title: Time to awakening and neurologic outcome in therapeutic hypothermia-treated cardiac arrest patients.
abstract: BACKGROUND
  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±8h and mean rewarming time was 14±13h. 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Emergency Medicine, Center for Resuscitation Science, University of Pennsylvania, United States.
authors.forename: Anne V
authors.initials: AV
authors.lastname: Grossestreuer
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Abella
authors.forename: Marion
authors.initials: M
authors.lastname: Leary
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Perman
authors.forename: Barry D
authors.initials: BD
authors.lastname: Fuchs
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Kolansky
authors.forename: Marie E
authors.initials: ME
authors.lastname: Beylin
authors.forename: David F
authors.initials: DF
authors.lastname: Gaieski
mesh_terms: D001831:Body Temperature; D005260:Female; D006323:Heart Arrest / Q000401:mortality / Q000628:therapy*; D006801:Humans; D007036:Hypothermia, Induced; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
keywords: Cardiac arrest; Neuroprognostication; Sudden death; Targeted temperature management; Therapeutic hypothermia