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Campaña-Duel E, Ceccato A, Morales-Quinteros L, Camprubí-Rimblas M, Artigas A. Hypercapnia and its relationship with respiratory infections. Expert Rev Respir Med 2024; 18:41-47. [PMID: 38489161 DOI: 10.1080/17476348.2024.2331767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Accepted: 03/13/2024] [Indexed: 03/17/2024]
Abstract
INTRODUCTION Hypercapnia is developed in patients with acute and/or chronic respiratory conditions. Clinical data concerning hypercapnia and respiratory infections interaction is limited. AREAS COVERED Currently, the relationship between hypercapnia and respiratory infections remains unclear. In this review, we summarize studies on the effects of hypercapnia on models of pulmonary infections to clarify the role of elevated CO2 in these pulmonary pathologies. Hypercapnia affects different cell types in the alveoli, leading to changes in the immune response. In vitro studies show that hypercapnia downregulates the NF-κβ pathway, reduces inflammation and impairs epithelial wound healing. While in vivo models show a dual role between short- and long-term effects of hypercapnia on lung infection. However, it is still controversial whether the effects observed under hypercapnia are pH dependent or not. EXPERT OPINION The role of hypercapnia is still a controversial debate. Hypercapnia could play a beneficial role in mechanically ventilated models, by lowering the inflammation produced by the stretch condition. But it could be detrimental in infectious scenarios, causing phagocyte dysfunction and lack of infection control. Further data concerning hypercapnia on respiratory infections is needed to elucidate this interaction.
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Affiliation(s)
- Elena Campaña-Duel
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| | - Adrian Ceccato
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
- Intensive care unit, Hospital Universitari Sagrat Cor, Grupo Quironsalud, Barcelona, Spain
| | - Luis Morales-Quinteros
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
- Servei de Medicina Intensiva, Hospital de la Santa Creu y Sant Pau, Barcelona, Spain
| | - Marta Camprubí-Rimblas
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
| | - Antonio Artigas
- Critical care center, Parc Taulí Hospital Universitari. Institut d'Investigació i Innovació Parc Taulí (I3PT-CERCA). Universitat Autònoma de Barcelona, Sabadell, Spain
- CIBER of Respiratory Diseases (CIBERES), Institute of Health Carlos III, Madrid, Spain
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Sperber J, Nyberg A, Lipcsey M, Melhus Å, Larsson A, Sjölin J, Castegren M. Protective ventilation reduces Pseudomonas aeruginosa growth in lung tissue in a porcine pneumonia model. Intensive Care Med Exp 2017; 5:40. [PMID: 28861863 PMCID: PMC5578946 DOI: 10.1186/s40635-017-0152-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 08/21/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Mechanical ventilation with positive end expiratory pressure and low tidal volume, i.e. protective ventilation, is recommended in patients with acute respiratory distress syndrome. However, the effect of protective ventilation on bacterial growth during early pneumonia in non-injured lungs is not extensively studied. The main objectives were to compare two different ventilator settings on Pseudomonas aeruginosa growth in lung tissue and the development of lung injury. METHODS A porcine model of severe pneumonia was used. The protective group (n = 10) had an end expiratory pressure of 10 cm H2O and a tidal volume of 6 ml x kg-1. The control group (n = 10) had an end expiratory pressure of 5 cm H2O and a tidal volume of 10 ml x kg-1. 1011 colony forming units of Pseudomonas aeruginosa were inoculated intra-tracheally at baseline, after which the experiment continued for 6 h. Two animals from each group received only saline, and served as sham animals. Lung tissue samples from each animal were used for bacterial cultures and wet-to-dry weight ratio measurements. RESULTS The protective group displayed lower numbers of Pseudomonas aeruginosa (p < 0.05) in the lung tissue, and a lower wet-to-dry ratio (p < 0.01) than the control group. The control group deteriorated in arterial oxygen tension/inspired oxygen fraction, whereas the protective group was unchanged (p < 0.01). CONCLUSIONS In early phase pneumonia, protective ventilation with lower tidal volume and higher end expiratory pressure has the potential to reduce the pulmonary bacterial burden and the development of lung injury.
