Helicopter EMS (HEMS) transport of trauma patients is used primarily to decrease the amount of time between injury and arrival at the trauma center. Unfortunately, efficacy studies have provided conflicting answers as to whether this is actually true. Last year, the CDC completed a large sample study of this issue using the National Trauma Data Bank (NTDB) in an attempt to determine if HEMS flights are effective.

Using almost 150,000 entries in the NTDB for 2007, they were able to isolate over 56,000 adult records with complete data points. They looked for mortality patterns based on age, injury severity, and revised trauma score, comparing patients who were transported by air vs ground.

They found the following:

• Odds of dying in-hospital were 39% lower overall when transported by helicopter
• This survival advantaged disappeared for patients age 55 and older, possibly because of decreased reserve, comorbidities, more complications, or medications that interfere with successful resuscitation
• Regardless of type of transport, males always fared worse than females

Bottom line: This is a large and intriguing study. About 85% of the US population has access to a Level I or II trauma center within an hour. However, a third of those can only get there in that period of time if transported by air. This mode of transport has a significantly lower mortality rate. However, there are cost and safety considerations as well. The key now is to figure out which patients will have the best outcomes after air transport. This will require more work, looking at more than just mortality (e.g. disability, complications).

Reference: Reduced mortality in injured adults transported by helicopter emergency medical services. Prehospital Emerg Care 15(3):295-302, 2011.