The effect of compositions of emergency medical technician teams on the outcomes of patients with out‑of‑hospital cardiac arrests
Pin‑Hui Fang, Ching‑Chi Lee, Chien‑Hsin Lu, Chih‑Hao Lin
Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Tainan, Taiwan.
Graduate Institute of Medical Sciences, College of Health Sciences, Chang Jung Christian University, Tainan, Taiwan, Tainan, Taiwan.

Abstract
Background: Emergency medical technicians (EMTs) as a team provide prehospital care for patients with out‑of‑hospital cardiac arrest (OHCA). EMT‑paramedics (EMTPs) could provide advance life supports for OHCAs. However, the evidence regarding the effect of compositions of EMT teams on the outcome of OHCAs is insufficient.
Methods and Materials: A retrospective cohort of non‑traumatic adults with OHCAs from January 2014 to December 2016 in Tainan, Taiwan was established. The outcomes included ever řeṱ.řǹ .f šṗ.ǹṱaǹe..š c.řc.ĺaṱ..ǹ (ROSC), a sustained (≥20 min) ROSC, and a 24‑hour ROSC. The EMT‑P ratio was defined as the proportion of the EMT‑P number among all of the EMT team. A multivariate regression was examined to overcome the confounding factors linked to the impact of EMT‑P ratio.
Results: Of 1,405 OHCAs, those having ever ROSC, a sustained ROSC, or a 24‑hour ROSC accounted for 27.8% (391 patients), 26.3% (370), or 20.4% (286), respectively. The EMT‑P ratio was striated as four groups: 0‑33%, 142 patients; 50%, 648; 66.7–75.0%, 101; and 100%, 514. A significant positive trend of ever ROSC, a sustained ROSC, or a 24‑hour ROSC was evidenced (all ř=1.00, P=0.01), as the EMT‑P ratio increased. In the multivariate regression, a significant beneficial influence of the EMTP ratio group of 66.7‑75.0% on ever ROSC was observed (adjusted hazard ratio [aHR], 1.45; 95% confidence interval [CI], 1.11‑1.89), compared to the group of 0‑33%. A significant beneficial influence of the EMT‑P ratio group of 50% (aHR, 1.63; 95% C.I., 1.04‑2.55) or that of 66.7‑75.0% (aHR, 1.46; 95% C.I., 1.12‑1.91) on the sustained ROSC was observed, compared to the group of 0‑33%.
Conclusions: The increased EMT‑P ratio was independently associated with the higher proportion of ever ROSC and a sustained ROSC. EMT‑P training programs could be promoted to better the outcomes of OHCAs.

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