scholarly journals Positive end-expiratory pressure alters the severity and spatial heterogeneity of ventilator-induced lung injury: An argument for cyclical airway collapse

2009 ◽  
Vol 24 (2) ◽  
pp. 206-211 ◽  
Author(s):  
Scott E. Sinclair ◽  
Emil Chi ◽  
Hen-I Lin ◽  
William A. Altemeier
1998 ◽  
Vol 26 (10) ◽  
pp. 1690-1697 ◽  
Author(s):  
Keith G. Hickling ◽  
Timothy Wright ◽  
Keith Laubscher ◽  
Ian G. Town ◽  
Andrew Tie ◽  
...  

2014 ◽  
Vol 120 (3) ◽  
pp. 694-702 ◽  
Author(s):  
José L. Izquierdo-García ◽  
Shama Naz ◽  
Nicolás Nin ◽  
Yeny Rojas ◽  
Marcela Erazo ◽  
...  

Abstract Background: Global metabolic profiling using quantitative nuclear magnetic resonance spectroscopy (MRS) and mass spectrometry (MS) is useful for biomarker discovery. The objective of this study was to discover biomarkers of acute lung injury induced by mechanical ventilation (ventilator-induced lung injury [VILI]), by using MRS and MS. Methods: Male Sprague–Dawley rats were subjected to two ventilatory strategies for 2.5 h: tidal volume 9 ml/kg, positive end-expiratory pressure 5 cm H2O (control, n = 14); and tidal volume 25 ml/kg and positive end-expiratory pressure 0 cm H2O (VILI, n = 10). Lung tissue, bronchoalveolar lavage fluid, and serum spectra were obtained by high-resolution magic angle spinning and 1H-MRS. Serum spectra were acquired by high-performance liquid chromatography coupled to quadupole-time of flight MS. Principal component and partial least squares analyses were performed. Results: Metabolic profiling discriminated characteristics between control and VILI animals. As compared with the controls, animals with VILI showed by MRS higher concentrations of lactate and lower concentration of glucose and glycine in lung tissue, accompanied by increased levels of glucose, lactate, acetate, 3-hydroxybutyrate, and creatine in bronchoalveolar lavage fluid. In serum, increased levels of phosphatidylcholine, oleamide, sphinganine, hexadecenal and lysine, and decreased levels of lyso-phosphatidylcholine and sphingosine were identified by MS. Conclusions: This pilot study suggests that VILI is characterized by a particular metabolic profile that can be identified by MRS and MS. The metabolic profile, though preliminary and pending confirmation in larger data sets, suggests alterations in energy and membrane lipids. SUPPLEMENTAL DIGITAL CONTENT IS AVAILABLE IN THE TEXT


2008 ◽  
Vol 108 (2) ◽  
pp. 261-268 ◽  
Author(s):  
Rosanna Vaschetto ◽  
Jan W. Kuiper ◽  
Shyh Ren Chiang ◽  
Jack J. Haitsma ◽  
Jonathan W. Juco ◽  
...  

Background Mechanical ventilation can induce organ injury associated with overwhelming inflammatory responses. Excessive activation of poly(adenosine diphosphate-ribose) polymerase enzyme after massive DNA damage may aggravate inflammatory responses. Therefore, the authors hypothesized that the pharmacologic inhibition of poly(adenosine diphosphate-ribose) polymerase by PJ-34 would attenuate ventilator-induced lung injury. Methods Anesthetized rats were subjected to intratracheal instillation of lipopolysaccharide at a dose of 6 mg/kg. The animals were then randomly assigned to receive mechanical ventilation at either low tidal volume (6 ml/kg) with 5 cm H2O positive end-expiratory pressure or high tidal volume (15 ml/kg) with zero positive end-expiratory pressure, in the presence and absence of intravenous administration of PJ-34. Results The high-tidal-volume ventilation resulted in an increase in poly(adenosine diphosphate-ribose) polymerase activity in the lung. The treatment with PJ-34 maintained a greater oxygenation and a lower airway plateau pressure than the vehicle control group. This was associated with a decreased level of interleukin 6, active plasminogen activator inhibitor 1 in the lung, attenuated leukocyte lung transmigration, and reduced pulmonary edema and apoptosis. The administration of PJ-34 also decreased the systemic levels of tumor necrosis factor alpha and interleukin 6, and attenuated the degree of apoptosis in the kidney. Conclusion The pharmacologic inhibition of poly(adenosine diphosphate-ribose) polymerase reduces ventilator-induced lung injury and protects kidney function.


2017 ◽  
Vol 126 (5) ◽  
pp. 909-922 ◽  
Author(s):  
Dennis Lex ◽  
Stefan Uhlig

