Medical Examiner

Under Pressure

Don’t listen to Tim Tebow: Hyperbaric oxygen chambers are mostly useless.

A patient in a hyperbaric chamber

In a world aswirl with medical uncertainty, one thing is for sure: When a remedy promises to cure everything from autism to hearing loss and broken bones, let the buyer beware.

Hyperbaric oxygen therapy is a resurgent darling in the world of cure-alls. Just a few years ago, Michael Jackson’s rumored habit of sleeping in a hyperbaric chamber was considered high up on his list of bizarre behaviors. Now its image has been rejuvenated after endorsement from an unlikely champion: the Denver Broncos’ third-string quarterback, all-around do-gooder, and hyperbariac, Tim Tebow. He travels with his own $20,000 gizmo and promises it will keep him fit as a fiddle as he rides the bench this season.

There’s just one problem: Hyperbaric oxygen treatment (HBOT) doesn’t seem to provide much bang for the buck—let alone 20,000 of them.

Before getting into the clinical details, though, let’s review how HBOT works.

Hyperbaric oxygen’s bedrock assumption is: If some oxygen is good, more oxygen must be better. The face-value logic is difficult to dispute: Anyone who has been at high altitude where oxygen is scarce knows the attendant headaches, nausea, and wobbly vision. Why, therefore, shouldn’t a corresponding bizarre-o world also exist, a magic place where oxygen is super-plentiful and human frailty unknown? Since we haven’t yet discovered that fantasy land, we have two options for oxygen-loading.

One way is to go to your corner oxygen bar and puff away. The air we breathe is about 21 percent oxygen; at the oxygen bar you can try 50 percent, even 100 percent concoctions that can make you feel buzzed. But to get really oxygenated, you need something with a bit more kick: You have to change the barometric pressure of your immediate environment. To learn how, or just to re-experience the trauma of high-school physics, click here.

Yankee know-how has solved the problem of just how to make super-oxygen available to the customer. You can go to a private airplane-like chamber where, other than the risk of perforating your eardrums, you can have a comfortable biosphere-like existence. These cost hundreds of thousands of dollars and are too pricey for home ownership. Instead, you can head to a (large) clinic for the three-seater. A step down is the Michael Jackson-Tim Tebow “monoplace” model, which can be rented or purchased for $12,000 and up; you can also try your luck on eBay. Should you decide to give it a whirl, please try not to think too much or too deeply about the close resemblance of your chamber to a casket.

Traditional American medicine is less enthusiastic about HBOT than many of those buying and selling. Many small clinical trials have examined HBOT across an amazingly wide variety of indications, but the results are inconclusive. To settle the dispute, we have the Cochrane Collaboration. Founded in 1993 by the Brits, Cochrane is a group of number crunchers who live outside the reach of drug company influence, pig-headed doctors, and wishful patients. They apply the black art of meta-analysis to adjudicate conflicting results. Though the limitations of such a shotgun marriage of results are many, talented statisticians often can squeeze out a clear answer.

Through the years, Cochrane has meta-analyzed countless HBOT studies. They’ve looked at HBOT for stroke, multiple sclerosis, severe ear infections affecting bone, and burns—and found that the therapy is without efficacy for all of those ailments. For persons with traumatic brain injury, HBOT might increase survival rates a bit, but it doesn’t help neurologic function. HBOT might help migraine and cluster headaches a little, and maybe, if you start treatment rapidly, hearing loss and heart attacks. The best evidence of efficacy is the use of HBOT in chronic wounds, especially related to diabetes. It’s also pretty useful for treating cases of the bends.

But as to the muscle soreness, sprains, and other football-related pains for which Tim Tebow trucks around his monoplace chamber, nine studies examining 219 participants have been published—yielding no evidence that HBOT does any good. If anything, studies suggest that HBOT recipients suffering from muscle soreness ended up experiencing more pain.

A particularly poignant potential application is the use of HBOT for autism. Cochrane has not yet trained its steely gaze on the issue, so we are left with the raw medical literature. The results are spotty at best and suggest both utility and futility. More work will need to be done before any confident statement can be made regarding this possible use.

So only the slimmest evidence supports the expensive HBOT for much of anything. Unfortunately, there is no evidence that anyone pays much attention to evidence. HBOT is just another foot soldier in the titanic struggle between those seeking objective measures of efficacy—the evidence-based movement in medicine—and the public’s fondness for a faith-based view of reality, an approach that gives you the OK to ignore any evidence (global warming, evolution, losing 25 pounds in 25 days without eating less) that doesn’t make you happy. After all, what chance does mere human observation have against the soaring fantasy-land edifice created by persons of strong faith who dream of a better yesterday? The current evidence would suggest none whatsoever.

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