-Abdomen-Metabolism, University Hospital Ambroise Paré, Boulogne-Billancourt, France.,Faculty of Medicine Paris Ile-de-France Ouest, University of Versailles Saint-Quentin en Yvelines, Saint-Quentin en Yvelines, France.,INSERM U-1018, CESP, Team 5 (EpReC, Renal and Cardiovascular Epidemiology), UVSQ, Villejuif, France
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Severe hypercapnia and outcome of mechanically ventilated patients with moderate or severe acute respiratory distress syndrome. Intensive Care Med 2017; 43:200-208. [PMID: 28108768 DOI: 10.1007/s00134-016-4611-1] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 10/25/2016] [Indexed: 12/11/2022]
Abstract
PURPOSE To analyze the relationship between hypercapnia developing within the first 48 h after the start of mechanical ventilation and outcome in patients with acute respiratory distress syndrome (ARDS). PATIENTS AND METHODS We performed a secondary analysis of three prospective non-interventional cohort studies focusing on ARDS patients from 927 intensive care units (ICUs) in 40 countries. These patients received mechanical ventilation for more than 12 h during 1-month periods in 1998, 2004, and 2010. We used multivariable logistic regression and a propensity score analysis to examine the association between hypercapnia and ICU mortality. MAIN OUTCOMES We included 1899 patients with ARDS in this study. The relationship between maximum PaCO2 in the first 48 h and mortality suggests higher mortality at or above PaCO2 of ≥50 mmHg. Patients with severe hypercapnia (PaCO2 ≥50 mmHg) had higher complication rates, more organ failures, and worse outcomes. After adjusting for age, SAPS II score, respiratory rate, positive end-expiratory pressure, PaO2/FiO2 ratio, driving pressure, pressure/volume limitation strategy (PLS), corrected minute ventilation, and presence of acidosis, severe hypercapnia was associated with increased risk of ICU mortality [odds ratio (OR) 1.93, 95% confidence interval (CI) 1.32 to 2.81; p = 0.001]. In patients with severe hypercapnia matched for all other variables, ventilation with PLS was associated with higher ICU mortality (OR 1.58, CI 95% 1.04-2.41; p = 0.032). CONCLUSIONS Severe hypercapnia appears to be independently associated with higher ICU mortality in patients with ARDS. TRIAL REGISTRATION Clinicaltrials.gov identifier, NCT01093482.
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Kuzkov VV, Rodionova LN, Ilyina YY, Ushakov AA, Sokolova MM, Fot EV, Duberman BL, Kirov MY. Protective Ventilation Improves Gas Exchange, Reduces Incidence of Atelectases, and Affects Metabolic Response in Major Pancreatoduodenal Surgery. Front Med (Lausanne) 2016; 3:66. [PMID: 27999775 PMCID: PMC5138232 DOI: 10.3389/fmed.2016.00066] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Accepted: 11/21/2016] [Indexed: 11/16/2022] Open
Abstract
Background Protective perioperative ventilation has been shown to improve outcomes and reduce the incidence of postoperative pulmonary complications. The goal of this study was to assess the effects of ventilation with low tidal volume (VT) either alone or in a combination with moderate permissive hypercapnia in major pancreatoduodenal interventions. Materials and methods Sixty adult patients scheduled for elective pancreatoduodenal surgery with duration >2 h were enrolled into a prospective single-center study. All patients were randomized to three groups receiving high VT [10 mL/kg of predicted body weight (PBW), the HVT group, n = 20], low VT (6 mL/kg PBW, the LVT group, n = 20), and low VT combined with a moderate hypercapnia and hypercapnic acidosis (6 mL/kg PBW, PaCO2 45–60 mm Hg, the LVT + HC group, n = 20). Cardiopulmonary parameters and the incidence of complications were registered during surgery and postoperatively. Results and discussion The values of VT were 610 (563–712), 370 (321–400), and 340 (312–430) mL/kg for the HVT, the LVT, and the LVT + HC groups, respectively (p < 0.001). Compared to the HVT group, PaO2/FiO2 ratio was increased in the LVT group by 15%: 333 (301–381) vs. 382 (349–423) mm Hg at 24 h postoperatively (p < 0.05). The HVT group had significantly higher incidence of atelectases (n = 6), despite lower incidence of smoking compared with the LVT (n = 1) group (p = 0.017) and demonstrated longer length of hospital stay. The patients of the LVT + HC group had lower arterial lactate and bicarbonate excess values by the end of surgery. Conclusion In major pancreatoduodenal interventions, preventively protective VT improves postoperative oxygenation, reduces the incidence of atelectases, and shortens length of hospital stay. The combination of low VT and permissive hypercapnia results in hypercapnic acidosis decreasing the lactate concentration but adding no additional benefits and warrants further investigations.
