Effect of partial liquid ventilation on lung function in oleic acid-induced lung injury model of piglets

Background Pediatric patients are susceptible to lung injury that does not respond to traditional therapies.Partial liquid ventilation （PLV） has been developed as an alternative 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.

A novel, recovery, and reproducible minimally invasive cardiopulmonary bypass model with lung injury in rats

Background Cardiopulmonary bypass （CPB） has been shown to be associated with a systemic inflammatory response leading to postoperative organ dysfunction. Elucidating the underlying mechanisms and developing protective strategies for the pathophysiological consequences of CPB have been hampered due to the absence of a satisfactory recovery animal model. The purpose of this study was to establish a good rat model of CPB to study the pathophysiology of potential complications. Methods Twenty adult male Sprague-Dawley rats weighing 450-560 g were randomly divided into a CPB group （n=10） and a control group （n=10）. All rats were anaesthetized and mechanically ventilated. The carotid artery and jugular vein were cannulated. The blood was drained from the right atrium via the right jugular and transferred by a miniaturized roller pump to a hollow fiber oxygenator and back to the rat via the left carotid artery. Priming consisted of 8 ml of homologous blood and 8 ml of colloid. The surface of the hollow fiber oxygenator was 0.075 m~. CPB was conducted for 60 minutes at a flow rate of 100-120 ml. kg-1. min-1 in the CPB group. Oxygen flow/perfusion flow was 0.8 to 1.0, and the mean arterial pressure remained 60-80 mmHg. Blood gas analysis, hemodynamic investigations, and lung histology were subsequently examined. Results All CPB rats recovered from the operative process without incident. Normal cardiac function after successful weaning was confirmed by electrocardiography and blood pressure measurements. Mean arterial pressure remained stable. The results of blood gas analysis at different times were within the normal range. Levels of IL-113 and TNF-a were higher in the lung tissue in the CPB group （P 〈0.005）. Histological examination revealed marked increases in interstitialcongestion, edema, and inflammation in the CPB group. Conclusion This novel, recovery, and reproducible minimally invasive CPB model may open the field for various studies on the pathophysiological process of CPB and systemic ischemia-reperfusion injury in vivo.