Rebecca E. Gompf

Induction and recovery characteristics and cardiopulmonary effects of sevoflurane and isoflurane in bald eagles

OBJECTIVE To compare induction and recovery characteristics and cardiopulmonary effects of isoflurane and sevoflurane in bald eagles. Animals-17 healthy adult bald eagles. PROCEDURES Anesthesia was induced with isoflurane or sevoflurane delivered in oxygen via a facemask in a crossover design with 4 weeks between treatments. Eagles were intubated, allowed to breathe spontaneously, and instrumented for cardiopulmonary measurements. Time to induction, extubation, and recovery, as well as smoothness of recovery, were recorded. RESULTS Administration of sevoflurane resulted in a significantly quicker recovery, compared with isoflurane. Temperature, heart rate, and respiratory rate significantly decreased over time, whereas systolic (SAP), diastolic (DAP), and mean arterial blood pressure (MAP) significantly increased over time with each treatment. Temperature, heart rate, SAP, DAP, and MAP were significantly higher with isoflurane. Blood pH significantly decreased, whereas PaCO(2) significantly increased over time with each treatment. Bicarbonate and total carbon dioxide concentrations significantly increased over time with each treatment; however, there was a significant time-treatment interaction. The PaO(2) and arterial oxygen saturation increased over time with isoflurane and decreased over time with sevoflurane with a significant time-treatment interaction. Six eagles developed cardiac arrhythmias with isoflurane, as did 4 with sevoflurane anesthesia. CONCLUSIONS AND CLINICAL RELEVANCE Isoflurane and sevoflurane administration resulted in smooth, rapid induction of and recovery from anesthesia similar to other species. Isoflurane administration resulted in tachycardia, hypertension, and more arrhythmias, compared with sevoflurane. Sevoflurane was associated with fewer adverse effects and may be particularly beneficial in compromised bald eagles.

Comparison of Presumptive Echocardiographic and Definitive Diagnoses of Cardiac Tumors in Dogs

BACKGROUND Echocardiography is used for identification of cardiac tumors and presumptive diagnoses often are made based on the location of identified masses. OBJECTIVES To determine the accuracy of echocardiographically based presumptive diagnoses of cardiac tumors when compared with clinicopathologic or histopathologic definitive diagnoses. ANIMALS A total of 24 client-owned dogs having a cardiac mass on echocardiogram that was subsequently definitively diagnosed by cytology or histopathology. METHODS Retrospective study. A Cardiac Veterinary Database search of animals seen at the University of Tennessee John and Ann Tickle Small Animal Hospital from 2006 to 2012 identified 24 dogs that fit the inclusion criteria. RESULTS The presumptive diagnosis of chemodectoma, ectopic thyroid carcinoma, or lymphoma in cases with heart base masses was correct in 7/9 cases. The presumptive diagnosis of hemangiosarcoma in cases with right atrial masses was correct in 4/8 cases. Seven cases had an open diagnosis because of the unusual presentation on echocardiogram (ECG); various neoplasms were diagnosed in these animals, but hemangiosarcoma, chemodectoma, ectopic thyroid carcinoma, and lymphoma accounted for 6 of them. Pericardial effusion was seen in 10/24 cases. ECG abnormalities were seen in 8/24 cases. Survival ranged from <1 to >150 days. CONCLUSIONS AND CLINICAL IMPORTANCE In this retrospective study, the presumptive diagnosis based on echocardiographic tumor location was only moderately accurate. Cardiac tumors that were considered unusual on echocardiogram were nonetheless frequently found to be the common cardiac tumor types seen in dogs.

SELECTED CLINICAL, BIOCHEMICAL, AND ELECTROLYTE ALTERATIONS IN ANESTHETIZED CAPTIVE TIGERS (PANTHERA TIGRIS) AND LIONS (PANTHERA LEO)

Abstract: A prospective study to assess changes in selected plasma biochemistry and electrolyte values, plasma insulin and aldosterone concentrations, and electrocardiography (ECG) was performed on eight female captive tigers (Panthera tigris) and three lions (Panthera leo) undergoing general anesthesia for elective laparoscopic ovariectomy. Each animal was sedated with medetomidine (18–25 μg/kg) and midazolam (0.06–0.1 mg/kg) intramuscularly, and anesthesia was induced with ketamine (1.9–3.5 mg/kg) intramuscularly and maintained with isoflurane. Venous blood samples were collected and analyzed for plasma biochemistry parameters and insulin and aldosterone concentrations. An ECG was recorded at the time of each blood sample collection. Mean plasma potassium, glucose, phosphorus, and aldosterone concentrations increased during anesthesia (P ≤ 0.05). One tiger developed hyperkalemia (6.5 mmol/L) 2.5 hr after anesthetic induction. Plasma insulin concentrations were initially below the low end of the domestic cat reference interval (72–583 pmol/L), but mean insulin concentration increased (P ≤ 0.05) over time compared with the baseline values. Three tigers and two lions had ECG changes that were representative of myocardial hypoxemia. Based on these results, continuous monitoring of clinical and biochemical alterations during general anesthesia in large nondomestic felids is warranted, and consideration should be given to reversal of medetomidine in these animals should significant changes in electrolytes or ECG occur.