Complications associated with anaesthesia for ocular surgery: a retrospective study 1989-1996

This retrospective study was initiated to identify complications of anaesth esia occurring during ocular surgery. Records of 74 horses anaesthetised fo r eye enucleation, 65 horses anaesthetised for surgery of the eye and adnex a, and 51 horses anaesthetised for splint bone excision mere reviewed. Fift y-three percent of the horses anaesthetised for eye enucleation moved durin g surgery which was significantly more frequent than in the other groups (P = 0.001). The incidence of moving was significantly reduced by use of an a naesthetic gas analyser for monitoring (P = 0.001). Transient hypertension was measured in 6 horses during removal of the eye. One horse experienced a momentary decrease in heart rate from 36 to 26 beats/min at the start of s urgery involving a mass on the third eyelid. The incidence of unsatisfactor y recovery from anaesthesia involving multiple attempts to stand was signif icantly greater after ocular surgery than after splint bone excision (P = 0 .036). Our conclusions were 1) the oculocardiac reflex was not active in these hor ses undergoing ocular surgery, 2) increased attention must be paid to provi sion of analgesia and adequate depth of anaesthesia, which may be facilitat ed by use of an anaesthetic gas analyser and 3) horses mere at greater risk for unsatisfactory recoveries from anaesthesia after ocular surgery.