3Rs-Centre Utrecht Life Sciences

Faculteit Dierengeneeskunde

January 2018
Refining anaesthesia with a supraglottic airway device

Yvonne van Zeeland, a specialist in avian medicine from the Division of Zoological Medicine of Utrecht University’s Clinic for Companion Animals, and her colleagues, were awarded a grant from the Utrecht University and University Medical Centre 3Rs Stimulus Fund for their research proposal “Refining anaesthesia procedures for guinea pigs, rats and mice through the use of species-specific supraglottic airway devices”. This could be a breakthrough in refining animal experiments in which anaesthesia is applied.

Yvonne van Zeeland and her colleagues are hoping to refine the techniques used for anaesthetising animals, both patients and laboratory animals. “Some of these techniques may cause discomfort to the animal,” explains Van Zeeland. “When intubating an animal, a relatively rigid silicone tube is inserted into the trachea in between the vocal cords. People who have been intubated often experience a sore throat afterwards, so it is likely that this occurs in animals too.” There can also be complications like spasms of the vocal cords, bleeding, swelling or formation of scars and strictures. For people, a good alternative has been developed, a so-called laryngeal mask or supraglottic airway device. This device is much softer and is positioned over the larynx, so that it does not have to pass through the vocal cords. Van Zeeland is now developing these airway devices for different animal species, and adjusting them to the anatomy of the throat area of the species, which is essential for the device to function properly. They are conducting the research in cooperation with the Central Laboratory Animal Research Facility of Utrecht University and the UMC Utrecht.

Origin of the device
The company that developed the device for people also wanted to have these devices developed for animals. In 2009, they approached Van Zeeland and her colleagues to see if they were interested in collaborating in the design process. The initial devices that were developed were predominantly designed for species commonly seen in the veterinary practice: dogs, cats, horses, and rabbits, which the clinic employees were happy to work on. “After all, we are veterinarians and want to provide animals the best possible care,” says Van Zeeland. At some point, these veterinarians also wanted to apply the same technique on laboratory animals. After all, there may not be too much surgery performed on pet rodents in veterinary practices, but it is quite common in animal experiments. Van Zeeland: “We want laboratory animals to have similar welfare benefits as pets.” In her studies, she has seen that supraglottic airway devices can be inserted easily and quickly without causing damage to the airway. This results in shortening of the anaesthetic procedure, and minimizes the discomfort experienced by the animal when it wakes up. Therefore, the device refines the surgical procedure. Furthermore, there is a lower risk of serious complications, which reduces drop-out, thus fewer animals are needed.

They made their first designs for the masks using cadavers that were plastinated by experts from the Pathobiology department. Once they were satisfied with the first prototypes, they fit them on fresh cadavers. Often they had to make some minor adaptations to refine the masks even more before going on to test them on live animals. Van Zeeland: “We found research groups performing experiments that already called for the animals to be put under terminal anaesthesia, so that additional discomfort wouldn’t be an issue, and we wouldn’t need any extra animals.” They have cooperated in this way with researchers from the University Medical Center Utrecht, the VU University Medical Center and the Academic Medical Center in Amsterdam.

Supraglottic device for rabbits,                            Dr. Yvonne van Zeeland
already available.

Future steps
Van Zeeland and her colleagues have now successfully developed and tested the devices for guinea pigs and for rats, and they have come a long way with mice. “We are about to start a study comparing ease of use, functionality and safety of the devices with the current methods, endotracheal intubation and face masks. We’ll compare the time needed to intubate versus placing the device, the quality of the anaesthesia, the level of fit and presence of leakage, and the presence and severity of tissue damage. Similar to the initial studies, we will again be trying to fit our research into existing experiments so that we need as few extra animals as possible.”

Van Zeeland is definitely hopeful about the results. So far, the animals on which they have used the devices recovered quickly and smoothly from anaesthesia, and researchers have even performed successful open-chest surgeries on guinea pigs using the devices. Nevertheless they have to wait for the results of the comparative studies to prove that the mask performs better in all areas. If the results are positive, Van Zeeland expects that the masks will be brought to the market within a year. And since pigs are used quite a lot for experiments as well, there are also plans to start developing a supraglottic airway device for this species.

The 3Rs Stimulus Fund
The grant by the 3Rs Stimulus Fund enabled dr. Van Zeeland and her colleagues to perform the comparative studies, which are essential to prove scientifically that the supraglottic airway device does what it is supposed to do, and that it is an improvement compared to the current methods. In principle, the manufacturer does not need this research to launch the product. Van Zeeland: “Strangely enough, the strict registration procedure required for drugs is not applicable to medical devices. But the company is committed, and wants animals to really profit from its products. And as researchers, we want to demonstrate that the devices we have developed perform better than the current methods. The funding we have obtained from the 3Rs Stimulus Fund enables us to obtain the scientific evidence to support this claim.

The 3Rs Stimulus Fund is a fund of University Utrecht and the UMC Utrecht for employees’ research initiatives aimed at Replacement, Reduction and Refinement of animal experiments.