OBJECTIVETo establish a good recoverable rat model of cardiopulmonary bypass (CPB) to lay the foundation for studying the pathophysiology of CPB.

METHODSTwenty adult male Sprague-Dawley rats weighing 480 g+/-20 g were randomly divided into CPB group (n equal to 10) and Sham group (n equal to 10). All rats were anaesthetized, intubated and ventilated. The carotid artery and jugular vein were cannulated. The blood was drained from the right atrium via the right jugular vein and further transferred by a miniaturized roller pump to a hollow fiber oxgenator and back to the rat via the left carotid artery. Priming consisted of 8 ml of homologous blood and 6 ml of colloid. The surface of the hollow fiber oxgenator was 0.075 m(2). Rats were catheterized and brought in bypass for 120 min at a flow rate of 100-120 ml/kg/min. Oxygen flow/perfusion flow was 0.8 to 1.0, the mean arterial pressure (MAP) kept in 60-80 mmHg. Blood gas analysis, lactate dehydrogenase (LDH), and survival rate were examined subsequently.

RESULTSAll CPB rats recovered from the operative process without incident and remained uneventful within one week. Normal cardiac function after successful weaning was confirmed by electrocardiography and blood pressure measurements. MAP remained stable. The results of blood gas analysis at different time points were within a normal range. No significant haemolysis could be detected in the given time frame under bypass condition by using LDH.

CONCLUSIONSThe rat model of CPB can principally simulate the clinical setting of human CPB. The non-transthoracic model is easy to establish and is associated with excellent recovery. This well reproducible model may open the field for various studies on pathophysiological process of CPB and also of systemic ischemia-reperfusion injury in vivo.