Researchers are investigating a radical new method of oxygen delivery: administering oxygen-rich liquid rectally. While unconventional, the approach could offer a temporary solution for critical oxygen shortages, though experts remain skeptical about its practicality.
The Quest for Alternative Oxygenation
The research, led by Takanori Takebe of Cincinnati Children’s Hospital Medical Center and the University of Osaka, began after witnessing the invasive nature of traditional ventilators. Takebe’s initial concern stemmed from his father’s pneumonia treatment, sparking a search for alternative oxygen delivery methods.
Inspired by animals like loaches—which absorb oxygen through their intestines—Takebe hypothesized that the human rectum, with its rich blood supply, could serve as an oxygen absorption point. This idea builds on the fact that enemas already deliver medicine into the bloodstream.
The Science Behind It
The process involves administering perfluorodecalin, a liquid capable of holding high concentrations of oxygen, into the rectum. Studies in mice and pigs demonstrated that this method could sustain oxygen levels for up to 30 minutes. The liquid releases oxygen into the bloodstream while absorbing carbon dioxide.
Early experiments revealed a visible change in blood color—shifting from deoxygenated to bright red—confirming oxygen absorption. The research even earned an Ig Nobel Prize in 2024, recognizing its blend of humor and potential impact.
Human Trials and Safety
Recent trials with 27 healthy men tested the safety of administering perfluorodecalin rectally. Most participants tolerated up to 1 liter of the liquid with mild discomfort (bloating, tummy pain). However, larger doses (1.5 liters) caused stomach pain in some, forcing early termination.
These findings suggest the treatment is physically tolerable, though efficacy remains unproven. Takebe’s company, EVA Therapeutics, is pursuing further development.
Skepticism and Potential Applications
The approach has drawn mixed reactions from the medical community. Dr. John Laffey of the University of Galway argues that lungs, even damaged ones, are far more efficient at gas exchange. He notes that the volume of oxygen delivered rectally is minimal compared to metabolic demand, making sustained support impractical.
Dr. Kevin Gibbs of Wake Forest University School of Medicine is more open-minded. He suggests the method could be useful as a short-term bridge during emergency situations where intubation is delayed. In such cases, temporary rectal oxygenation could stabilize patients until full life support is established.
Conclusion
Rectal oxygenation remains a highly experimental field. While safety concerns appear manageable, its practicality is still uncertain. The technique represents a desperate measure for oxygen emergencies, but whether it will become a viable clinical option remains to be seen.
