Home Paramedicine/The Job Common Sense Versus Evidence Based Medicine

Common Sense Versus Evidence Based Medicine


This article is about ten years old, but it’s still relevant.

Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials


Objectives To determine whether parachutes are effective in preventing major trauma related to gravitational challenge.

Design Systematic review of randomised controlled trials.

Data sources: Medline, Web of Science, Embase, and the Cochrane Library databases; appropriate internet sites and citation lists.

Study selection: Studies showing the effects of using a parachute during free fall.

Main outcome measure Death or major trauma, defined as an injury severity score > 15.

Results We were unable to identify any randomised controlled trials of parachute intervention.

Conclusions As with many interventions intended to prevent ill health, the effectiveness of parachutes has not been subjected to rigorous evaluation by using randomised controlled trials. Advocates of evidence based medicine have criticised the adoption of interventions evaluated by using only observational data. We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute.

As the saying goes, read the whole thing.

Keep in mind that the British Medical Journal is a real publication and a serious one at that. It’s not the Journal of Iatrogenic Medicine*, so you can trust it for the most part. A friend of mine who reads the BMJ regularly assures me that this article was in fact peer reviewed before it was published. The references are real, I clicked on them to be certain. Another friend who spends a lot of time teaching fellows who jump out of perfectly good aircraft all too often, tells me that he uses this in his classes. The guys get a kick out of it when they are discussing EBM.

A call to (broken) arms

Only two options exist. The first is that we accept that, under exceptional circumstances, common sense might be applied when considering the potential risks and benefits of interventions. The second is that we continue our quest for the holy grail of exclusively evidence based interventions and preclude parachute use outside the context of a properly conducted trial. The dependency we have created in our population may make recruitment of the unenlightened masses to such a trial difficult. If so, we feel assured that those who advocate evidence based medicine and criticise use of interventions that lack an evidence base will not hesitate to demonstrate their commitment by volunteering for a double blind, randomised, placebo controlled, crossover trial.

The authors point is valid. Not everything we do in medicine or EMS has a lot of science behind it. Sometimes we have good evidence, but sometimes we don’t have good evidence and yet a procedure or technique seems to work.

I can’t wait for Rogue Medics 73 part, multicolor, 17 font, rebuttal.

I  really ,really, really, need to Trade Mark that or something before someone uses the name.
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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. The research paper of the anti-science movement. What took you so long to find it?

    As I have already written, this is from the satire issue of BMJ.

    Their Christmas issue is the BMJ’s satire issue every year.

    The authors were writing very tongue in cheek.

    There is no EBM requirement that all treatments have large scale randomized controlled trials.

    We also test seat belts without placebo groups because we do not need to compare the damages.

    This is the favorite paper of quacks pushing their bizarre treatments and claiming that they do not need to demonstrate that the treatment works.

    They will be thrilled to know that you are on their side.


    • If EBM doesn’t require large scale trials, how is the evidence collected? After all, we only have anecdotes from people who jumped out of airplanes with parachutes to suggest that parachutes work. As we all know, the plural of anecdote is not data, it’s war stories. We test seat belts and airbags with artfully constructed crash test dummies that are designed to collect data. That data is then carefully reviewed to suggest ways to improve their efficacy. That’s EBM, right there. Despite that, there are many people who will tell you that they were saved by being thrown clear of cars and that the seat belts would have killed them if they had been used.

      Quacks also point to studies that support their suppositions as data. Often they do that to misdirect inquiries and quiet critics.

      While the authors were writing tongue in cheek, they had a valid point in doing so. Sometimes in medicine we might have to do something because we think it works. We do that until someone comes along with several well designed studies to prove or disprove our theories. While I’m a big proponent of not just doing something because we can, sometimes we have to make decisions about treatment without having all of the data we’d like.

      Which I think was their point.

      • This is the crux of the argument for supporting the “Science-Based Medicine” wing of “Evidence-Based Medicine.” Both movements have the same common goal, and SBM is in-fact a subset of EBM, but those who identify with SBM tend to emphasize the importance of basic science and prior probability when evaluating the medical literature, not just rigid evidence-hierarchies and topped by RCT’s.

        Here’s a nice little overview of the SBM community:

        SBM works around the parachute conundrum because, although no RCT’s evaluating parachute use vs. placebo have been done, a whole lot of basic physics can explain how and why they do work. The reasoning and scientific laws behind their use are robust enough that it would take a RCT with a sample size of infinity to overturn that logic.

        If something has no science AND no evidence behind it, like long-board spinal immobilization, then it is time to let that procedure die, but if something has science but little evidence, like giving STEMI patients nitro, then we can keep doing so until there is evidence sufficient to over-ride the basic premise behind its use.

