1
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Baumann P, Wiegert S, Greco F, Ersch J, Cannizzaro V. Strain-specific differences in lung tissue viscoelasticity of mechanically ventilated infant Sprague-Dawley and Wistar rats. Am J Physiol Lung Cell Mol Physiol 2020; 320:L220-L231. [PMID: 33207919 DOI: 10.1152/ajplung.00100.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Rats are often used in ventilator-induced lung injury (VILI) models. However, strain-specific susceptibility for VILI has not been elucidated yet. The aim of this study was to demonstrate strain-specific differences in VILI in infant Sprague-Dawley and Wistar rats. VILI was compared in 2-wk-old pups after 8 h of protective or injurious ventilation. Pups were ventilated with tidal volumes (VT) of ∼7 mL/kg and positive end-expiratory pressures (PEEP) of 6 cmH2O (VT7 PEEP6) or with VT of ∼21 mL/kg and PEEP 2 cmH2O (VT21 PEEP2). Interleukin-6, macrophage inflammatory protein-2 (MIP-2), inflammatory cells, and albumin in bronchoalveolar lavage fluid (BALF); histology; and low-frequency forced oscillation technique (LFOT) and pressure-volume (PV) maneuvers were assessed. Alveolar macrophages, neutrophils, and MIP-2 derived from BALF revealed more pronounced VILI after VT21 PEEP2 in both strains. LFOT and PV analyses demonstrated rat strain-specific differences both at baseline and particularly in response to VT21 PEEP2 ventilation. Sprague-Dawley rats showed higher airway and tissue resistance and elastance values with no difference in hysteresivity between ventilation strategies. Wister rats challenged by VT21 PEEP2 experienced significantly more energy dissipation when compared with VT7 PEEP6 ventilation. In conclusion, both rat strains are useful for VILI models. The degree of VILI severity depends on ventilation strategy and selected strain. However, fundamental and time-dependent differences in respiratory system mechanics exist and reflect different lung tissue viscoelasticity. Hence, strain-specific characteristics of the respiratory system need to be considered when planning and interpreting VILI studies with infant rats.
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Affiliation(s)
- Philipp Baumann
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Susanne Wiegert
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Francesco Greco
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Joerg Ersch
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Vincenzo Cannizzaro
- Department of Intensive Care Medicine and Neonatology, University Children's Hospital Zurich, Zurich, Switzerland.,Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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2
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Yen S, Preissner M, Bennett E, Dubsky S, Carnibella R, O'Toole R, Roddam L, Jones H, Dargaville PA, Fouras A, Zosky GR. The Link between Regional Tidal Stretch and Lung Injury during Mechanical Ventilation. Am J Respir Cell Mol Biol 2019; 60:569-577. [PMID: 30428271 DOI: 10.1165/rcmb.2018-0143oc] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The aim of this study was to assess the association between regional tidal volume (Vt), regional functional residual capacity (FRC), and the expression of genes linked with ventilator-induced lung injury. Two groups of BALB/c mice (n = 8 per group) were ventilated for 2 hours using a protective or injurious ventilation strategy, with free-breathing mice used as control animals. Regional Vt and FRC of the ventilated mice was determined by analysis of high-resolution four-dimensional computed tomographic images taken at baseline and after 2 hours of ventilation and corrected for the volume of the region (i.e., specific [s]Vt and specific [s]FRC). RNA concentrations of 21 genes in 10 different lung regions were quantified using a quantitative PCR array. sFRC at baseline varied regionally, independent of ventilation strategy, whereas sVt varied regionally depending on ventilation strategy. The expression of IL-6 (P = 0.04), Ccl2 (P < 0.01), and Ang-2 (P < 0.05) was associated with sVt but not sFRC. The expression of seven other genes varied regionally (IL-1β and RAGE [receptor for advanced glycation end products]) or depended on ventilation strategy (Nfe2l2 [nuclear factor erythroid-derived 2 factor 2], c-fos, and Wnt1) or both (TNF-α and Cxcl2), but it was not associated with regional sFRC or sVt. These observations suggest that regional inflammatory responses to mechanical ventilation are driven primarily by tidal stretch.