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Affiliation(s)
- Jesper Sperber
- Centre for Clinical Research Sörmland, Uppsala University, Uppsala, Sweden. .,Centre for Clinical Research Sörmland, Department of Anesthesiology & Intensive Care Mälarsjukhuset, SE-631 88, Eskilstuna, Sweden.
| | - Axel Nyberg
- Centre for Clinical Research Sörmland, Uppsala University, Uppsala, Sweden.,Centre for Clinical Research Sörmland, Department of Anesthesiology & Intensive Care Mälarsjukhuset, SE-631 88, Eskilstuna, Sweden
| | - Miklos Lipcsey
- Hedenstierna laboratory, Department of Surgical Sciences, Anesthesiology and Intensive Care, Uppsala University, Uppsala, Sweden
| | - Åsa Melhus
- Department of Medical Sciences, Section of Clinical Microbiology, Uppsala University, Uppsala, Sweden
| | - Anders Larsson
- Department of Medical Sciences, Biochemical structure and function, Uppsala University, Uppsala, Sweden
| | - Jan Sjölin
- Department of Medical Sciences, Infectious Diseases, Uppsala University, Uppsala, Sweden
| | - Markus Castegren
- Centre for Clinical Research Sörmland, Uppsala University, Uppsala, Sweden.,Hedenstierna laboratory, Department of Surgical Sciences, Anesthesiology and Intensive Care, Uppsala University, Uppsala, Sweden.,Perioperative Medicine and Intensive Care, Karolinska University Hospital and CLINTEC, Karolinska Institute, Stockholm, Sweden
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Ota S, Yazawa T, Tojo K, Baba Y, Uchiyama M, Goto T, Kurahashi K. Adrenaline aggravates lung injury caused by liver ischemia-reperfusion and high-tidal-volume ventilation in rats. J Intensive Care 2016; 4:8. [PMID: 26807260 PMCID: PMC4722720 DOI: 10.1186/s40560-016-0130-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 01/14/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We often administer adrenaline to improve hypotension of patients undergoing systemic inflammation that is not treated with volume resuscitation. The effects of adrenaline on injured lungs during shock status have not been elucidated. We previously demonstrated that hepatic ischemia-reperfusion followed by high-tidal-volume ventilation-induced systemic inflammation, hypotension, and lung injury in rats. Using this animal model, we investigated the effects of adrenaline on lung injury and hemodynamics. METHODS Anesthetized rats were ventilated and underwent hepatic inflow interruption for 15 min twice. After the second liver ischemia-reperfusion, the tidal volume was increased to 24 ml · kg(-1) body weight from 6 ml · kg(-1), and 12 rats in each group were observed for 360 min after reperfusion with or without continuous intravenous adrenaline administration. Extra fluid was administered according to the decline in the arterial blood pressure. RESULTS Adrenaline administration significantly reduced the volume of intravenous resuscitation fluid. The wet-to-dry weight ratio of the lungs was higher (7.53 ± 0.37 vs. 4.63 ± 0.35, P < 0.001), the partial oxygen pressure in arterial blood was lower (213 ± 48 vs. 411 ± 33, P = 0.004), and the tumor necrosis factor-α concentration in bronchoalveolar lavage (BAL) fluid was higher (10(2.64) ± 10(0.22) vs. 10(1.91) ± 10(0.27), P = 0.015), with adrenaline. Histopathological examinations revealed marked exudation in the alveolar spaces in rats receiving adrenaline. CONCLUSIONS Continuous administration of adrenaline partially prevented a rapid decline in blood pressure but deteriorated lung injury in a rat model of liver ischemia-reperfusion with high-tidal-volume ventilation. A possibility that adrenaline administration aggravate ventilator-induced lung injury during systemic inflammation should be considered.
