Schnobel Prize-winning "rectal breathing" method successfully tested on humans

Scientists have tested a method of rectal ventilation on humans for the first time and confirmed its safety, Cincinnati Children's Hospital Medical Centre reports.

This is a concept in which oxygen is delivered to the body not through the lungs, but through the colon - with the help of a specially oxygenated liquid. The researchers call it enteral ventilation. The idea may sound absurd, but it has the potential to save lives in cases of severe trauma, inflammation or infection where traditional breathing is not possible.

The method involves injecting oxygenated perfluorocarbon liquid into the intestines, similar to an enema. The oxygen is absorbed into the bloodstream through the intestinal mucosa - similar to what happens in the gills of fish. The project was inspired by bream, which can survive in oxygen-poor waters by absorbing air through the intestines.

In the study, 27 healthy volunteers in Japan had various volumes of perfluorodecalin (the liquid was not yet oxygenated) kept inside their bodies for 60 minutes. Twenty participants tolerated the entire allotted time, including the maximum volume of 1.5 litres. Side effects were limited to discomfort and abdominal bloating - no serious complications were recorded.

"This is the first clinical confirmation of the tolerability of the method. We have not yet evaluated its effectiveness in oxygenating the blood, but now we are ready to move forward," said project leader Dr Takanori Takebe, an organoid specialist at Cincinnati Children's Hospital and Osaka University.

The idea is not new: back in the 1980s, scientist Leland Clarke developed a liquid called Oxycyte that could serve as a substitute for blood. It was inspired by the famous scene in the film The Abyss (1989), where a rat "breathes" the liquid underwater.

The current development of the project relies on both those developments and innovative approaches in cellular and transplantation medicine. A startup EVA Therapeutics has already been established to commercialise the technology.

In the future, scientists expect to conduct repeated tests with oxygenated liquid, measuring the efficiency of oxygen delivery to the blood. They are also considering the possibility of applying the method in neonatal (newborn) medicine.