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Affiliation(s)
| | - Melissa Preissner
- 2 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria, Australia
| | | | - Stephen Dubsky
- 2 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria, Australia
| | | | | | | | - Heather Jones
- 4 Biomedical Imaging Research Institute.,5 Department of Medicine, and.,6 Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Peter A Dargaville
- 7 Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Graeme R Zosky
- 1 School of Medicine and.,7 Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, Tasmania, Australia
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3
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Vermillion MS, Nelson A, Vom Steeg L, Loube J, Mitzner W, Klein SL. Pregnancy preserves pulmonary function following influenza virus infection in C57BL/6 mice. Am J Physiol Lung Cell Mol Physiol 2018; 315:L517-L525. [PMID: 29847990 DOI: 10.1152/ajplung.00066.2018] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Pregnancy is associated with significant anatomic and functional changes to the cardiopulmonary system. Using pregnant C57BL/6 mice, we characterized changes in pulmonary structure and function during pregnancy in healthy animals and following infection with influenza A virus (IAV). We hypothesized that pregnancy-associated alterations in pulmonary physiology would contribute to the more severe outcome of IAV infection. Nonpregnant and pregnant females (at embryonic day 10.5) were either mock-infected or infected with 2009 H1N1 IAV for assessment of pulmonary function, structure, and inflammation at 8 days postinoculation. There were baseline differences in pulmonary function, with pregnant females having greater lung compliance, total lung capacity, and fixed lung volume than nonpregnant females. Following IAV infection, both pregnant and nonpregnant females exhibited reduced circulating progesterone, which in nonpregnant females was associated with increased pulmonary resistance and decreased lung compliance, minute ventilation, and oxygen diffusing capacity compared with uninfected nonpregnant females. In pregnant females, reduced concentrations of progesterone were associated with adverse pregnancy outcomes, but measures of pulmonary function were preserved following IAV infection and were not significantly different from uninfected pregnant mice. Following IAV infection, infectious virus titers and total numbers of pulmonary leukocytes were similar between pregnant and nonpregnant females, but the histological density of pulmonary inflammation was reduced in pregnant animals. These data suggest that pregnancy in mice is associated with significant alterations in pulmonary physiology but that these changes served to preserve lung function during IAV infection. Pregnancy-associated alterations in pulmonary physiology may serve to protect females during severe influenza.
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Affiliation(s)
- Meghan S Vermillion
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland.,Department of Molecular and Comparative Pathobiology, The Johns Hopkins School of Medicine , Baltimore, Maryland
| | - Andrew Nelson
- Department of Environmental Health and Engineering, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland
| | - Landon Vom Steeg
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland
| | - Jeffery Loube
- Department of Environmental Health and Engineering, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland
| | - Wayne Mitzner
- Department of Environmental Health and Engineering, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland
| | - Sabra L Klein
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland.,Department of Biochemistry and Molecular Biology, The Johns Hopkins Bloomberg School of Public Health , Baltimore, Maryland
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4
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Fonceca AM, Zosky GR, Bozanich EM, Sutanto EN, Kicic A, McNamara PS, Knight DA, Sly PD, Turner DJ, Stick SM. Accumulation mode particles and LPS exposure induce TLR-4 dependent and independent inflammatory responses in the lung. Respir Res 2018; 19:15. [PMID: 29357863 PMCID: PMC5778683 DOI: 10.1186/s12931-017-0701-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/13/2017] [Indexed: 02/08/2023] Open
Abstract
Background Accumulation mode particles (AMP) are formed from engine combustion and make up the inhalable vapour cloud of ambient particulate matter pollution. Their small size facilitates dispersal and subsequent exposure far from their original source, as well as the ability to penetrate alveolar spaces and capillary walls of the lung when inhaled. A significant immuno-stimulatory component of AMP is lipopolysaccharide (LPS), a product of Gram negative bacteria breakdown. As LPS is implicated in the onset and exacerbation of asthma, the presence or absence of LPS in ambient particulate matter (PM) may explain the onset of asthmatic exacerbations to PM exposure. This study aimed to delineate the effects of LPS and AMP on airway inflammation, and potential contribution to airways disease by measuring airway inflammatory responses induced via activation of the LPS cellular receptor, Toll-like receptor 4 (TLR-4). Methods The effects of nebulized AMP, LPS and AMP administered with LPS on lung function, cellular inflammatory infiltrate and cytokine responses were compared between wildtype mice and mice not expressing TLR-4. Results The presence of LPS administered with AMP appeared to drive elevated airway resistance and sensitivity via TLR-4. Augmented TLR4 driven eosinophilia and greater TNF-α responses observed in AMP-LPS treated mice independent of TLR-4 expression, suggests activation of allergic responses by TLR4 and non-TLR4 pathways larger than those induced by LPS administered alone. Treatment with AMP induced macrophage recruitment independent of TLR-4 expression. Conclusions These findings suggest AMP-LPS as a stronger stimulus for allergic inflammation in the airways then LPS alone. Electronic supplementary material The online version of this article (10.1186/s12931-017-0701-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Angela M Fonceca
- School of Paediatrics and Child Health, University of Western Australia, Nedlands, WA, Australia.