        Unfortunately we are still in a quagmire with things like epi during cardiac arrest, where the science and evidence seem to be stuck in equipoise, but folks like RM (and probably myself) will still argue that the burden of proof is on the intervention to prove that it works, not the nay-sayers to prove that it doesn’t…

        • Vince D,

          I was not going to bring up SBM and complicate things more.

          We are hopeless optimists. We think that every new treatment will be wonderful, and we only have to stop the FDA from requiring so much research to approve the treatment, but this has probably saved a huge number of lives.

          The drugs that are approved without good evidence are removed, or black boxed soon after they are approved by the FDA.

          The cases where they are not, such as droperidol, are often due to bad decisions by the FDA.

          I am not saying that the FDA is great, but that we need to stop assuming that a lack of evidence is anything other than a great big danger sign.

          “Alternative” medicine depends on people ignoring the lack of evidence of benefit and lack of evidence of safety.

          We need to be smarter than that.


          • If I were a cynic, I’d suggest that you didn’t want to bring up SBM because it sort of undermines your position. Or maybe you think that you’re the only one smart enough to understand the distinction. It’s fortunate that I’m not a cynic.

  2. If EBM doesn’t require large scale trials, how is the evidence collected?

    The point was about the requirement for placebo controls., which you have stated is not essential.

    Why would anyone think that observational data of people falling from planes, cliffs, windows, or other heights is inadequate to demonstrate the harm of falling from a significant height?

    They are using the rare survival of people who fall from planes without parachutes to suggest that placebo trials are important – and doing it tongue in cheek.

    In a fall from a plane, it would be foolish to expect to be one of the rare survivors.

    Similarly, people claim that they were saved by not wearing a seat belt. These cousin’s mother’s sister in the next town over stories are not a good basis for decisions about wearing seat belts.

    In a life-threatening crash, it would be foolish to expect to be one of the rare survivors.

    Despite that, there are many people who will tell you that they were saved by being thrown clear of cars and that the seat belts would have killed them if they had been used.

    There are many people who will tell you that they save lives by flying patients due to mechanism.

    While I’m a big proponent of not just doing something because we can, sometimes we have to make decisions about treatment without having all of the data we’d like.

    And EBM does not insist that we have the highest quality of evidence for all treatment recommendations.

    The problem is that people use this paper to claim that evidence is useless, which is not at all what the authors intended.

    The rapid responses to the article have some interesting observations and are worth reading.


  3. tooldtowork,

    If I were a cynic, I’d suggest that you didn’t want to bring up SBM because it sort of undermines your position.

    As Vince D demonstrates, it makes my position much stronger.

    Or maybe you think that you’re the only one smart enough to understand the distinction.

    I just didn’t want to write a lot about it.

    With a lack of understanding of EBM, adding SBM to the discussion did not seem to me to be the way to clarify things.

    Vince D showed that I was wrong.

    It’s fortunate that I’m not a cynic.

    I didn’t know that about you.


  4. Ok, I’ll bite.

    The parachute paper is indeed satire; my EBM teacher in med school kept this paper taped to his office door. Of course, while it may be humorous, all the best satire contains a healthy dose of truth (although this has never been proven). Nonetheless, how could we apply this satire to a real problem in EMS, say….. epi in cardiac arrest? (If Rogue will allow me to intrude into his domain?)

    Say that epi was the “parachute” in the paper above. We could re-write part of the paper as:

    “Parachutes are the standard of care for leaving airplanes in mid-air, based on studies of basic science, animal studies, and extensive clinical experience. Quality clinical trials of parachutes, especially randomized trials with patient-oriented outcomes, have been few, however. The results of those limited number of higher quality studies showed that, consistent with clinical experience, more subjects who used parachutes had a pulse immediately after landing than did subjects who did not receive parachutes. However, the data also showed that subjects who used parachutes were more likely to be dead 1 month later, or have severe neurologic injury, than the non-parachute cohort. Thus, while parachutes are associated with improvements in short-term, surrogate markers of survival, they appear to worsen outcomes of most interest to those who jump from planes. It is unknown if this data would also apply to those who jump from helicopters, bridges, or especially people with those cool wing-suits.”

    I’m no Rogue, so that’s the best satire I cam muster up!

    • Your quote is more parody than satire. I think that the original article was meant as satire, not parody. The authors used a comical post to drive home a serious point about over reliance on EBM and even SBM. If it were parody, then they would just be poking fun at EBM with no serious underlying message.

      I think that there is a real take home message about understanding the numbers, but not the reality underlying them.

