Identifying clinical phenotypes of injured patients who meet Air Medical Prehospital Triage (AMPT) score criteria for helicopter transport.
The journal of trauma and acute care surgery · 2026-04-24 · Observational study
Abstract
BACKGROUND: Air medical transport (AMT) has demonstrated a survival benefit for select patients. The Air Medical Prehospital Triage (AMPT) score identifies patients with a survival benefit from AMT. Patients with positive AMPT score may be heterogenous with different levels of benefit. Our objective was to identify phenotypes of injured patients with a positive AMPT score with differential benefits of AMT compared with ground emergency medical services. METHODS: Patients 16 years or above transported by AMT or ground emergency medical services from the scene (>3 and <40 miles) and met AMPT score criteria in the Pennsylvania Trauma Outcomes Study 2000-2017 were included. Patients were clustered using latent class analysis (LCA) and k-modes clustering. From the two class memberships, we then assessed the association between in-hospital survival and actual transport mode using multilevel generalized linear models, adjusting for demographics, injury characteristics, vital signs, and in-hospital variables. To validate our membership assignments, the same analysis was performed on separately on NTDB data. RESULTS: In total, 22,569 patients were included from the Pennsylvania Trauma Outcomes Study, with 7,607 (35%) actually undergoing AMT. LCA resulted in five phenotype classes. Among these, Class 2, composed of patients with physiological plus anatomic triage criteria and Glasgow Coma Scale (GCS)≤13, and Class 5, composed of a GCS≤13 plus abnormal respiratory rate, demonstrated profound survival benefit [aOR, 1.83 (1.41, 2.36) and 2.23 (1.76, 2.81)]. K-modes also resulted in five classes. Among these, Classes 2, 4, and 5 also composed of patients with physiological plus anatomic criteria, GCS≤13 and/or abnormal respiratory rate. These groups also demonstrated profound survival benefit [aOR, 1.85 (1.33, 2.59), 2.02 (1.49, 2.73) and 2.5 (1.97, 3.17)]. Replication in NTDB illustrated similar results. CONCLUSIONS: These findings suggest that patients with GCS≤13 and abnormal respiratory rate or physiological plus anatomic triage criteria should be prioritized in AMT use. ( J Trauma Acute Care Surg . 2026;101: 71-79. Copyright © 2026 Wolters Kluwer Health, Inc. All rights reserved.). LEVEL OF EVIDENCE: Prognostic; Level IV.