| | | | | | - Erika N Sutanto
- Telethon Kids Institute, Subiaco, WA, Australia.,Department of Respiratory Medicine Princess Margaret Hospital for Children Perth, Subiaco, WA, Australia
| | - Anthony Kicic
- School of Paediatrics and Child Health, University of Western Australia, Nedlands, WA, Australia.,Telethon Kids Institute, Subiaco, WA, Australia.,Department of Respiratory Medicine Princess Margaret Hospital for Children Perth, Subiaco, WA, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Paul S McNamara
- Department of Women's and Children's Health, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - Darryl A Knight
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia.,Priority Research Centre for Asthma and Respiratory Disease, Hunter Medical Research Institute, Newcastle, NSW, Australia.,Department of Anesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, Canada
| | - Peter D Sly
- Queensland Children's Medical Research Institute, University of Queensland, Royal Children's Hospital, Herston, QLD, Australia
| | | | - Stephen M Stick
- School of Paediatrics and Child Health, University of Western Australia, Nedlands, WA, Australia.,Telethon Kids Institute, Subiaco, WA, Australia.,Department of Respiratory Medicine Princess Margaret Hospital for Children Perth, Subiaco, WA, Australia.,Centre for Cell Therapy and Regenerative Medicine, School of Medicine and Pharmacology, The University of Western Australia, Nedlands, WA, 6009, Australia
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5
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Kim EH, Preissner M, Carnibella RP, Samarage CR, Bennett E, Diniz MA, Fouras A, Zosky GR, Jones HD. Novel analysis of 4DCT imaging quantifies progressive increases in anatomic dead space during mechanical ventilation in mice. J Appl Physiol (1985) 2017; 123:578-584. [PMID: 28596273 DOI: 10.1152/japplphysiol.00903.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 06/02/2017] [Accepted: 06/04/2017] [Indexed: 11/22/2022] Open
Abstract
Increased dead space is an important prognostic marker in early acute respiratory distress syndrome (ARDS) that correlates with mortality. The cause of increased dead space in ARDS has largely been attributed to increased alveolar dead space due to ventilation/perfusion mismatching and shunt. We sought to determine whether anatomic dead space also increases in response to mechanical ventilation. Mice received intratracheal lipopolysaccharide (LPS) or saline and mechanical ventilation (MV). Four-dimensional computed tomography (4DCT) scans were performed at onset of MV and after 5 h of MV. Detailed measurements of airway volumes and lung tidal volumes were performed using image analysis software. The forced oscillation technique was used to obtain measures of airway resistance, tissue damping, and tissue elastance. The ratio of airway volumes to total tidal volume increased significantly in response to 5 h of mechanical ventilation, regardless of LPS exposure, and airways demonstrated significant variation in volumes over the respiratory cycle. These findings were associated with an increase in tissue elastance (decreased lung compliance) but without changes in tidal volumes. Airway volumes increased over time with exposure to mechanical ventilation without a concomitant increase in tidal volumes. These findings suggest that anatomic dead space fraction increases progressively with exposure to positive pressure ventilation and may represent a pathological process.NEW & NOTEWORTHY We demonstrate that anatomic dead space ventilation increases significantly over time in mice in response to mechanical ventilation. The novel functional lung-imaging techniques applied here yield sensitive measures of airway volumes that may have wide applications.
