Did hyperbaric oxygen therapy really reverse brain damage in a two-year-old girl who nearly drowned?

Eden Carlson (Eden Carlson Miracles / Screenshot)

The apparent success of scientists in reversing brain damage in a two-year-old who nearly drowned in a swimming pool has been called a “miracle” by her family.

Doctors at the LSU New Orleans School of Medicine said they used hyperbaric oxygen therapy, which involves breathing pure oxygen in a pressurised enclosed chamber, to revive toddler Eden Carlson after the accident that left her without a heartbeat for two hours.

But experts have reacted to the news with scepticism, with one noting “there has been a long history of claims for hyperbaric therapy which have not been supported by evidence”.

Eden’s mother Kristal Carlson, from the southeastern US state of Arkansas, told ABC’s Good Morning America she found her daughter “floating face down in the water” at their home in the southeastern US state of Arkansas.

“She had gone through her baby gate, pushed open a heavy door, and gotten into the pool. When I found her, I immediately pulled her out of the water and started CPR,” said Ms Carlson.

The toddler, who is said to have spent at least 10 minutes underwater, was rushed to hospital, where doctors saved her life but confirmed she had suffered serious, irreversible brain damage.

Five weeks later, she was discharged from hospital and her parents were given an oxygen tank so they could quickly resuscitate her if she stopped breathing.

Desperate to find a treatment for their daughter and having researched hyperbaric oxygen therapy online, Ms Carlson and her husband Chris contacted Dr Paul Harch, a clinical professor at Louisiana State University in New Orleans.

Dr Harch offers the experimental treatment, which has long been used to treat divers suffering from decompression sickness known as 'the bends' but is not approved by the US Food and Drug Administration (FDA) as a medical treatment for other diseases.

The FDA website states that “hyperbaric oxygen therapy (HBOT) has not been clinically proven to cure or be effective in the treatment of cancer, autism, or diabetes” despite “all kinds of claims” made online that it can be used to treat these and other diseases.

Dr Harch told the BBC he advised Eden’s parents not to use the oxygen tank they had been given “just for rescue”, but to “give her the oxygen a little bit in her nose 45 minutes twice a day”.

“I told them to video her from right before and then after these initial treatments. I’ve done this before with other patients, adults, and I knew we had a chance to improve this child,” he said.

Video footage posted by her parents on a Facebook page titled “Eden’s Miracles” appears to show the girl making a marked improvement, from barely responsive to smiling, laughing and playing.

“What was captured on video was the near immediate improvement in her condition. We did this for three weeks at home until they could come to New Orleans where I could give them some hyperbaric therapy. Once that was done she had an immediate boost in her level of neurological function again,” said Dr Harch.

“The surprise was when she went home and was walking, and her speech was at a level beyond what we had at the drowning.

“We repeated the MRI of the brain showing that the shrinkage of her brain that had happened in the hospital had almost completely regrown, which was unprecedented.”

When questioned on whether this could bring hope to others who have had brain injuries, Dr Harch said: “Unquestionably. It is so low risk. There is almost no downside to this, and the potential is huge, as we found out here.”

But while the reported improvement in Eden’s condition is unquestionably good news, some doctors remain unconvinced hyperbaric oxygen therapy is the reason for her recovery.

Dr Oliver Sykes, a consultant anaesthetist at University College London Hospitals (UCLH) who is himself a hyperbaric physician, offering the treatment to divers in emergencies, told The Independent hyperbaric therapy “is not a recognised treatment for brain injury, as occurs for example during drowning”.

“We don’t use hyperbaric therapy for anything like this in the UK,” he said, adding that Dr Harch’s claims “seem far-fetched to me”.

“I can’t think of a reason why what has been reported would have happened, and I’d be very surprised if this was a repeatable result. I haven’t heard of this kind of reported outcome before.

“In the UK we know hyperbaric therapy is good for things like the bends, experienced when divers surface too rapidly; and for arterial gas embolism (when gas bubbles are introduced into the bloodstream) – NHS England funds hyperbaric therapy for those two things.

“In the US, hyperbaric therapy is also used for treatment of diabetic foot ulcers, but whether it works for that is more controversial in this country.

“There has been a long history of claims for hyperbaric therapy which have not been supported by evidence. There has been some research looking at whether there could be benefits after hypoxic brain injury (similar to what happens during drowning) but this has only been looked at in rats.

“There is no evidence in humans that supports the suggestion that hyperbaric therapy could be effective in treating brain damage suffered after drowning.

“If the claims made here were true I think we’d know about it by now.”

The FDA website says that hyperbaric therapy has not been “proven to be the kind of universal treatment it has been touted to be on some Internet sites”, raising concerns some of the claims made by HBOT treatment centres “may give consumers a wrong impression that could ultimately endanger their health”.