Background Pediatric patients are susceptible to lung injury that does not respond to traditional therapies.Partial liquid ventilation (PLV) has been developed as an altative ventilatory strategy for treating severe lung injury.The aim of this study is to investigate the effect of PLV on lung function in immature piglets.Methods Acute lung injury was induced in 12 Chinese immature piglets by oleic acid (OA).The animals were randomly assigned to two groups (n=6 each group):(1) conventional mechanical ventilation (MV) group and (2) PLV with FC-77 (10 ml/kg) group.Mean arterial blood pressure (MAP),mean pulmonary arterial pressure (MPAP),central venous pressure (CVP),left atrial pressure (LAP),systemic vascular resistance (SVR),pulmonary vascular resistance (PVR),cardiac output (CO),mean pressure of airway (Paw),dynamic lung compliance (Cydn),and arterial blood gases were measured during the observation period.Results No piglet died in either group with severe lung injury.After four hours of ventilation,pH in the MV group gradually decreased to lower than 7.20,while in the PLV group,pH also gradually decreased but remained higher than 7.20 (P ＜0.05).Partial pressure of oxygen in artery (PaO2) decreased in both groups,but with a significant difference between the PLV group and MV group (P ＜0.05).Partial pressure of carbon dioxide in artery (PaCO2) increased in both groups,but with a significant difference between the PLV group and MV group (P ＜0.05).Paw increased in both groups,but was not significantly different (P ＞0.05).Cydn decreased in both groups,but without a significant difference (P ＞0.05).At four hours,heart rate (HR) and MAP in both groups decreased.MPAP in both groups increased,and there was a significant difference between the two groups (P ＜0.05).CVP was stable in both groups.At four hours,PVR and LAP were increased in both groups.CO was decreased in both groups (P ＜0.05).SVR was stable during the observation time.Conclusion PLV did not improve outcome in changes of lung function.