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Affiliation(s)
- Elizabeth H Kim
- Department of Medicine and Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Melissa Preissner
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Victoria, Australia
| | | | | | - Ellen Bennett
- School of Medicine, Faculty of Health, University of Tasmania, Hobart, Tasmania, Australia
| | - Marcio A Diniz
- Biostatistics and Bioinformatics Research Center, Cedars-Sinai Medical Center, Los Angeles, California; and
| | - Andreas Fouras
- 4Dx Limited, Melbourne, Victoria, Australia.,Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Graeme R Zosky
- School of Medicine, Faculty of Health, University of Tasmania, Hobart, Tasmania, Australia
| | - Heather D Jones
- Department of Medicine and Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California; .,Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California
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6
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Barroso SPC, Nico D, Nascimento D, Santos ACV, Couceiro JNSS, Bozza FA, Ferreira AMA, Ferreira DF, Palatnik-de-Sousa CB, Souza TML, Gomes AMO, Silva JL, Oliveira AC. Intranasal Immunization with Pressure Inactivated Avian Influenza Elicits Cellular and Humoral Responses in Mice. PLoS One 2015; 10:e0128785. [PMID: 26056825 PMCID: PMC4461174 DOI: 10.1371/journal.pone.0128785] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 04/30/2015] [Indexed: 01/19/2023] Open
Abstract
Influenza viruses pose a serious global health threat, particularly in light of newly emerging strains, such as the avian influenza H5N1 and H7N9 viruses. Vaccination remains the primary method for preventing acquiring influenza or for avoiding developing serious complications related to the disease. Vaccinations based on inactivated split virus vaccines or on chemically inactivated whole virus have some important drawbacks, including changes in the immunogenic properties of the virus. To induce a greater mucosal immune response, intranasally administered vaccines are highly desired as they not only prevent disease but can also block the infection at its primary site. To avoid these drawbacks, hydrostatic pressure has been used as a potential method for viral inactivation and vaccine production. In this study, we show that hydrostatic pressure inactivates the avian influenza A H3N8 virus, while still maintaining hemagglutinin and neuraminidase functionalities. Challenged vaccinated animals showed no disease signs (ruffled fur, lethargy, weight loss, and huddling). Similarly, these animals showed less Evans Blue dye leakage and lower cell counts in their bronchoalveolar lavage fluid compared with the challenged non-vaccinated group. We found that the whole inactivated particles were capable of generating a neutralizing antibody response in serum, and IgA was also found in nasal mucosa and feces. After the vaccination and challenge we observed Th1/Th2 cytokine secretion with a prevalence of IFN-γ. Our data indicate that the animals present a satisfactory immune response after vaccination and are protected against infection. Our results may pave the way for the development of a novel pressure-based vaccine against influenza virus.
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Affiliation(s)
- Shana P. C. Barroso
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
- Laboratório de Vírus Respiratórios, WHO/NIC, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Dirlei Nico
- Instituto de Microbiologia Paulo Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941–590, Brazil
| | - Danielle Nascimento
- Fundação de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana Clara V. Santos
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
| | - José Nelson S. S. Couceiro
- Instituto de Microbiologia Paulo Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941–590, Brazil
| | - Fernando A. Bozza
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
- Fundação de Pesquisa Clínica Evandro Chagas, Fundação Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ana M. A. Ferreira
- Instituto de Microbiologia Paulo Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941–590, Brazil
| | - Davis F. Ferreira
- Instituto de Microbiologia Paulo Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941–590, Brazil
| | - Clarisa B. Palatnik-de-Sousa
- Instituto de Microbiologia Paulo Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro 21941–590, Brazil
| | - Thiago Moreno L. Souza
- Laboratório de Vírus Respiratórios, WHO/NIC, Instituto Oswaldo Cruz/FIOCRUZ, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Andre M. O. Gomes
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
| | - Jerson L. Silva
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
| | - Andréa C. Oliveira
- Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, 21941–902, Brazil
- Instituto Nacional de Ciência e Tecnologia de Biologia Estrutural e Bioimagem, Rio de Janeiro, Brazil
- * E-mail:
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7
