Effect of Obesity on Awakening Time after Isoflurane/Sevoflurane Inhalation Anesthesia in Dogs

To elucidate the relationship between obesity, awakening time, and anesthesia in dogs, we conducted a comparative analysis of the awakening time following isoflurane and sevoflurane anesthesia in both standard-weight and obese groups. Six female beagle dogs within the standard weight range underwent 1-hour inhalation anesthesia with either isoflurane or sevoflurane. We recorded the time of extubation, head lift, and standing. Additionally, a parallel experiment was conducted on the same test animals after inducing obesity through nutritional management, with criteria for obesity defined as a body conditioning score of 4 or higher and a body fat percentage of 30% or higher. Under isoflurane anesthesia, we observed a tendency for a longer awakening time in the obese group compared to the standard weight group. However, this trend was not evident with sevoflurane anesthesia. Furthermore, when comparing awakening time with both anesthetics, no significant difference was found between the standard weight groups. In contrast, within the obese group, awakening time was significantly prolonged with isoflurane anesthesia compared to sevoflurane anesthesia. These results confirm that obesity contributes to delay awakening in dogs. Additionally, in the anesthesia management of obese dogs, the use of sevoflurane is anticipated to reduce awakening time compared to isoflurane.