Helicopter emergency medical service inter-facility transfer: a retrospective study on an urban case-mix
Background
Helicopter emergency medical services are popular rescue systems despite inconsistent evidence in the scientific literature to support their use for primary interventions, as well as for inter-facility transfer. There is little research about inter-facility transfer by helicopter emergency medical services, hence questions remain about the appropriateness of this method of transport. The aim of this study was to describe a case-mix of operational and medical characteristics for inter-facility transfer activity of a sole helicopter emergency medical services base, and identify indicators of over-triage.
Methods
This is a retrospective study on helicopter emergency medical services inter-facility transfer over 36 months, from January 1st 2013 to December 31st 2015. Medical and operational data from the database of the Emergency Department of Lausanne University Hospital which provides the emergency physicians for this helicopter base were reviewed. It included distance and time of flight transport, type of care during flight, and estimated distance of transport if conducted by ground to allow benchmarking. Limitation: the reason emergency physician within the hospital requested an helicopter rather than an ambulance is not collected in the medical files and therefore is not known.
Results
There were 2194 HEMS missions including 979 IFT (44.6%). Most transfers involved adults (>17 years old; 799 patients, 81.6%). Forty patients (4.1%) were classified by the physician on board as having benefitted from resuscitation or life-saving measures performed in flight, 615 (62.8%) from emergency treatment and 324 (33.1%) from simple clinical examination. The median distance by air between hospitals was 35.4 km. The estimated median distance by road was 47.7 km. The median duration time from origin to destination by air was 12 min. At 48 hours, the majority of patients were hospitalized in intensive care unit regardless of the type of care received.
Conclusions
This case-mix of inter-facility transfer by helicopter emergency medical services presents a high severity. There are many signs in favour of over-triage. We propose to use indicators such as the patient condition, geography, and medical competences available aboard ground ambulances to help choosing whether helicopter emergency medical services is the most appropriate mean of transport to perform the transfer regarding. We also suggest a medical decision within the dispatch to authorize the use of the helicopter for the transfer is also a possibility; all those options may contribute to reduce over-triage.
Other
This is the first study on a global inter-facility transfert by helicopter emergency medical services; previous studies would only concentrate on cardiac arrest or trauma. This work may not be applicable to other emergency medical services regarding the geography and medical competences available on ground ambulances, but we hope this will stimulate new research on that topic; we need data to allow benchmarking and therefore be able to propose guidelines.
