Abstract 83: Sex Does Not Predict the Probability of ROSC or Short Term Survival in a Swine Model of Prolonged Ventricular Fibrillation
Introduction- Recent studies have demonstrated a possible survival benefit in female patients experiencing cardiac arrest. This finding potentially affects the interpretation of all in vivo animal studies.
Hypothesis- We hypothesized that sex is not an independent predictor of return of spontaneous circulation (ROSC) or short term survival in porcine studies of prolonged ventricular fibrillation (VF).
Methods- We conducted a retrospective analysis of the last five experiments performed in our lab using mixed-breed domestic swine of either sex (weighing 23–30 kg). All experiments include CPR, defibrillation and IV medications. We defined ROSC as a systolic blood pressure of 80 mmHg or greater, sustained for one minute. Short term survival varied between 20 and 60 minutes. Multiple logistic regressions determined predictors of ROSC and short term survival. Candidate variables included: sex, duration of VF, duration of anesthesia, weight, and resuscitation protocol.
Results- We included 191 swine in the analyses (85 female, 106 male). The rate of ROSC for females was 73% and for males was 64%. The rate of short term survival was 63% for females and 53% for males. Duration of VF alone was a predictor of ROSC (Odds Ratio .00004; 95% CI .00003, .00004). Duration of VF (OR .00003; 95% CI .00002, .00003) and one treatment group (OR 4.56; 95% CI 1.66, 12.53) were predictors of short term survival. This group was exposed to prolonged VF as part of the experiment. Both models had good fit with Hosmer-Lemeshow values of 0.76 in the ROSC model and 0.43 in the short term survival model. This study had an observed power of 0.90 to detect absolute differences of 12% between females and males with an alpha of 0.05.
Conclusions- Sex does not predict the likelihood of ROSC or short term survival in this swine model of ventricular fibrillation.