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Affiliation(s)
- Shuhei Ota
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
| | - Takuya Yazawa
- Department of Pathology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
| | - Kentaro Tojo
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
| | - Yasuko Baba
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
| | - Munehito Uchiyama
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
| | - Takahisa Goto
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
| | - Kiyoyasu Kurahashi
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004 Japan
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Barbas CSV, Ísola AM, Farias AMDC, Cavalcanti AB, Gama AMC, Duarte ACM, Vianna A, Serpa A, Bravim BDA, Pinheiro BDV, Mazza BF, de Carvalho CRR, Toufen C, David CMN, Taniguchi C, Mazza DDDS, Dragosavac D, Toledo DO, Costa EL, Caser EB, Silva E, Amorim FF, Saddy F, Galas FRBG, Silva GS, de Matos GFJ, Emmerich JC, Valiatti JLDS, Teles JMM, Victorino JA, Ferreira JC, Prodomo LPDV, Hajjar LA, Martins LC, Malbouisson LMS, Vargas MADO, Reis MAS, Amato MBP, Holanda MA, Park M, Jacomelli M, Tavares M, Damasceno MCP, Assunção MSC, Damasceno MPCD, Youssef NCM, Teixeira PJZ, Caruso P, Duarte PAD, Messeder O, Eid RC, Rodrigues RG, de Jesus RF, Kairalla RA, Justino S, Nemer SN, Romero SB, Amado VM. Brazilian recommendations of mechanical ventilation 2013. Part I. Rev Bras Ter Intensiva 2015; 26:89-121. [PMID: 25028944 PMCID: PMC4103936 DOI: 10.5935/0103-507x.20140017] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Indexed: 12/19/2022] Open
Abstract
Perspectives on invasive and noninvasive ventilatory support for critically ill patients are evolving, as much evidence indicates that ventilation may have positive effects on patient survival and the quality of the care provided in intensive care units in Brazil. For those reasons, the Brazilian Association of Intensive Care Medicine (Associação de Medicina Intensiva Brasileira - AMIB) and the Brazilian Thoracic Society (Sociedade Brasileira de Pneumonia e Tisiologia - SBPT), represented by the Mechanical Ventilation Committee and the Commission of Intensive Therapy, respectively, decided to review the literature and draft recommendations for mechanical ventilation with the goal of creating a document for bedside guidance as to the best practices on mechanical ventilation available to their members. The document was based on the available evidence regarding 29 subtopics selected as the most relevant for the subject of interest. The project was developed in several stages, during which the selected topics were distributed among experts recommended by both societies with recent publications on the subject of interest and/or significant teaching and research activity in the field of mechanical ventilation in Brazil. The experts were divided into pairs that were charged with performing a thorough review of the international literature on each topic. All the experts met at the Forum on Mechanical Ventilation, which was held at the headquarters of AMIB in São Paulo on August 3 and 4, 2013, to collaboratively draft the final text corresponding to each sub-topic, which was presented to, appraised, discussed and approved in a plenary session that included all 58 participants and aimed to create the final document.
