In the new report, the authors describe the case of 2-year-old Eden Carlson, who fell into her family's swimming pool last year and was submerged in 41-degree-Fahrenheit (5 degrees Celsius) water, for about 15 minutes.
The saga began with every parent's nightmare.
On the day she nearly drowned, Eden's mother found her and pulled her out, then performed CPR on her. Doctors at the local hospital in Fayetteville, Arkansas, were able to revive her two hours later. Over the next 23 days, the doctors reported the girl laughing, making short sentences, and increasing the movement of her limbs. Alive, but just barely. The little girl's heart had stopped beating.
Recovery can happen because of the brain's plasticity, or flexibility, meaning that different brain areas can take over for those that have been damaged, Cifu said. "And when they did, she had lab values that you rarely see in a living human being".
The two-year-old girl had experienced a cardiac arrest after a drowning accident in a swimming pool, leading to substantial grey and white matter loss in her brain. She was losing both gray matter - critical to muscle control, sensory perception and speech - and white matter, the network of central nervous system wiring that makes up the lion's share of the brain. The lack of oxygen caused a severe brain injury, leaving her unable to speak, walk, or even provide a response to verbal cues.
The tide only started to turn at the two-month mark, when under the guidance of Harch, Eden started undergoing HBOT, the therapy that he describes as the "most misunderstood therapy in the history of science".
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".
"The largest clusters of genes that are turned on are those that code for growth and fix hormones, i.e. heal wounds, and the largest clusters that are turned off are pro-inflammatory genes and those that code for cell death".
"We were early in the entry process", said Dr Paul Harch, of Louisiana State University. "Although it's impossible to conclude from this single case if the sequential application of normobaric oxygen then HBOT would be more effective than HBOT alone, in the absence of HBOT therapy, short duration, repetitive normobaric oxygen therapy may be an option until HBOT is available". They called his clinic near New Orleans to see if hyperbaric treatment could bring her back. Her family traveled to New Orleans for he next phase of treatment, where she went into a hyperbaric chamber for 45 minutes per day, five days a week, for 39 sessions. After just 10 short sessions, she had nearly completely recovered.
She was able to walk and speak better than before the accident, and improved in all of her neurological, motor function and cognition tests. That was evident in the MRI scans of her brain.
"And that is nearly never seen", he added.
Harch noted that the regrowth of the tissue due to the therapy was possible because they were working on a young child.
Studies on hyperbaric oxygen for treating brain injury have had mixed results, with some studies suggesting a benefit in the case of stroke patients, while other studies, like Cifu's research, finding no effect.
Still, Harch believes the therapy could be useful, and he doesn't believe this positive outcome is age-dependent.
Because HBOT was inaccessible at the patient's location, doctors first administered normobaric oxygen therapy to prevent further brain tissue degeneration while the child is not yet in a treatment center for HBOT. "But the potential benefit is incredibly encouraging".