title: High in comparison with low tidal volume ventilation aggravates oxidative stress-induced lung injury.
abstract: Ventilator settings influence the development and outcome of acute lung injury. This study investigates the influence of low versus high tidal volume (V(t)) on oxidative stress-induced lung injury. Isolated rabbit lungs were subjected to one of three ventilation patterns (V(t)-positive end-expiratory pressure, PEEP): LVZP (6 ml/kg-0 cm H(2)O), HVZP (12 ml/kg-0 cm H(2)O), LV5P (6 ml/kg-5 cm H(2)O). These ventilation patterns allowed a comparison between low and high V(t) without dependence on peak inspiratory pressure (PIP). Infusion of hypochlorite (1000 nmol/min) or buffer (control) was started at t=0 min. Pulmonary artery pressure (PAP), PIP and weight were continuously recorded. Capillary filtration coefficient [K(f,c) (10(-4) ml s(-1) cm H(2)O(-1) g(-1))] was gravimetrically determined (-15/30/60/90/120 min).PIP averaged 5.8+/-0.6/13.9+/-0.6/13.9+/-0.4 cm H(2)O in the LVZP, HVZP and LV5P groups. PIP, K(f,c) or PAP did not change in control groups, indicating that none of the ventilation patterns caused lung injury by themselves. Hypochlorite-induced increase in K(f,c) but not hypochlorite-induced increase in PAP, was significantly attenuated in the LVZP-/LV5P- versus the HVZP-group (K(f,c,max.) 1.0+/-0.23/1.4+/-0.40 versus 3.2+/-1.0*). Experiments with hypochlorite were terminated due to excessive edema (>50 g) at 97+/-2.2/94.5+/-4.5 min in the LVZP-/LV5P-group versus 82+/-3.8* min in the HVZP-group (*: P<0.05). Low V(t) attenuated oxidative stress-induced increase in vascular permeability independently from PIP and PEEP.
authors.affiliation: Department of Pulmonary Medicine, Critical Care and Cardiology, University Leipzig, Leipzig, Germany. stefan.hammerschmidt@t-online.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Hammerschmidt
authors.forename: Torsten
authors.initials: T
authors.lastname: Sandvoss
authors.forename: Christian
authors.initials: C
authors.lastname: Gessner
authors.forename: Joachim
authors.initials: J
authors.lastname: Schauer
authors.forename: Hubert
authors.initials: H
authors.lastname: Wirtz
mesh_terms: D000818:Animals; D002199:Capillary Permeability; D004487:Edema / Q000209:etiology; D006997:Hypochlorous Acid; D066298:In Vitro Techniques; D008168:Lung / Q000503:physiopathology; D055370:Lung Injury; D018384:Oxidative Stress; D011175:Positive-Pressure Respiration; D011817:Rabbits; D012121:Respiration, Artificial / Q000009:adverse effects / Q000379:methods*; D013990:Tidal Volume
chemical_list: D006997:Hypochlorous Acid