Experimental Study Of Partial Liquid Ventilation In The Treatment Of Acute Lung Injury

SECTION 1. A stable and reproducible piglets model of acute lung injury induced by small injections of oleic acidObjective Acute lung injury and acute respiratory distress syndrome are syndromes of acute diffuse damage to the pulmonary parenchyma by a variety of local or systemic insults. Oleic acid has often been used to induce an experimental model of respiratory distress in animal. In these studies oleic acid was given either as a single bolus or as a continuous infusion, and the amount administered differed between studies. And most of these animal models have a high mortality due to hemodynamic instability. The aim of this study was development of a stable and reproducible piglets model of acute lung injury induced by small injections of oleic acid.Methods 12 Chinese mini-piglets were randomized into two groups:Control group (saline-ehanol was administered in a series of multiple injections of 0.1 ml), Study group (oleic acid which was dissolved 1:1 in 95% alcohol was administered in a series of multiple injection of 0.1 ml). Careful titration of saline-ethanol and OA-ehanol injections on guidance of PaO2. And both groups hemodynamic were stable at least 4h. Hemodynamic and pulmonary function data were monitored. Histopathological was detected.Results There is no significant changes in hemodynamics and pulmonary function in control group. Study group showed the moderate decrease in blood pressure and cardiac output. Pulmonary pressure was increased after OA injection. Study group showed sever lung injury in pathologic.Conclusion With the use of multiple injection of oleic acid, a stable model of early respiratory distress in piglets can be achieved. Such a stable model allows for a diversity studies on early respiratory distress. Section 2 Partial liquid ventilation reduced lung inflammatory reaction in piglets after oleic acid-induced acute lung injuryObjective To investigate the effective of partial liquid ventilation on pulmonary inflammatory reaction in piglets after oleic acid-induced acute lung injury.Method Twelve Chinese immature piglets were induced acute lung injury by oleic acid. The animal were randomly divided into conventional mechanical ventilation group (control group) and experimental group (received partial liquid ventilation with FC-77). Sample for blood gas analysis were collected before and after lung injury every hour. After 4 hours of acute lung injury, the levels of TNF-α, IL-1β, MPO in plasma and tissue were measured.Results There is no significant changes in hemodynamics and pulmonary function in both groups at baseline. After OA administration induced drastratic hemodynamic changes in both groups. The hemodynamics and pulmonary function were significantly increased in study group. The concentrations of TNF-a, interleukin-1β, myeloperoxidase in plasma and tissue were significant lower in study group than control group (plasma:TNF-α:30.7150±5.5174 vs.63.0520±12.4000,IL-1β:48.1305±12.3000vs.149.757 5±37.3850,MPO:119.8280±18.665vs.99.028;tissue:TNF-α:31.2650±2.3370vs.62.2880±5 .1114, IL-1β:15.5515±7.0108vs.37.2285±6.1911, MPO:13.6270±3.041vs.6.898±1.147, P<0.05).Conclusion Partial liquid ventilation provides protective effects against inflammatory responses in the lungs during oleic acid-induced in immature piglets.