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Affiliation(s)
- Vsevolod V Kuzkov
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russian Federation; Department of Anesthesiology, City Hospital # 1, Arkhangelsk, Russian Federation
| | - Ludmila N Rodionova
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russian Federation; Department of Anesthesiology, City Hospital # 1, Arkhangelsk, Russian Federation
| | - Yana Y Ilyina
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russian Federation; Department of Anesthesiology, City Hospital # 1, Arkhangelsk, Russian Federation
| | - Aleksey A Ushakov
- Department of Anesthesiology and Intensive Care, Northern State Medical University , Arkhangelsk , Russian Federation
| | - Maria M Sokolova
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russian Federation; Department of Anesthesiology, City Hospital # 1, Arkhangelsk, Russian Federation
| | - Eugenia V Fot
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russian Federation; Department of Anesthesiology, City Hospital # 1, Arkhangelsk, Russian Federation
| | - Boris L Duberman
- Department of Surgery, Northern State Medical University , Arkhangelsk , Russian Federation
| | - Mikhail Y Kirov
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russian Federation; Department of Anesthesiology, City Hospital # 1, Arkhangelsk, Russian Federation
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Hummler HD, Banke K, Wolfson MR, Buonocore G, Ebsen M, Bernhard W, Tsikas D, Fuchs H. The Effects of Lung Protective Ventilation or Hypercapnic Acidosis on Gas Exchange and Lung Injury in Surfactant Deficient Rabbits. PLoS One 2016; 11:e0147807. [PMID: 26840779 PMCID: PMC4739580 DOI: 10.1371/journal.pone.0147807] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/08/2016] [Indexed: 01/11/2023] Open
Abstract
Background Permissive hypercapnia has been shown to reduce lung injury in subjects with surfactant deficiency. Experimental studies suggest that hypercapnic acidosis by itself rather than decreased tidal volume may be a key protective factor. Objectives To study the differential effects of a lung protective ventilatory strategy or hypercapnic acidosis on gas exchange, hemodynamics and lung injury in an animal model of surfactant deficiency. Methods 30 anesthetized, surfactant-depleted rabbits were mechanically ventilated (FiO2 = 0.8, PEEP = 7cmH2O) and randomized into three groups: Normoventilation-Normocapnia (NN)-group: tidal volume (Vt) = 7.5 ml/kg, target PaCO2 = 40 mmHg; Normoventilation-Hypercapnia (NH)-group: Vt = 7.5 ml/kg, target PaCO2 = 80 mmHg by increasing FiCO2; and a Hypoventilation-Hypercapnia (HH)-group: Vt = 4.5 ml/kg, target PaCO2 = 80 mmHg. Plasma lactate and interleukin (IL)-8 were measured every 2 h. Animals were sacrificed after 6 h to perform bronchoalveolar lavage (BAL), to measure lung wet-to-dry weight, lung tissue IL-8, and to obtain lung histology. Results PaO2 was significantly higher in the HH-group compared to the NN-group (p<0.05), with values of the NH-group between the HH- and NN-groups. Other markers of lung injury (wet-dry-weight, BAL-Protein, histology-score, plasma-IL-8 and lung tissue IL-8) resulted in significantly lower values for the HH-group compared to the NN-group and trends for the NH-group towards lower values compared to the NN-group. Lactate was significantly lower in both hypercapnia groups compared to the NN-group. Conclusion Whereas hypercapnic acidosis may have some beneficial effects, a significant effect on lung injury and systemic inflammatory response is dependent upon a lower tidal volume rather than resultant arterial CO2 tensions and pH alone.
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Affiliation(s)
- Helmut D. Hummler
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics, Children’s Hospital, Ulm University, 89070 Ulm, Germany
- * E-mail:
| | - Katharina Banke
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics, Children’s Hospital, Ulm University, 89070 Ulm, Germany
| | - Marla R. Wolfson
- Departments of Physiology, Medicine and Pediatrics, CENTRe: Collaborative for Environmental and Neonatal Therapeutics Research; Temple Lung Center; Center for Inflammation, Translational and Clinical Lung Research, Temple University School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Giuseppe Buonocore
- Pediatric Neonatology Unit, Department of Molecular and Developmental Medicine, University Hospital of Siena, Siena, Italy
| | - Michael Ebsen
- Institute for Pathology, Medizinisches Versorgungszentrum, Staedtisches Krankenhaus Kiel, Germany
| | - Wolfgang Bernhard
- Department of Neonatology, Children’s Hospital, University of Tuebingen, Tuebingen, Germany
| | - Dimitrios Tsikas
- Centre of Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany
| | - Hans Fuchs
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics, Children’s Hospital, Ulm University, 89070 Ulm, Germany
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Abstract
PURPOSE OF REVIEW Multiple clinical and laboratory studies have been conducted to illustrate the effects of hypercapnia in a range of injuries, and to understand the mechanisms underlying these effects. The aim of this review is to highlight and interpret information obtained from these recent reports and discuss how they may inform the clinical context. RECENT FINDINGS In the last decade, several important articles have addressed key elements of how carbon dioxide interacts in critical illness states. Among them the most important insights relate to how hypercapnia affects critical illness and include the effects and mechanisms of carbon dioxide in pulmonary hypertension, infection, inflammation, diaphragm dysfunction, and cerebral ischemia. In addition, we discuss molecular insights that apply to multiple aspects of critical illness. SUMMARY Experiments involving hypercapnia have covered a wide range of illness models with varying degrees of success. It is becoming evident that deliberate hypercapnia in the clinical setting should seldom be used, except wherever necessitated to avoid ventilator-associated lung injury. A more complete understanding of the molecular mechanisms must be established.
