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Objective: To determine clinical outcome of permanent tracheostomy in cats with upper airway obstruction., Design: Retrospective case series., Animals: 21 cats., Procedures: Medical records were reviewed for information on history, signalment, clinical signs, results of preoperative clinicopathologic testing, cause of upper airway obstruction, surgical procedure, postoperative complications, and outcome., Results: Causes of upper airway obstruction included neoplasia (squamous cell carcinoma [n = 6] or malignant lymphoma [2]), inflammatory laryngeal disease (5), laryngeal paralysis (4), trauma (3), and a laryngeal mass of unknown cause (1). Fourteen cats had dyspnea in the immediate postoperative period; dyspnea most often resulted from mucous plugs at the stoma or elsewhere in the respiratory tract. Eleven cats died, including 6 cats that died while hospitalized after surgery and 5 cats that died after discharge; 7 cats were euthanatized, most often because of progression of neoplasia; and 2 were still alive at the time of the study. The remaining cat was lost to follow-up after discharge from the hospital. Overall, median survival time for the 20 cats for which information was available was 20.5 days (range, 1 day to 5 years). Cats that underwent permanent tracheostomy because of inflammatory laryngeal disease were 6.61 times as likely to die as cats that underwent permanent tracheostomy for any other reason., Conclusions and Clinical Relevance: Results indicated that permanent tracheostomy was an uncommon procedure in cats with upper airway obstruction that was associated with high complication and mortality rates.

Background: Some studies in dogs undergoing adrenalectomy for pheochromocytoma suggest that anesthetic complications and perioperative mortality are common. In humans, surgical outcome has improved with the use of phenoxybenzamine (PBZ) before adrenalectomy., Hypothesis: Dogs treated with PBZ before adrenalectomy have increased survival compared with untreated dogs., Animals: Forty-eight dogs that underwent adrenalectomy for pheochromocytoma., Methods: A retrospective medical record review for dogs that underwent adrenalectomy for pheochromocytoma at a veterinary medical teaching hospital over the period from January 1986 through December 2005., Results: Twenty-three of 48 dogs were pretreated with PBZ (median dosage: 0.6 mg/kg PO q12h) for a median duration of 20 days before adrenalectomy. Duration of anesthesia and surgery, percentage of dogs with pheochromocytoma involving the right versus left adrenal gland, size of tumor, and presence of vascular invasion were similar for PBZ-treated and untreated dogs. Thirty-three (69%) of 48 dogs survived adrenalectomy in the perioperative period. PBZ-treated dogs had a significantly (P = .014) decreased mortality rate compared with untreated dogs (13 versus 48%, respectively). Additional significant prognostic factors for improved survival included younger age (P = .028), lack of intraoperative arrhythmias (P = .0075), and decreased surgical time (P = .0089)., Conclusions and Clinical Importance: Results from this retrospective study support treatment with PBZ before surgical removal of pheochromocytoma in dogs.

Objective: To evaluate long-term clinical outcome in dogs with upper airway obstruction treated with laryngeal web resection and mucosal apposition., Design: Retrospective case series., Animals: 15 client-owned dogs with laryngeal web formation., Procedures: Medical records of dogs with laryngeal webs treated with a single procedure of web resection with mucosal apposition by use of a ventral laryngotomy were reviewed. Signalment, history, clinical signs, intraoperative complications, postoperative complications, and hospitalization time were recorded. Owners were interviewed 6 months to 6 years after surgery., Results: Most dogs had a history of oral ventriculocordectomy. Duration of clinical signs ranged from 3 months to 3 years. The most common clinical sign reported was exercise intolerance. Postoperative complications were observed in 4 dogs. Follow-up information was available in 10 dogs, and clinical outcome was classified as excellent in 7 and good in 3., Conclusions and Clinical Relevance: A single surgical procedure of web resection with mucosal apposition for the treatment of laryngeal web formation in dogs resulted in low morbidity and was associated with a good to excellent outcome.

