Volume versus outcome: More emergency medical services personnel on-scene and increased survival after out-of-hospital cardiac arrest

Abstract

a b s t r a c tBackground and aim: : The large regional variation in survival after treatment of out-of-hospital cardiac arrest (OHCA) is incompletely explained. Communities respond to OHCA with differing number of emergency medical services (EMS) personnel who respond to the scene. The effect of different numbers of EMS personnel on-scene upon outcomes is unclear. We sought to evaluate the association between number of EMS personnel on-scene and survival after OHCA. Methods: We performed a retrospective review of prospectively collected data on 16,122 EMS-treated OHCA events from December 1, 2005 to May 31, 2007 from a combined population over 21 million people residing in an area of over 33,000 square miles in Canada and the United States. Number of EMS personnel on-scene was defined as the number of EMS personnel who responded to the scene of OHCA within 15 min after 9-1-1 call receipt and prior to patient death or transport away from the scene. Associations with survival to hospital discharge were assessed by using generalized estimating equations to construct multivariable logistic regression models. Results: Compared to a reference number of EMS personnel on-scene of 5 or 6, 7 or 8 EMS personnel onscene was associated with a higher rate of survival to hospital discharge, adjusted odds ratio [OR], 1.35 (95% CI: 1.05, 1.73). There was no significant difference in survival between 5 or 6 personnel on-scene versus fewer. Conclusion: More EMS personnel on-scene within 15 min of 9-1-1 call was associated with improved survival of out-of-hospital cardiac arrest. It is unlikely that this finding was mediated solely by earlier CPR or earlier defibrillation.

Impacts of Emergency Medical Technician Configurations on Outcomes of Patients with Out-Of-Hospital Cardiac Arrest

“…The number and proportion of EMTs on the scene for OHCA resuscitation has remained a modifiable factor linked to ROSC [13][14][15][16][17]. Until now, the influences of the EMT configuration on outcomes of OHCA patients remain controversial.…”

“…Until now, the influences of the EMT configuration on outcomes of OHCA patients remain controversial. Sam A. Warren et al and Kajino et al both indicated that the number of EMTs was associated with survival rate and even neurological outcome in patients with OHCA [13,14], whereas Hagiwara S. et al and Eschmann NM et al found opposite results [15,16]. In our cohort, the association of EMT number and patient outcomes, in terms of sustained ROSC, survival to discharge, and favorable neurologic status at discharge, were trivial after adjustment for all the independent predictors of sustained ROSC.…”

“…Since the level of EMTs differs in the resuscitation they can provide, the number and level of EMTs in the field are considered crucial determinants for the outcomes of OHCA patients. However, the impact of the EMT configuration on patient survival remains debated [13][14][15][16][17].…”

“…Numerous previous reports only discussed EMT numbers [13,14,16], whereas other investigations took both total EMT number and the contribution of EMT-Ps as exposure variables [15,17]. The EMT-P is capable of administering more advanced management [12] and is more confident in performing clinical activities and tasks [18].…”

Variation in Survival After Out-of-Hospital Cardiac Arrest Between Emergency Medical Services Agencies

“…19 These covariates were chosen a priori based on their known associations with survival from prior studies of OHCA, biologic plausibility, and adequate ascertainment. 11, [15][16][17][18][19][20][21][22][23]…”