Prehospital endotracheal intubation and return of spontaneous circulation in out-of-hospital cardiac arrest patients: a retrospective cohort study based on prehospital emergency registry data

Background The optimal airway strategy during out-of-hospital cardiac arrest (OHCA) remains uncertain. This study investigated the association between prehospital endotracheal intubation (ETI) and return of spontaneous circulation (ROSC) using a regional emergency medical services registry. Methods This retrospective cohort study analyzed 6,162 adult non-traumatic OHCA patients treated by emergency medical services between October 2023 and November 2024. Patients were categorized into an ETI group ( n = 1,448) and a basic airway (BA) group ( n = 4,714). The primary outcome was prehospital ROSC. Long-term survival and neurological outcomes were not available in the registry. Multivariable logistic regression and propensity score-matched sensitivity analysis were used to evaluate the association between ETI and ROSC while accounting for measured confounders. Airway strategy was selected by on-scene physicians during routine EMS care, and rhythm-stratified unadjusted analyses were performed to describe whether the ETI-ROSC association differed by initial rhythm category. Results ROSC occurred more frequently in the ETI group than in the BA group (21.1% vs. 3.8%, P < 0.001). In multivariable analysis, ETI was strongly associated with ROSC (OR = 7.61, 95% CI: 6.07–9.53, P < 0.001). Shockable initial rhythm (OR = 5.42, 95% CI: 3.80–7.74, P < 0.001) and defibrillation (OR = 1.82, 95% CI: 1.37–2.42, P < 0.001) were also positively associated with ROSC, whereas longer response time and epinephrine administration were negatively associated with ROSC. In 1:1 propensity score-matched analysis, the association between ETI and ROSC remained significant (OR = 6.33, 95% CI: 4.72–8.47, P < 0.001). Rhythm-stratified analyses showed that the unadjusted association was strongest in non-shockable and other/unknown rhythm strata and was not statistically significant in the shockable rhythm stratum. Conclusions In this retrospective prehospital registry cohort, ETI during OHCA resuscitation was strongly associated with higher ROSC rates. Because airway timing relative to collapse and ROSC, survival to discharge, and neurological outcomes were not captured, these findings should be interpreted as an association with immediate resuscitation success rather than evidence of a causal survival benefit. The observed association may also reflect physician selection of airway strategy and other unmeasured resuscitation factors, and should therefore be considered hypothesis-generating. Clinical trial number Not applicable.