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Surprise, Surprise, Surprise


Study: Helicopter beats ambulance for trauma patients

BALTIMORE, Md. — If you are severely injured, a helicopter flight to a top-level trauma center will boost your chance of survival over ground transport. That’s the conclusion of a rigorous, national comparison of the effectiveness of helicopter versus ground emergency medical services, published in the April 18, 2012, issue of the Journal of the American Medical Association.


According to this study, if you are severely injured and get to a trauma center faster (by helicopter) as opposed to slower (by ambulance), you stand a better chance of survival. That makes sense, since in many cases quicker surgery results in better survival rates. We’ve known since the Civil War that getting patients into surgery earlier increases the chances of survival. Not exactly news.

Survival after trauma has increased in recent years with improvements in emergency medical services coupled with the rapid transportation of trauma patients to centers capable of providing the most advanced care. What has not been clear until this study, is the effectiveness of helicopter emergency medical services (HEMS), a limited and expensive resource, compared to its alternative, ground emergency medical services (GEMS).

Well, not exactly true, and this study isn’t going to answer the real question. Which, as has been raised for a number of years now, is this. Are we (as an industry) flying too many patients for whom time is not important and who will do as well by being driven as opposed to flown. In other words, where is the cutoff in acuity for flying versus driving?

“We looked at the sickest patients with the most severe injuries and applied sophisticated statistical analyses to the largest aggregation of trauma data in the world,” says the study’s principal investigator, Samuel M. Galvagno Jr., D.O., Ph.D., assistant professor, Department of Anesthesiology, Divisions of Trauma Anesthesiology and Critical Care Medicine, University of Maryland School of Medicine. “We were careful at every step to balance all the potential other factors that could explain any benefit of the helicopter. After all that, the survival advantage of helicopters remained,” says Galvagno.

Dr. Galvagno is on the staff of the R Adams Cowley Shock Trauma Center at the University of Maryland Medical Center, where many of the life-saving practices in modern trauma medicine were pioneered. The Shock Trauma Center was the first fully integrated trauma center in the world, and remains the epicenter for trauma research and training both nationally and internationally today.

The principal investigator for this study works at the R. Adams Cowley Shock Trauma Center, which coincidentally is heavily invested in HEMS. How surprised should I be that a study run by a doctor at a trauma center that gets the vast majority of it’s patients by helicopter shows that patients who arrive by helicopter fare better than those that don’t?

“The use of helicopter emergency medical services in the United States has been a controversial subject over the last decade or so, centering on the costs and the potential for crashes, says Thomas M. Scalea, M.D., the Francis X. Kelly Professor of Trauma in the Department of Surgery; director of the Program in Trauma, University of Maryland School of Medicine; and physician-in-chief at the R Adams Cowley Shock Trauma Center. “Previous studies have found a survival benefit by using helicopters, but the studies were small and left some doubt. This study in JAMA is very robust,” says Dr. Scalea.

Dr. Scalea as you will note is the boss at the R. Adams Cowley Shock Trauma Center, so presumably he’s Dr. Galvagno’s boss. So, the guy who is the boss to the guy that says that helicopters are better is the guy who runs the center that is heavily invested in having patients coming in by helicopter. Another big surprise here.

Dr. Galvagno’s research demonstrates how statistics and technology can be used to help researchers mine huge databases for useful information to help determine best care for patients and appropriate utilization of limited health care funds,” says E. Albert Reece, M.D., Ph.D., M.B.A., vice president for medical affairs, University of Maryland; the John Z. and Akiko K. Bowers Distinguished Professor; and dean, University of Maryland School of Medicine.

Were I the skeptical type, I’d says that Dr. Galvagno’s research shows how statistics and technology can be used to prove anything you want to prove. Good thing I’m the non skeptical, trusting sort.

The question that isn’t answered here, in fact it’s not even asked, is where is the cutoff for sending patients in by helicopter as opposed to sending them by ground ambulance? The second unasked question is, when do patients need a trauma center? The study looked at severely injured patients, those who unquestionably needed a trauma center. It looked at two different modes of transportation, one faster, one slower. It asked which would do better, those getting to definitive care sooner or those getting to definitive care later. Unsurprisingly the study found that severely injured patients did better when they get to trauma centers more quickly. You don’t need a Ph.D. to figure that one out, but surprisingly Dr. Galvagno used this research as part of his Doctorate in Public Health program.

This study was performed without any commercial funding or extramural sponsorship. Dr. Galvagno was funded, in part, by an institutional training grant when this study was initiated as part of his Ph.D. program at the Johns Hopkins Bloomberg School of Public Health.

Pretty neat, getting your homework published in the Journal of the American Medical Association. All I ever got was mine taped to the refrigerator.

Still, it seems like a PH.D. in Duh! to me. Getting acutely injured patients to definitive care faster means that more of them will survive. We’ve only known that since the 1860s, but now we have numbers to prove it. Even at that, the study showed that one life was saved for each 65 or 69 patients flown to a Level 1 or Level 2 trauma center. Now, we need to compare that in a meaningful way to the number of crashes and lives lost to see if the cost in lives outweighs the benefits lives or vice versa.

Again, what we don’t know is where is the cutoff for defining who goes by air and who goes by ground. Until we know that, which is what patients will have a good outcome or no change in outcome no matter which mode of transport is used, we can’t have a real debate over to what extent helicopters are really helpful in saving lives.

