Helicopter Emergency Ambulance Service (HEAS) Transfer: An Analysis of Trauma Patient Case-Mix, Injury Severity and Outcome

Abstract

Ann R Coll Surg Engl 2007; 89: [513][514][515][516] 513 Helicopters were used very successfully for the transfer of wounded soldiers from the battlefields in the Korean and Vietnam wars and this model of patient transfer was then put into use in a civilian setting, initially in the US. In 1987, the first helicopter-based ambulance service in the UK was introduced in the Greater London region. 1Although this service carries an emergency physician as crew, it is unique in that respect. All other 15 dedicated HEAS providers in the UK are usually manned by one pilot and two paramedics. Advanced trauma and life-support (ATLS) teaching is that there are three peaks of mortality following major trauma. An early peak is due to patients who will die immediately with fatal injuries, a second peak of patients who will die in the 60 min following trauma and a third peak representing patients who will die of delayed complications of their injuries such as organ failure and sepsis. The second peak of mortality within 60 min of injury (the so-called 'golden hour' in ATLS teaching) represents the patients for whom rapid transfer to an emergency medical care facility from the scene of injury is potentially life-saving. 3The perceived benefit of helicopter transfer is the faster speed of transfer to hospital. This will maximise the proportion of the 'golden hour' spent in a hospital setting where potentially reversible conditions such as tension pneumothorax or cardiac tamponade can be treated. The most commonly used helicopter for HEAS in the UK is the Eurocopter 'Bolkow' 105, 2 which has a maximum speed of 252 km/h, clearly faster than ground ambulance. However, when factors such as mobilisation time, weather conditions, ease of access and the availability of helipad for landing at destination hospitals is considered, quicker transfer by helicopter is not always guaranteed. Many studies have found that patient transfer by helicopter is often not faster than by ground ambulance transfer overall except when large distances (over 45 km) are involved or when roads are poor or traffic conditions bad. These studies have questioned which

Retrospective review of injury severity, interventions and outcomes among helicopter and nonhelicopter transport patients at a Level 1 urban trauma centre

“…[15][16][17][18][19][20][21] A study from a single institution in Great Britain of 156 injured patients with a mean ISS of 12 transported by helicopter reported that 45 patients were discharged within 24 hours. 22 This ISS was much lower than the mean ISS for the patients transported by helicopter in the present study and was more comparable to that of the patients transported by ground ambulance. A large meta-analysis of 22 studies with 37 350 patients by Bledsoe and colleagues 23 noted that 60% of patients had an ISS of 15 or less and that 24% were discharged within 24 hours.…”

Helicopter emergency medical rescue for the traumatized: experience in the metropolitan region of Campinas, Brazil

“…A study by Melton et al, involving three services of aeromedical rescue in the England countryside, showed an average ISS of 12 among their patients, 41% of them having been discharged directly from the emergency department (mean ISS of 1 to the latter group) 28 . Shatney et al conducted a retrospective analysis of 947 patients taken by AR to a trauma center in California over a period of ten years and found an average ISS of 8.9, only 148 of them (15.6% ) having ISS > 15 29 .…”

An analysis of patients transported by a private helicopter emergency medical service in South Africa

“…A HEMS operation is usually only faster over distances >45 km, in poor road conditions and when traffic conditions are congested. [12] The majority of the patients transported were adult males. This appears to be in line with international trends, although many studies have only included patients aged >15 years.…”