Thermoregulation in post-cardiac arrest patients treated with targeted temperature management

Evaluate the relationship between heat generation during rewarming in post-cardiac arrest patients receiving targeted temperature management (TTM) as a surrogate of thermoregulatory ability and clinical outcomes.

This is a prospective observational single-centre study conducted at an urban tertiary-care hospital. We included post-cardiac arrest adults who received TTM via surface cooling device between April 2018 and June 2019.

Patient heat generation was calculated by multiplying the inverse of the average machine water temperature with time to rewarm to 37 °C and standardized in two ways to account for target temperature variation: (1) divided by number of degrees between target temperature and 37 °C, and (2) limited to when patient was rewarmed from 36 °C to 37 °C. The primary outcome was poor neurologic status, defined as Cerebral Performance Category (CPC) score 3-5, and the secondary outcome was 30-day survival. Sixty-six patients were included: 45 (68%) had a CPC-score of 3-5 and 23 (35%) were alive at 30 days. Besides initial rhythm and arrest downtime, baseline characteristics were similar between outcomes. Heat generation was not associated with poor neurological outcome (CPC 3-5: 6.6 [IQR: 6.1, 7.4] versus CPC 1-2: 6.6 [IQR: 5.7, 7.6], p = 0.89) or survival at 30 days (non-survivors: 6.6 [IQR: 6.6, 7.4] vs. survivors: 6.6 [IQR: 5.7, 8.0, p = 0.78]).

Heat generation during rewarming was not associated with neurologic outcomes. However, there was a relationship between poor neurological outcome and higher median water temperatures. Time to rewarm was prolonged in patients with poor neurological outcome.