Time to awakening and neurologic outcome in therapeutic hypothermia-treated cardiac arrest patients

Introduction: Therapeutic hypothermia (TH) has been shown to improve outcomes in comatose Post-Cardiac Arrest Syndrome (PCAS) patients. It is unclear how long it takes these patients to regain neurologic responsiveness post-arrest. We sought to determine the duration to post-arrest awakening and factors associated with times to such responsiveness. Methods: We performed a retrospective chart review of consecutive TH-treated PCAS patients at three hospitals participating in a US cardiac arrest registry from 2005 to 2011. We measured the time from arrest until first documentation of awakening, defined as following commands purposefully. Results: We included 194 consecutive TH-treated PCAS patients; mean age was 57 +/- 16 years; 59% were male; 40% had an initial shockable rhythm. Mean cooling duration was 24 +/- 8 h and mean rewarming time was 14 +/- 13 h. Survival to discharge was 44%, with 78% of these discharged with a good neurologic outcome. Of the 85 patients who awakened, median time to awakening was 3.2 days (IQR 2.2, 4.5) post-cardiac arrest. Median time to awakening for a patient discharged in good neurological condition was 2.8 days (IQR 2.0, 4.5) vs. 4.0 days (IQR 3.5, 7.6) for those who survived to discharge without a good neurological outcome (p = 0.035). There was no significant association between initial rhythm, renal insufficiency, paralytic use, post-arrest seizure, or location of arrest and time to awakening. Conclusion: In TH-treated PCAS patients, time to awakening after resuscitation was highly variable and often longer than three days. Earlier awakening was associated with better neurologic status at hospital discharge. (C) 2013 Elsevier Ireland Ltd. All rights reserved.