Risk factors for adverse incidents in patients during helicopter emergency medical services transports: a scoping review

INTRODUCTION: Risk management is essential for maintaining the quality and safety of helicopter emergency medical services (HEMS) worldwide. The scarcity of consolidated evidence on HEMS-specific risk factors hinders effective early prevention and risk mitigation. This scoping review aimed to summarize and map current research progress on risk factors for adverse incidents in patients during HEMS transports. METHODS: This review was performed following the PRISMA-ScR guidelines. Five electronic databases (PubMed, Web of Science Core Collection, ProQuest, CNKI, Wanfang Databases) were searched from January 1, 2006 to April 9, 2026. Studies in English or Chinese that focused on risk factors during HEMS were included. Two independent reviewers carried out study selection, quality assessment and data extraction. RESULTS: A total of 48 peer-reviewed studies were included. The results revealed that risk factors varied across man, machine, environment, management (MMEM) system. Patient factors included baseline characteristics, disease-related characteristics, demand for medical interventions, and special patient populations. Crew factors encompassed operational execution, decision-making judgement, physiological and psychological factors, and team collaboration. Machinery factors comprised medical equipment and consumables, mission support and service systems, and aircraft platforms and airworthiness. Environment factors included natural environment factors, environment temporal characteristics, aircraft environment factors, and ground environment factors. Management factors involved system, procedure, culture, resource allocation, team management, and technical support. CONCLUSIONS: The findings highlighted the multifaceted risk factors during HEMS transports. This synthesis underscores that effective risk mitigation requires a systematic approach addressing patient, crew, machinery, environment, and management elements. Future efforts should focus on developing individualized, patient-centered risk assessments tailored to specific acute conditions. Enhancing preparedness in these key areas is crucial for the early prevention of adverse events and for ultimately improving the safety and quality of care for HEMS.