Anesthesia; Pain Management
6th Annual Gulf-Atlantic Veterinary Conference
The risk of anesthetic-related death in dogs and cats has decreased since the last comparable survey in the mid-1980s, but these numbers compare poorly to data for humans where the anesthetic-related death rate is reported to be between 0.02 and 0.005 percent. Differences in the standards of anesthesia – including training of those administering anesthesia, having a person dedicated to anesthesia alone and sophisticated monitoring equipment – are likely the reason between the human and animal data, more than species differences alone. A recent retrospective study focused on a high volume spay-neuter clinic reported the risk of mortality in cats as 0.05 percent and dogs as 0.009 percent with the latter approaching mortality rates in human anesthesia. The risk of mortality in females (dog or cat) was twice that of males. The lower risk of death in these patients compared to the Confidential Enquiry into Perioperative Small Animal Fatality (CEPSAF) study is probably due to a combination of factors, including the young, healthy population and the experience and skills of veterinarians that specialize in specific surgical procedures. Most deaths occur post-operatively; in the CEPSAF study 47 percent of deaths in dogs occur during this time and in cats the figure is 61 percent. Within the post-operative period, the most critical time appears to be the first three hours after the end of anesthesia. Cardiovascular or respiratory causes accounted for the majority of deaths in dogs and cats. As in human anesthetic-related deaths, human error plays a role, for example when the pressure relief valve of the anesthesia machine is left closed. Increasing age, health status and obesity are risk factors. Monitoring the pulse or pulse rate decreases the risk of death in cats. With identified risk factors it should be possible to decrease mortality rates in small animal practice with appropriate intervention.