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Affiliation(s)
- Carmen Sílvia Valente Barbas
- Corresponding author: Carmen Silvia Valente Barbas, Disicplina de
Pneumologia, Hospital das Clínicas da Faculdade de Medicina da Universidade de São
Paulo, Avenida Dr. Eneas de Carvalho Aguiar, 44, Zip code - 05403-900 - São Paulo
(SP), Brazil. E-mail:
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Abstract
Perspectives on invasive and noninvasive ventilatory support for critically ill
patients are evolving, as much evidence indicates that ventilation may have positive
effects on patient survival and the quality of the care provided in intensive care
units in Brazil. For those reasons, the Brazilian Association of Intensive Care
Medicine (Associação de Medicina Intensiva Brasileira - AMIB) and
the Brazilian Thoracic Society (Sociedade Brasileira de Pneumologia e
Tisiologia - SBPT), represented by the Mechanical Ventilation Committee
and the Commission of Intensive Therapy, respectively, decided to review the
literature and draft recommendations for mechanical ventilation with the goal of
creating a document for bedside guidance as to the best practices on mechanical
ventilation available to their members. The document was based on the available
evidence regarding 29 subtopics selected as the most relevant for the subject of
interest. The project was developed in several stages, during which the selected
topics were distributed among experts recommended by both societies with recent
publications on the subject of interest and/or significant teaching and research
activity in the field of mechanical ventilation in Brazil. The experts were divided
into pairs that were charged with performing a thorough review of the international
literature on each topic. All the experts met at the Forum on Mechanical Ventilation,
which was held at the headquarters of AMIB in São Paulo on August 3 and 4, 2013, to
collaboratively draft the final text corresponding to each sub-topic, which was
presented to, appraised, discussed and approved in a plenary session that included
all 58 participants and aimed to create the final document.
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Impact of the Prone Position in an Animal Model of Unilateral Bacterial Pneumonia Undergoing Mechanical Ventilation. Anesthesiology 2013; 118:1150-9. [DOI: 10.1097/aln.0b013e31828a7016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Abstract
Background:
The prone position (PP) has proven beneficial in patients with severe lung injury subjected to mechanical ventilation (MV), especially in those with lobar involvement. We assessed the impact of PP on unilateral pneumonia in rabbits subjected to MV.
Methods:
After endobronchial challenge with Enterobacter aerogenes, adult rabbits were subjected to either “adverse” (peak inspiratory pressure = 30 cm H2O, zero end-expiratory pressure; n = 10) or “protective” (tidal volume = 8 ml/kg, 5 cm H2O positive end-expiratory pressure; n = 10) MV and then randomly kept supine or turned to the PP. Pneumonia was assessed 8 h later. Data are presented as median (interquartile range).
Results:
Compared with the supine position, PP was associated with significantly lower bacterial concentrations within the infected lung, even if a “protective” MV was applied (5.93 [0.34] vs. 6.66 [0.86] log10 cfu/g, respectively; P = 0.008). Bacterial concentrations in the spleen were also decreased by the PP if the “adverse” MV was used (3.62 [1.74] vs. 6.55 [3.67] log10 cfu/g, respectively; P = 0.038). In addition, the noninfected lung was less severely injured in the PP group. Finally, lung and systemic inflammation as assessed through interleukin-8 and tumor necrosis factor-α measurement was attenuated by the PP.
Conclusions:
The PP could be protective if the host is subjected to MV and unilateral bacterial pneumonia. It improves lung injury even if it is utilized after lung injury has occurred and nonprotective ventilation has been administered.
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Kopterides P, Siempos II, Armaganidis A. Prone positioning in hypoxemic respiratory failure: meta-analysis of randomized controlled trials. J Crit Care 2009; 24:89-100. [PMID: 19272544 DOI: 10.1016/j.jcrc.2007.12.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 12/28/2007] [Indexed: 02/07/2023]
Abstract
PURPOSE Prone positioning is used to improve oxygenation in patients with hypoxemic respiratory failure (HRF). However, its role in clinical practice is not yet clearly defined. The aim of this meta-analysis was to assess the effect of prone positioning on relevant clinical outcomes, such as intensive care unit (ICU) and hospital mortality, days of mechanical ventilation, length of stay, incidence of ventilator-associated pneumonia (VAP) and pneumothorax, and associated complications. METHODS We used literature search of MEDLINE, Current Contents, and Cochrane Central Register of Controlled Trials. We focused only on randomized controlled trials reporting clinical outcomes in adult patients with HRF. Four trials met our inclusion criteria, including 662 patients randomized to prone ventilation and 609 patients to supine ventilation. RESULTS The pooled odds ratio (OR) for the ICU mortality in the intention-to-treat analysis was 0.97 (95% confidence interval [CI], 0.77-1.22), for the comparison between prone and supine ventilated patients. Interestingly, the pooled OR for the ICU mortality in the selected group of the more severely ill patients favored prone positioning (OR, 0.34; 95% CI, 0.18-0.66). The duration of mechanical ventilation and the incidence of pneumothorax were not different between the 2 groups. The incidence of VAP was lower but not statistically significant in patients treated with prone positioning (OR, 0.81; 95% CI, 0.61-1.10). However, prone positioning was associated with a higher risk of pressure sores (OR, 1.49; 95% CI, 1.17-1.89) and a trend for more complications related to the endotracheal tube (OR, 1.30; 95% CI, 0.94-1.80). CONCLUSIONS Despite the inherent limitations of the meta-analytic approach, it seems that prone positioning has no discernible effect on mortality in patients with HRF. It may decrease the incidence of VAP at the expense of more pressure sores and complications related to the endotracheal tube. However, a subgroup of the most severely ill patients may benefit most from this intervention.
