Abstract 262: Slight Therapeutic Hypothermia (35°C to 36°C) for Post--Cardiac Arrest Syndrome Due to Ventricular Fibrillation with Low Left Cardiac Function Is a Feasible and Safe Possibility

Abstract

Background: Mild therapeutic hypothermia (32-34°C, 24-48 hours: mild TH) for post cardiac arrest syndrome (PCAS) due to ventricular fibrillation (VF) had been recommended in the American Heart Association (AHA) Guidelines 2005 (class IIa) and the International Liaison Committee on Resuscitation (ILCOR). In the AHA guidelines 2010, it has been recommended more strongly (class I). But it is still unknown what temperature is best for low cardiac function patients including acute myocardial infarction (AMI) cases. Sometimes executing mild TH for patients with severe left ventricular dysfunction are not so easy and safe because of hypotension, arrhythmias, unstable vital signs and so on. So we studied whether slight therapeutic hypothermia (35-36°C: Slight TH) was effective and safe compare with mild TH for PCAS due to VF. Methods: Consecutive PCAS patients who were witnessed, done by-stander cardiopulmonary resuscitation (CPR), confirmed VF caused by cardiac or coronary events and introduced therapeutic hypothermia for the latest 45 months were sorted into the GroupM (Mild TH, 34°C, 24-72 hours) and the GroupS (Slight TH, 35-36°C, 24-72 hours).The primary end point was a favorable neurologic outcome (cerebral performance category: CPC 1 or 2) in 28th days after cardiac arrest. Secondary end points were the changes of cardiac index (CI) after introducing therapeutic hypothermia, the time required to reach target temperature and the rate of complications (infections, bleeding, arrhythmias etc.) within fourteen days. Results: Thirty-five patients (twenty AMI cases) were studied (GroupM 20 patients and GroupS 15 patients). The rate of favorable neurologic outcome was available and did not differ significantly between the two groups (50% vs. 53%, p=0.85). The time to reach target temperature was significantly shorter in the GroupS (5.9h vs. 0.9h, p<0.01). The decrease of CI was remarkable in the groupM (before TH/during TH, GroupM 2.8/2.2, GroupS 1.9/2.1, the changes of them were Δ32% vs. +0.05%, p<0.01). The rate of complications did not differ significantly between them and there were no major complications. Conclusion: Slight therapeutic hypothermia for PCAS due to VF with low cardiac function is possibility feasible and safe.