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Yang W, Yue Z, Cui X, Guo Y, Zhang L, Zhou H, Li W. Comparison of the effects of moderate and severe hypercapnic acidosis on ventilation-induced lung injury. BMC Anesthesiol 2015; 15:67. [PMID: 25924944 PMCID: PMC4443663 DOI: 10.1186/s12871-015-0050-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 04/22/2015] [Indexed: 01/12/2023] Open
Abstract
Background We have proved that hypercapnic acidosis (a PaCO2 of 80-100 mmHg) protects against ventilator-induced lung injury in rats. However, there remains uncertainty regarding the appropriate target PaCO2 or if greater CO2 “doses” (PaCO2 > 100 mmHg) demonstrate this effect. We wished to determine whether severe acute hypercapnic acidosis can reduce stretch-induced injury, as well as the role of nuclear factor-κB (NF-κB) in the effects of acute hypercapnic acidosis. Methods Fifty-four rats were ventilated for 4 hours with a pressure-controlled ventilation mode set at a peak inspiratory pressure (PIP) of 30 cmH2O. A gas mixture of carbon dioxide with oxygen (FiCO2 = 4-5%, FiCO2 = 11-12% or FiCO2 = 16-17%; FiO2 = 0.7; balance N2) was immediately administered to maintain the target PaCO2 in the NC (a PaCO2 of 35-45 mmHg), MHA (a PaCO2 of 80-100 mmHg) and SHA (a PaCO2 of 130-150 mmHg) groups. Nine normal or non-ventilated rats served as controls. The hemodynamics, gas exchange and inflammatory parameters were measured. The role of NF-κB pathway in hypercapnic acidosis-mediated protection from high-pressure stretch injury was then determined. Results In the NC group, high-pressure ventilation resulted in a decrease in PaO2/FiO2 from 415.6 (37.1) mmHg to 179.1 (23.5) mmHg (p < 0.001), but improved by MHA (379.9 ± 34.5 mmHg) and SHA (298.6 ± 35.3 mmHg). The lung injury score in the SHA group (7.8 ± 1.6) was lower than the NC group (11.8 ± 2.3, P < 0.05) but was higher than the MHA group (4.4 ± 1.3, P < 0.05). Compared with the NC group, after 4 h of high pressure ventilation, the MHA and SHA groups had decreases in MPO activity of 67% and 33%, respectively, and also declined the levels of TNF-α (58% versus 72%) and MIP-2 (76% versus 60%) in the BALF. Additionally, both hypercapnic acidosis groups reduced stretch–induced NF-κB activation (p < 0.05) and significantly decreased lung ICAM-1 expression (p < 0.05). Conclusions Moderate hypercapnic acidosis (PaCO2 maintained at 80-100 mmHg) has a greater protective effect on high-pressure ventilation-induced inflammatory injury. The potential mechanisms may involve alterations in NF-κB activity.
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Affiliation(s)
- Wanchao Yang
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Ziyong Yue
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Xiaoguang Cui
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Yueping Guo
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Lili Zhang
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Huacheng Zhou
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China. .,Education Department of Heilongjiang Province, Anesthesiology Key Laboratory, Harbin Medical University, Harbin, Heilongjiang Province, China.
| | - Wenzhi Li
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University; Anesthesiology Key Laboratory, Harbin Medical University, Harbin, 150086, China.
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Chiu S, Kanter J, Sun H, Bharat A, Sporn PHS, Bharat A. Effects of Hypercapnia in Lung Tissue Repair and Transplant. CURRENT TRANSPLANTATION REPORTS 2015. [DOI: 10.1007/s40472-014-0047-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Gates KL, Howell HA, Nair A, Vohwinkel CU, Welch LC, Beitel GJ, Hauser AR, Sznajder JI, Sporn PHS. Hypercapnia impairs lung neutrophil function and increases mortality in murine pseudomonas pneumonia. Am J Respir Cell Mol Biol 2013; 49:821-8. [PMID: 23777386 DOI: 10.1165/rcmb.2012-0487oc] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Hypercapnia, an elevation of the level of carbon dioxide (CO2) in blood and tissues, is a marker of poor prognosis in chronic obstructive pulmonary disease and other pulmonary disorders. We previously reported that hypercapnia inhibits the expression of TNF and IL-6 and phagocytosis in macrophages in vitro. In the present study, we determined the effects of normoxic hypercapnia (10% CO2, 21% O2, and 69% N2) on outcomes of Pseudomonas aeruginosa pneumonia in BALB/c mice and on pulmonary neutrophil function. We found that the mortality of P. aeruginosa pneumonia was increased in 10% CO2-exposed compared with air-exposed mice. Hypercapnia increased pneumonia mortality similarly in mice with acute and chronic respiratory acidosis, indicating an effect unrelated to the degree of acidosis. Exposure to 10% CO2 increased the burden of P. aeruginosa in the lungs, spleen, and liver, but did not alter lung injury attributable to pneumonia. Hypercapnia did not reduce pulmonary neutrophil recruitment during infection, but alveolar neutrophils from 10% CO2-exposed mice phagocytosed fewer bacteria and produced less H2O2 than neutrophils from air-exposed mice. Secretion of IL-6 and TNF in the lungs of 10% CO2-exposed mice was decreased 7 hours, but not 15 hours, after the onset of pneumonia, indicating that hypercapnia inhibited the early cytokine response to infection. The increase in pneumonia mortality caused by elevated CO2 was reversible when hypercapnic mice were returned to breathing air before or immediately after infection. These results suggest that hypercapnia may increase the susceptibility to and/or worsen the outcome of lung infections in patients with severe lung disease.
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Affiliation(s)
- Khalilah L Gates
- 1 Division of Pulmonary and Critical Care Medicine, Department of Medicine
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Yang WC, Song CY, Wang N, Zhang LL, Yue ZY, Cui XG, Zhou HC. Hypercapnic acidosis confers antioxidant and anti-apoptosis effects against ventilator-induced lung injury. J Transl Med 2013; 93:1339-49. [PMID: 24126891 DOI: 10.1038/labinvest.2013.118] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 09/13/2013] [Accepted: 09/23/2013] [Indexed: 11/09/2022] Open
Abstract
Hypercapnic acidosis may attenuate ventilator-induced lung oxidative stress injury and alveolar cell apoptosis, but the underlying mechanisms are poorly understood. We examined the effects of hypercapnic acidosis on the role of apoptosis signal-regulating kinase 1 (ASK1), which activates the c-Jun N-terminal kinase (JNK) and p38 cascade in both apoptosis and oxidative reactions, in high-pressure ventilation stimulated rat lungs. Rats were ventilated with a peak inspiratory pressure (PIP) of 30 cmH2O for 4 h and randomly given FiCO2 to achieve normocapnia (PaCO2 at 35-45 mm Hg) or hypercapnia (PaCO2 at 80-100 mm Hg); normally ventilated rats with PIP of 15 cmH2O were used as controls. Lung injury was quantified by gas exchange, microvascular leaks, histology, levels of inflammatory cytokines, and pulmonary oxidative reactions. Apoptosis through the ASK1-JNK/p38 mitogen-activated protein kinase (MAPK) cascade in type II alveolar epithelial cells (AECIIs) were evaluated by examination of caspase-3 activation. The results showed that injurious ventilation caused significant lung injury, including deteriorative oxygenation, changes of histology, and the release of inflammatory cytokines. In addition, the high-pressure mechanical stretch also induced apoptosis and caspase-3 activation in the AECIIs. Hypercapnia attenuated these responses, suppressing the ASK1 signal pathways with its downstream kinase phosphorylation of p38 MAPK and JNK, and caspase-3 activation. Thus, hypercapnia can attenuate cell apoptosis and oxidative stress damage in rat lungs during injurious ventilation, at least in part, due to the suppression of the ASK1-JNK/p38 MAPK pathways.