Objectives: To evaluate use of an ameroid ring constrictor (ARC) for treatment for single extrahepatic portosystemic shunts (PSSs) and identify factors associated with postoperative death, continued portosystemic shunting, and long-term outcome in dogs., Design: Retrospective study., Animals: 168 dogs with a single extrahepatic PSS., Procedure: Medical records of dogs that had a single extrahepatic PSS and were treated with an ARC were reviewed. Signalment, history, clinical signs, results of preoperative blood analyses and portal pressure measurements, PSS location, ARC size, postoperative complications, and postoperative scintigraphy results were recorded. Owners were interviewed 6 months to 6 years after surgery. Results-Postoperative complications developed in 10% of dogs. Postoperative mortality rate was 7.1%. Predictive factors for postoperative death included high preoperative WBC count and postoperative complications. Twenty-one percent of dogs in which portal scintigraphy was performed 6 to 10 weeks after surgery had continued shunting. Predictive factors for persistent shunting included low preoperative plasma albumin concentration, high portal pressure after complete occlusion, and high portal pressure difference (postocclusion minus baseline). Clinical outcome in 108 dogs was classified as excellent (80%), good (14%), or poor (6%). Predictive factors for excellent long-term clinical outcome included high preoperative plasma albumin concentration, low preoperative leukocytosis, low portal pressure after complete occlusion, absence of postoperative seizures, and absence of continued shunting., Conclusions and Clinical Relevance: Use of an ARC for treatment for a single extrahepatic PSS resulted in low morbidity and mortality rates. Certain preoperative factors were associated with increased risk of postoperative death, continued portosystemic shunting, and long-term outcome.

Spontaneous regression of primary malignant bone tumors is rare but has been reported in the human literature. To the authors' knowledge, spontaneous regression of primary bone tumors in dogs or cats has not been reported. Osteosarcoma (OSA) is the most common primary bone tumor in humans, and it has been reported that the incidence of OSA is 40 to 50 times greater in dogs than humans. In this report, high-grade OSA was diagnosed in biopsy specimens obtained from 4 dogs that subsequently underwent spontaneous regression without tumor-specific treatment. Osteosarcoma in dogs has characteristics similar to that of OSA in humans.

Objective: To determine the relationship between plasma beta-endorphin (EN) concentrations and exercise intensity and duration in horses., Animals: 8 mares with a mean age of 6 years (range, 3 to 13 years) and mean body weight of 450 kg., Procedure: Horses were exercised for 20 minutes at 60% of maximal oxygen consumption (VO2max) and to fatigue at 95% V02max. Plasma EN concentrations were determined before exercise, after a 10-minute warmup period, after 5, 10, 15, and 20 minutes at 60% VO2max or at the point of fatigue (95% VO2max), and at regular intervals after exercise. Glucose concentrations were determined at the same times EN concentrations were measured. Plasma lactate concentration was measured 5 minutes after exercise., Results: Maximum EN values were recorded 0 to 45 minutes after horses completed each test. Significant time and intensity effects on EN concentrations were detected. Concentrations were significantly higher following exercise at 95% VO2max, compared with those after 20 minutes of exercise at 60% VO2max (605.2 +/- 140.6 vs 312.3 +/- 53.1 pg/ml). Plasma EN concentration was not related to lactate concentration and was significantly but weakly correlated with glucose concentration for exercise at both intensities (r = 0.21 and 0.30 for 60 and 95% VO2max, respectively)., Conclusions and Clinical Relevance: A critical exercise threshold exists for EN concentration in horses, which is 60% VO2max or less and is related to exercise intensity and duration. Even under conditions of controlled exercise there may be considerable differences in EN concentrations between horses. This makes the value of comparing horses on the basis of their EN concentration questionable.

A 5-year-old Quarter Horse was examined after it developed signs of abdominal discomfort as a result of a training accident. Oral mucous membranes were pale, and capillary refill time was > 3 seconds. Hematologically, the PCV was low, and abdominocentesis yielded a serosanguineous fluid. Abdominal ultrasonography was performed and revealed a large hypoechoic mass associated with the cranial margin of the spleen. Because differentiation between subcapsular hematoma and extracapsular hematoma could not be made with certainty, further evaluation of the spleen was indicated. Abdominal laparoscopy was performed, with the horse standing, to evaluate the extent, severity, and nature of the splenic hematoma. Laparoscopic examination revealed a 7.5-cm-diameter splenic hematoma contained within the splenic capsule, confirming the diagnosis of subcapsular splenic hematoma. Abdominal laparoscopy provided excellent observation of the spleen and allowed for thorough evaluation and determination of the extent of the lesion. This information aided the clinician in reaching a definitive diagnosis and choosing between splenectomy and medical treatment.