Western Journal of Emergency Medicine: Integrating Emergency Care with Population Health

Introduction: Prehospital triage challenges often lead to suboptimal choices and delayed treatment for stroke patients. The objective of the study was to evaluate whether a decision-support interface to assist in stroke triage to an appropriate hospital could reduce emergency medical technicians’ (EMT) mental workload.

Methods: This randomized crossover study was conducted between February and March 2025. Each participant completed two 12-minute simulated trials in randomized order: current dispatch orders without decision support and a decision-support interface. We assessed mental workload—the mental effort required to make hospital transport decisions under time pressure during prehospital stroke triage—using heart rate variability (HRV) metrics and the National Aeronautics and Space Administration Task Load Index (NASA-TLX). System usability was assessed using the System Usability Scale. The primary outcome was the root mean square of successive differences for each participant after completing the two trials. The secondary outcomes included the differences of NASA-TLX, System Usability Scale, and other heart rate variability parameters, including mean R-R interval (meanRR), mean heart rate, percentage of successive R-R intervals that differ by more than 50 milliseconds, low-frequency power (LF), high-frequency (HF) power, and the LF/HF ratio. Subgroup analyses examined differences by sex, education, age, and years of service.

Results: A total of 35 emergency medical technician (EMT)-intermediate participants (mean age, 27.5 [5.3] years) completed the study. For the primary outcome, the root mean square of successive differences increased significantly (28.1 [13.0] vs 32.4 [13.6] milliseconds; mean difference, 4.3 milliseconds [95% CI, 1.57–6.99]; P < .01), indicating reduced mental workload when the participants used the decision-support interface. For the secondary outcomes, mean heart rate (77.5 [8.6] vs 73.8 [10.6], P < .01) decreased, mean R (784.2 [89.5] vs 808.9 [87.3], P < .01) increased, and HF power (370.1 [291.7] versus 482.6 [433.9], P = .02) increased, suggesting reduced mental workload when the participants used the decision-support interface. The mental demand scores in NASA-TLX decreased from 62.5 (14.6) to 35.5 (17.0). Emergency medical technicians with 1.0–1.5 years of service reported higher System Usability Scale scores than those with 1.5–3.0 years (84.4 versus 71.3, P = .02), and 82.9% of participants rated the system as acceptable (System Usability Scale score ≥ 70).

Conclusion: This study demonstrated that integrating a web-based decision-support interface effectively reduces mental workload and psychological stress among EMTs in stroke triage.