An analysis of trauma care covering nearly a decade shows that pre-hospital medical services provided by air ambulance helicopters may give seriously injured patients a better chance of survival than traditional statistical models predict. The study believes that the clinical benefit of helicopter emergency care in severe trauma treatment far exceeds the level that previous literature has been able to quantify.
The study, published in the Journal of Emergency Medicine, looked back at a total of 3,225 trauma patients who received pre-hospital care from a helicopter emergency medical service team in Kent, Surrey and Sussex in southeastern England between 2013 and 2022. The research team used the so-called "Ws analysis" statistical method to calculate the expected survival probability of each patient after taking into account multiple factors such as the severity of the injury, and then evaluated the difference between the actual outcome and the model prediction.
The results showed that among all enrolled patients, a total of 2,125 survived at least 30 days after injury, and the actual survival rate was 85%, which was significantly higher than the 81% expected value given by the model. Calculated, that is, for every 100 severe trauma patients, there are about 5 "extra survivors" who are unlikely to survive according to the existing statistical model. Combined with the number of cases handled by the service each year, the study estimates that this difference could mean around 115 additional lives could be saved each year.
Further stratified analysis found that those seriously injured patients who "originally still had a glimmer of hope" benefited most. Of the group with expected survival probabilities ranging from 25% to 45%, 35% ultimately survived 30 days, far exceeding model expectations. Even among patients whose expected survival probability was less than 50% and whose injuries were extremely serious, 39% still achieved unexpected survival.
The study also sorted out the common characteristics of patients who have "turned against the wind". Younger age and higher initial Glasgow Coma Score (GCS) were the two most significant predictors of "reversal survival." The full score of GCS is 15 points, which is used to evaluate the state of consciousness after brain trauma. The higher the score, the more conscious the patient is. In addition, emergency anesthesia—a procedure in which a patient is placed in an artificially induced coma—administered by a senior medical team before arriving at the hospital was also significantly associated with unexpected survival. This high-risk operation is usually only performed by advanced pre-hospital medical forces such as helicopter emergency teams.
In more extreme traumatic cardiac arrest scenarios, air ambulance intervention also shows positive signs. A total of 1,316 patients with traumatic cardiac arrest were included in the analysis, of whom 356 (approximately 27%) recovered their spontaneous heartbeat during transport, and the remaining 960 were pronounced dead at the scene. Among the 356 patients who once regained circulation, the study obtained 30-day follow-up data for 185 people. The results showed that 46 people (25%) were still alive at 30 days, and the remaining 139 people died during hospitalization. The study also pointed out that between 2013 and 2022, the probability of recovery of heartbeat in patients with traumatic cardiac arrest increased by about 6% per year, suggesting that pre-hospital first aid technology and procedures may continue to be optimized.
However, the research team also emphasized that these conclusions cannot directly prove that helicopter emergency care itself is the only reason for improved survival. They note that the analysis is based on several assumptions, such as that patient composition and service levels remain generally stable across years, and that in reality these factors may change. In addition, this study mainly presents the phenomenon of "actual survival rate is higher than statistical prediction", rather than a strictly one-to-one controlled trial with other emergency modes.
Despite the limitations, the researchers believe that these results at least reveal the potentially huge clinical value of air ambulance in severe trauma treatment and are consistent with previous economic and social benefit assessments. The paper concluded that these findings provide strong support for the continued investment in helicopter emergency medical services, especially in the treatment of seriously injured patients, but more rigorous comparative studies with other emergency routes are still needed in the future to further clarify its causal effects.
Compiled from /scitechdaily