Air Ambulance Services Linked to Increased Survival Rates for Trauma Patients
New analysis of nearly a decade of data suggests helicopter emergency medical services (HEMS) may considerably improve outcomes for severely injured individuals.
People with life-threatening injuries are demonstrably more likely to survive when rapid, advanced medical care reaches them via helicopter. A thorough review of survival data from a regional air ambulance service in South East England reveals outcomes exceeding expectations for major trauma patients. The analysis, recently published in Emergency Medicine Journal, indicates approximately five additional people survive for every 100 severely injured patients treated by HEMS.
The Challenge of Quantifying HEMS Impact
Researchers have long recognized the potential benefits of Helicopter Emergency Medical Services (HEMS), but definitive proof of their impact has been elusive. This study aimed to address this gap by providing a robust dataset for analysis.
The team employed a refined statistical method – Ws analysis – to estimate each patient’s probability of survival. This approach accounted for variations in injury severity adn individual patient characteristics,while also identifying factors associated with mortality within 30 days.
Unexpected Survival and Cardiac Arrest Outcomes
The study also delved into cases of unexpected survival and the critical outcomes of traumatic cardiac arrest, a condition where the heart stops beating following severe injury, such as major bleeding or chest trauma. A central focus was determining whether return of spontaneous circulation (ROSC) – the resumption of heartbeat before reaching the hospital – could be reliably achieved.
Notable Gains in Survival Rates
Of the 3,225 patients studied, 2,125 survived for at least 30 days post-injury, representing an actual survival rate of 85% compared to an expected rate of 81%. This translates to five extra survivors per 100 patients, possibly equating to as many as 115 additional lives saved annually based on the service’s typical caseload.
Identifying Those Who Benefit Most
The analysis revealed that patients with severe injuries and a moderate predicted chance of survival (25-45%) experienced some of the most substantial gains.in this group, 35% survived for 30 days despite initial projections suggesting or else.
Furthermore, survival rates were higher than predicted among patients with a low probability of survival (less than 50%). Remarkably, 39% of these severely injured individuals survived for at least 30 days.
Key Factors Influencing Positive Outcomes
Several factors were strongly correlated with unexpected survival. younger age and a higher initial Glasgow Coma Scale (GCS) score – a 3 to 15 point measure used to assess consciousness after a brain injury – were significant predictors.
Crucially, pre-hospital emergency anesthesia, an intervention involving induced coma delivered by advanced medical teams like HEMS, was independently linked to improved survival in severely injured patients.
Traumatic Cardiac Arrest: A Glimmer of Hope
Among 1,316 patients who experienced traumatic cardiac arrest, 356 (27%) regained circulation during transport to the hospital. The remaining 960 patients were pronounced dead at the scene.
Of the 356 patients who initially survived, 30-day outcome data were available for 185 (52%). Of those, 46 (25%) were still alive after 30 days, while 139 ultimately succumbed to their injuries after hospitalization. The likelihood of ROSC increased by 6% each year between 2013 and 2022, suggesting continuous improvement in resuscitation techniques.
Cautious Optimism and Future research
The researchers emphasize that their findings demonstrate survival rates higher than statistical predictions, rather than definitive proof of causation. They acknowledge that their estimates rely on the assumption of consistent patient characteristics and service performance over time, wich may not always hold true.
Nevertheless, the team asserts that the results underscore “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, notably for severely injured patients, though comparative studies with option care pathways are needed to establish causal effectiveness.”