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Liu X, Ma T, Qu B, Ji Y, Liu Z. Efficacy of lung recruitment maneuver with high-level positive end-expiratory pressure in patients with influenza-associated acute respiratory distress: a single-center prospective study. Curr Ther Res Clin Exp 2014; 75:83-7. [PMID: 24465049 PMCID: PMC3898194 DOI: 10.1016/j.curtheres.2013.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2013] [Indexed: 01/22/2023] Open
Abstract
Background The latest data released to the public from the Chinese Ministry of Health reported 120,940 confirmed H1N1 cases and 659 deaths on the Chinese mainland. Objective We performed a prospective, single-center study to investigate the efficacy of lung recruitment maneuver (RM) with high-level positive end-expiratory pressure (PEEP) in patients with the 2009 influenza A (H1N1)-associated acute respiratory distress syndrome (ARDS). Methods Eighty-four patients with H1N1-associated ARDS were admitted to emergency intensive care units between October 2009 and February 2012. During pressure control ventilation, if arterial oxygen saturation (SpO2) is consistently <88% for >30 minutes, an RM with high-level PEEP is performed to normalize lung volume at 30 cmH2O for 60 seconds. The RM was considered initially a responder if SpO2 increased >3% within 15 minutes; otherwise, an SpO2 increase <3% would be considered initially a nonresponder. Variations on oxygen metabolism and hemodynamic parameters were also measured before and after initial RM with high-level PEEP. Results After the initial RM, 40 patients (47.6%) with influenza-associated ARDS displayed an increase (≥3%) in SpO2 (the responder group), and 44 patients (52.4%) had no significant improvement (<3%) in SpO2 (the nonresponder group). Among 84 patients with influenza-associated ARDS, 56 patients survived and 28 patients died. There was significant difference in mortality rate between the responder group and the nonresponder group (7 out of 40 vs 18 out of 44; P = 0.019). The initial PEEP level in the responder group was lower than that of the nonresponder group (P = 0.028). The initial mean duration of mechanical ventilation in the responder group was also shorter than that of the nonresponder group (P = 0.011). Furthermore, the initial dynamic lung-thorax compliance was obviously higher in the initially responder group than in the nonresponder group (P = 0.038). Conclusions Initial response of lung RM with high-level PEEP may be associated with good clinical outcome of patients with influenza-associated ARDS. The initial PEEP level, duration of mechanical ventilation, and dynamic lung-thorax compliance dynamic lung-thorax compliance may be potential factors in influencing the initial response to RM.
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Affiliation(s)
- Xiaowei Liu
- Emergency Department, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Tao Ma
- Emergency Department, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Bo Qu
- Department of Biostatistics, School of Public Health, China Medical University, Shenyang, China
| | - Yan Ji
- Emergency Department, The First Affiliated Hospital of China Medical University, Shenyang, China
| | - Zhi Liu
- Emergency Department, The First Affiliated Hospital of China Medical University, Shenyang, China
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8
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Abstract
OBJECTIVE Respiratory syncytial virus lower respiratory tract infection is the most frequent cause of respiratory insufficiency necessitating mechanical ventilation in infants during the winter season. Recently, we presented a new animal model to show that mechanical ventilation aggravates respiratory syncytial virus-induced pulmonary inflammation by distinct mechanisms. We now use this model to study whether low tidal volume mechanical ventilation causes less ventilator-induced lung injury in the presence of respiratory syncytial virus lower respiratory tract infection. DESIGN Randomized controlled experimental study. SETTING University Medical Center animal laboratory. SUBJECTS Male BALB/c mice, 6-8 weeks old and weighing 20-28 g. INTERVENTIONS Mice were inoculated with respiratory syncytial virus or mock virus on day 0 and ventilated on day 1 or 5 with high (12 mL/kg) or low (6 mL/kg) tidal volume for 5 hours. MEASUREMENTS AND MAIN RESULTS Total and differential cell counts as well as cytokine concentrations were determined in bronchoalveolar lavage fluid. Compared with nonventilated respiratory syncytial virus-infected mice, high tidal volume ventilation of respiratory syncytial virus-infected mice on day 5 enhanced bronchoalveolar lavage fluid total cell count (0.35 vs 0.99 × 10e6/mL; p < 0.01), neutrophils (0.02 vs 0.17 × 10e6/mL; p < 0.01), interleukin-6 (58 vs 250 pg/mL; p < 0.01), and keratinocyte-derived chemokine (95 vs 335 pg/mL; p < 0.01) levels. In low tidal volume ventilation of respiratory syncytial virus-infected mice, no significant difference in cell counts or cytokine concentrations was observed compared with spontaneous breathing respiratory syncytial virus-infected controls on both days. CONCLUSIONS Low tidal volume mechanical ventilation causes less ventilation-induced cellular and cytokine influx into the bronchoalveolar space during respiratory syncytial virus lower respiratory tract infection.