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Affiliation(s)
- Wan-Chao Yang
- Department of Anesthesiology, Second Affiliated Hospital of Harbin Medical University, Harbin, China
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Cummins EP, Selfridge AC, Sporn PH, Sznajder JI, Taylor CT. Carbon dioxide-sensing in organisms and its implications for human disease. Cell Mol Life Sci 2013; 71:831-45. [PMID: 24045706 DOI: 10.1007/s00018-013-1470-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 08/22/2013] [Accepted: 08/30/2013] [Indexed: 12/29/2022]
Abstract
The capacity of organisms to sense changes in the levels of internal and external gases and to respond accordingly is central to a range of physiologic and pathophysiologic processes. Carbon dioxide, a primary product of oxidative metabolism is one such gas that can be sensed by both prokaryotic and eukaryotic cells and in response to altered levels, elicit the activation of multiple adaptive pathways. The outcomes of activating CO2-sensitive pathways in various species include increased virulence of fungal and bacterial pathogens, prey-seeking behavior in insects as well as taste perception, lung function, and the control of immunity in mammals. In this review, we discuss what is known about the mechanisms underpinning CO2 sensing across a range of species and consider the implications of this for physiology, disease progression, and the possibility of developing new therapeutics for inflammatory and infectious disease.
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Affiliation(s)
- Eoin P Cummins
- School of Medicine and Medical Science, UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
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Sevoflurane, but not propofol, reduces the lung inflammatory response and improves oxygenation in an acute respiratory distress syndrome model. Eur J Anaesthesiol 2013; 30:455-63. [DOI: 10.1097/eja.0b013e32835f0aa5] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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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
In critical care, the monitoring is essential to the daily care of ICU patients, as the optimization of patient's hemodynamic, ventilation, temperature, nutrition, and metabolism is the key to improve patients' survival. Indeed, the decisive endpoint is the supply of oxygen to tissues according to their metabolic needs in order to fuel mitochondrial respiration and, therefore, life. In this sense, both oxygenation and perfusion must be monitored in the implementation of any resuscitation strategy. The emerging concept has been the enhancement of macrocirculation through sequential optimization of heart function and then judging the adequacy of perfusion/oxygenation on specific parameters in a strategy which was aptly coined “goal directed therapy.” On the other hand, the maintenance of normal temperature is critical and should be regularly monitored. Regarding respiratory monitoring of ventilated ICU patients, it includes serial assessment of gas exchange, of respiratory system mechanics, and of patients' readiness for liberation from invasive positive pressure ventilation. Also, the monitoring of nutritional and metabolic care should allow controlling nutrients delivery, adequation between energy needs and delivery, and blood glucose. The present paper will describe the physiological basis, interpretation of, and clinical use of the major endpoints of perfusion/oxygenation adequacy and of temperature, respiratory, nutritional, and metabolic monitorings.
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Acute lung injury and acute respiratory distress syndrome: experimental and clinical investigations. J Geriatr Cardiol 2012; 8:44-54. [PMID: 22783284 PMCID: PMC3390060 DOI: 10.3724/sp.j.1263.2011.00044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/12/2011] [Accepted: 03/19/2011] [Indexed: 01/11/2023] Open
Abstract
Acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) can be associated with various disorders. Recent investigation has involved clinical studies in collaboration with clinical investigators and pathologists on the pathogenetic mechanisms of ALI or ARDS caused by various disorders. This literature review includes a brief historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the long-term experimental studies and clinical investigations from our laboratory, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.
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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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Su CF, Kao SJ, Chen HI. Acute respiratory distress syndrome and lung injury: Pathogenetic mechanism and therapeutic implication. World J Crit Care Med 2012; 1:50-60. [PMID: 24701402 PMCID: PMC3953859 DOI: 10.5492/wjccm.v1.i2.50] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 10/14/2011] [Accepted: 03/10/2012] [Indexed: 02/06/2023] Open
Abstract
To review possible mechanisms and therapeutics for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). ALI/ARDS causes high mortality. The risk factors include head injury, intracranial disorders, sepsis, infections and others. Investigations have indicated the detrimental role of nitric oxide (NO) through the inducible NO synthase (iNOS). The possible therapeutic regimen includes extracorporeal membrane oxygenation, prone position, fluid and hemodynamic management and permissive hypercapnic acidosis etc. Other pharmacological treatments are anti-inflammatory and/or antimicrobial agents, inhalation of NO, glucocorticoids, surfactant therapy and agents facilitating lung water resolution and ion transports. β-adrenergic agonists are able to accelerate lung fluid and ion removal and to stimulate surfactant secretion. In conscious rats, regular exercise training alleviates the endotoxin-induced ALI. Propofol and N-acetylcysteine exert protective effect on the ALI induced by endotoxin. Insulin possesses anti-inflammatory effect. Pentobarbital is capable of reducing the endotoxin-induced ALI. In addition, nicotinamide or niacinamide abrogates the ALI caused by ischemia/reperfusion or endotoxemia. This review includes historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.
