Abstract
Objective This study sought to assess the impact of a helicopter emergency medical service (HEMS) capable of night operations. Methods This is a retrospective case review of all night HEMS missions attended by a charity air ambulance service in South East England over a 2-year period (October 1, 2013, to October 1, 2015). Results During the 2-year trial period, the HEMS service undertook a total of 5,004 missions and attended to 3,728 patients. Of these, 1,373 missions, or 27.4% of the total HEMS activity, were night missions. Night missions increased from year 1 (n = 617) to year 2 (n = 756). A mean of 1.9 missions per night were conducted, resulting in the treatment of 1.3 patients per night. A higher proportion of patients were transported to a major trauma center at night (64% vs. 51%, χ2 = 41.8, P < .0001). Weather conditions prevented HEMS from responding at night via air for 15% of the night operational hours. Conclusion A 2-year trial period of a night HEMS service in South East England showed the predicted activation rate, with a mean of 1.3 patients attended to per night. Patients transported to a major trauma center had a mean Injury Severity Score of 23. Further research is warranted to determine if the night HEMS service conveys a patient outcome benefit. Major trauma is a leading cause of serious morbidity and mortality.1,2 Advanced prehospital care can improve the outcome for major trauma patients.3,4 Kent, Surrey & Sussex Air Ambulance Trust (KSSAAT) delivers advanced prehospital care by deploying 2 doctor/paramedic teams by aircraft or response car. The 2 teams respond from 2 separate bases in South East England, 1 based in Surrey and 1 based in Kent. Historically, KSSAAT was operational between 0700 and 1900 hours 7 days per week. However, major trauma frequently occurs overnight, and the lack of a night helicopter emergency medical service (HEMS) was felt to be detrimental to enhanced patient care because no enhanced prehospital medical care was available overnight. Before any night HEMS service was available, KSSAAT undertook a prospective study in 2010 to explore the possible impact that a night HEMS service may have.5 This study showed the likely need of a night HEMS team being tasked 1.7 times per night during the hours of 1900 to 0700. The incidence of these predicted cases continued throughout the entire night period but with gradually decreasing frequency. Most nights of the week were predicted to have similar levels of activity with the exception of Saturday, which appeared to be the busiest night of the week. A high number of the cases identified resulted in the patient being transported to a major trauma center (MTC), indicating that HEMS activation may well have been warranted. Based on this study, KSSAAT made the decision to commit itself to exploring the options for night HEMS operations. This commitment was the start of a 3-year research, development, and training process, which culminated with the launch of a 2-year night HEMS operational trial on the night of September 26, 2013. At this point, KSSAAT became the first 24/7 helicopter-based HEMS in the United Kingdom. The purpose of this study is to review the activity, case mix, and demographics of the 2-year night HEMS trial period. We sought to compare the actual activity of the night HEMS service with the previously estimated need.