EMS1.com posted an article from the University of Maryland titled: Helicopter beats ambulance for trauma patients.
Please take a moment to read the article, then come back for a few questions I have.
First, this is a summary of a study published in the Journal of the American Medical Association. I do not have access to JAMA, so I have not been able to review the actual study.
A total of 223,475 adult patients met the criteria: ground transport accounted for 161,566, while 61,909 patients were flown in helicopters. Overall, 7,813 (12.6 percent) HEMS patients died compared to 17,775 (11 percent) transported by GEMS.
The raw data suggests that more HEMS patients do not survive. Appears obvious to me, since we should only be flying the most critically injured patients. If you only fly the most critically injured patients, then mortality should be higher. It’s the next line in the article that bothers me a little.
This raw data shows a significant difference, but Dr. Galvagno says the odds for helicopter transport improved when statistical models were applied to the numbers to factor in so-called “confounding” factors that could lead to a misinterpretation of the data.
So the raw data wasn’t enough, they applied their own statistical model to get their results. I raised an eyebrow, but not being a statistician, I will just have to accept that this is normal. The last sentence in the paragraph really made me wonder.
The researchers also developed statistical models to account for missing data in the NTDB, including travel time and distance to trauma centers, key bits of information that could impact survival.
Missing bits of data? I think the most important pieces of data are, time of incident, time of EMS activation, time of EMS arrival, time of transport to level I or II trauma center and time from incident to arrival at Level I or II trauma center.
First, I am not going to rail about the theoretical golden hour, which studies are now showing to be ineffective. The times I want to see included in this study are comparisons between ground and HEMS. Theoretically, this study says if I am 2 blocks from a hospital, transport by a helicopter would give me a better statistical chance for survival.
The article states, as above, that they used a statistical model for the travel time and distance. Is a 20 minute helicopter ride better than a 20 minute ambulance ride? I doubt it, but the study doesn’t allow us to see these numbers. Now, let’s be realistic, the 20 minute helicopter ride will travel further than the 20 minute ambulance ride. The case should be made, that if a patient is over X miles from a level I or II trauma center, they would benefit from a helicopter ride. That’s the study that I would like to read, and the study that needs to performed.