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Affiliation(s)
- Chain-Fa Su
- Chain-Fa Su, Department of Neurosurgery, Tzu Chi University Hospital, Hualien 97004, Taiwan, China
| | - Shang Jyh Kao
- Chain-Fa Su, Department of Neurosurgery, Tzu Chi University Hospital, Hualien 97004, Taiwan, China
| | - Hsing I Chen
- Chain-Fa Su, Department of Neurosurgery, Tzu Chi University Hospital, Hualien 97004, Taiwan, China
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Vadász I, Hubmayr RD, Nin N, Sporn PHS, Sznajder JI. Hypercapnia: a nonpermissive environment for the lung. Am J Respir Cell Mol Biol 2012; 46:417-21. [PMID: 22246860 DOI: 10.1165/rcmb.2011-0395ps] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Patients with severe acute and chronic lung diseases develop derangements in gas exchange that may result in increased levels of CO(2) (hypercapnia), the effects of which on human health are incompletely understood. It has been proposed that hypercapnia may have beneficial effects in patients with acute lung injury, and the concepts of "permissive" and even "therapeutic" hypercapnia have emerged. However, recent work suggests that CO(2) can act as a signaling molecule via pH-independent mechanisms, resulting in deleterious effects in the lung. Here we review recent research on how elevated CO(2) is sensed by cells in the lung and the potential harmful effects of hypercapnia on epithelial and endothelial barrier, lung edema clearance, innate immunity, and host defense. In view of these findings, we raise concerns about the potentially deleterious effects hypercapnia may have in patients with acute and chronic lung diseases.
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Affiliation(s)
- István Vadász
- Department of Internal Medicine, University of Giessen Lung Center, Justus Liebig University, Germany.
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Xia J, Sun B, He H, Zhang H, Wang C, Zhan Q. Effect of spontaneous breathing on ventilator-induced lung injury in mechanically ventilated healthy rabbits: a randomized, controlled, experimental study. Crit Care 2011; 15:R244. [PMID: 22018091 PMCID: PMC3334795 DOI: 10.1186/cc10502] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 08/09/2011] [Accepted: 10/21/2011] [Indexed: 11/10/2022] Open
Abstract
INTRODUCTION Ventilator-induced lung injury (VILI), one of the most serious complications of mechanical ventilation (MV), can impact patients' clinical prognoses. Compared to control ventilation, preserving spontaneous breathing can improve many physiological features in ventilated patients, such as gas distribution, cardiac performance, and ventilation-perfusion matching. However, the effect of spontaneous breathing on VILI is unknown. The goal of this study was to compare the effects of spontaneous breathing and control ventilation on lung injury in mechanically-ventilated healthy rabbits. METHODS Sixteen healthy New Zealand white rabbits were randomly placed into a spontaneous breathing group (SB Group) and a control ventilation group (CV Group). Both groups were ventilated for eight hours using biphasic positive airway pressure (BIPAP) with similar ventilator parameters: inspiration pressure (PI) resulting in a tidal volume (VT) of 10 to 15 ml/kg, inspiratory-to-expiratory ratio of 1:1, positive end-expiration pressure (PEEP) of 2 cmH₂O, and FiO₂ of 0.5. Inflammatory markers in blood serum, lung homogenates and bronchoalveolar lavage fluid (BALF), total protein levels in BALF, mRNA expressions of selected cytokines in lung tissue, and lung injury histopathology scores were determined. RESULTS Animals remained hemodynamically stable throughout the entire experiment. After eight hours of MV, compared to the CV Group, the SB Group had lower PaCO₂ values and ratios of dead space to tidal volume, and higher lung compliance. The levels of cytokines in blood serum and BALF in both groups were similar, but spontaneous breathing led to significantly lower cytokine mRNA expressions in lung tissues and lower lung injury histological scores. CONCLUSIONS Preserving spontaneous breathing can not only improve ventilatory function, but can also attenuate selected markers of VILI in the mechanically-ventilated healthy lung.
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Affiliation(s)
- Jingen Xia
- Department of Respiratory and Critical Care Medicine, Beijing Institute of Respiratory Medicine, Beijing Chao-Yang Hospital, Capital Medical University, 8 Gongren Tiyuchang South Road, Beijing, 100020, PR China
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Fuchs H, Mendler MR, Scharnbeck D, Ebsen M, Hummler HD. Very low tidal volume ventilation with associated hypercapnia--effects on lung injury in a model for acute respiratory distress syndrome. PLoS One 2011; 6:e23816. [PMID: 21886825 PMCID: PMC3158784 DOI: 10.1371/journal.pone.0023816] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 07/27/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Ventilation using low tidal volumes with permission of hypercapnia is recommended to protect the lung in acute respiratory distress syndrome. However, the most lung protective tidal volume in association with hypercapnia is unknown. The aim of this study was to assess the effects of different tidal volumes with associated hypercapnia on lung injury and gas exchange in a model for acute respiratory distress syndrome. METHODOLOGY/PRINCIPAL FINDINGS In this randomized controlled experiment sixty-four surfactant-depleted rabbits were exposed to 6 hours of mechanical ventilation with the following targets: Group 1: tidal volume = 8-10 ml/kg/PaCO(2) = 40 mm Hg; Group 2: tidal volume = 4-5 ml/kg/PaCO(2) = 80 mm Hg; Group 3: tidal volume = 3-4 ml/kg/PaCO(2) = 120 mm Hg; Group 4: tidal volume = 2-3 ml/kg/PaCO(2) = 160 mm Hg. Decreased wet-dry weight ratios of the lungs, lower histological lung injury scores and higher PaO(2) were found in all low tidal volume/hypercapnia groups (group 2, 3, 4) as compared to the group with conventional tidal volume/normocapnia (group 1). The reduction of the tidal volume below 4-5 ml/kg did not enhance lung protection. However, oxygenation and lung protection were maintained at extremely low tidal volumes in association with very severe hypercapnia and no adverse hemodynamic effects were observed with this strategy. CONCLUSION Ventilation with low tidal volumes and associated hypercapnia was lung protective. A tidal volume below 4-5 ml/kg/PaCO(2) 80 mm Hg with concomitant more severe hypercapnic acidosis did not increase lung protection in this surfactant deficiency model. However, even at extremely low tidal volumes in association with severe hypercapnia lung protection and oxygenation were maintained.
