Mammals Can Breathe Through Anus in Emergencies

How the heck?:

A team of Japanese scientists has shown it is possible for mammals to absorb oxygen via the anus.

Intrigued by how certain sea creatures breathe through their intestines in emergencies, researchers at Tokyo Medical and Dental University were able to prove the same was true under experimental circumstances for mice, rats and pigs, publishing their findings in the journal Med on Friday.

..."The rectum has a mesh of fine blood vessels just beneath the surface of its lining, which means that drugs administered through the anus are readily absorbed into the bloodstream," lead author Ryo Okabe said.

This made the team wonder whether oxygen could be delivered into the bloodstream in the same way.

To answer the question, they decided to carry out experiments on oxygen-deprived mice, pigs and rats using two methods: delivering the oxygen into the rectum in gas form, and infusing an oxygen-rich enema via the same route.

The researchers prepared the lining of the rectum by rubbing it to cause inflammation and increase blood flow, which improved the effectiveness of oxygen delivery.

However, since such a preparation would likely be unacceptable for humans, they also tried using oxygenated perfluorodecalin, a liquid that has already been shown to be safe and is in selective clinical use. 

Delivery of oxygen both as gas and in liquid form increased oxygenation, normalized the animals' behavior and prolonged their survival.