Nobody really knows for sure if the Heimlich Maneuver—er, abdominal thrusts—is the best way to save a choking person. No one, not the Red Cross nor Dr. Henry Heimlich himself, ever proved it was more effective than back slaps or compared them in a quality medical study. For decades, we were taught that back slaps would only force food farther down into airways, and the Heimlich Maneuver became so ingrained in pop culture that it became a TV-show trope and lunchroom poster favorite, but in 2006, the medical consensus changed again. All the indecisiveness, it turns out, has been based on nothing but anecdotal evidence and shaky studies that barely qualify as studies.
Medical organizations including the American Red Cross and American Heart Association have been flip-flopping for and against the Heimlich Maneuver since it was unveiled publicly in a June 1974 article in the medical journal Emergency Medicine, but for all its teaching in classrooms and first aid courses, there's never been hard evidence for why it'd work better than a slap on the back. As Richard Bradley of the American Red Cross Scientific Advisory Council told USA Today in 2013: “To the best of my knowledge, after doing a pretty thorough literature search, no controlled studies exist comparing back blows to abdominal thrusts or anything else."
Since then, Bradley says, in the follow-up interview, no one has attempted a comparative study. The American Red Cross, in other words, has no compelling evidence nudging them toward or away from either abdominal thrusts or back blows when trying to save someone who is choking. “The way we like to do high-quality studies requires a randomized, double-blinded control study,” he says, “and studies of unpredictable emergencies are very, very difficult to evaluate in that way.”
For a study to be randomized, test subjects would have to be chosen at random to receive either abdominal thrusts or back blows. For it to be double-blind, subjects and researchers would be kept in the dark about who's receiving which. In layman's terms, you can't drag a hundred people into a lab, choke them, and randomly choose which 50 to save with the Heimlich and which 50 to save by slapping them on the back.
So why does everybody know how to do the Heimlich Maneuver, and how did it catch on in the first place without any hard evidence? Part of the reason is that Henry Heimlich, a thoracic surgeon and researcher who died in 2016, was a natural at generating publicity and knew how to work the public. When the maneuver was unveiled in the journal Emergency Medicine in 1974, Heimlich stipulated to the journal's editors that it also be covered by a medical reporter, Arthur Snider, at the Chicago Daily News.
A week later, a Seattle newspaper reported that a man had read Snider's article and used the maneuver to save a choking person on vacation. It was the first reported use of the maneuver, it had worked, and it was by an average civilian who'd just happened to have the good fortune to read about it seven days earlier. Newspapers ate it up, and a string of similar stories spread nationwide over the summer. Later that year, an editorial in the Journal of the American Medical Association labeled it the Heimlich Maneuver. Heimlich had always been insistent that back blows were unsafe, calling them "death blows" at every opportunity, and by 1985 he'd convinced US Surgeon General C. Everett Koop to call the use of back blows lethal.
More from VICE:
All the publicity and anecdotal success stories bled over into a field that typically demands objective, measurable proof, and that's around the time all the flip-flopping began. From 1933 to 1969, the American Red Cross had recommended you use the heel of your hand to deliver blows to a choking person's back, between the shoulder blades, but in 1970, based on the (not scientifically supported) advice of the American Broncho-Esophagological Association, it cautioned not to give back blows, but it also didn't endorse abdominal thrusts.
From 1976 to 1984, the American Red Cross said to use back blows first and abdominal thrusts if those don't work. By 1985, it decided back blows were dangerous again and that you should only try abdominal thrusts. And in 2006, it reverted to recommending five back blows as your initial resort and, if that doesn't work, five abdominal thrusts, cycling between five of this and five of that until the object dislodges.
The AHA has been more consistent, but also more puzzling: By 1976, it was recommending abdominal thrusts alongside back blows, and by 1985 the organization cut back blows out of the picture entirely. It still teaches abdominal thrusts as the only method to help a choking person. But although the AHA's current Guidelines for CPR and Emergency Cardiovascular Care admits that back slaps “are feasible and effective for relieving severe FBAO (foreign body airway obstruction),” it doesn't teach back blows because it says teaching just one method is a simpler way to train people.
Heimlich's obsession with studies played a part in convincing the American Red Cross and AHA, and all the hospitals, first aid instructional courses, and schools that follow their guidelines. Most referenced, then and now, is a 1982 Yale study partially funded by Heimlich through his Dysphagia Foundation, later renamed the Heimlich Institute. “They used an accelerometer taped to a normal human Adam's apple,” Bradley says. “It was an animal study that was done on humans.” The three Yale researchers made up a theoretical model based on data that showed back blows produced less than 10 millimeters of change in airway pressure, while abdominal thrusts produced 10 to 20 millimeters, and extrapolated that to conclude back blows may move an object more deeply into the airway. “So while I'm not saying the conclusions were wrong,” Bradley says, “the conclusions carry lesser weight than other studies because it didn't use real people who were really choking.”
The American Red Cross weighted the Yale paper as Evidence Level 4, according to a five-point industry-standard scale for evaluating clinical studies. A Level 1 study would be of high-quality, randomized and systematically controlled. The Yale study was rated as poorly as an actual study could be rated, only one level above “Level 5: expert opinion." There have been other attempts to compare abdominal thrusts to back blows, but according to the American Red Cross, none of them have been any good. They're not controlled, double-blind, or have the criteria that prevent confirmation bias, and because of that most are rated Level 3, Bradley says. Level 3 studies are inconsistently conducted, with researchers often trying to make comparisons after the study is over.
Actual evidence is weak, so when the American Red Cross Scientific Advisory Council reviewed the body of evidence most recently in 2015, it concluded, “Based strictly on our review of the evidence, there was no evidence that allowed us to establish any standard” that a rescuer should do all the time, Bradley says. That's how we ended up with the re-embracing of the back blow alongside the abdominal thrust. Bradley says the two techniques do two different things, which is why the American Red Cross teaches both methods. Abdominal thrusts move air up the airway, he says, whereas back blows don't really move air but provide a higher temporary pressure spike that could dislodge something blocking the airway. “Think of it as a big gust of air versus a very sudden, sharp pressure change,” he says about abdominal thrusts and back blows, respectively.
An AHA spokesperson says the AHA began advocating abdominal thrusts “after the publication of scientific literature supporting this use,” and that they “provide recommendations based on relevant science." But when we asked the AHA to provide the evidence or the studies they consulted, they sent nothing. We still don't know what, if any studies the AHA used to form its choking guidelines between 1976 and now.
Choking is the fourth leading cause of accidental death in the US, killing 4,700 people each year. Nothing has become more conclusive in the 44 years since the Heimlich Maneuver saved its first life. We don't even know if calling it the Heimlich Maneuver is fair anymore, since Heimlich's colleague, Edward Patrick, alleged in 2003 that Heimlich took all the credit for the maneuver even though Patrick helped develop it.
All we know is that we're a little less sure than we were in the '70s and '80s, and since there are no quality comparative studies planned to settle the issue, it won't change anytime soon. The Mayo Clinic, for example, hedges on caution and teaches both methods. In either case, it helps to know when to step in and when to let a choking person work it out alone. If a person is making noise while choking, then keep your hands off; noise means they're still getting air, and they could cough the obstruction up. If they're quietly choking, however, then either abdominal thrusts or back blows are fair game. At that point, it's not what you choose to do so long as you do something.
Sign up for our newsletter to get the best of Tonic delivered to your inbox.