Haemodynamic Changes in Adult Patients Transported in Emergency Medical Helicopters. A Systematic Review

Objective: Patients transported by Helicopter Emergency Medical Services (HEMS) suffer a series of haemodynamic changes, mainly in terms of blood pressure, heart rate, and oxygen saturation, which worsen at different stages of the flight. The aim of this study was to identify haemodynamic changes in adult patients transported by the Helicopter Emergency Medical Service.

Methods: A systematic review of studies published between January 2013 to April 2023 was conducted following the PRISMA 2020 guidelines criteria in the Pubmed, Scopus and Web of Science electronic databases. Methodological quality was assessed using the critical appraisal tool for non-randomised studies of the Joanna Briggs Institute (JBI). The followed protocol has been registered in the International Prospective Register of Systematic Reviews (PROSPERO) with code CRD4202222355798. Two independent reviewers read and extracted the information of the studies.

Results: Eight studies were included in the review, which showed significant haemodynamic changes during transport by HEMS. All studies recorded readings at three points of the mission: pre-flight, in-flight, and post-flight. The greatest change in physiological variables is visible in oxygen saturation, during the in-flight phase, with a decrease in this value. Blood pressure mainly increased in various phases of the mission, especially in the in-flight phase. Heart rate also changed across the mission phases, mainly in the pre-flight and post-flight phases, increasing and decreasing during the flight.

Conclusion: Patients transported by helicopter undergo haemodynamic changes during the different stages of evacuation (pre-flight, in-flight, and post-flight). However, there is a need for further studies on helicopter transport of patients due to the paucity of publications on this topic.