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Affiliation(s)
- Petros Kopterides
- 2nd Critical Care Department, University of Athens Medical School, Attiko University Hospital, Athens 12462, Greece.
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Ota S, Nakamura K, Yazawa T, Kawaguchi Y, Baba Y, Kitaoka R, Morimura N, Goto T, Yamada Y, Kurahashi K. High tidal volume ventilation induces lung injury after hepatic ischemia-reperfusion. Am J Physiol Lung Cell Mol Physiol 2007; 292:L625-31. [PMID: 17056704 DOI: 10.1152/ajplung.00151.2006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ischemia-reperfusion not only damages the affected organ but also leads to remote organ injuries. Hepatic inflow interruption usually occurs during hepatic surgery. To investigate the influence of liver ischemia-reperfusion on lung injury and to determine the contribution of tidal volume settings on liver ischemia-reperfusion-induced lung injury, we studied anesthetized and mechanically ventilated rats in which the hepatic inflow was transiently interrupted twice for 15 min. Two tidal volumes, 6 ml/kg as a low tidal volume (IR-LT) and 24 ml/kg as a high tidal volume (IR-HT), were assessed after liver ischemia-reperfusion, as well as after a sham operation, 6 ml/kg (NC-LT) and 24 ml/kg (NC-HT). Both the IR-HT and IR-LT groups had a gradual decline in the systemic blood pressure and a significant increase in plasma TNF-α concentrations. Of the four groups, only the IR-HT group developed lung injury, as assessed by an increase in the lung wet-to-dry weight ratio, the presence of significant histopathological changes, such as perivascular edema and intravascular leukocyte aggregation, and an increase in the bronchoalveolar lavage fluid TNF-α concentration. Furthermore, only in the IR-HT group was airway pressure increased significantly during the 6-h reperfusion period. These findings suggest that liver ischemia-reperfusion caused systemic inflammation and that lung injury is triggered when high tidal volume ventilation follows liver ischemia-reperfusion.
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Affiliation(s)
- Shuhei Ota
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
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Abstract
Patients with severe acute respiratory distress syndrome who die usually succumb to multiorgan failure as opposed to hypoxia. Despite appropriate resuscitation, some patients' symptoms persist on a downward spiral, apparently propagated by an uncontained systemic inflammatory response. This phenomenon is not well understood. However, a novel hypothesis to explain this observation proposes that it is related to the life-saving ventilatory support used to treat the respiratory failure. According to this hypothesis, mechanical ventilation per se, by altering both the magnitude and the pattern of lung stretch, can cause changes in gene expression and/or cellular metabolism that ultimately can lead to the development of an overwhelming inflammatory response-even in the absence of overt structural damage. This mechanism of injury has been termed biotrauma. In this review we explore the biotrauma hypothesis, the causal relationship between biophysical injury and organ failure, and its implications for the future therapy and management of critically ill patients.