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Affiliation(s)
- Hans Fuchs
- Division of Neonatology and Pediatric Critical Care, Department of Pediatrics and Adolescent Medicine, Ulm University, Ulm, Germany.
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Chuang IC, Yang RC, Chou SH, Huang LR, Tsai TN, Dong HP, Huang MS. Effect of carbon dioxide inhalation on pulmonary hypertension induced by increased blood flow and hypoxia. Kaohsiung J Med Sci 2011; 27:336-43. [DOI: 10.1016/j.kjms.2011.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Accepted: 11/10/2010] [Indexed: 11/16/2022] Open
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Kapetanakis T, Siempos II, Metaxas EI, Kopterides P, Agrogiannis G, Patsouris E, Lazaris AC, Stravodimos KG, Roussos C, Armaganidis A. Metabolic acidosis may be as protective as hypercapnic acidosis in an ex-vivo model of severe ventilator-induced lung injury: a pilot study. BMC Anesthesiol 2011; 11:8. [PMID: 21486492 PMCID: PMC3087686 DOI: 10.1186/1471-2253-11-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2010] [Accepted: 04/13/2011] [Indexed: 11/10/2022] Open
Abstract
Background There is mounting experimental evidence that hypercapnic acidosis protects against lung injury. However, it is unclear if acidosis per se rather than hypercapnia is responsible for this beneficial effect. Therefore, we sought to evaluate the effects of hypercapnic (respiratory) versus normocapnic (metabolic) acidosis in an ex vivo model of ventilator-induced lung injury (VILI). Methods Sixty New Zealand white rabbit ventilated and perfused heart-lung preparations were used. Six study groups were evaluated. Respiratory acidosis (RA), metabolic acidosis (MA) and normocapnic-normoxic (Control - C) groups were randomized into high and low peak inspiratory pressures, respectively. Each preparation was ventilated for 1 hour according to a standardized ventilation protocol. Lung injury was evaluated by means of pulmonary edema formation (weight gain), changes in ultrafiltration coefficient, mean pulmonary artery pressure changes as well as histological alterations. Results HPC group gained significantly greater weight than HPMA, HPRA and all three LP groups (P = 0.024), while no difference was observed between HPMA and HPRA groups regarding weight gain. Neither group differ on ultrafiltration coefficient. HPMA group experienced greater increase in the mean pulmonary artery pressure at 20 min (P = 0.0276) and 40 min (P = 0.0012) compared with all other groups. Histology scores were significantly greater in HP vs. LP groups (p < 0.001). Conclusions In our experimental VILI model both metabolic acidosis and hypercapnic acidosis attenuated VILI-induced pulmonary edema implying a mechanism other than possible synergistic effects of acidosis with CO2 for VILI attenuation.
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Affiliation(s)
- Theodoros Kapetanakis
- "G, P, Livanos and M, Simou" Laboratories, "Evangelismos" General Hospital, University of Athens Medical School, Athens, Greece.
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Airway pressure release ventilation reduces the increase in bronchoalveolar lavage fluid high-mobility group box-1 levels and lung water in experimental acute respiratory distress syndrome induced by lung lavage. Eur J Anaesthesiol 2011; 27:726-33. [PMID: 20611003 DOI: 10.1097/eja.0b013e328333c2b0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND OBJECTIVE Airway pressure release ventilation (APRV) may provide better alveolar recruitment at a lower peak airway pressure than conventional mechanical ventilation (CMV) and, therefore, decrease the risk of barotrauma in patients with acute lung injury and acute respiratory distress syndrome. The present study compared the effects of APRV with low tidal volume ventilation (LTV) and CMV on the ongoing response in lung injury induced by whole lung lavage. METHODS Lung injury was induced by whole lung lavage. Twenty-one Japanese white rabbits were randomized to receive CMV (tidal volume 10 ml kg, positive end-expiratory pressure 3 cmH2O), LTV (tidal volume 6 ml kg, positive end-expiratory pressure 10 cmH2O), or APRV (Phigh 20 cmH2O, Plow 5 cmH2O). After 4 h of treatment, the lungs and heart were excised en bloc. The left lung was lavaged, and high-mobility group box-1 (HMGB1) levels were measured in the lavage. The right lung was analysed histologically and its wet-to-dry weight ratio was calculated. RESULTS PaO2 was decreased after the induction of lung injury, but the values were significantly higher in the APRV and LTV groups after treatment than in the CMV group. Serum HMGB1 levels did not change before and after lung injury; however, bronchoalveolar lavage fluid HMGB1 levels were significantly increased at the end of the experiment (266.8 +/- 47.9 in the CMV group, 137.4 +/- 23.4 in the LTV group, and 91.2 +/- 5.4 ng ml in the APRV group). The bronchoalveolar lavage fluid HMGB1 levels after experiment were significantly lower in the APRV group than in the CMV and LTV groups (P < 0.0001 and P = 0.0391, respectively). Wet-to-dry weight ratios were also lowest in the APRV group. CONCLUSION APRV reduces bronchoalveolar lavage fluid HMGB1 levels and lung water and it preserves oxygenation and systemic blood pressure in experimental acute respiratory distress syndrome. The results suggest that APRV could be as protective for acute respiratory distress syndrome as LTV with positive end-expiratory pressure.
