Abstract P147: Early Induction of Mild Hypothermia During Cardiac Arrest Enhances Neurological Benefits for Patients With Out-of-hospital Cardiac Arrest Who Underwent Extracorporeal Cardiopulmonary Resuscitation
Background Neurological benefits have demonstrated for therapeutic hypothermia in comatose survivors following out-of-hospital cardiac arrest. Although early cooling during cardiac arrest enhances its efficacy in animal studies, few clinical studies were available.
Methods We did a prospective study of extracorporeal cardiopulmonary resuscitation (CPR) for induction of therapeutic hypothermia in adult patients who failed to respond to conventional CPR. In patients meeting the criteria, we performed emergency cardiopulmonary bypass (CPB) and intra-aortic balloon pumping, with subsequent percutaneous coronary intervention (PCI) if needed. During cardiac arrest or after return of spontaneous circulation, mild hypothermia (34°C for 3 days) was induced using the internal plus extracorporeal cooling methods. The primary endpoint was a favorable neurological outcome at hospital discharge.
Results Of the171 patients who underwent extracorporeal CPR for induction of hypothermia with PCI, a favorable neurological outcome was seen in 21 (12.3%). Generally, the four groups of patients according to the quartiles of collapse-to-34°C interval had similar baseline characteristics, but significant differences were seen in the collapse-to-CPB interval and the CPB-to-34°C interval as principal components of the collapse-to-34°C interval. An unadjusted rate of a favorable neurological outcome decreased in a stepwise fashion for increasing quartiles of the CPB-to-34°C interval (p=0.02). Adjusted odds ratios for a favorable neurological outcome after the collapse-to-CPB interval was 0.89 (95% CI 0.82 to 0.97) and after the CPB-to-34°C interval, 0.99 (95% CI 0.98 to 0.99). Favorable neurological accuracies of the collapse-to-CPB interval at a cutoff of 55.5 min and the CPB-to-34°C interval at a cutoff 21.5 min were 85.4% and 89.5%, respectively. Significant difference was seen in a favorable neurological outcome among four subsets of patients who were classified those cutoff values (p=0.0001).
Conclusions Early attainment of a core temperature of 34°C during extracorporeal CPR with PCI enhanced neurological benefits for adult patients with out-of-hospital cardiac arrest who failed to respond to conventional CPR.