Purpose: Patients who are successfully resuscitated following out‑of‑hospital cardiac arrest (OHCA) are still at a highrisk of neurological damage and death. Inflammation and brain injury are components of the post‑cardiac arrestsyndrome, and can be assessed by systemic interleukin 6 (IL‑6) and neuron‑specific enolase (NSE). Anti‑inflammatorytreatment with methylprednisolone may dampen inflammation, thereby improving outcome. This study aimed todetermine if prehospital high‑dose methylprednisolone could reduce IL‑6 and NSE in comatose OHCA patients.

Methods: The STEROHCA trial was a randomized, blinded, placebo‑controlled, phase II prehospital trial performedat two cardiac arrest centers in Denmark. Resuscitated comatose patients with suspected cardiac etiology wererandomly assigned 1:1 to a single intravenous injection of 250 mg methylprednisolone or placebo. The co‑primaryoutcome was reduction of IL‑6 and NSE‑blood levels measured daily for 72 h from admission. The main secondaryoutcome was survival at 180 days follow‑up.

Results: We randomized 137 patients to methylprednisolone (n = 68) or placebo (n = 69). We found reduced IL‑6levels (p < 0.0001) in the intervention group, with median (interquartile range, IQR) levels at 24 h of 2.1 pg/ml (1.0; 7.1)and 30.7 pg/ml (14.2; 59) in the placebo group. We observed no difference between groups in NSE levels (p = 0.22),with levels at 48 h of 18.8 ug/L (14.4; 24.6) and 14.8 ug/L (11.2; 19.4) in the intervention and placebo group, respec‑tively. In the intervention group, 51 (75%) patients survived and 44 (64%) in the placebo group.

Conclusion: Prehospital treatment with high‑dose methylprednisolone to resuscitated comatose OHCA patients,resulted in reduced IL‑6 levels after 24 h, but did not reduce NSE levels.