Introduction: Cardiac arrest incurs high mortality and causes a significant neurological deficit in those who survive. Therapeutic hypothermia (TH) has been shown to improve neurological function and survival when applied in post-cardiac arrest care. However, currently there exist unanswered questions in the therapeutic effect of ice-cold intravenous fluid infusion during cardiopulmonary resuscitation in cardiac arrest population.
Hypothesis: This retrospective control study was to compare the rate of return of spontaneous circulation, hospital survival, neurological status, and 6-month survival in patients with cardiac arrest who were treated with intra-resuscitation versus pre-hospital induced therapeutic hypothermia.
Methods: Retrospective data were collected from Dec 1, 2012, to Dec 31, 2015, in cardiac arrested patients received 4°C intravenous saline, up to 2 liters, either during cardiopulmonary resuscitation or after attained return of spontaneous circulation. All other treatments and intervention followed the standards of care according to the existing protocols. Statistical calculations include two-tailed t-test and the chi-square test.
Results: EMS responded to 1742 cases of cardiac arrest. The rate of return of spontaneous circulation was 39.9% (n=217) in the intra-resuscitated group as compared to 37.2% (n=379) in the pre-hospital group, (p=0.30). For all other outcome analysis, mean weight and pulseless electrical activity as initial rhythm were statistically significant between treatment groups. Neurological status at hospital discharge, time to return of spontaneous circulation, and time to target temperature of 33°C were not statistically significant between treatment groups. Survival at hospital discharge was 42.9% vs 52.5% (p=0.36) between treatment groups. Six-month survival was 39.7% vs 49.2% (p=0.22) between treatment groups.
Conclusions: Intra-resuscitated induced therapeutic hypothermia confers no benefit in the rate of return of spontaneous circulation, hospital survival, neurological status, and 6-month survival in patients with cardiac arrest as compared to pre-hospital induced therapeutic hypothermia.