ANESTHESIA IN A CAPTIVE JUVENILE BLACK RHINOCEROS (DICEROS BICORNIS) FOR MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY.

A hand-reared, 53-kg, female, 30-day-old black rhinoceros ( Diceros bicornis ) calf presented for magnetic resonance imaging and computed tomography after demonstrating neurologic signs. The rhino was premedicated intramuscularly with butorphanol and midazolam, yielding satisfactory sedation. Induction was achieved using intravenous propofol until the trachea could be intubated. Anesthesia was maintained with sevoflurane in 100% oxygen (mean end-tidal concentration of 2 ± 0.5%). Mean values recorded during anesthesia included were heart rate, end-tidal carbon dioxide, respiratory rate, noninvasive blood pressure, and pulse oximetry. A balanced electrolyte solution of 10 mL/kg per hour was given intravenously. It was concluded that anesthesia was safely induced and maintained with a combination of butorphanol, midazolam, propofol, and sevoflurane. Total anesthesia time was 3 hr, with no perianesthetic complications and an uneventful recovery.

Traumatic tracheal diverticulum corrected with resection and anastomosis during one-lung ventilation and total intravenous anesthesia in a cat.

OBJECTIVE: This report describes the clinical findings and diagnostic images of a traumatic intrathoracic tracheal avulsion with a tracheal diverticulum in a cat. Furthermore, a complete description of the tracheal resection and anastomosis using one-lung ventilation (OLV) with total and partial intravenous anesthesia is made. CASE SUMMARY: A 3-year-old neutered male domestic shorthair cat weighing 6.8 kg was presented to the University Teaching Hospital for evaluation of increased respiratory noise 3 months following unknown trauma. Approximately 12 weeks prior to presentation, the cat had been seen by the primary care veterinarian for respiratory distress. At that time, the cat had undergone a tracheal ballooning procedure for a distal tracheal stricture diagnosed by tracheoscopy. The tracheal ballooning had provided only temporary relief. At presentation to our institution, the cat had increased respiratory effort with harsh upper airway noise auscultated during thoracic examination. The remainder of the physical examination was normal. Diagnostics included a tracheoscopy and a thoracic computed tomographic examination. The cat was diagnosed with tracheal avulsion, pseudotrachea with a tracheal diverticulum, and stenosis of the avulsed tracheal ends. Surgical correction of the tracheal stricture via a thoracotomy was performed using OLV with total and partial intravenous anesthesia. The cat recovered uneventfully and at last follow-up was active and doing well. UNIQUE INFORMATION PROVIDED: This case report describes OLV using standard anesthesia equipment that is available at most private practices. Furthermore, this case describes the computed tomographic images of the intrathoracic tracheal avulsion and offers a positive outcome for tracheal resection and anastomosis.

Effects of oxymorphone hydrochloride or hydromorphone hydrochloride on minimal alveolar concentration of desflurane in sheep.

OBJECTIVE: To establish the minimum alveolar concentration (MAC) of desflurane and evaluate the effects of 2 opioids on MAC in sheep. ANIMALS: 8 adult nulliparous mixed-breed sheep. PROCEDURES: A randomized crossover design was used. Each sheep was evaluated individually on 2 occasions (to allow assessment of the effects of each of 2 opioids), separated by a minimum of 10 days. On each occasion, sheep were anesthetized with desflurane in 100% oxygen, MAC of desflurane was determined, oxymorphone (0.05 mg/kg) or hydromorphone (0.10 mg/kg) was administered IV, and MAC was redetermined. Physiologic variables and arterial blood gas and electrolyte concentrations were measured at baseline (before MAC determination, with end-tidal desflurane concentration maintained at 10%) and each time MAC was determined. Timing of various stages of anesthesia was recorded for both occasions. RESULTS: Mean ± SEM MAC of desflurane was 8.6 ± 0.2%. Oxymorphone or hydromorphone administration resulted in significantly lower MAC (7.6 ± 0.4% and 7.9 ± 0.2%, respectively). Cardiac output at MAC determination for desflurane alone and for desflurane with opioid administration was higher than that at baseline. No difference was identified among hematologic values at any point. Effects of oxymorphone and hydromorphone on durations of various stages of anesthesia did not differ significantly. CONCLUSIONS AND CLINICAL RELEVANCE: MAC of desflurane in nulliparous adult sheep was established. Intravenous administration of oxymorphone or hydromorphone led to a decrease in MAC; however, the clinical importance of that decrease was minor relative to the effect in other species.

Formulation of a standardized protocol and determination of the size and appearance of the spleen in healthy cats.

Standard protocol for splenic measurement is warranted to aid in interpretation when sonographically imaging the spleen of cats. The purpose of this study was to describe the appearance and size of healthy cat spleens, and to develop a standard method of evaluation. Data were obtained from 31 clinically healthy non-sedated cats with no sonographic abnormalities. The sonographic appearance of the spleen's relative echogenicity compared to the left renal cortex and the hepatic parenchyma was recorded. Splenic height was measured at three sites. Three measurements were determined at each site, and the mean value of these three measurements was determined and used for data analysis. A significance level of P <0.05 was used for analysis, which was performed using S-PLUS software (version 8.1). The mean proximal height of the spleen was 7.1 mm. The mean body sagittal height was 9.3 mm. The mean height of the tail of the spleen was 8.7 mm (95% confidence interval). The splenic parenchymal echogenicity was less than the left renal cortex echogenicity and greater than the liver in 17/31cats; less than the left kidney cortex and equal to the liver in 5/31cats; equal to the cortex of the left kidney and greater than the liver in 5/31 cats; equal to the liver and renal cortex in 2/31 cats; and less than the liver and kidney with the renal cortex less than the liver in 2/31 cats. The protocol recommended for consistent evaluation of the spleen in the cat includes three specific measurements.

Accidental and experimentally induced 5-fluorouracil toxicity in dogs.

OBJECTIVE: To summarize the literature involving 5-fluorouracil (5-FU) toxicosis in dogs. ETIOLOGY: 5-Fluorouracil's mechanism of action revolves around the metabolism of 5-FU into fluorouridine triphosphate which then interferes with RNA synthesis and function as well as the inhibition of thymidylate synthase which ultimately impairs DNA stability. Toxicity of 5-FU is the most pronounced on rapidly dividing cells. Toxicity manifests itself mainly in the neurologic, gastrointestinal, respiratory, or hematopoietic systems. DIAGNOSIS: History of accidental exposure to 5-FU-containing products. THERAPY: Therapy for 5-FU toxicosis involves typical decontamination procedures and symptomatic therapy for the subsequent toxicity. Seizure control and treatment of the severe gastrointestinal signs that follow are the primary goals in the acute setting. As the disease progresses, management of the sequelae to bone marrow suppression and pulmonary complications are essential. PROGNOSIS: The prognosis for dogs with ingestion of 5-FU is dependent on the amount consumed, with severe intoxication carrying a poor prognosis. Toxic doses can be as little as 5 mg/kg, and doses ≥40 mg/kg are reported to be uniformly fatal.

Imaging diagnosis-heterobilharzia americana infection in a dog.

An approximately three-year-old mixed breed female dog was evaluated for peritoneal effusion, anorexia, intermittent vomiting, and diarrhea. Radiographically, there was mineralization of the wall of small intestinal segments. Sonographic findings were consistent with multisystemic mineralization of liver, small intestinal wall, and pancreas. Multifocal granulomas containing schistosome eggs (Heterobilharzia americana) were identified histologically. The mineralization pattern described herein is an uncommon presentation of severe diffuse heterobilharziasis in a dog.