A while back I read JaneA Kelley’s article on the use of cats for breathing tube training at Washington University in St. Louis. I have been mulling it ever since.
Here are the basics of the story: According to JaneA, Washington University’s medical school, despite protests from animal rights groups and doctors’ groups, maintains a group of nine cats for training purposes. The cats are used in pediatric life support training. Specifically, the cats are used to train students to perform a technique called intubation. Many people believe that human simulators are not only more humane, but more effective. JaneA discussed many ethical and humane concerns in her article. I largely agree with them.
Intubation is a crucial skill for any medical practitioner. It allows practitioners to “secure the airway,” which is crucial for performing anesthesia, CPR, and ventilatory assistance. It protects against aspiration, a devastating condition in which vomit, food, or other debris is inhaled into the lungs leading to severe pneumonia.
Intubation is performed by passing a breathing tube (called an endotracheal tube) through the mouth, through the vocal cords (the larynx), and into the windpipe (trachea). There is no doubt that every medical practitioner must be proficient at intubation.
There also is no doubt that people, and especially infants and children, are hard to intubate. JaneA’s article cites a statistic that only 20 percent to 35 percent of pediatric residents succeed in intubating infants on their first try (no mention is made of second, third, fourth, and fifth tries, all of which can occur within a minute on the same individual).
Given the critical nature of the procedure along with its difficulty, some might say that it makes sense for residents to have some experience passing tubes through real larynxes in addition to simulators before being unleashed upon the innocent children of St. Louis.
Although such a notion makes sense in theory, there is a significant problem: anatomy. When it comes to intubation, cats are like oranges and humans are like apples. And I know from personal experience that proficiency at peeling oranges does not provide much help when it comes time to peel an apple.
Simply put, cats are easy to intubate. Their mouths extend across the majority of their faces. Their temporomandibular joints allow their mouths to open to gaping proportions. The larynx (voice box) can be visualized without using any instruments (although a laryngoscope is often used to make the procedure even simpler). The approach is straightforward. Place the cat on its stomach and approach from the front. Retract the tongue, and visualize the larynx. Wait for the cat to take a breath, and the larynx will open. Slip the tube into the larynx when it’s open and affix the tube in place. If the cat’s larynx spasms closed during the attempt, simply wait for the spasming to end (or place a drop of a numbing agent on the larynx) and try again. Most people can become proficient at intubating cats within a day.
Compare this to humans. Our narrow little mouths barely open at all. Our larynx is deep in our throat and very hard to visualize even with a laryngoscope. The approach to intubation is the exact opposite of that in cats: People are placed on their backs, and they are approached from behind their heads. It can require a great deal of experience to attain proficiency in the procedure.
Washington University is a well-respected institution, and I have no doubts that it follows humane best practices with its group of cats. But I also strongly doubt that the procedures performed on the cats are providing any true benefit to the residents or, more importantly, to the children they serve.
In fact, when I was in veterinary school it was repeatedly emphasized that cats and dogs serve as poor intubation models for primates (we don’t study humans, but we do study our closest relatives — and we are all primates). It turns out that there is actually a far better model for human intubation: pigs.
In laryngeal anatomy as in so many things, the similarities between pigs and humans are striking. The approach to intubation is the same in both species. And although I’ve never intubated a primate, I have attempted the procedure in pigs. Note that I say “attempted”; those guys are seriously difficult to intubate. During my vet school porcine intubation laboratory, several nursing students also were present. I don’t believe any student in the class, vet or nurse, successfully placed an endotracheal tube that day.
And what of the ethics of that laboratory? I was too young and na├»ve to spend much time worrying about it at the time, but the ethical concerns are the exact same as they would be for cats. Pigs, despite their bad reputations, are intelligent creatures with rich emotional lives. I would never dream of participating in such a laboratory in my current life.
Although I am not opposed to all animal use and research (some research is impossible to perform outside of animal models, and that research benefits not only humans but also animals), I do strongly believe that the highest standards of enrichment and humane care need to be followed at all times. And, even more, I believe that there has to be some potential tangible benefit to humans and animals when animals are used by people for training or research. In many cases the potential benefits can’t be known until after the research is performed. I don’t believe the Washington University program is such a case. It is my opinion that the cats used in the program provide minimal benefit to anybody. I agree with the doctors who protested the training. It simply doesn’t make sense.
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