A long-term survival model of 40-min deep hypothermic circulatory arrest in rats

Objective To establish a long-term survival model of deep hypothermic circulatory arrest (DHCA) in rats, which could contribute to the research of organ damage mechanism and clinical treatments related to DHCA. Methods Twenty Sprague-Dawley rats were randomly (random number) divided into the sham group (n=10) and DHCA group (n=10). After anesthesia, a 20 G catheter was cannulated in the tail artery for arterial inflow, a multiorificed catheter in the right jugular vein for venous drainage, and a 24G catheter in the branch of left femoral artery for artery blood pressure monitoring. Rats in the DHCA group underwent DHCA procedure for 40 min after brain temperature cooled to 18℃, then rewarmed for 40 min, till the brain temperature were above 34℃. Rats in the sham group were cannulated but did not undergo cardiopulmonary bypass (CPB). Hemodynamic parameters and blood gas analysis were measured for 5 times (pre-CPB, 15 min after CPB, 10 min after rewarming, 40 min after rewarming, and 30 min after CPB). Results One rat in the DHCA group died, and the rest rats survived. The lactate level in the DHCA group after rewarming during operation was significantly higher than that in the sham group (7.84 mmol/L vs 1.93 mmol/L, P<0.05). Conclusions In this study, 40-min DHCA model in rats is characterized by safe and long-term survival. Key words: Rats; Cardiopulmonary bypass; Deep hypothermic circulatory arrest; Animal Model; lactate level; Organ damage