Abstract:Objective To explore factors affecting the success of and prognosis for cardiac arrest-cardiopulmonary resuscitation (CA-CPR) in a rat model induced by asphyxia. Methods The CA-CPR model was established in 50 SD rats, which were divided into three groups according to weight: group Ⅰ (n = 10, 250~ 300 g), group Ⅱ (n = 30, 300~ 350 g), and group Ⅲ (n = 10, 350~ 400 g). Baseline data, the rate of return of spontaneous circulation (ROSC), and the time needed for cardiopulmonary resuscitation (CPR) were recorded, and the hemodynamics after ROSC were assessed. Results The ROSC rates for group Ⅰ, group Ⅱ, and group Ⅲ were 90. 00% (9 / 10), 60. 00% (18 / 30), and 60. 00% (6 / 10), respectively, and were not significantly different (P >0. 05). Compared with group Ⅱ (417. 19 ± 92. 00) s and group Ⅲ (60. 80 ± 115. 40)s, group Ⅰ exhibited a significantly shorter CPR time ( 365. 16 ± 76. 66; P < 0. 05). The heart rate (HR) of rats in group Ⅰ (306. 22±41. 99 beats/ min) 30 minutes after ROSC was significantly different to that of rats in group Ⅱ ( 264. 47± 33. 28 beats/ min; P < 0. 05), and there were no significant differences between the other groups (all P>0. 05). A binary logistic regression model was used to evaluate the predictive index for ROSC (χ2= 25. 115, P <0. 001) and 72-hour survival (χ2= 14. 191, P = 0. 001). Six items were included: body weight, anal temperature, HR, mean arterial pressure, asphyxia to cardiac arrest (ACA) time, and CA duration. ROSC was positively correlated with ACA time (OR= 1. 087, 95% confidence interval (95% CI): 1. 031-1. 146); and 72-hour survival was negatively related to body weight (OR= 0. 953, 95% CI: 0. 915-0. 992) and HR (OR = 0. 957, 95% CI: 0. 921-0. 994). Conclusions Our findings show that rats with lower weight, lower baseline HR, and longer ACA time were more likely to have a good outcome.