Breathing through Butts?
You’re probably breathing while you’re sitting here reading these sentences. Down, via your lungs, through the upper respiratory tract, which involves your mouth and nose; up, out the same way, after delivering the vital oxygen payload.
We believe that this is how most mammals breathe, but it’s possible that this isn’t the case. Rodents and pigs can even breathe from their butts, according to new findings.
New Way to Ventilate Patients
If the same strange capacity can be demonstrated in humans, delivery of oxygen through their rectal intestines like in pigs and rodents suggests a new, enema-like method of ventilating patients in respiratory distress.
Intestinal respiration can sound strange, but it’s been known about for a long time – at least in fish. Some aquatic animals, such as sea cucumbers, freshwater catfish, and freshwater loaches, may increase their oxygen intake by breathing through their guts in emergency low oxygen, or hypoxic, conditions.
Naturally, this posed the intriguing question of whether other species, including mammals, would do the same. Despite the odds, a group of Japanese and American scientists led by Kyoto University thoracic surgeon Ryo Okabe agreed to find out, in the hopes of evaluating the viability of rectal ventilators for human patients.
Testing is Important
Gastroenterologist Takanori Takebe of the Tokyo Medical and Dental University and the Cincinnati Children’s Hospital Medical Center said that artificial respiratory support is crucial in the treatment of respiratory failure caused by serious illnesses like pneumonia or acute respiratory distress syndrome. Our approach may offer a new model for supporting critically ill patients with respiratory failure, but the side effects and safety must be carefully tested in humans.
Standard treatment solutions for patients with respiratory failure depend on mechanical ventilation or artificial lung systems, as the team points out; however, due to the current pandemic, there is a critical shortage of such instruments, and a safe alternative approach could provide life-saving additional support for patients in desperate situations.
Their test subjects were mice at first, but they were luckily anaesthetized for the next part. The researchers created an anally implantable oxygen ventilation system, induced hypoxia via tracheal intubation, and compared mice ventilated via the intestine to mice who did not receive any ventilation.
Not a single control mouse lived for more than 11 minutes. In comparison, mice given intestinal oxygen lived for an average of 50 minutes, with 75% of them surviving.
It took abrasion of the intestinal mucosa to achieve the most effective oxygen delivery to the gut lumen, which is a fascinating finding. The mice who were given intestinal ventilation without abrasion lived for just 18 minutes on average.
Since gut abrasion is unlikely to be feasible for human patients – especially those who are sick enough that intestinal ventilation is a viable choice – the team looked for other options.
They used liquid perfluorochemicals, which are chemicals in which the hydrogen atoms have been substituted with fluorine.
What was Ensured?
These have a number of characteristics that make them a good candidate for ventilation, including high gas solubility and physical properties. Patients with respiratory failure have been treated with liquid perfluorochemicals in the past, with varying degrees of effectiveness, by partially filling their lungs to allow oxygen transfer. For this reason, perfluorochemicals have been deemed clinically safe.
As a result, the researchers experimented with enriching a perfluorocarbon with oxygen and treating mice, rats, and pigs with it.
The mice were put in a low-oxygen chamber; those who were given perfluorocarbon ventilation were able to walk for longer periods of time and had more oxygen enter their hearts than those who were not. Rats were also given the perfluorochemical to see if it was absorbed by their bodies and if it was clean.
Finally, respiratory distress was minimised in anaesthetized pigs under non-lethal hypoxic conditions using perfluorochemical intestinal ventilation. Their skin became warm and flushed, and their oxygen levels rose, all without any noticeable side effects.
So Next are Humans? Will it work ?
It’s uncertain if a similar strategy will work in humans, but the researchers are hopeful.
Takebe said that it’s uncertain if a similar method will work in humans, but the team believes that the amount of arterial oxygenation provided by our ventilation system, if scaled up for human use, would likely be adequate to treat patients with serious respiratory failure, potentially saving lives.
You can read the findings published in Med.