Introduction: Patients suffering a time-critical medical condition require rapid prehospital assessment and treatment and most often quick transportation to definitive care. This can be decisive for patient outcome. In order to minimize time from assessment to treatment, thus lowering mortality and morbidity, it is important to have a well-coordinated chain of care. The efficient use of Ground Emergency Medical Services (GEMS) and Helicopter Emergency Medical Services (HEMS) is essential in such a chain of care.

Objectives: The aim is to describe differences in mortality, morbidity, assessment and treatment of two time-critical conditions, traumatic brain injury (TBI) and acute myocardial infarction (MI), in patients assessed by GEMS and HEMS respectively.

Method: The project consists of a descriptive observational study and comparative cohort study. Inclusion criteria are patients considered to be suffering from TBI and acute MI, which are treated by GEMS or HEMS in the regions of Uppsala, Jämtland, Dalarna and Värmland.

Clinical significance: The results expect to be the basis for further studies aiming to optimize the utilization of GEMS and HEMS.