Point-of-Care Ultrasound in Helicopter Emergency Medical Services and Impact on Clinical Bedside Times

Abstract

Objective

Time constraints and concerns for delays in transport are often cited by helicopter emergency medical services (HEMS) providers as factors for not performing point-of-care ultrasound (POCUS). The objective of this study is to evaluate the impact of POCUS on clinical bedside times in HEMS transports.

Methods

This is a single-center, retrospective, observational cohort study of adult patients aged >18 years transported via HEMS from March 1, 2018 to April 7, 2023, at a single academic medical center who received a POCUS examination. Exclusion criteria were: patients aged <18 years of age and of vulnerable populations (e.g., prisoners, pregnant women), studies with missing data (e.g., medical record numbers), and studies which were not submitted for quality assurance. The POCUS group was matched to a cohort of patients transported in 2022 who did not receive POCUS. A linear regression model was fit to evaluate the effect of POCUS on clinical bedside time, adjusting for confounders. Covariates adjusted for included: age, sex, type of transfer (interfacility vs. scene), type of call (medical vs. scene), air vs. ground transport, red blood cell, vasopressor, or IV fluids administration, intubation, disposition, and specialty call (e.g., ECMO). Since the data for the control group was only for a single year, a second model was fit matching the same time-period for both groups. A sensitivity analysis was performed for each model.

Results

In total, 439 patients were included; 242 patients (55.1%) received POCUS and 197 patients (44.9%) had no POCUS performed. Overall mean clinical bedside time was 48 ± 33 minutes in the POCUS group versus 32 ± 23 minutes in the non-POCUS group. POCUS cases were more likely to be scene calls (39% vs. 14%), trauma cases (42% vs. 26%), were more likely to receive red blood cells (20% vs. 7.6%), vasopressors (44% vs. 16%), or more likely intubated in the field (48% vs. 28%). When evaluating the entire cohort, patients exposed to POCUS experienced times 21% longer than those in the non-POCUS group (β = 0.19, 95% CI 0.09-0.29, p <0.001; R² = 56.6%). However, when considering only the period-matched cohort (2022, n=290), no significant difference in clinical beside times was observed in the POCUS group (β = 0.09, 95% CI -0.05-0.23, p = 0.23; R² = 56.0%). In this model, a nonsignificant increase in time was estimated to be two minutes, with the upper limit of confidence at five minutes.

Conclusions

In the entire cohort, patients with HEMS-performed POCUS exam had significantly longer bedside times. However, these patients were also more likely to be scene calls, trauma cases, and more critically ill compared to non-POCUS cases. When evaluating a period-matched cohort of patients in 2022, no significant differences in cases where POCUS was utilized was observed. This may be due to improved provider comfort and efficiency performing studies and/or improved integration of POCUS into the HEMS environment.