Outcome, timing and adverse events in therapeutic hypothermia after out-of-hospital cardiac arrest

Background Therapeutic hypothermia (TH) after cardiac arrest protects from neurological sequels and death and is recommended in guidelines. The Hypothermia Registry was founded to the monitor outcome, performance and complications of TH. Methods Data on out-of-hospital cardiac arrest (OHCA) patients admitted to intensive care for TH were registered. Hospital survival and long-term outcome (6-12 months) were documented using the Cerebral Performance Category (CPC) scale, CPC 1-2 representing a good outcome and 3-5 a bad outcome. Results From October 2004 to October 2008, 986 TH-treated OHCA patients of all causes were included in the registry. Long-term outcome was reported in 975 patients. The median time from arrest to initiation of TH was 90 min (interquartile range, 60-165 min) and time to achieving the target temperature (< 34 degrees C) was 260 min (178-400 min). Half of the patients underwent coronary angiography and one-third underwent percutaneous coronary intervention (PCI). Higher age, longer time to return of spontaneous circulation, lower Glasgow Coma Scale at admission, unwitnessed arrest and initial rhythm asystole were all predictors of bad outcome, whereas time to initiation of TH and time to reach the goal temperature had no significant association. Bleeding requiring transfusion occurred in 4% of patients, with a significantly higher risk if angiography/PCI was performed (2.8% vs. 6.2% P=0.02). Conclusions Half of the patients survived, with > 90% having a good neurological function at long-term follow-up. Factors related to the timing of TH had no apparent association to outcome. The incidence of adverse events was acceptable but the risk of bleeding was increased if angiography/PCI was performed.