Despite past clinical trials demonstrating that exposure to
pure oxygen can help stubborn wounds heal, a large new study of diabetes
patients with severe foot ulcers finds no benefit from oxygen treatments and
possibly some harm.
Researchers following more than 6 000 diabetes patients
receiving treatment for deep foot wounds found that patients who got
oxygen-chamber treatments along with standard wound care were no more likely to
heal and more than twice as likely to undergo amputations as those getting
standard care alone.
The results, published in the journal Diabetes Care,
surprised the study team from the University of Pennsylvania, not least because
they defy so much previous research."We really thought we would see a
replication of what occurred in the randomised trials.
How the study was
The data demonstrates
that didn't come to pass," said Dr Stephen Thom, a professor at the
Perelman School of Medicine in Philadelphia who worked on the study.
For more than 20 years, people with serious open wounds or
burns have been put into pressurised chambers or rooms that expose them to pure
oxygen, in the belief that it helps to promote tissue growth and speed healing.
Because of nerve and blood vessel damage, people with
diabetes are at risk of persistent ulcers forming on their toes and heels -
wounds that can become infected and even lead to gangrene and amputation.
Oxygen treatments are sometimes added to standard care of diabetic foot wounds
to enhance healing.
Experts’ studies oxygen
For the new study, researchers wanted to see whether the
oxygen therapy was making a difference in real-world settings. They analysed
data on 6 259 diabetes patients treated for foot ulcers at wound care centers
around the US between November 2005 and May 2011.Of those patients, only 793
ended up having the oxygen therapy on top of standard care.
Their sessions lasted from 45 minutes to two hours in the
pressurised chambers, and were done once or twice per day over four to five
times per week. Thom told Reuters Health that such treatments typically cost
between $300 (R2 669) and $600(R5 338) per session.
After 16 weeks, about 43% of oxygen therapy patients had
fully healed wounds, compared to about 50% of patients who did not use oxygen
therapy. And about 7% of oxygen therapy patients had an amputation, compared to
just 2% of those who did not get oxygen treatments."It does not only say
it's not equal, it says it may be worse.
You're seeing a higher amputation rate and a longer healing
of a foot wound," said Dr Nicholas Morrissey, a vascular surgeon at New
York-Presbyterian Hospital. But Morrissey, who was not involved in the new
research, also noted that all the previous studies and trials to have looked at
oxygen therapy have had limitations, as did this one.
More studies needed in
The authors point out in their report as well that further
study is needed to better understand the current results and the effects of
For example, the team
attempted to adjust for issues that might have influenced the outcomes, such as
whether patients with worse wounds or additional illnesses might have been more
likely to get oxygen treatments.
But the nature of the
study makes it impossible to know for sure, they write."It certainly could
be that they're picking people who are more severe (for oxygen treatment), but
we tried to compensate for that," the study's lead author Dr David Margolis,
also from the Perelman School of Medicine, told Reuters Health.
"It's like many things in medicine, it's just one other
study and you have to look at the totality of the information available,"
Morrissey said that until a definitive study is done,
patients shouldn't be afraid or concerned that they're going to have an
amputation after oxygen therapy."As a physician who takes care of these
wounds all the time, I wouldn't tell patients to be concerned... I would not
take that home from this paper," he said.