It is unclear whether scene time interval (STI) is associated with better neurological recovery in the emergency medical service (EMS) system with intermediate service level.Methods:
Adult out-of-hospital cardiac arrest (OHCA) patients with presumed cardiac etiology (2012 to 2014) were analyzed, excluding patients not-resuscitated, occurred in ambulance/medical/nursing facility, unknown STI or extremely longer STI (> 60 min), and unknown outcomes. STI was classified into short (0.0–3.9 min), middle (4.0–7.9 min), long (8.0–11.9 min), and very-long (12.0–59.9 min), respectively. The end point was a good cerebral performance category (CPC) 1 or 2. Multivariable logistic regression by STI group (reference = short) was performed to calculate adjusted odds ratios (AORs) with 95% confidence intervals (95% CIs) for outcomes with or without interaction term (STI * prehospital return of spontaneous circulation, (PROSC)).Results:
Of 79,832 OHCA patients, 41,054 cases were analyzed; good CPC in the short (3.0%), middle (3.2%), long (3.0%), and very-long (2.9%) STI groups were similar, respectively (p = 0.55). The AORs (95% CI) for good CPC in the final model without interaction term were 0.74 (0.58–0.95) for the middle, 0.51 (0.39–0.67) for the long, and 0.45 (0.33–0.61) for the very-long STI group (reference = short STI). The AORs in PROSC group were 1.18 (0.97–1.44) for middle STI group, 0.72 (0.57–0.92) for long group, and 0.56 (0.42–0.77) for very-long group. The AORs in non-PROSC group were 1.22 (1.06–1.40) for middle STI group, 0.82 (0.70–0.96) for long group, and 0.70 (0.57–0.85) for very-long group.Conclusion:
The middle STI (4–7 min) was associated with the highest odds of neurological recovery for patients who could not be restored in the field. The STI may be a clinically useful predictor of good neurology outcome in victims of cardiac arrest.