Which patient factor increases the risk during anesthesia?

The age of the animal is a significant factor that can increase the risk during anesthesia. As animals age, they often experience changes in their physiological and metabolic functions. Older animals may have reduced organ function, particularly in the liver and kidneys, which can affect drug metabolism and excretion. Additionally, older animals may have comorbidities or chronic health issues that make them more sensitive to the effects of anesthetic agents. The body's ability to respond to stress can also diminish with age, which may complicate their response to anesthesia and recovery.

While other factors like the animal's weight, general fitness level, and small size can influence anesthesia risk, they do not generally carry the same level of increased risk associated with age. For instance, a healthy weight or a small size may affect anesthetic drug dosages but does not inherently lead to the same complications seen in older patients. Similarly, a good general fitness level typically suggests that the animal may respond better to anesthesia compared to one that is not fit. Therefore, age is a particularly critical criterion when evaluating anesthesia risk in veterinary patients.