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9
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Hennus MP, van Vught AJ, Brabander M, Brus F, Jansen NJ, Bont LJ. Mechanical ventilation drives inflammation in severe viral bronchiolitis. PLoS One 2013; 8:e83035. [PMID: 24349427 PMCID: PMC3859624 DOI: 10.1371/journal.pone.0083035] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 10/29/2013] [Indexed: 11/19/2022] Open
Abstract
Introduction Respiratory insufficiency due to severe respiratory syncytial virus (RSV) infection is the most frequent cause of paediatric intensive care unit admission in infants during the winter season. Previous studies have shown increased levels of inflammatory mediators in airways of mechanically ventilated children compared to spontaneous breathing children with viral bronchiolitis. In this prospective observational multi-center study we aimed to investigate whether this increase was related to disease severity or caused by mechanical ventilation. Materials and Methods Nasopharyngeal aspirates were collected <1 hour before intubation and 24 hours later in RSV bronchiolitis patients with respiratory failure (n = 18) and non-ventilated RSV bronchiolitis controls (n = 18). Concentrations of the following cytokines were measured: interleukin (IL)-1α, IL-1β, IL-6, monocyte chemotactic protein (MCP)-1 and macrophage inflammatory protein (MIP)-1α. Results Baseline cytokine levels were comparable between ventilated and non-ventilated infants. After 24 hours of mechanical ventilation mean cytokine levels, except for MIP-1α, were elevated compared to non-ventilated infected controls: IL-1α (159 versus 4 pg/ml, p<0.01), IL-1β (1068 versus 99 pg/ml, p<0.01), IL-6 (2343 versus 958 pg/ml, p<0.05) and MCP-1 (174 versus 26 pg/ml, p<0.05). Conclusions Using pre- and post-intubation observations, this study suggests that endotracheal intubation and subsequent mechanical ventilation cause a robust pulmonary inflammation in infants with RSV bronchiolitis.
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Affiliation(s)
- Marije P. Hennus
- Department of Paediatric Intensive Care, Wilhelmina Children’s Hospital / University Medical Center Utrecht, Utrecht, The Netherlands
- * E-mail:
| | - Adrianus J. van Vught
- Department of Paediatric Intensive Care, Wilhelmina Children’s Hospital / University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mark Brabander
- Department of Paediatric Intensive Care, Wilhelmina Children’s Hospital / University Medical Center Utrecht, Utrecht, The Netherlands
| | - Frank Brus
- Department of Paediatrics, Haga Hospital/Location Juliana Children’s Hospital, The Hague, The Netherlands
| | - Nicolaas J. Jansen
- Department of Paediatric Intensive Care, Wilhelmina Children’s Hospital / University Medical Center Utrecht, Utrecht, The Netherlands
| | - Louis J. Bont
- Department of Paediatric Infectious Diseases, Wilhelmina Children’s Hospital/University Medical Center Utrecht, Utrecht, The Netherlands
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10
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Abstract
Mechanical ventilation (MV) is, by definition, the application of external forces to the lungs. Depending on their magnitude, these forces can cause a continuum of pathophysiological alterations ranging from the stimulation of inflammation to the disruption of cell-cell contacts and cell membranes. These side effects of MV are particularly relevant for patients with inhomogeneously injured lungs such as in acute lung injury (ALI). These patients require supraphysiological ventilation pressures to guarantee even the most modest gas exchange. In this situation, ventilation causes additional strain by overdistension of the yet non-injured region, and additional stress that forms because of the interdependence between intact and atelectatic areas. Cells are equipped with elaborate mechanotransduction machineries that respond to strain and stress by the activation of inflammation and repair mechanisms. Inflammation is the fundamental response of the host to external assaults, be they of mechanical or of microbial origin and can, if excessive, injure the parenchymal tissue leading to ALI. Here, we will discuss the forces generated by MV and how they may injure the lungs mechanically and through inflammation. We will give an overview of the mechanotransduction and how it leads to inflammation and review studies demonstrating that ventilator-induced lung injury can be prevented by blocking pathways of mechanotransduction or inflammation.
