A case report on the use of guaifenesin-ketamine-xylazine anesthesia for equine dystocia.

In 4 mares suffering from dystocia, general anesthesia was induced with xylazine (1.1 mg/kg, IV) and ketamine (2.2 mg/kg, IV) and maintained with continuous intravenous infusion of ketamine (2 mg/ml), xylazine (0.5 mg/ml) and guaifenesin (50 mg/ml) in 1 L of 5% dextrose. The duration of the procedure of these mares were 40, 45, 180, and 35 minutes, respectively. For procedures required more than 1 hour (Mare 3), the dose of ketamine and xylazine in the mixture was reduced to 1 mg/ml and 0.25 mg/ml, respectively. Average infusion rate of the mixture used to maintain anesthesia for each mare was 2.5, 2.67, 2.28, and 2.21 ml/kg/hr. Recovery to standing occurred at 55, 75, and 180 minutes after termination of infusion for mares 1, 2, and 3, respectively. Xylazine reversal agent, tolazoline (2.2 mg/kg), was given to mare 1 to hasten the recovery; the mare stood within 30 minutes after tolazoline administration. Continuous infusion of guaifenesin-ketamine-xylazine can be an alternative anesthetic technique for prolonged obstetrical procedures under field conditions when suitable anesthetic equipment is not available. If recovery to standing is extended over 30 to 40 minutes, yohimbine or tolazoline can be administered to hasten recovery.

Attempted reinnervation of the equine larynx using a muscle pedicle graft.

Laryngeal hemiplegia was induced in 4 ponies via a left recurrent laryngeal neurectomy. Reinnervation of the denervated left cricoarytenoideus dorsalis muscle was then attempted using a muscle pedicle graft from the right cricoarytenoideus dorsalis muscle. In 3 ponies there was no return of abductor function and failure of graft survival. In the fourth pony there was return of abductor function along with survival of the muscle bridge, however, there was evidence of reinnervation across the neurectomy site. Muscle-to-muscle neurotization of the paralyzed equine larynx, utilizing the cricoarytenoideus dorsalis muscle, does not appear to be a clinically useful technique.

Presuturing as a means of reducing skin tension in excisional biopsy wounds in four horses.

Excisional biopsy of a skin lesion was performed in 4 horses after stretching the surrounding skin with mattress sutures. The technique of presuturing allowed all biopsy wounds to be closed without excessive tension on the suture lines.

Surgical correction of a traumatic esophageal diverticulum in a horse.

A nine-year-old gelding was presented to the Auburn University Large Animal Clinic with discharge of saliva and food material from both nostrils. A diagnosis of esophageal diverticulum was made; treatment is described.

Cecal torsion in a horse as a consequence of cecocolic fold hypoplasia.

Cecal torsion in horses is relatively rare. This clinical report describes cecocolic fold hypoplasia, producing increased cecal mobility, as a predisposing cause of cecal torsion in a horse.

Sternothyrohyoideus myectomy in horses: 17 cases (1984-1985).

Review of medical records of 78 horses admitted to the George D. Widener Hospital for Large Animals with dorsal displacement of the soft palate revealed 94% of these horses to have evidence of an intermittent abnormal "gurgling" respiratory noise at the time of exercise. Sternothyrohyoideus myectomy was used as a primary treatment for 17 of these horses, with a success rate of 58%. Anatomic dissection of 30 horses indicated that the midcervical region is the optimal site for sternothyrohyoideus myectomy to alleviate dorsal displacement of the soft palate.

Partial arytenoidectomy in the horse with and without mucosal closure.

Left-sided partial arytenoidectomy was performed in eight horses to evaluate healing. Four horses underwent conventional partial arytenoidectomy with suture apposition of the mucosa. In four horses, most of the arytenoid cartilage, including overlying mucosa, vocal fold, and laryngeal saccule, were excised en bloc without mucosal closure. The horses were monitored clinically by endoscopic examination. One horse from each group was euthanatized at weeks 2, 4, 8, and 16. Complete necropsies with gross and histologic examination of the arytenoidectomy sites were performed. Postoperative complications such as coughing, dysphagia, and aspiration pneumonia were not encountered and problems with wound healing were minimal in both groups. The defect created by partial arytenoidectomy without mucosal closure initially filled to the level of the luminal surface with granulation tissue, with a gradual transition to mature fibrous connective tissue. Grossly, the defect appeared to be healed and was completely epithelialized by week 16 without apparent narrowing of the laryngeal lumen. Partial arytenoidectomy sites with mucosal closure healed in a similar pattern by week 8. Partial dehiscence of the dorsal portion of the sutured mucosa occurred in three horses.

Equine large intestinal volvulus. A review of 124 cases.

