Epidemiology and outcomes in patients with out-of-hospital cardiac arrest without coma after return of spontaneous circulation: a multicentre cohort study

BACKGROUND: In clinical practice, we encounter patients with out-of-hospital cardiac arrest (OHCA) without coma after return of spontaneous circulation (ROSC). However, the epidemiology, characteristics and outcomes in this population remain unclear. The primary aim was to describe the epidemiology, characteristics and outcomes of patients with OHCA who did not experience coma after ROSC. The secondary aim was to identify factors associated with survival and good functional outcomes in this patient population. METHODS: This was a secondary analysis of the data from the Japan Association for Acute Medicine (JAAM)-OHCA Registry. Adult patients with OHCA without coma (Glasgow Coma Scale (GCS) Score ≥8) after ROSC between June 2014 and December 2019 were included. The primary endpoint was 30-day survival with good functional outcomes (Cerebral Performance Category Score of 1-2). Multivariable logistic regression analysis with a generalised estimating equation was performed to examine the factors associated with 30-day survival with good functional outcomes. RESULTS: During the study period, 57 754 patients with OHCA were enrolled in the JAAM-OHCA Registry, of which 874 (1.5%) adult patients without coma after ROSC were analysed. Among them, the proportion of patients with 30-day survival with good functional outcomes was 76.0% (n=664), and the 30-day survival rate was 86.4% (n=755). Multivariable analysis revealed that younger age, witnessed cardiac arrest, shockable rhythms at the scene, GCS Motor Response (GCS-M) Score of 5 or 6 after ROSC, lower lactate levels and higher pH levels (pH≥7.10) were associated with 30-day survival with good functional outcomes. CONCLUSIONS: Even among the patients with OHCA who achieved ROSC without coma, approximately a quarter of patients had poor functional outcomes. Older age, non-witnessed cardiac arrest, non-shockable rhythms at the scene, lower GCS-M Score after ROSC, higher lactate levels and lower pH levels predicted poorer outcomes.