A recent analysis published in the Emergency Medicine Journal suggests that pre-hospital care provided by air ambulance services, known as Helicopter Emergency Medical Services (HEMS), may increase survival rates for patients with major trauma. The study focused on data from a regional HEMS team serving Kent, Surrey, and Sussex in South East England between 2013 and 2022.
Researchers examined outcomes for 3,225 trauma patients who received care from this HEMS service. Using statistical methods to adjust for case-mix and predict survival within 30 days of injury, they found that 2,125 patients survived beyond 30 days after their incident. This equates to an observed survival rate of 85%, compared to an expected rate of 81%. The difference translates to approximately five additional survivors per hundred cases, or up to 115 extra lives saved annually based on average patient volumes.
The analysis identified that patients most likely to benefit were those with severe injuries and a moderate (25-45%) predicted probability of survival; in this group, 35% unexpectedly survived past 30 days. Among those with less than a 50% chance of survival due to the severity of their injuries, the unexpected survival rate was even higher at 39%.
Key factors linked to unexpected survival included younger age and a higher initial Glasgow Coma Scale score—a tool used to assess consciousness after brain injury. Additionally, pre-hospital emergency anaesthesia—an induced coma performed by advanced care teams such as HEMS—was independently associated with better-than-expected outcomes.
In cases involving traumatic cardiac arrest (when the heart stops after severe injury), out of 1,316 patients attended by HEMS teams, return of spontaneous circulation was achieved en route to hospital in 356 cases (27%). Of these, data showed that one quarter survived beyond thirty days. The probability of restoring heartbeat increased by six percent each year during the study period.
The researchers note that these results reflect excess survival compared with modelled predictions rather than direct causality from HEMS intervention. They caution that assumptions about consistent performance and patient mix over time may not always hold true.
Despite these limitations, the authors state: "These findings provide supportive evidence for continued investment in HEMS, particularly for severely injured patients, though comparative studies with alternative care pathways are needed to establish causal effectiveness." They add that their findings demonstrate "the potential magnitude of clinical benefit, consistent with previous economic and social benefits demonstrated in previous studies."
