The Pig Behind the Mask: Creation of an Anesthesia Mask to Fit Big Pigs. Melissa Davis, AS, LATg; Alexandria Moen, BS, RLATg; and Misty Williams-Fritze, DVM, MS, DALCAM.
Gas anesthetics are safe, effective, short acting agents frequently administered to swine. Typically, gas (either isoflurane or sevoflurane) is administered in combination with oxygen through a vaporizer and delivered via a nose cone over the pig’s snout or through an endotracheal tube. Gas anesthetics are used for induction of anesthesia to enable sedation, as well as endotracheal intubation and general anesthesia. A properly fitting nose cone covers the
entire mouth and nose of an animal to ensure that they breathe in only oxygen combined with isoflurane or sevoflurane and exposure of waste gas to staff is limited. Typically, anesthetic masks marketed for canine patients are utilized and work very well for small pigs. However, this is not the case for larger sized animals. In sows, this is primarily due to their large size; in boars, additionally, there is tusk development along with square, cheeky, jowls. Larger nose cone options are not available for purchase. Therefore, we sought to fashion an anesthetic mask able to fit a larger animal with readily available materials.
Inspiration was found via collaboration with colleagues, google images from zoos, and Society for Pediatric Anesthesia. Over the course of a few generations of test masks, we found that using 1 gallon hard plastic jugs with 2 L bags (cut in half) attached to the opening are very effective for creating a mask that is able to be used on big pigs (>100 kg). For even larger swine (>300 kg), a 1 gallon water jug with a 4 L bag (cut in half) also proved effective. Each bag is fixed to the jug with durable tape, as it proved more pliable than super glue and other fixatives. A circle is drilled in the cap of the jug for connection of a standard breathing circuit. The connector is secured with electrical tape.
To conclude, large animal anesthesia nose cones can be made with cost- effective supplies that are readily available in any veterinary or research facility. We continue to improve and refine the model with every use and search for improved durability and functionality. Overall, this is a safe and effective way to successfully mask extremely large swine and can be applicable across other species in various settings requiring sedation and anesthesia.