The incidence of post anaesthetic myopathy (PAM) in horses after general anaesthesia for MRI in comparison to the incidence of PAM in horses anaesthetised for other reasons

Abstract

In a retrospective study the anaesthetic records of 1270 horses were evaluated to determine the incidence of post anaesthetic myopathy (PAM). These horses were grouped into four categories: surgery in dorsal recumbency (n=493), surgery in lateral recumbency (n=546), MRI (n=150) and CT (n=74). The aim of the study was to determine whether the incidence of PAM is higher in the MRI group, and to evaluate the possible risk factors. It was found that the incidence of PAM in the MRI group is significantly higher compared to the surgery in lateral recumbency group. The body weight was not significantly different between the horses with and without PAM, but anaesthetic duration was significantly longer in horses that developed PAM compared to horses that did not develop PAM within the groups. There was a significant difference in the incidence of PAM when comparing emergency surgery patients to elective surgery patients. PAM has a higher incidence in the emergency surgery group.The overall incidence of PAM in this study was 1.35% with a mortality of 0.16%.