Chest. 2022 Mar 19:S0012-3692(22)00491-3. doi: 10.1016/j.chest.2022.02.056. Online ahead of print.
BACKGROUND: Targeted temperature management (TTM) is currently the only treatment with demonstrated efficacy in attenuating the harmful effects on the brain of ischemia-reperfusion injury after cardiac arrest. However, whether TTM is beneficial in the subset of patients with in-hospital cardiac arrest (IHCA) remains unclear.
RESEARCH QUESTION: Is TTM at 33°C associated with better neurological outcomes after IHCA) in a non-shockable rhythm, compared to targeted normothermia (TN, 37°C)?
STUDY DESIGN AND METHODS: We performed a post hoc analysis of data from the published Targeted Temperature Management for Cardiac Arrest with Nonshockable Rhythm (HYPERION) randomized controlled trial in 584 patients. We included the 159 patients with IHCA; 73 were randomized to 33°C and 86 to 37°C. The primary outcome was survival with a good neurological outcome (Cerebral Performance Category [CPC] score 1 or 2) on day 90. Mixed multivariable adjusted logistic regression analysis was performed to determine whether survival with CPC 1 or 2 on day 90 was associated with type of temperature management after adjustment on baseline characteristics not balanced by randomization.
RESULTS: Compared to TN for 48 h, hypothermia at 33°C for 24 h was associated with a higher percentage of patients who were alive with good neurological outcomes on day 90 (16.4% vs. 5.8%; P=0.03). Day-90 mortality was not significantly different between the two groups (68.5% vs. 76.7%; P=0.24). By mixed multivariable analysis adjusted on the CAHP score and circulatory shock, hypothermia was significantly associated with good day-90 neurological outcomes (2.40 [1.17;13.03]; P=0.03).
INTERPRETATION: Hypothermia at 33°C was associated with better day-90 neurological outcomes after IHCA in a non-shockable rhythm, compared to TN. However, our limited sample size resulted in wide confidence intervals. Further studies of patients after cardiac arrest from any cause, including IHCA, are needed.