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Affiliation(s)
- Claudia C dos Santos
- Department of Medicine, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada.
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Gattinoni L, Caironi P, Carlesso E. How to ventilate patients with acute lung injury and acute respiratory distress syndrome. Curr Opin Crit Care 2005; 11:69-76. [PMID: 15659948 DOI: 10.1097/00075198-200502000-00011] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW The purpose of this paper is to review the mechanisms of ventilator-induced lung injury as a basis for providing the less damaging mechanical ventilation in patients with acute respiratory failure. RECENT FINDINGS In normal lungs, high tidal volume causes an immediate gene upregulation and downregulation. Although the importance of alveolar inflammatory reaction is well known, recent findings suggest the potential role of airway distension in causing ventilator-induced lung injury. The initial activation has been shown to occur in the airways, accounting for the damages induced by high peak flow. The healthier lung regions are more exposed to the injury, since they may be subjected to strain. Challenge with endotoxin enhances in a synergistic manner the pulmonary inflammation induced by mechanical ventilation. However, mechanical strain and endotoxin seem to trigger lung inflammation through two different pathways. Despite convincing experimental and clinical evidences of lung injury, the clinical implementation of low tidal volume ventilation is still limited and has not yet become part of standard clinical practice. Setting positive end-expiratory pressure remains an open problem because the ALVEOLI study did not provide any exhaustive answers, likely because of methodologic problems and, unphysiologic design. SUMMARY Gentle lung ventilation must be standard practice. Because stress and strain are the triggers of ventilator-induced lung injury, their clinical equivalents should be measured (transpulmonary pressure and the ratio between tidal volume and end-expiratory lung volume). For a rational application of positive end-expiratory pressure, the potential for recruitment in any single patient should be estimated.
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Affiliation(s)
- Luciano Gattinoni
- Istituto di Anestesia e Rianimazione, Ospedale Maggiore di Milano-IRCCS, Università degli Studi di Milano, Milano, Italy.
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Tremblay LN, Slutsky AS. Pathogenesis of ventilator-induced lung injury: trials and tribulations. Am J Physiol Lung Cell Mol Physiol 2005; 288:L596-8. [PMID: 15757952 DOI: 10.1152/ajplung.00438.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Sadikot RT, Blackwell TS, Christman JW, Prince AS. Pathogen-host interactions in Pseudomonas aeruginosa pneumonia. Am J Respir Crit Care Med 2005; 171:1209-23. [PMID: 15695491 PMCID: PMC2718459 DOI: 10.1164/rccm.200408-1044so] [Citation(s) in RCA: 563] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Pseudomonas aeruginosa is an important pathogen causing a wide range of acute and chronic infections. P. aeruginosa rarely causes infection in the normal host, but is an efficient opportunistic pathogen causing serious infections in patients who are mechanically ventilated, individuals who are immunocompromised, and patients with malignancies or HIV infection. Among these risk groups, the most vulnerable hosts are neutropenic and patients who are mechanically ventilated. In addition, P. aeruginosa is the most prevalent chronic infection contributing to the pathogenesis of cystic fibrosis. Because of the ubiquitous nature of P. aeruginosa and its ability to develop resistance to antibiotics, it continues to be problematic from a treatment perspective. The pathogenicity of P. aeruginosa is largely caused by multiple bacterial virulence factors and genetic flexibility enabling it to survive in varied environments. Lung injury associated with P. aeruginosa infection results from both the direct destructive effects of the organism on the lung parenchyma and exuberant host immune responses. This article focuses on the major bacterial virulence factors and important aspects of the host immunity that are involved in the pathogenesis of serious P. aeruginosa infection. In addition to antibiotic therapy, strategies directed toward enhancing host defense and/or limiting excessive inflammation could be important to improve outcome in P. aeruginosa lung infections.
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Affiliation(s)
- Ruxana T Sadikot
- Department of Veterans Affairs Medical Center, Nashville, Tennessee, USA.
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