Bilateral arytenoid cartilage paralysis after inhalation anesthesia in a horse

An 8-year-old Quarter Horse gelding was anesthetized for surgical exploration and debridement of a chronic draining wound in the intermandibular space. Anesthesia was without complication other than persistently low PaO2. Severe airway obstruction was evident immediately after extubation, requiring tracheostomy. Endoscopic diagnosis was bilateral arytenoid paralysis, which gradually resolved over the next 7 days. Compression, trauma, or tension of the recurrent laryngeal nerves are the postulated causes of idiopathic laryngeal hemiplegia in horses. The extremely extended position of the head and neck during anesthesia, perhaps compounded by low arterial oxygen content, may have resulted in a hypoxemic insult to the recurrent laryngeal nerves and caused bilateral arytenoid paralysis in this horse.     

Tearing of the dura mater in three dogs

Tearing of the thoracolumbar dura mater was diagnosed after myelography in three large breed dogs. All three dogs lost the ability to walk suddenly, after a period of vigorous running or struggling. Radiographic changes suggested that the tearing of the dura was associated with intervertebral disc injury in two dogs. These dogs regained the ability to walk after medical treatment. Postmortem findings suggested that the tearing of the dura mater in the third dog was associated with nerve root injury and spinal cord haemorrhage after an episode of violent struggling.     

Increasing halothane concentration abolishes anesthesia-associated arrhythmias in cats and dogs

Fifteen cats and 6 dogs developed ventricular arrhythmias during halothane anesthesia. Halothane was administered by precision vaporizer, using a semiclosed anesthetic system. Cardiac arrhythmias were diagnosed within 5 to 10 minutes after a surgical plane of anesthesia was achieved. Arrhythmias in 9 of 15 cats and 3 of 6 dogs were converted to sinus rhythm by increasing the inspired halothane concentration. Conversion to sinus rhythm occurred within 4 minutes. Cardiac arrhythmias were reestablished in 8 of 9 cats and 2 of 3 dogs, after decreasing the inspired halothane concentration to its original value. Increasing the inspired halothane concentration can convert anesthetic-associated ventricular arrhythmias to sinus rhythm in dogs and cats.     

Comparison of fixation methods for treatment of long bone fractures in llamas and alpacas

Objective: To determine outcome after repair of long bone fractures in llamas and alpacas. Study Design: Case series. Animals: Llamas (n=11) and alpacas (8). Methods: Medical records (1998–2008) of camelids with long bone fractures were reviewed for history, repair method, and complications. Outcome was also assessed by owner telephone questionnaire. Results: Mean age at repair was 39 months. There were 8 males and 11 females. Fracture distribution was tibia (n=6), metatarsus (5), metacarpus (4), radius and ulna (2), humerus (1), and femur (1), with 13 closed and 6 open fractures. Fracture repair was by internal fixation (n=11), external fixation with a transfixation pin cast (5), external coaptation (2), and cross‐pinning (1). In 1 llama, the limb was amputated to revise a failed external fixation repair. Seventeen animals (89%) were discharged, and 2 were euthanatized. Outcome was available for 13 animals: 9 were used for breeding and 4 as pets. Fewer major complications occurred with internal fixation than with external fixation with a transfixation pin cast (P<.005); however, there were no significant differences in minor complications between groups. Conclusions: Internal fixation with bone plates was associated with fewer major complications than external fixation with a transfixation pin cast.     

Comparison of the cardiopulmonary effects of etomidate and thiamylal in dogs.

The cardiopulmonary effects of etomidate, a nonbarbiturate, short-acting, IV anesthetic, were compared and contrasted with those of thiamylal sodium in chronically instrumented conscious dogs. Etomidate, when administered IV at dosages of 1.5 and 3.0 mg/kg of body weight, produced anesthesia lasting from 8 +/- 5 and 21 +/- 9 minutes, respectively. Heart rate, aortic blood pressure, left ventricular peak pressure, left ventricular end diastolic pressure, left ventricular contractile force, and myocardial oxygen consumption were unchanged after administration of either dose of etomidate; however, the dosage of 1.5 mg/kg produced significant (P less than 0.05) increases in respiratory rate and decreases in tidal volume. The minute volume remained unchanged from base-line values. Significant (P less than 0.05) decreases in tidal volume, arterial pH, and partial pressure of oxygen were produced, and minute volume remained unchanged when 3.0 mg of etomidate/kg of body weight was administered. Thiamylal sodium (8.0 mg/kg of body weight; given IV) produced anesthesia lasting for 14 +/- 5 minutes. Significant increases (P less than 0.05) in heart rate, arterial blood pressure, left ventricular peak pressure, and myocardial oxygen consumption were observed after IV administration. Left ventricular contractility was significantly (P less than 0.05) decreased. Respiratory rate was not significantly (P less than 0.05) affected by thiamylal although tidal volume and minute volume were decreased. These respiratory alterations resulted in significant (P less than 0.05) increases in the arterial partial pressure of carbon dioxide and decreases in pH and the partial pressure of oxygen. On the basis of cardiopulmonary function, etomidate offered rapid, safe, short duration anesthesia superior to that of thiamylal sodium.     

Effects of acetylpromazine on ventilatory variables in the horse.

The influence of breathing various concentrations of carbon dioxide and oxygen upon minute volume, tidal volume, and respiratory rate were examined in acetylpromazine-tranquilized horses. Responses in the horses before (control period) and after tranquilization were qualitatively similar to increases in carbon dioxide and to alterations in oxygen. The quantitative responses to these changes were less in tranquilized horses than in the same horses studied in the untranquilized state. Tranquilization had its most prominent effect upon respiratory rate in horses breathing room air.