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

BACKGROUND

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.

OBJECTIVE

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).

METHODS

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 72 h after the return of spontaneous circulation (ROSC). Poor neurologic outcome, defined as Cerebral Performance Category 3-5 at 3 months after cardiac arrest, was the primary outcome.

RESULTS

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.

CONCLUSIONS

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.