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Bench-to-bedside review: hypercapnic acidosis in lung injury--from 'permissive' to 'therapeutic'. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2010; 14:237. [PMID: 21067531 PMCID: PMC3220022 DOI: 10.1186/cc9238] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Modern ventilation strategies for patients with acute lung injury and acute respiratory distress syndrome frequently result in hypercapnic acidosis (HCA), which is regarded as an acceptable side effect ('permissive hypercapnia'). Multiple experimental studies have demonstrated advantageous effects of HCA in several lung injury models. To date, however, human trials studying the effect of carbon dioxide per se on outcome in patients with lung injury have not been performed. While significant concerns regarding HCA remain, in particular the possible unfavorable effects on bacterial killing and the inhibition of pulmonary epithelial wound repair, the potential for HCA in attenuating lung injury is promising. The underlying mechanisms by which HCA exerts its protective effects are complex, but dampening of the inflammatory response seems to play a pivotal role. After briefly summarizing the physiological effects of HCA, a critical analysis of the available evidence on the potential beneficial effects of therapeutic HCA from in vitro, ex vivo and in vivo lung injury models and from human studies will be reviewed. In addition, the potential concerns in the clinical setting will be outlined.
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Valenza F, Chevallard G, Fossali T, Salice V, Pizzocri M, Gattinoni L. Management of mechanical ventilation during laparoscopic surgery. Best Pract Res Clin Anaesthesiol 2010; 24:227-41. [PMID: 20608559 DOI: 10.1016/j.bpa.2010.02.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Laparoscopy is widely used in the surgical treatment of a number of diseases. Its advantages are generally believed to lie on its minimal invasiveness, better cosmetic outcome and shorter length of hospital stay based on surgical expertise and state-of-the-art equipment. Thousands of laparoscopic surgical procedures performed safely prove that mechanical ventilation during anaesthesia for laparoscopy is well tolerated by a vast majority of patients. However, the effects of pneumoperitoneum are particularly relevant to patients with underlying lung disease as well as to the increasing number of patients with higher-than-normal body mass index. Moreover, many surgical procedures are significantly longer in duration when performed with laparoscopic techniques. Taken together, these factors impose special care for the management of mechanical ventilation during laparoscopic surgery. The purpose of the review is to summarise the consequences of pneumoperitoneum on the standard monitoring of mechanical ventilation during anaesthesia and to discuss the rationale of using a protective ventilation strategy during laparoscopic surgery. The consequences of chest wall derangement occurring during pneumoperitoneum on airway pressure and central venous pressure, together with the role of end-tidal-CO2 monitoring are emphasised. Ventilatory and non-ventilatory strategies to protect the lung are discussed.
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Affiliation(s)
- Franco Valenza
- Università degli Studi di Milano, Dipartimento di Anestesiologia, Terapia Intensiva e Scienze Dermatologiche, Via Festa del Perdono n.7, Milano, Italy.
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Honoré JC, Kooli A, Hou X, Hamel D, Rivera JC, Picard É, Hardy P, Tremblay S, Varma DR, Jankov RP, Mancini JA, Balazy M, Chemtob S. Sustained hypercapnia induces cerebral microvascular degeneration in the immature brain through induction of nitrative stress. Am J Physiol Regul Integr Comp Physiol 2010; 298:R1522-30. [DOI: 10.1152/ajpregu.00807.2009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Hypercapnia is regularly observed in chronic lung disease, such as bronchopulmonary dysplasia in preterm infants. Hypercapnia results in increased nitric oxide synthase activity and in vitro formation of nitrates. Neural vasculature of the immature subject is particularly sensitive to nitrative stress. We investigated whether exposure to clinically relevant sustained high CO2 causes microvascular degeneration in the newborn brain by inducing nitrative stress, and whether this microvascular degeneration has an impact on brain growth. Newborn rat pups were exposed to 10% CO2 as inspired gas (PaCO2 = 60–70 mmHg) starting within 24 h of birth until postnatal day 7 (P7). Brains were notably collected at different time points to measure vascular density, determine brain cortical nitrite/nitrate, and trans-arachidonic acids (TAAs; products of nitration) levels as effectors of vessel damage. Chronic exposure of rat pups to high CO2 (PaCO2 ≈ 65 mmHg) induced a 20% loss in cerebrovascular density at P3 and a 15% decrease in brain mass at P7; at P30, brain mass remained lower in CO2-exposed animals. Within 24 h of exposure to CO2, brain eNOS expression and production of nitrite/nitrate doubled, lipid nitration products (TAAs) increased, and protein nitration (3-nitrotyrosine immunoreactivity) was also coincidently augmented on brain microvessels (lectin positive). Intracerebroventricular injection of TAAs (10 μM) replicated cerebrovascular degeneration. Treatment of rat pups with NOS inhibitor (l-Nω-nitroarginine methyl ester) or a peroxynitrite decomposition catalyst (FeTPPS) prevented hypercapnia-induced microvascular degeneration and preserved brain mass. Cytotoxic effects of high CO2 were reproduced in vitro /ex vivo on cultured endothelial cells and sprouting microvessels. In summary, hypercapnia at values frequently observed in preterm infants with chronic lung disease results in increased nitrative stress, which leads to cerebral cortical microvascular degeneration and curtails brain growth.
