Statistics from Altmetric.com
ANAESTHETISING pigs is difficult. This species presents a number of challenges to veterinarians embarking upon the mission of rendering these muscle-bound, vocal powerhouses unconscious in a controlled and gracious fashion. It is difficult to perform a thorough physical examination, venous access is limited, endotracheal intubation is tricky, pigs have a rapid growth rate and they present in a range of sizes from 500 g to 400 kg. Despite these challenges, pigs are presented for anaesthesia frequently as they are one of the major animal species used in translational research and surgical teaching (Thurmon and Smith 2007, Swindle and others 2012, Larsson and others 2015) and their popularity as pets is increasing.
Pigs are also known for their predisposition to malignant hyperthermia, which is a genetic hypermetabolic disorder that manifests as hypercapnia, cyanosis, hyperthermia, acidosis and skeletal muscle contracture following exposure to triggers such as inhalant anaesthetics, depolarising neuromuscular blockers and stress (Do Carmo and others 2010). This syndrome is an anaesthetic crisis and warrants prompt management or euthanasia. Malignant hyperthermia is most prevalent in breeds with a high ratio of muscle to total body mass and rapid growth but with genetic testing the incidence of this condition is decreasing (Thurmon and Smith 2007).
For most species, the approach to anaesthesia starts with a thorough preanaesthetic examination and review of the animal's history and test results. Pigs are very difficult to examine and the magnitude of the observer effect cannot be understated as these animals mount a definite physiological response to physical restraint. Consequently, most preanaesthetic examinations of pigs involve observations from a distance of body condition, gait, temperament, respiratory rate and character. Reviewing the history and test results may not be possible as …