Effects of Variation in Temperature Management on Cerebral Performance Category Scores in Patients Who Received Therapeutic Hypothermia Post Cardiac Arrest

Aim: To assess differences in cerebral performance category (CPC) in patients who received therapeutic hypothermia post cardiac arrest by time to initiation, time to target temperature, and duration of therapeutic hypothermia (TH).

Methods: A secondary data analysis was conducted using hospital-specific data from the international cardiac arrest registry (INTCAR) database. The analytic sample included 172 adult patients who experienced an out-of-hospital cardiac arrest and were treated in one Midwestern hospital. Measures included time from arrest to ROSC, arrest to TH, arrest to target temperature, and length of time target temperature was maintained. CPC was assessed at three points: transfer from ICU, discharge from hospital, and post discharge follow-up.

Results: Average age was 63.6 years and 74.4% of subjects were male. Subjects had TH initiation a mean of 94.4 min (SD 81.6) after cardiac arrest and reached target temperature after 309.0 min (SD 151.0). In adjusted models, the odds of a poor neurological outcome increased with each 5 min delay in initiating TH at transfer from ICU (OR=1.06, 95% C.I. 1.02-1.10). Similar results were seen for neurological outcomes at hospital discharge (OR=1.06, 95% C.I. 1.02-1.11) and post-discharge follow-up (OR=1.08, 95% C.I. 1.03-1.13). Additionally the odds of a poor neurological outcome increased for every 30 min delay in time to target temperature at post-discharge follow-up (OR=1.17, 95% C.I. 1.01-1.36).

Conclusion: In adults undergoing TH post cardiac arrest, delay in initiation of TH and reaching target temperature differentiated poor versus good neurologic outcomes. Randomized trials assessing the range of current recommended guidelines for TH should be conducted to establish optimal treatment protocols.