Association Between Helicopter vs Ground Emergency Medical Services and Survival for Adults With Major Trauma.
Galvagno SM Jr, Haut ER, Zafar SN, Millin MG, Efron DT, Koenig GJ Jr, Baker SP, Bowman SM, Pronovost PJ, Haider AH
JAMA. 2012 Apr 18;307(15):1602-10
This study adds to the recent body of literature which suggests that there exists a cohort of the most-sick major trauma patients on whom utilization of HEMS confers a survival advantage. The authors report numbers needed to treat (transported by HEMS) as 65 and 69 to save one life, for patients taken to Level 1 and Level 2 trauma centers, respectively.
It would be hard if not impossible to conduct a randomized prospective study of HEMS vs. ground EMS for poly-trauma. Thus, past studies have typically relied on retrospective database review, or have used the “before and after” approach (HEMS being the intervention added or taken away in a region).
The authors in this retrospective cohort study have undertaken a rigorous statistical analysis of over two hundred thousand patients who fit the selection criteria, using 2007-2009 data from the ACS National Trauma Data Bank. They found that “In the propensity score–matched multivariable regression model, for patients transported to level I [and II] trauma centers, helicopter transport was associated with an improved odds of survival compared with ground transport.” (OR 1.16, 95% CI, 1.14-1.17 for Level I).
Along with other similar research, this study speaks to the larger and controversial topic of “appropriate HEMS utilization”, with the term appropriate being the subject of opinion and debate. The issue revolves around three overlapping considerations – 1) existence of any true benefit of HEMS for a patient population over ground EMS, 2) ethically sound justification of HEMS cost (if #1 is satisfied) vs. extent of the benefit, and 3) which component of HEMS services (crew expertise, transport time, transport destination) contributes the most – and if it may be reached via an alternative (EMS system re-design, ground EMS improvement, etc.).
While the answers are unclear even after a most thorough review of over 30 years of literature, it is important to both have an informed opinion at present, and to maintain an open mind towards new studies undoubtedly yet to come.