Cornell veterinarians have developed a method for intubating cats that helps veterinary students complete the procedure more easily, reducing the risk of airway trauma during surgery.

Tracheal intubation – the placement of a flexible tube in the breathing pipe – is a vital part of general anesthesia; it is used to provide oxygen and anesthetic gases, monitor breathing and protect the airway from foreign materials. Cats typically have a strong laryngeal response, where the throat closes to prevent materials from entering their airway. During intubation, this may lead to pushing harder on the endotracheal tube, which can cause trauma.

The new method uses a tool – a thin, flexible tube called an endotracheal tube introducer (ETI) – previously reserved for especially difficult cases. The veterinarian threads the flexible tube down the cat’s airway first, and then uses it to guide the endotracheal tube more easily.

“I have always found cats more difficult to intubate, so I started using this tool every time I intubated a cat, and I found it easier,” explained Dr. Manuel Martin-Flores, lead author of the paper, and associate professor of anesthesiology and pain medicine at the College of Veterinary Medicine. “I began teaching my students to use it every time, and many of them found it easier as well.”

In a study published this summer in the Journal of the Veterinary Medical Association, Martin-Flores and his colleagues observed veterinary students intubate 125 cats, half using the new method with the flexible tube, and half using the traditional method.

A team from the College of Veterinary Medicine collaborated on the study, including veterinary anesthesiologists, students and technicians. “This research would not be possible without the help of our entire team,” Martin-Flores said.

For students using the new method, 79 percent intubated the cat successfully on the first attempt; using the traditional methods, only 46 percent were successful on the first attempt. Both methods took about 30 seconds to complete.

“An anesthesiologist is a specialist at a few levels; perhaps the most important one is at airway instrumentation and management,” said Dr. Luis Campoy, clinical professor of anesthesiology and pain medicine at the College of Veterinary Medicine and a co-author of the paper. “Cats present an airway that can pose more of a challenge than dogs. This piece of equipment was developed in the human field to facilitate endotracheal intubation when visualization of the larynx was either partially or greatly compromised. Our study proves that it helps our professionals carry out endotracheal intubations in a more efficient way.”

There is another benefit to using the ETI for every case: students learn how to manipulate the tool efficiently. This prepares them for handling more difficult cases when they arise.

“When using the ETI, you have to change the way you hold the tracheal tube so that you can hold both in one hand,” Martin-Flores said. “As a trainer, I would like students to be familiar with this technique before an emergency occurs. We want to train for the unexpected before it’s here.”

Martin-Flores hopes the method will help other veterinary trainers and students, and ultimately improve the surgical care for cats. “The more we help each other, the better for the cats, the owners and the veterinarians too,” he said.

Written by Sheri Hall