      VinceD talks about the uselessness of back boarding patients and from a scientific standpoint, he’s right. We should get rid of them, but we won’t, at least not in the near future. Right now the people who make those decisions are more concerned about being sued for having their systems not immobilize someone than they are about being sued for having their providers immobilize someone. Until there is a financial penalty for inappropriately boarding patients, it will continue because the doctors and administrators who make those decisions know two important things. 1) They will not have to perform the procedure. 2) It is very unlikely that they will have the procedure performed on them.

      They have zero skin in the game, so they are free to make a decision that they think immunizes them from liability. When a patient who suffers harm from being immobilized realizes that this was iatrongenic medicine and just not “just one of those things”, they’ll contact a personal injury lawyer and the game will be on.

      Then and only then will EMS providers and their patients no longer be subjected to this silly procedure.

      • How about, I wrote a parody with satirical intent? (Actually, both these forms require some element of comedy as well, so I shouldn’t so quick to assume that I was funny…)

        Well, whatever the form, I can assure you that there IS some skin in the game. Pressure ulcers are a “never” event, and will kill the hospitals’ reimbursement. “Never” events get the attention of the hospital administration. Maybe the relationship has not been pointed out to many people, but others are aware. Nursing probably could be our big ally here – they’re the ones doing all the Braden scores & other stuff I don’t understand.

        • This is a good point. Except that the people who literally and figuratively have skin in the game are not the people being held responsible. So, your hospital gets screwed because EMS immobilized someone who didn’t need it. How do you go about limiting your exposure? Sure, you can get the patient off the board as quickly as possible, that’s just good medicine. But, if the ulceration happened before the patient got to the hospital, what does the EMS system care? The medics were following the protocols and procedures of their region and their system. Your hospital has to bare the financial burden, not the EMS system?

          So, what approach does the hospital administration take that will impact the EMS system as a whole and bring about change?

          That’s an essay question, so there is no multiple choice answer form provided.


          • The worst harm from backboards and rigid EMS collars is not the stuff you are describing, although developing sepsis from decubiti caused by laying on one of these sterile instruments for too long would be a very bad outcome.

            The worst harm is if the results of the Hauswald study are accurate, or if the results underestimate the amount of increased disability due to strapping injured people to backboards.

            If backboarding patients results in a doubling of the rate of disability, then the bad outcomes are the patients who are permanently disabled because of immobilization.

            There was less neurologic disability in the unimmobilized Malaysian patients (OR 2.03; 95% CI 1.03-3.99; p = 0.04). This corresponds to a <2% chance that immobilization has any beneficial effect. Results were similar when the analysis was limited to patients with cervical injuries (OR 1.52; 95% CI 0.64-3.62; p = 0.34).

            Out-of-hospital spinal immobilization: its effect on neurologic injury.
            Hauswald M, Ong G, Tandberg D, Omar Z.
            Acad Emerg Med. 1998 Mar;5(3):214-9.
            PMID: 9523928 [PubMed – indexed for MEDLINE]

            Then there is the Cochrane Review –

            The review authors could not find any randomised controlled trials of spinal immobilisation strategies in trauma patients. It is feasible to have trials comparing the different spinal immobilisation strategies. From studies of healthy volunteers it has been suggested that patients who are conscious, might reposition themselves to relieve the discomfort caused by immobilisation, which could theoretically worsen any existing spinal injuries.

            We did not find any randomised controlled trials that met the inclusion criteria. The effect of spinal immobilisation on mortality, neurological injury, spinal stability and adverse effects in trauma patients remains uncertain. Because airway obstruction is a major cause of preventable death in trauma patients, and spinal immobilisation, particularly of the cervical spine, can contribute to airway compromise, the possibility that immobilisation may increase mortality and morbidity cannot be excluded.

            Common sense is the basis for EMS Spinal immobilization.

            I wrote bit of a longer response to this.

            Word count 1,011, but most of that is footnotes. 😉

            Common Sense vs. Evidence


  5. tooldtowork,

    I think you missed the point that Brooks and I were trying to make.

    You two were discussing skin. I was pointing out that the real skin in the game is the spinal cord.

    We do not know the actual effect of spinal immobilization on the spinal cord of patients with unstable spinal fractures.

    From the patient’s point of view and the liability point of view, what is more devastating than a permanent disability due to being strapped to a backboard?

    Should backboards be eliminated? Since there is no good evidence to support their use and they have been around for probably tens of millions of uses, we should demand evidence that they are not causing permanent disability and that they provide some benefit to justify the harm they do cause (time, money, pain, physical injury, . . .).

    To juries and administrators, nothing says liability like permanent disability.

    How many patients do we take from unstable vertebral fracture to permanent spinal cord injury by strapping them to a board and applying a rigid ICP raising EMS collar?

    Connecticut OEMS is one organization that has taken the approach that should decrease disability for Nutmeggers. They are not the first, but we will have to see how it works out and how many others the gravitas to do the same.



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