A Surprising New Solution For Low Oxygen: Breathing Through the RectumNews
The Problem: Patients suffering from lung failure are often put on ventilators, but as we have seen during the COVID-19 pandemic, these tools aren’t always readily available and can run out.
The Study: ‘Breathing through the rectum’ via a suppository containing oxygen seems to be a surprisingly effective strategy for treating oxygen deprivation, finds a new study in mice and pigs published in Med by NYSCF – Robertson Stem Cell Investigator Takanori Takebe, MD of Cincinnati Children’s Hospital and Tokyo Medical and Dental University.
Why it Matters: This study demonstrates the great potential of this new oxygen delivery system as a simple and scalable way to treat patients suffering from low oxygen.
Dr. Takebe was inspired to explore new solutions for low oxygen after watching his father’s battle with lung disease. He observed during the height of the pandemic that ventilator supply is limited, and started thinking about how we may be able to deliver oxygen by leveraging organs other than the lungs.
“We clearly need different strategies to help out patients with severe lung failure,” he told The New York Times.
Dr. Takebe turned his attention to the animal kingdom – specifically, fish. He learned that some fish absorb oxygen through their gills, but can also bob their heads above the water to breathe in air, which they absorb through their intestines.
Could mammalian intestines also absorb oxygen? Dr. Takebe first tested this theory by delivering oxygen gas to anesthetized, oxygen-deprived pigs and mice via their rectums. The method worked, but getting it to the required efficacy meant thinning out the intestinal walls – not very appealing for human patients.
The team then wondered whether a liquid would solve the problem. They used a perfluorochemical – a liquid that can absorb gases – to deliver oxygen to the pigs and mice through their rectums, and saw marked improvements in the animals’ oxygen levels. Mice regained their ability to walk, and the pigs’ pale skin returned to its signature pink.
“They are completely recovering from the very, very severe hypoxia,” said Dr. Takebe. “That was really astonishing to me.”
The method, while unconventional, makes sense given what we know about the body. The colon’s thin walls are particularly adept at delivering substances to the body (think: suppositories), and doctors have long known that the GI tract can absorb gases.
Next, Dr. Takebe hopes to adapt this method for human patients in need.
“I am really keen on pursuing the clinical translation potentials as fast as possible,” he said.
His new startup, EVA (an acronym for ‘enteral ventilation via anus’) is aiming to move the technique into clinical trials as soon as next year.
Caleb Kelly, MD, PhD, a gastroenterology fellow at Yale University who reviewed Dr. Takebe’s study, urges people to set aside their initial reactions to the method’s, well, ‘weirdness’, and focus on the results.
“It’s kind of a startling idea, to use that part of human anatomy for gas exchange,” he said. “But it really should be the data, rather than our visceral reactions to the concept, that guide us.”
Mammalian enteral ventilation ameliorates respiratory failure
Ryo Okabe, Toyofumi F. Chen-Yoshikawa, Yosuke Yoneyama, Eiji Kobayashi, Hiroshi Date, Takanori Takebe. Med. 2021. DOI: https://doi.org/10.1016/j.medj.2021.04.004
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