Abstract 14282: Cold Saline Infusion is an Effective Method to Achieve Intra-Cardiopulmonary Resuscitation Therapeutic Hypothermia

Objective: Therapeutic hypothermia (TH) is thought to improve neurologically intact survival when applied after return of spontaneous circulation (ROSC) is achieved in patients who suffer a cardiac arrest. Intra-CPR cooling may accelerate the time to reach TH and thus enhance its neurological benefit. Sodium nitroprusside enhanced cardiopulmonary resuscitation (SNPeCPR), consisting of active compression decompression (ACD) with an impedance threshold device (ITD), abdominal binding, and bolus doses of SNP, has been shown to accelerate intra-CPR cooling compared to standard CPR. The aim of this study is to compare the rate of cooling achieved during CPR using various cooling methods as part of the resuscitation effort.

Methods: This study included 24 intubated and anesthetized swine. Brain temperature probes were surgically placed. After induction of ventricular fibrillation (VF), animals were randomized to one of the following groups: 500cc cold saline infusion (group A), 500cc cold saline infusion plus surface cooling with ice packs (group B), surface cooling with ethanol soaked towels (group C) or control (group D). After 10 minutes of VF, ACD-ITD CPR was initiated. One minute after the initiation of CPR, the randomized intervention was initiated and abdominal binding was applied. SNP (2 mg) was administered at minutes 1, 4 and 8. Animals were defibrillated at minute 10.

Results: Group A and Group B had the fastest decrease in temperature during CPR with a rate of 0.12 °C/min and 0.13 °C/min, respectively. This was compared to a rate of 0.03 °C/min, and 0.02 °C/min in the ethanol based surface cooling and control groups, respectively (using ANOVA, p<0.05 between group A and C, A and D, B and C, B and D).

Conclusions: A cold saline infusion initiated at the start of CPR was determined as the most effective method to achieve intra-CPR TH during SNPeCPR. Further studies will assess the potential neurologic benefit of the combination of SNPeCPR with intra-CPR infusion of cold saline.