Theoretically, if we were able to use teleportation to instantly transport patients they’d do even better. Dr. McCoy said so, didn’t he? Then again, if our molecular pattern were stored in the transporter’s memory banks, what is to keep patients from being treated by being transported and using the molecular pattern to restore them to their pre injury state of health? I need a grant. Well, two. One to invent the transporter and one to see if patient’s do better when beamed to Shock Trauma as opposed to being flown in by archaic helicopters. But, I digress into Sheldon Cooper like fantasy.

The big question yet to be answered, and I’m repeating it for the sake of clarity, is where is the cut off for flying patients versus driving them? The related question is, where is the cut off for patients needing to be in a Level 1 or Level 2 trauma center and those that will do just as well in a community hospital?

Once we know the answers then we’ll have a much more realistic idea of when patients need to be flown and when they don’t.

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After a long career as a field EMS provider, I'm now doing all that back office stuff I used to laugh at. Life is full of ironies, isn't it? I still live in the Northeast corner of the United States, although I hope to change that to another part of the country more in tune with my values and beliefs. I still write about EMS, but I'm adding more and more non EMS subject matter. Thanks for visiting.


  1. TOTW –

    When you look more closely at the methods and results, you find (or rather don’t find) the one aspect that you, me, and most everyone else thought would be the data point of most interest.

    That is, prehospital transport tines.

    The authors explain in the methods: “Total elapsed EMS times from dispatch to ED arrival were excluded as a variable because of a 57.8% prevalence of missing data.” They do use the 42% of records with EMS times recorded to do a limited analysis, which found that “results were not qualitatively different from our primary analyses.” They shy away from concluding anything, though, given that the data “cannot be assumed to be missing at random.”

    Sooo, helicopters save lives, but we can’t say if it’s because of faster transport, or in spite of slower transport – we just don’t know.

    In a way, it reminds me of a paper I reviewed that suggested that EMS placement of an IV saves lives, but they have no idea why or how: http://millhillavecommand.blogspot.com/2012/01/iv-placed-by-ems-too-much-yet-not.html

    • As non scientist, it seems rather clear to me that if you don’t have 58% of the data available with which to make your analysis, then your analysis is meaningless.

      As Doctor Frankenstein might say,

      “My Grandfather’s work was doo doo!”

      As to the IV study, without reading it, I have an alternative theory. IV starts are usually done by paramedics. In some systems when paramedics transport, they call the hospital sooner and are more likely to go to a trauma center than just the nearest hospital. So, it’s not the IV, it’s the entire process around the IV that makes the difference.

      It’s as sound as most other theories.

  2. “As non scientist, it seems rather clear to me that if you don’t have 58% of the data available with which to make your analysis, then your analysis is meaningless.” Depends on what field I guess. Astrophysics has given mankind a lot of knowledge. But we only understand 4% of the universe.

    IVs aid oxygenation, by counteracting dehydration, and making the blood flow better, so I’m not entirely surprised it often helps.

    I am however reminded of an old post by Ambulance Driver where he talks about how “the Borg” requires helicopter for certain injuries, and he was on a call where he had to wait 10 minutes for the helicopter, and then it took them another 30 minutes to prep and load the patient up, and another 5 minutes for it to fly, or so. And it would’ve taken him something like something like 10-15 minutes to drive there. So the helicopter option ended up being over half an hour slower.

    • IV’s don’t aid oxgenation and in hypotensive patients fluid resuscitation without surgical intervention increases mortality. The current data coming out of Iraq and Afghanistan shows that keeping trauma patients warm and with a BP of around 90 systolic until the get into the OR increases survival. The days of two large bore IVs and fluid boluses should be over pretty soon.

      • Perhaps I phrased it badly. It replenishes liquid in the cardiovascular system, which if dehydrated, or from blood loss can become sluggish, leading to lower oxygenation which can lead to cardiovascular shock. Cardiovascular shock being hypoxia.

        It rarely hurts, and sometimes patients go from fading fast to cheerful and perky, during just the brief ride in the ambulance, thanks to IV. (I’m not sure how often, I’m not in EMS myself, I just read the blogs, though I am a first aid & CPR instructor, and emergency oxygen provider instructor).

        • PS: I’m coming from a diving background, so I may be inherently biased where it comes to dehydration.

        • Bleeding does not lead to dehydration as the ratio of plasma to Red Blood Cells (RBCs) stays the same. While fluid resuscitation might have salutatory effects in the short term, research has shown that it is related to coagulopathies and increased mortality in the long run. It’s why we don’t infuse large boluses of fluids in trauma patients. In patients who a dehydrated because they have not taken in enough fluid to replace that which they lost by sweating, urinating, defecating, or just breathing, dehydration is a serious concern and fluid is appropriate. The two are different though, and require different approaches for treatment.

          I won’t go into the definition of Cardiogenic Shock, since it’s beyond the scope of my post. Nor will I explain the difference between Hypovolemic Shock and Cardiogenic Shock.

  3. I read the study. They said there was no conflict of interest with the physicians conducting the analysis and study, so using the same line my parents told me when I asked, “Why?” It must be true, “Because I said so!”

  4. While I understand picking at their data for response times, helicopter EMS is studied by people who practice it and are invested in it for the same reason that new drugs are studied by drug companies. They have the means, motive, and opportunity to perform such studies. It’s not enough to say “they like helicopters, so they put their reputations and untold lives on the line to falsify a study to support their point of view”… that’s a pretty serious allegation.

    And for the record, as Kaerius points out initially, in many types of research having 42% of the data is pretty darn good. Unless the missing cases are all supportive of the opposite conclusion, you can still draw inferences from the 42% because it’s representative. Same reason you don’t need to look at every helicopter EMS system in the world independently…

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