Do Lower Target Temperatures or Prolonged Cooling Provide Improved Outcomes for Comatose Survivors of Cardiac Arrest Treated With Hypothermia?
BACKGROUND
Optimal protocols for targeted temperature management are still unclear. This study investigated whether lower target temperatures and/or prolonged cooling could provide improved outcomes in comatose survivors of cardiac arrest.


METHODS AND RESULTS
This observational study was conducted using the prospectively collected targeted temperature management database in Hiroshima, Japan. Between September 2003 and September 2014, 237 patients treated with TTM after cardiac arrest were enrolled in this study. The target temperatures and durations were assigned by the treating physicians regardless of the patients' conditions. Favorable outcomes were defined as a cerebral performance category scale of 1 or 2 at the 90-day follow-up time point. The rate of favorable outcomes were similar between the patients whose protocols of target temperature were <34°C and ≥34°C (40% versus 35%, P=0.41), cooling durations were <28 and ≥28 hours (33% versus 44%, P=0.11), and rewarming durations were <28 and ≥28 hours (35% versus 41%, P=0.39). However, in patients treated with extracorporeal cardiopulmonary resuscitation, target temperatures <34°C were associated with more favorable outcomes (29% versus 8%, P=0.01). The cooling and rewarming durations >28 hours and target temperatures <34°C were associated with more frequent lethal arrhythmia, pneumonia, and/or bleedings.


CONCLUSIONS
Prolonged durations of cooling and rewarming ≥28 hours may not improve outcomes and may increase complications. Further studies are necessary to assess the hypothesis that target temperatures <34°C provide improved outcomes in patients treated with extracorporeal cardiopulmonary resuscitation.
['Kagawa|Eisuke|E|', 'Dote|Keigo|K|', 'Kato|Masaya|M|', 'Sasaki|Shota|S|', 'Oda|Noboru|N|', 'Nakano|Yoshinori|Y|', 'Miura|Katsuya|K|', 'Inoue|Ichiro|I|', 'Kihara|Yasuki|Y|']
D000368:Aged D001833:Body Temperature Regulation D016887:Cardiopulmonary Resuscitation D003128:Coma D005112:Extracorporeal Circulation D005260:Female D006323:Heart Arrest D006801:Humans D007036:Hypothermia, Induced D007564:Japan D008297:Male D008875:Middle Aged D012042:Registries D012189:Retrospective Studies D018570:Risk Assessment D012307:Risk Factors D013997:Time Factors D016896:Treatment Outcome
targeted temperature management cardiopulmonary resuscitation extracorporeal circulation heart arrest therapeutic hypothermia