In Japan, Emergency Life-Saving Technicians (ELSTs) cannot independently perform diagnostic ultrasound under the current legal framework. If ELST-performed focused assessment with sonography for trauma (FAST) is to be introduced in the prehospital setting, technical feasibility during ambulance motion and the viability of remote physician observation must be established.

The study aimed to evaluate the feasibility of ELST-performed FAST in moving ambulances in a controlled manikin setting and to descriptively assess an integrated monitoring system for remote observation.

A prospective observational pilot study was conducted at the Okayama City Fire Department Training Center in Okayama Prefecture, Japan on March 3, 2025. Twenty ELSTs completed structured e-learning and a hands-on workshop using standardized FAST/ER FAN manikins. Participants performed FAST under three fixed-order conditions: stationary (STOP), 15km/hour, and 30km/hour on a 250-m circular course. The primary outcome was the total Task-Specific Checklist (TSC) score (0-24 points). Secondary outcomes were examination time, site-specific TSC subscores, inter-rater agreement, and a descriptive assessment of transmitted image quality by two specialist physicians.

All 20 ELSTs completed the study. Mean total TSC scores were 23.4 (SD = 0.8) in the STOP condition, 23.4 (SD = 0.9) at 15km/hour, and 23.7 (SD = 0.6) at 30km/hour. Compared with the STOP condition, the mean difference in total TSC score was 0.08 points (95% CI, −0.24 to 0.39; P for noninferiority < 0.001) at 15km/hour and 0.33 points (95% CI, −0.04 to 0.69; P for noninferiority < 0.001) at 30km/hour. Both moving conditions met the pre-specified noninferiority criterion relative to the STOP condition. Mean examination times were 36.7 (SD = 14.4) seconds in the STOP condition, 30.3 (SD = 9.8) seconds at 15km/hour, and 31.9 (SD = 14.8) seconds at 30km/hour. Inter-rater agreement for TSC scoring was moderate (weighted kappa, 0.56). Descriptive ratings suggested that transmitted image quality was generally favorable for remote review in this controlled setting.

In this controlled manikin-based pilot study, ELST-performed FAST was technically feasible during moderate ambulance motion, and remote physician observation was feasible. These findings may help inform staged prehospital ultrasound training and future clinical validation under legal and operational constraints.

Prehospital ultrasound (PHUS) assessments by physicians and non-physicians are performed on medical and trauma patients with increasing frequency. Prehospital ultrasound has been shown to be of benefit by supporting interventions.

Which patients may benefit from PHUS has not been clearly identified.

A multi-variable logistic regression analysis was performed on a previously created retrospective dataset of five years of physician- and non-physician-performed ultrasound scans in a Canadian critical care Helicopter Emergency Medical Service (HEMS). For separate medical and trauma patient groups, the a-priori outcome assessed was patient characteristics associated with the outcome variable of “PHUS-supported intervention.”

Both models were assessed (Likelihood Ratio, Score, and Wald) as a good fit. For medical patients, the characteristics of heart rate (HR) and shock index (SI) were found to be most significant for an intervention being supported by PHUS. An extremely low HR was found to be the most significant (OR=15.86 [95% confidence interval (CI), 1.46-171.73]; P=.02). The higher the SI, the more likely that an intervention was supported by PHUS (SI 0.9 to<1.3: OR=9.15 [95% CI, 1.36-61.69]; P=.02; and SI 1.3+: OR=8.37 [95% CI, 0.69-101.66]; P=.09). For trauma patients, the characteristics of Prehospital Index (PHI) and SI were found to be most significant for PHUS support. The greatest effect was PHI, where increasing ORs were seen with increasing PHI (PHI 14-19: OR=13.36 [95% CI, 1.92-92.81]; P=.008; and PHI 20-24: OR=53.10 [95% CI, 4.83-583.86]; P=.001). Shock index was found to be similar, though, with lower impact and significance (SI 0.9 to<1.3: OR=9.11 [95% CI, 1.31-63.32]; P=.025; and SI 1.3+: OR=35.75 [95% CI, 2.51-509.81]; P=.008).

In a critical care HEMS, markers of higher patient acuity in both medical and trauma patients were associated with occurrences when an intervention was supported by PHUS. Prospective study with in-hospital follow-up is required to confirm these hypothesis-generating results.

O’DochartaighD , DoumaM , AlexiuC , RyanS , MacKenzieM . Utilization Criteria for Prehospital Ultrasound in a Canadian Critical Care Helicopter Emergency Medical Service: Determining Who Might Benefit. Prehosp Disaster Med. 2017;32(5):536–540.