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Affiliation(s)
- Jean-Claude Honoré
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Amna Kooli
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
| | - Xin Hou
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
| | - David Hamel
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - José Carlos Rivera
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Émilie Picard
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Pierre Hardy
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
| | - Sophie Tremblay
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
| | - Daya R. Varma
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
| | - Robert P. Jankov
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; and
| | - Joseph A. Mancini
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
| | - Michael Balazy
- Department of Pathology, New York Medical College, New York, New York
| | - Sylvain Chemtob
- Department of Pediatrics, Research Center-Centre Hospitalier Universitaire Ste-Justine, Montréal, Quebec, Canada
- Department of Pharmacology, Université de Montréal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Quebec, Canada
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Thaler U, Kraincuk P, Kamolz LP, Frey M, Metnitz PGH. [Inhalation injury--epidemiology, diagnosis and therapy]. Wien Klin Wochenschr 2010; 122:11-21. [PMID: 20177854 DOI: 10.1007/s00508-010-1303-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 01/13/2010] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Inhalation injury is a vitally threatening medical syndrome, which might appear in patients with or without burn injuries. Thus, knowledge about development, diagnosis and treatment of inhalation injury should be available for each physician working in an intensive care unit. METHODS This review starts with the causal and formal pathogenesis of inhalation injuries. Furthermore, diagnosis and treatment in the critical care setting are presented, followed by the discussion of possible complications. Specific intoxications such as carbon monoxide are due to their importance separately discussed. CONCLUSIONS Inhalation injury present with an attributable excess mortality and thus worsen the prognosis of burned patients. New insights into the pathogenesis of inhalation injury, however, have led to improved therapeutic possibilities with improved outcome. Necessary prerequisites are a timely diagnosis and restrictive volume management, especially in patients with extensive burns. Prospective studies are needed to be able to answer the many emerging questions.
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Affiliation(s)
- Ulrich Thaler
- Universitätsklinik für Anästhesie, Allgemeine Intensivmedizin und Schmerztherapie, Medizinische Universität Wien, Wien, Austria
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Chuang IC, Dong HP, Yang RC, Wang TH, Tsai JH, Yang PH, Huang MS. Effect of Carbon Dioxide on Pulmonary Vascular Tone at Various Pulmonary Arterial Pressure Levels Induced by Endothelin-1. Lung 2010; 188:199-207. [DOI: 10.1007/s00408-010-9234-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 02/16/2010] [Indexed: 10/19/2022]
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Peltekova V, Engelberts D, Otulakowski G, Uematsu S, Post M, Kavanagh BP. Hypercapnic acidosis in ventilator-induced lung injury. Intensive Care Med 2010; 36:869-78. [PMID: 20213072 DOI: 10.1007/s00134-010-1787-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/09/2010] [Indexed: 10/19/2022]
Abstract
RATIONALE Permissive hypercapnia is established in lung injury management. Therapeutic hypercapnia causes benefit or harm, depending on the context. Ventilator-associated lung injury has a wide spectrum of candidate mechanisms, affording multiple opportunities for intervention such as hypercapnia to exert benefit or harm. OBJECTIVES To confirm (1) that hypercapnia attenuates in vivo ventilator-induced lung injury (VILI); (2) biological plausibility of such protection (e.g., dose-response, time series, inflammatory profile); and (3) that the associated biochemical events are consistently beneficial. METHODS A mouse model of VILI was established in vivo. Injurious ventilation was established, hypercapnia applied and markers of inflammation measured. MEASUREMENTS Lung injury was quantified by gas exchange, elastance, microvascular leak, histology and levels of cytokines and eicosanoids, cyclooxygenase and tissue nitrotyrosine. MAIN RESULTS Injurious ventilation caused significant lung injury (mechanics, microvascular leak, histology) and release of inflammatory cytokines, chemokines and eicosanoids. Hypercapnia attenuated these responses, with dose-response and time-dependent effects. No adverse effects of hypercapnia were observed in controls. Hypercapnia suppressed the transcription (mRNA) and translation (protein) of the major inducible prostanoid-generating enzyme (COX-2), but the effects on the downstream eicosanoids were modest. However, hypercapnia significantly increased lung tissue nitrotyrosine-at PaCO(2) levels that were protective. CONCLUSIONS Hypercapnia provided consistent and biologically plausible in vivo protection against VILI, but elevated lung tissue levels of nitro-tyrosine as previously described in sepsis. Clinicians and those designing clinical trials need to be aware of the potential for detrimental effects when using hypercapnia in order to balance benefits versus harm with this approach.
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Affiliation(s)
- Vanya Peltekova
- Physiology and Experimental Medicine, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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Wang N, Gates KL, Trejo H, Favoreto S, Schleimer RP, Sznajder JI, Beitel GJ, Sporn PHS. Elevated CO2 selectively inhibits interleukin-6 and tumor necrosis factor expression and decreases phagocytosis in the macrophage. FASEB J 2010; 24:2178-90. [PMID: 20181940 DOI: 10.1096/fj.09-136895] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Elevated blood and tissue CO(2), or hypercapnia, is common in severe lung disease. Patients with hypercapnia often develop lung infections and have an increased risk of death following pneumonia. To explore whether hypercapnia interferes with host defense, we studied the effects of elevated P(CO2) on macrophage innate immune responses. In differentiated human THP-1 macrophages and human and mouse alveolar macrophages stimulated with lipopolysaccharide (LPS) and other Toll-like receptor ligands, hypercapnia inhibited expression of tumor necrosis factor and interleukin (IL)-6, nuclear factor (NF)-kappaB-dependent cytokines critical for antimicrobial host defense. Inhibition of IL-6 expression by hypercapnia was concentration dependent, rapid, reversible, and independent of extracellular and intracellular acidosis. In contrast, hypercapnia did not down-regulate IL-10 or interferon-beta, which do not require NF-kappaB. Notably, hypercapnia did not affect LPS-induced degradation of IkappaB alpha, nuclear translocation of RelA/p65, or activation of mitogen-activated protein kinases, but it did block IL-6 promoter-driven luciferase activity in mouse RAW 264.7 macrophages. Elevated P(CO2) also decreased phagocytosis of opsonized polystyrene beads and heat-killed bacteria in THP-1 and human alveolar macrophages. By interfering with essential innate immune functions in the macrophage, hypercapnia may cause a previously unrecognized defect in resistance to pulmonary infection in patients with advanced lung disease.
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Affiliation(s)
- Naizhen Wang
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, 240 E. Huron St., Chicago, IL 60611, USA
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