HEMORRHAGIC MYELOMALACIA FOLLOWING GENERAL-ANESTHESIA IN A HORSE

An 18-month-old male Belgian horse was anesthetized and placed in dors al recumbency for cryptorchidectomy. Xylazine was used for sedation an d guaifenesin with thiamylal for induction of anesthesia. A surgical p lane of anesthesia was maintained with halothane. During anesthesia, s econd-degree atrio-ventricular blocks, hypoventilation and a 1-minute duration rise of mean arterial pressure (80 to 130 mm Hg) occurred. To tal anesthesia time was 1 hour. On recovery from anesthesia, the horse exhibited flaccid paralysis of the hind limbs and was only able to el evate himself to a dog sitting position. The horse was humanely euthan ized 22 hours postoperatively due to a lack of improvement in clinical signs. Hemorrhagic poliomyelomalacic lesions of the spinal cord were observed on histopathological examination of the spinal cord.