Scene time interval and good neurological recovery in out-of-hospital cardiac arrest.

OBJECTIVES

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 (4-7min) 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.