A new study has found that transport by helicopter to a level I or II trauma center was associated with improved survival to hospital discharge compared with ground emergency medical services. The study, which appears in the April 18 issue of JAMA, included data on more than 200,000 adult patients.
Researchers noted that trauma remains the leading cause of death and disability among young people around the world. In the United States, more than 50 million people per year suffer traumatic injuries, resulting in 169,000 deaths a year and a lifetime cost of $406 billion. The use of helicopter EMS and its possible effect on outcomes for traumatically injured patients has been the subject of debate, the authors noted.
Adil H. Haider, of the Johns Hopkins University School of Medicine in Baltimore, and colleagues conducted a study to compare the association between the use of helicopter vs. ground EMS and survival among adults with traumatic injuries. The study included 223,475 patients older than 15 who had an injury severity score that was defined as major trauma, having sustained blunt or penetrating trauma that required transport to U.S level I or II trauma centers. Of the study population, 61,909 patients were transported by helicopter and 161,566 by ground to trauma centers.
Unadjusted mortality was higher for those transported by helicopter (12.6%) than those by ground (11%); however, a higher proportion of both level I and level II patients transported by helicopter had higher injury severity scores. After further analyses and controlling for multiple known confounders, helicopter transport was associated with a 16% improved odds of survival compared with ground transport for patients transported to level I trauma centers (absolute risk reduction of 1.5%). For patients transported to level II trauma centers, helicopter transport was associated with a 15% improved odds of survival (absolute risk reduction of 1.4%).
“Thus, for patients transported to level I trauma centers by helicopter, 65 patients would need to be transported to save one life,” the authors wrote. “For patients transported to level II trauma centers, the number needed to treat is 69.”
On why this happens Dr. Samuel Galvagno Jr., assistant professor for the Department of Anesthesiology, Divisions of Trauma Anesthesiology and Critical Care Medicine for the University of Maryland School of Medicine, said, “It's likely some combination. It's likely not going to be one specific element.” Galvagno said there could be other unmeasured differences between patients that influenced the findings. “It may be that (ground crews) don't have the same tools available to them that helicopter crews do,” he told Reuters Health. “There is a lot of work to be done on this area still. This is by no means a final answer.”
“Future studies should investigate specific components of helicopter EMS such as pre-hospital interventions, total pre-hospital time, crew configuration and distance as factors that may in part or whole explain the benefit of helicopter EMS for adults with major trauma because understanding the effectiveness of each may help determine which patients benefit most from this resource,” authors write.
The development and use of effective pre-hospital triage tools that can identify adults with a high injury severity score have remained elusive, the researchers said. “Future studies should focus on efficient and user-friendly pre-hospital assessment tools to properly identify injured adults who will be the most likely to benefit from helicopter transport.”
The new findings echo the results of some previous studies, including one published last year and led by Dr. Mark Gestring, director of the Kessler Trauma Center at the University of Rochester Medical Center in New York. Gestring told Reuters Health that until the last few years it's been hard to say if there's a clear benefit to transporting patients by helicopter, but now doctors can say those people tend to do better. “I think the trick is when do you use helicopters and when do you not use helicopters… and that is very regional,” he said. What might work for Rochester or Baltimore, Gestring said, might not work for the rest of the country. “It certainly doesn't make sense to take a helicopter if you are within 30 minutes by ground,” said Galvagno. But he added, “If it was my family member, I'd want them flown if they didn't have timely access to a trauma center.”
There is also a cost associated with using helicopters to transport patients. While cost estimates vary widely, Galvagno and his colleagues estimated that each helicopter transport costs about $5,000 in Maryland, where flights are typically done by the state police. That means $325,000 would be spent transporting people to the most specialized trauma centers for each life saved, they calculated. Galvagno said that amount is not insignificant, but is comparable to other lifesaving procedures such as open-heart surgery.
Haider presented the findings April 17 at the National Press Club in Washington, D.C., as part of a JAMA media briefing on comparative effectiveness research.
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