Oxygen-deprived patients may have a better chance of surviving the next time a COVID-19-like pandemic emerges and ventilators are a rare commodity, thanks to new research from doctors in the US and Japan.
However, there is a catch: they will have to breathe through their bottoms.
That’s the gist of the recently published study showing that mammals given an oxygen-enriched liquid enema were able to absorb that oxygen into their blood.
His research, conducted so far in mice, rats and pigs, shows that some mammals were able to absorb oxygen through their rectums efficiently enough that their blood was oxygenated even when undergoing respiratory failure.
The technique, called enteral ventilation through the anus (EVA), tested two methods of oxygen delivery: one in which oxygen gas was bubbled into the intestine and the other in which an oxygen-saturated liquid called perfluorocarbon was pumped, in the form of an enema. .
The researchers found the latter technique to be more effective, establishing the possibility of compact, enema-like kits that could be widely distributed for purposes as diverse as immediate oxygenation for drowning victims or ongoing help for patients with respiratory distress for whom ventilator intubation is necessary. not possible or available.
“Essentially, if we infuse, for example, 500 ml of the oxygen-containing fluids, we may be able to help patients with respiratory failure (induced by COVID-19),” said lead author Takanori Takebe. “There may be some indication that we could save patients in various respiratory distress conditions with our simple option.”
The research has not yet entered human trials, but, if sustained, Takebe says, infusion of oxygen through the rectum, in some circumstances, could provide a temporary remedy for patients who might face ventilator shortages, as was the case in the early days. of the pandemic.
The lining of the small intestine is highly vascular (it has many blood vessels relatively close to the surface) and doctors have taken advantage of this for decades to administer medications anally, via suppositories.
But those suppositories have been designed to be absorbed rapidly through the mucous lining of the intestine, and it turns out that that mucous membrane makes it difficult for mammals to absorb oxygen gas.
“Over time, we found that this approach to delivery in liquid form is a more robust approach for clinical applications, because we can (provide) enough oxygen without any prior preconditioning of the gut,” Takebe said.
Perfluorocarbon is a liquid with a low surface tension, in which oxygen dissolves easily. Its use is nothing new: it has been used in the lungs to aid ventilation, to administer medications and even to aid in the induction of therapeutic hypothermia, after a heart attack, for example.
He also appeared in the movie “The Abyss” in which a character breathes liquid in an attempt to prevent decompression sickness while diving to the bottom of the ocean. So far, that practice hasn’t reached humans in the real world (actor Ed Harris was holding his breath during the scene), although the rat used to demonstrate perfluorocarbon earlier in the movie, reportedly actually breathing in the liquid and survived.
Takebe, a professor at Tokyo Medical and Dental University and an associate professor at Cincinnati Children’s Hospital Medical Center, said he was inspired by loaches, freshwater fish that can absorb oxygen through the anus and absorb it in the intestines.
Takebe said that a likely case of EVA use would be in conjunction with an oxygen mask to avoid the need and invasiveness of intubation ventilation. As an added benefit, infusing oxygen through the rectum would be less invasive than ventilators, which can damage the lungs.
Pending the results of the next trials, Takebe estimates that an initial dose of about 500 ml of perfluorocarbon could keep a patient oxygenated for about an hour, after which the fluid would have to be replaced.
“We can do this simply by manual injections of fluid, and patients can simply excrete or remove existing perfluorocarbons out of the body,” he said.
But developing the machinery for perfluorocarbons to automatically circulate through the body would take many years and add complexity and cost to the technique.
That limited time span of effectiveness could be the factor preventing VAS from being useful in real clinical settings, said John Granton, an intensive care physician at University Health Network in Toronto.
He said that when there is a shortage of fans, it is not just a matter of a few hours before the next fan is available.
“It’s interesting, but it certainly has a long, very long way to go,” he said of the investigation. “Maybe in some setting, where the lungs failed and we are considering ECMO (where blood is pumped out of the body, oxygenated and then replaced), if there was another alternative that would be great,” he said.
“He’s not entirely sure how much a perfluorocarbon could do that effectively. Is it just a temporary thing? Or can you continue with that for hours, days, and weeks? “
Takebe estimates that by the time his method works through a clinical trial, it will take approximately two years before a useful product is ready to be distributed to hospitals.
Granton, potentially one of the end users of that product, said there does not appear to be a clear link to clinical utility yet. Takebe’s research doesn’t seem to indicate that it could replace a ventilator, but it could provide supplemental oxygen for a period of time in case the lungs completely failed.
And any research that might make your life easier the next time a pandemic arises is research that he will watch with “cautious interest” as it progresses through the testing process, he said.
Reference-www.thestar.com