Anaesthetic management and complications during hypophysectomy in 37 cats with acromegaly.

OBJECTIVES: The aim of this study was to describe the anaesthetic management and perianaesthetic complications encountered during hypophysectomy surgery in acromegalic cats. We explored relationships between animal demographic data, the anaesthetic protocol used and presence of perioperative complications. METHODS: Cats having undergone hypophysectomy surgery for the treatment of feline acromegaly at a single veterinary referral hospital were identified from hospital records. The anaesthesia records and clinical notes of these animals were retrospectively reviewed. Descriptive statistics were produced and binary logistic regression run to assess for any relationship between patient factors, anaesthetic management and complications during the perioperative period. RESULTS: Perianaesthetic complications identified included hypothermia, hypotension, bradycardia and airway obstruction. Mortality at 24 h post-anaesthesia was 8%. The use of alpha (α)2 agonists was associated with a lower incidence of hypotension. Fentanyl infusion was associated with a higher incidence of airway obstruction compared with remifentanil. Subjectively assessed anaesthetic recovery quality had an association with the number of days spent in the intensive care ward postoperatively. CONCLUSIONS AND RELEVANCE: The anaesthetic management described seems effective for hypophysectomy surgery in cats. Intraoperative complications were common and, while not apparently associated with 24 h patient outcome, drugs and equipment to manage these complications should be available.

The effects of ephedrine on intramuscular blood flow and other cardiopulmonary parameters in halothane-anesthetized ponies.

OBJECTIVE: To evaluate the effect of ephedrine on intramuscular blood flow and hemodynamic parameters during equine anesthesia. STUDY DESIGN: Prospective experimental study. ANIMALS: Six healthy adult Welsh Mountain ponies (five males, one female, mean weight: 267 kg, range: 213-347 kg). METHODS: Halothane-anesthetized ponies received an IV bolus of ephedrine (0.1 mg kg-1), followed 30 minutes later by a second IV ephedrine injection (0.2 mg kg-1). Changes in intramuscular blood flows (IMBF) in upper and lower triceps brachii were measured by laser Doppler flowmetry. Cardiopulmonary measurements were made at intervals for 30 minutes following each injection. Results were compared with values from a control group, similarly anesthetized but given saline in an earlier study. RESULTS: Ephedrine at either dose increased heart rate, arterial blood pressure (AP), cardiac index (CI) and intramuscular blood flow (IMBF), the effects on these parameters being significant and long-lasting following the higher dose. Systemic vascular resistance remained unchanged, and was significantly lower than in the control saline group. PaO2 decreased significantly immediately following the first injection of ephedrine, then remained unchanged for the remainder of the experiment. PaCO2 increased slowly throughout the anesthetic period. One pony developed supraventricular premature complexes following the second injection. No other side effects were seen. CONCLUSION: Ephedrine at dose rates of 0.2 mg kg-1 IV consistently increased in CI, AP, and IMBF in both forelimbs. CLINICAL RELEVANCE: Ephedrine may be of use to improve AP, CI and IMBF during halothane anesthesia, although the occurrence of an arrhythmia in one pony is of concern.