This Emergency Response May Be Saving More Lives Than Expected

Air ambulances may be tipping the balance between life and death—saving more trauma patients than statistics say should survive.

Air ambulance pre-hospital care (HEMS) may improve the chances of surviving a critical injury, according to a new analysis of survival data from a regional service in South East England. The study, published today in Emergency Medicine Journal, found that HEMS care was associated with five more survivors per 100 major trauma patients than would normally be expected.

Why the Benefits of HEMS Have Been Hard to Measure

Researchers note that international evidence on whether Helicopter Emergency Medical Services improve survival after major trauma has been difficult to interpret. Past studies have used different methods, included too few patients, and lacked consistent definitions of outcomes. As a result, it has remained unclear which trauma patients are most likely to benefit from these services.

Studying Trauma Outcomes Over Nearly a Decade

To better understand the impact, the research team reviewed outcomes for 3,225 trauma patients who received pre-hospital care from a single HEMS team serving Kent, Surrey, and Sussex between 2013 and 2022.

They used a statistical approach known as Ws analysis to estimate each patient’s probability of survival. This method adjusts for differences in injury severity and other factors, and it also identifies predictors of death within 30 days of injury.

The researchers also examined factors linked to unexpected survival and rates of resumption of heartbeat (return of spontaneous circulation) in traumatic cardiac arrest, a condition in which the heart stops beating after severe injury such as major blood loss or chest trauma.

More Survivors Than Expected

Overall, 2,125 patients survived for at least 30 days after their injuries. This represented an 85% survival rate, compared with an expected rate of 81%. The difference translates to about five additional survivors for every 100 trauma patients. Based on the typical number of cases handled by the service, this could mean up to 115 extra lives saved each year.

Patients who appeared to benefit most were those who were badly injured but still had a moderate chance of survival, defined as a 25 to 45% predicted probability. In this group, 35% survived for 30 days despite expectations to the contrary.

Even among patients with a predicted survival probability below 50%, reflecting very severe injuries, 39% survived unexpectedly.

Who Was Most Likely to Survive Against the Odds

Two factors stood out as strong predictors of unexpected survival: being younger and having a higher initial Glasgow Coma Scale score. This score ranges from 3 to 15 and is used to measure a person’s level of consciousness after a brain injury.

Emergency anesthesia given before reaching the hospital was also linked to unexpected survival. This procedure places the patient in an induced coma and can only be performed by advanced medical teams such as HEMS.

Traumatic Cardiac Arrest Outcomes

The analysis included 1,316 patients who experienced traumatic cardiac arrest. Of these, 356 patients, or 27%, regained a heartbeat while being transported to the hospital. The remaining 960 patients were declared dead at the scene.

Among the 356 patients who initially regained circulation, 30-day survival data were available for 185 individuals. Of those, 46 patients, or 25%, were still alive after 30 days, while 139 died in the hospital. The likelihood of regaining a heartbeat increased by about 6% each year between 2013 and 2022.

Important Limits and What the Findings Suggest

The researchers emphasize that their results reflect survival rates that were higher than predicted by statistical models, not direct proof that HEMS caused the improved outcomes. Their analysis also assumes that patient mix and service performance remained consistent over time, which may not always be the case.

Still, the team says the results highlight “the potential magnitude of clinical benefit, consistent with previous economic and social benefits demonstrated in previous studies.”

They conclude: “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.”

Reference: “Helicopter Emergency Medical Services attendance is associated with favourable survival outcomes in major trauma: derivation and internal validation of prediction models in a regional trauma system” by Joanne Griggs, Jenny Harris, Jack Barrett, Scott Clarke, John O’Neill, Leigh Curtis, Malcolm Tunnicliff, Claire Baker, Duncan Bootland, Emma Ream and Richard Lyon, 3 February 2026, Emergency Medicine Journal.
DOI: 10.1136/emermed-2025-215451

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