Abstract Background One important explanation for the detrimental effects of conventional mechanical ventilation is the biotrauma hypothesis that ventilation may trigger proinflammatory responses that subsequently cause lung injury. This hypothesis has frequently been studied in so-called one-hit models (overventilation of healthy lungs) that so far have failed to establish an unequivocal link between inflammation and hypoxemic lung failure. This study was designed to develop a one-hit biotrauma model. Methods Mice (six per group) were ventilated for up to 7 h (positive end-expiratory pressure 2 cm H2O) and received 300 μl/h fluid support. Series_1: initial plateau pressures of 10, 24, 27, or 30 cm H2O. Series_2: ventilation with pressure release at 34 cm H2O and initial plateau pressure of 10, 24, 27, or 30 cm H2O. To study the significance of inflammation, the latter groups were also pretreated with the steroid dexamethasone. Results Within 7 h, 20 of 24 mice ventilated with plateau pressure of 27 cm H2O or more died of a catastrophic lung failure characterized by strongly increased proinflammatory markers and a precipitous decrease in pulmonary compliance, blood pressure, and oxygenation. Pretreatment with dexamethasone reduced inflammation, but prolonged median survival time by 30 min. Conclusions Our findings demonstrate a sharp distinction between ventilation with 24 cm H2O that was well tolerated and ventilation with 27 cm H2O that was lethal for most animals due to catastrophic lung failure. In the former case, inflammation was benign and in the latter, a by-product that only accelerated lung failure. The authors suggest that biotrauma—when defined as a ventilation-induced and inflammation-dependent hypoxemia—is difficult to study in murine one-hit models of ventilation, at least not within 7 h. (Anesthesiology 2017; 126:909-22)


2005 ◽  
Vol 102 (3) ◽  
pp. 597-605 ◽  
Author(s):  
Marcelo Gama de Abreu ◽  
Beate Wilmink ◽  
Matthias Hübler ◽  
Thea Koch

Background The authors tested the hypothesis that administration of vaporized perfluorohexane may attenuate ventilator-induced lung injury. Methods In isolated, perfused rabbit lungs, airway pressure-versus-time curves were recorded. At baseline, peak inspiratory pressure and positive end-expiratory pressure of mechanically ventilated lungs were set to obtain straight pressure-versus-time curves in both the lower and upper ranges, which are associated with less collapse and overdistension, respectively. After that, peak inspiratory pressure and positive end-expiratory pressure were set at 30 cm H2O and 0, respectively, and animals were randomly assigned to one of two groups: (1) simultaneous administration of 14% perfluorohexane vapor in room air (n = 7) and (2) control group-ventilation with room air (n = 7). After 20 min of cycling collapse and overdistension, tidal volume and positive end-expiratory pressure were set back to baseline levels, administration of perfluorohexane in the therapy group was stopped, and mechanical ventilation was continued for up to 60 min. Lung weight, mean pulmonary artery pressure, and concentration of thromboxane B2 in the perfusate were measured. In addition, the distribution of pulmonary perfusate flow was assessed by using fluorescent-labeled microspheres. Results Significantly higher peak inspiratory values developed in control lungs than in lungs treated with perfluorohexane. In addition, upper ranges of pressure-versus-time curves were closer to straight lines in the perfluorohexane group. Lung weight, mean pulmonary arterial pressure, and release of thromboxane B2 were significantly higher in controls than in perfluorohexane-treated lungs. Also, redistribution of pulmonary perfusate flow from caudal to cranial zones was less important in the treatment group. Conclusion The authors conclude that the administration of perfluorohexane vapor attenuates the development of ventilator-induced lung injury in isolated, perfused rabbit lungs.


2012 ◽  
Vol 117 (3) ◽  
pp. 592-601 ◽  
Author(s):  
Philipp A. Pickerodt ◽  
Michael J. Emery ◽  
Rachel Zarndt ◽  
William Martin ◽  
Roland C. E. Francis ◽  
...  

Background Nitrite (NO2) is a physiologic source of nitric oxide and protects against ischemia-reperfusion injuries. We hypothesized that nitrite would be protective in a rat model of ventilator-induced lung injury and sought to determine if nitrite protection is mediated by enzymic catalytic reduction to nitric oxide. Methods Rats were anesthetized and mechanically ventilated. Group 1 had low tidal volume ventilation (LVT) (6 ml/kg and 2 cm H2O positive end-expiratory pressure; n=10); group 2 had high tidal volume ventilation (HVT) (2 h of 35 cm H2O inspiratory peak pressure and 0 cm H2O positive end-expiratory pressure; n=14); groups 3-5: HVT with sodium nitrite (NaNO2) pretreatment (0.25, 2.5, 25 μmol/kg IV; n=6-8); group 6: HVT+NaNO2+nitric oxide scavenger 2-(4-carboxyphenyl)-4,5dihydro-4,4,5,5-tetramethyl-1H-imidazolyl-1-oxy-3oxide(n=6); group 7: HVT+NaNO2+nitric oxide synthase inhibitor N-nitro-L-arginine methyl ester (n=7); and group 8: HVT+NaNO2+xanthine oxidoreductase inhibitor allopurinol (n=6). Injury assessment included physiologic measurements (gas exchange, lung compliance, lung edema formation, vascular perfusion pressures) with histologic and biochemical correlates of lung injury and protection. Results Injurious ventilation caused statistically significant injury in untreated animals. NaNO2 pretreatment mitigated the gas exchange deterioration, lung edema formation, and histologic injury with maximal protection at 2.5 μmol/kg. Decreasing nitric oxide bioavailability by nitric oxide scavenging, nitric oxide synthase inhibition, or xanthine oxidoreductase inhibition abolished the protection by NaNO2. Conclusions Nitrite confers protection against ventilator-induced lung injury in rats. Catalytic reduction to nitric oxide and mitigation of ventilator-induced lung injury is dependent on both xanthine oxidoreductase and nitric oxide synthases.


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