Identifying clinical phenotypes of injured patients who meet Air Medical Prehospital Triage (AMPT) score criteria for helicopter transport.

Abstract

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. 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. 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. 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;00: 00-00. Copyright © 2026 Wolters Kluwer Health, Inc. All rights reserved.). Prognostic; Level IV.