Interleukin-6 as a Potential Predictor of Neurologic Outcomes in Cardiac Arrest Survivors Who Underwent Target Temperature Management.

Abstract

Serum interleukin-6 (IL-6) is a cytokine released in response to an inflammatory stimulus or tissue injury. IL-6 levels are known to increase in patients with brain injury. We investigated the neurologic outcomes associated with serum IL-6 levels in out-of-hospital cardiac arrest (OHCA) survivors who underwent target temperature management (TTM). This was a prospective single-center observational study from October 2018 to November 2019 in a cohort of 45 patients. Serum inflammatory markers (IL-6, C-reactive protein, white blood cells) were determined in samples obtained immediately and at 24, 48, and 72h after the return of spontaneous circulation (ROSC). Poor neurologic outcome, defined as Cerebral Performance Category 3-5 at 3months after cardiac arrest, was the primary outcome. Among 45 patients enrolled in this study, 25 (55.6%) patients showed a poor neurologic outcome. IL-6 levels were significantly higher in the poor neurologic outcome group immediately (IL-60) after ROSC. The area under the curve (AUC) value of IL-60 was the highest among those of serum IL-6, CRP, and WBC at each time point. The IL-6 levels for predicting poor neurologic outcome had a sensitivity of 75.0%, with 80% specificity at IL-60. The AUC of IL-60 was 0.810 (95% confidence interval 0.664-0.913), with a cutoff value of 346.7 pg mL-1. Serum IL-6 level immediately after ROSC was a highly specific and sensitive marker for the 3-month poor neurologic outcome, and may be a useful early predictive marker of neurologic outcome in OHCA survivors treated with TTM.