Canine and feline geriatric anaesthesia

As suggested by Wise et al (2002) approximately 30% of the veterinary population is geriatric. Many of these animals require anaesthesia for dental care, diagnostic or surgical procedures. There is wide species and breed variation in lifespan, therefore there is not one specific age which can define ‘geriatric’. Instead, the term geriatric is normally used to define those animals that have reached 75–80% of their expected lifespan. The chronological age does not always match the physiological age, therefore each patient must be evaluated as an individual (Carpenter et al, 2005). Factors influencing the ageing process include: breed, size, genetics, nutrition and environment (Neiger-Aeschbacher, 2007). Age is not a disease, however the likelihood of morbidity increases with age, and age-related physiological changes and diseases will affect the anaesthetic management (Carpenter et al, 2005). Brodbelt et al demonstrated in 2007 that dogs 12 years old or more were approximately seven times as likely to experience an anaesthetic-related death than younger adult dogs, and cats aged 12 years and older were twice as likely to die as a result of anaesthesia (Brodbelt, 2007). These results combined with the increasing numbers of geriatric patients demonstrate a need for careful planning and preparation when anaesthetizing these animals. This article will discuss the physiology, pharmacology and anaesthetic management relevant to geriatric patients, concentrating on factors relevant to nurses.