The average age of 122 horses with ascending colon volvulus was 6.6 +/- 0.4 years. Gastric reflux was a presenting sign in 35% of the cases. Peritoneal fluid protein levels had a mean of 2.54 +/- 0.14 g/dl and 20 horses had grossly normal peritoneal fluid at the time of presentation. Ascending colon volvulus was most commonly found at the level of the cecocolic fold with the initial ventral colon movement in a dorsomedial direction about the ascending mesocolic axis. The overall survival rate was 34.7% with a recurrence rate of only 4.9%.

Complications of umbilical hernias in horses: 13 cases (1972-1986).

Of 147 horses treated for umbilical hernias over a 13.5-year period, 13 horses (8.8%) developed complications in association with umbilical defects. Six horses had intestinal incarceration; the incarceration was reduced manually in 3 horses before admission, resolved without treatment in 2 others, and was surgically reduced in one. Herniorrhaphy was performed on 4 of the 5 horses in which the incarceration did not require surgical reduction, and the fifth was managed conservatively. A horse with a parietal hernia and a horse with intestinal stragulation were treated surgically; in the latter, the involved intestine was resected. These 8 horses recovered. Three horses developed an umbilical abscess and 2 developed an enterocutaneous fistula through their umbilical hernias. Four of these horses responded well to surgery, but one horse with an enterocutaneous fistula died from electrolyte imbalances and peritonitis after an unsuccessful attempt at simple closure. The results of this study confirmed that complications of umbilical hernias are rare in horses; however, when they do develop, they may be one of various forms, some of which are insidious in onset.

Management of arytenoid chondropathy and failed laryngoplasty in horses: 75 cases (1979-1985).

By use of endoscopy, 75 horses with respiratory noise and/or exercise intolerance were determined to have structural arytenoid cartilage abnormalities (60 primary, 11 after previous laryngeal surgery), or failed left laryngoplasty (4 horses) for laryngeal hemiplegia in which the arytenoid cartilage still appeared normal. Eighty-eight percent of the horses were either Thoroughbred (54 horses; 72%) or Standardbred (12 horses; 16%) racehorses; only 9 horses (12%) had occupations not related to racing. Seventy-six percent of the racehorses were 2 to 4 years old; all non-racehorses were greater than 4 years old. The male:female ratio was approximately 2:1. Of the horses with cartilage abnormalities, 28 had left-sided involvement, 22 had right-sided involvement, and 21 had bilateral involvement. Sixty-two arytenoidectomies were performed, 58 for cartilage abnormalities (22 left, 19 right, 17 bilateral), and 4 for failed left laryngoplasties. Overall, 45% of the Thoroughbred racehorses that returned to racing after arytenoidectomy raced successfully (50% left, 75% right, 22% bilateral); only 20% of the Standardbreds were able to race. Seventy-five percent of non-racehorses were able to return to their previous use. Many horses were retired intentionally after surgery.

Dorsal glottic stenosis after bilateral arytenoidectomy in two horses.

Bilateral arytenoidectomy had been performed as treatment for bilateral arytenoid chondritis in 2 horses. After surgery, dorsal mucosal defects were associated with subsequent development of dorsal glottic stenosis in the 2 horses. When performing bilateral arytenoidectomy in the horse, care must be taken to eliminate dorsal mucosal defects that cross the midline. Failure to close these defects may result in glottic stenosis.

Complications associated with left dorsal displacement of the large colon in the horse.

Four horses operated on for left dorsal displacement of the large colon (LDDLC) had major intraoperative or postoperative complications. One horse was euthanatized during surgery because of extensive necrosis of the large colon. Three horses that were discharged after surgical correction of LDDLC were readmitted with signs of abdominal pain between 5 weeks and 13 months after surgery. Two horses had recurrence of LDDLC, and the third horse had an omental adhesion attached to and obstructing the pelvic flexure. The displacements were corrected, the adhesion was broken down, and the horses were discharged. One horse was readmitted a third time 16 months after the second surgery and required a third surgical correction of LDDLC.

Pulmonary haemorrhage in standardbred horses after racing.

Endoscopic examinations of the upper respiratory tract were done on 92 of 314 Standardbred horses that raced one or more times at 4 consecutive, weekly race meetings. Although participation was voluntary, the characteristics of the population of horses examined were not statistically different from those of all horses that raced. No horse showed epistaxis, but 34 (32.4%) examinations of the trachea revealed blood that ranged from a trace in the tracheal mucus to large amounts scattered over the tracheal walls. Forty-four horses exhibited minor degrees of pharyngeal lymphoid hyperplasia, 2 had asynchronous movement of the left arytenoid cartilage and 15 had grains of sand in the respiratory tract. There was no association between bleeding and age, sex, distance of race, place in race or date of race. Mucus and mucopurulent material occurred less often after longer races and more often on the last 3 race nights.