Difficult-to-transport cases and neurological outcomes of out-of-hospital cardiac arrest: A population-based nationwide study in Japan

Abstract

Aim

In Japan, emergency medical service personnel often have difficulty obtaining hospitals' acceptance of emergency cases owing to congestion in the emergency unit; such cases are called difficult-to-transport cases. Increased difficult-to-transport cases at a regional level may be associated with the prognosis of out-of-hospital cardiac arrest (OHCA). This study aimed to investigate the association between the proportion of difficult-to-transport cases at a regional level and neurological outcomes in patients with OHCA, using the nationwide Utstein database linked to ambulance records in Japan.

Methods

In this retrospective cohort study from 2017 to 2021 in Japan, the proportion of difficult-to-transport cases was calculated as the number of difficult-to-transport cases divided by the number of emergency calls in each district on each day. Patients with OHCA were categorized into no, low, and high difficult-to-transport cases groups. The primary outcome was a Cerebral Performance Category 1 or 2 at 1 month. The secondary outcome was transportation time intervals. Multivariate regression analyses were conducted to assess the association between difficult-to-transport cases and patient outcomes.

Results

Among 592,021 eligible patients, the no, low, and high difficult-to-transport case groups included 282,747 (48%), 155,167 (26%), and 154,107 (26%) patients, respectively. The high difficult-to-transport cases group was associated with decreased favorable neurological outcomes (adjusted odds ratio, 0.91; 95% confidence interval, 0.86–0.95) and longer total transportation time (difference, 4.1 min; 95% confidence interval, 3.8–4.4).

Conclusion

A higher proportion of difficult-to-transport cases was associated with poorer neurological outcomes and longer total transportation times in patients with OHCA.