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Affiliation(s)
- Ulrike Uhlig
- Department of Pharmacology & Toxicology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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Scholz AW, Weiler N, David M, Markstaller K. Respiratory mechanics measured by forced oscillations during mechanical ventilation through a tracheal tube. Physiol Meas 2011; 32:571-83. [PMID: 21454925 DOI: 10.1088/0967-3334/32/5/006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The forced oscillation technique (FOT) allows the measurement of respiratory mechanics in the intensive care setting. The aim of this study was to compare the FOT with a reference method during mechanical ventilation through a tracheal tube. The respiratory impedance spectra were measured by FOT in nine anaesthetized pigs, and resistance and compliance were estimated on the basis of a linear resistance-compliance inertance model. In comparison, resistance and compliance were quantified by the multiple linear regression analysis (LSF) of conventional ventilator waveforms to the equation of motion. The resistance of the sample was found to range from 6 to 21 cmH(2)O s l(-1) and the compliance from 12 to 32 ml cmH(2)O(-1). A Bland-Altman analysis of the resistance resulted in a sufficient agreement (bias -0.4 cmH(2)O s l(-1); standard deviation of differences 1.4 cmH(2)O s l(-1); correlation coefficient 0.93) and test-retest reliability (coefficient of variation of repeated measurements: FOT 2.1%; LSF 1.9%). The compliance, however, was poor in agreement (bias -8 ml cmH(2)O(-1), standard deviation of differences 7 ml cmH(2)O(-1), correlation coefficient 0.74) and repeatability (coefficient of variation: FOT 23%; LSF 1.7%). In conclusion, FOT provides an alternative for monitoring resistance, but not compliance, in tracheally intubated and ventilated subjects.
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Affiliation(s)
- Alexander-Wigbert Scholz
- Department of Anaesthesiology, University Medical Centre of the Johannes Gutenberg-University, 55131 Mainz, Germany.
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Cannizzaro V, Hantos Z, Sly PD, Zosky GR. Linking lung function and inflammatory responses in ventilator-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2010; 300:L112-20. [PMID: 20952494 DOI: 10.1152/ajplung.00158.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite decades of research, the mechanisms of ventilator-induced lung injury are poorly understood. We used strain-dependent responses to mechanical ventilation in mice to identify associations between mechanical and inflammatory responses in the lung. BALB/c, C57BL/6, and 129/Sv mice were ventilated using a protective [low tidal volume and moderate positive end-expiratory pressure (PEEP) and recruitment maneuvers] or injurious (high tidal volume and zero PEEP) ventilation strategy. Lung mechanics and lung volume were monitored using the forced oscillation technique and plethysmography, respectively. Inflammation was assessed by measuring numbers of inflammatory cells, cytokine (IL-6, IL-1β, and TNF-α) levels, and protein content of the BAL. Principal components factor analysis was used to identify independent associations between lung function and inflammation. Mechanical and inflammatory responses in the lung were dependent on ventilation strategy and mouse strain. Three factors were identified linking 1) pulmonary edema, protein leak, and macrophages, 2) atelectasis, IL-6, and TNF-α, and 3) IL-1β and neutrophils, which were independent of responses in lung mechanics. This approach has allowed us to identify specific inflammatory responses that are independently associated with overstretch of the lung parenchyma and loss of lung volume. These data provide critical insight into the mechanical responses in the lung that drive local inflammation in ventilator-induced lung injury and the basis for future mechanistic studies in this field.
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Affiliation(s)
- Vincenzo Cannizzaro
- Department of Intensive Care and Neonatology, University Children’s Hospital, Zurich, Switzerland
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Foong RE, Sly PD, Larcombe AN, Zosky GR. No role for neutrophil elastase in influenza-induced cellular recruitment, cytokine production or airway hyperresponsiveness in mice. Respir Physiol Neurobiol 2010; 173:164-70. [DOI: 10.1016/j.resp.2010.08.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 08/03/2010] [Accepted: 08/03/2010] [Indexed: 10/19/2022]
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Abstract
PURPOSE OF REVIEW We report on the evolution of airway pressure and flow monitoring from a pathophysiological tool to the cornerstone of ventilator-induced lung injury (VILI) prevention. RECENT FINDINGS Protective ventilatory strategies are based on reduction of volume and pressures delivered to the lungs. New evidence, which will need confirmation in further studies, suggests that transpulmonary pressure (alveolar pressure minus pleural pressure), could be used to titrate both the positive end-expiratory pressure (PEEP) level and the inspiratory pressure applied by the ventilator. A limited number of animal studies are strongly supporting a role for inspiratory flow on the development of VILI.Moreover, different airway flow patterns may affect secretion movement, both global, to the alveoli or the glottis, and regional, from lower to higher compliance regions. This intra-lung transfer may be a primary mechanism for the propagation of infections and inflammatory mediators.Alternative monitoring techniques (among others) are the rapid interrupter technique, which can be used to measure airway resistance and patients' inspiratory effort and the forced oscillation technique which could become a bedside technique to estimate recruitment/derecruitment and titrate PEEP. SUMMARY Airway pressure and flow monitoring is essential for VILI prevention and for an appropriate setting of mechanical ventilation.
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