Paramedics can provide advanced life support (ALS) for patients with out-of-hospital cardiac arrest (OHCA). However, the impact of emergency medical technician (EMT) configuration on their outcomes remains debated. A three-year cohort study consisted of non-traumatic OHCA adults transported by ALS teams was retrospectively conducted in Tainan City using an Utstein-style population database. The EMT-paramedic (EMT-P) ratio was defined as the EMT-P proportion out of all on-scene EMTs. Among the 1357 eligible cases, the median (interquartile range) number of on-scene EMTs and the EMT-P ratio were 2 (2-2) persons and 50% (50%-100%), respectively. The multivariate analysis identified five independent predictors of sustained return of spontaneous circulation (ROSC): younger adults, witnessed cardiac arrest, prehospital ROSC, prehospital defibrillation, and comorbid diabetes mellitus. After adjustment, every 10% increase in the EMT-P ratio was on average associated with an 8% increased chance (adjusted odds ratio [aOR], 1.08; p < 0.01) of sustained ROSC and a 12% increase change (aOR, 1.12; p = 0.048) of favorable neurologic status at discharge. However, increased number of on-scene EMTs was not linked to better outcomes. For nontraumatic OHCA adults, an increase in the on-scene EMT-P ratio resulted in a higher proportion of improved patient outcomes.
Keywords: emergency medical technician; out-of-hospital cardiac arrest; paramedic; return of spontaneous circulation.