Pulmonary Artery-Left Atrium Pumpless Lung Assist For Acute Lung Injury In Piglets

SECTION1.ANovel and Stable "two-hit" Acute Lung Injury Model Induced by Oleic Acid in PigletsObjective Children are susceptible to pulmonary injury,and acute lung injury(ALI) often results in a high mortality and financial cost in pediatric patients.Evidences have showed that oleic acid(OA) maybe play a very important role in ALI pathological process.Therefore,it has special significance to study pediatric patient's ALI with OA-induced animal models.Unfortunately,the animal models have a high mortality due to hemodynamic instability.The aim of this study was to establish a novel hemodynamically stable OA-induced ALI model in piglets with two hits methods.Methods 12 Chinese mini-piglets were randomized into three groups:group S(received saline-ethanol solution),group C(received OA-ethanol solution in two-hit manner).In the first stage of OA administration,about two thirds of the dosage was injected through right atrial appendage.The other one third of OA was administrated one hr late. Hemodynamic and pulmonary function data were monitored.Histopathological assessments were performed.Results There is no significant changes in hemodynamcis and pulmonary function of grouop S.Group C showed the moderate decrease in artery pressure and cardiac output, without extremely change trends.The pulmonary artery pressure and central venous pressure of group C increased after OA administration.Group C produced severe lung injury,while group C had no significant pathologic changes.There is no significant change in left atrial pressure throughout the protocol.Conclusions It is the first report on hemodynamic stable ALI animal model in piglets induced by OA using two-hit method.The model fulfils the ALI criteria and has the following characteristics:hemodynamic stability,stable damage to gas exchange and comparability with pediatric patients in body weight and corresponding age. To investigate the feasibility and validity of pulmonary artery-left atrium pumpless lung assist for acute lung injury animal model in piglets.Methods 12piglets were randomized into two groups after acute lung injury was induced with two-hits method.Group C(n=6) received mechanical ventilation without lung assit.Group A(n=6) received pumoanry arter-left atrium pumpless lung assist,in which the membrane oxygenator was connected in parallel with the native lungs.Hemodynamic parameters,pump flow rate and pulmonary function were monitored.Results All parameters showed no significance between groups.The OA administration induced drastric hemodynamic changes in group C,however,the lung assist reverse the hemodynamic changes of group A.The lung assist could increase the oxygen tension and pH in arterial blood;and caused the decrease of carbon bioxide tension in arterial blood and airway pressure.The severity of pathological injury scores in group A was significantly lower than group C(5.3±0.8 vs.4.0±1.1, P=0.0379).The wet/ dry ratio in group A was significantly higher than that of group A(10.8±1.5 vs.5.7±0.5,P=0.0022).The pump flow rate was positive correlated with pulmonary hypertension induced by OA administration.Conclusion The pulmonary artery-left atrium lung assist is feasible and valid to treat acute lung injury and acute respiratory distress,and can reduce the afterload of right ventricle.