Anesthesia Case of the Month

History A 7-year-old sexually intact female 7.4-kg (16.3-lb) Jack Russell Terrier with a history of exercise intolerance, coughing, and weight loss was referred to the Companion Animal Clinic of the Faculty of Veterinary Medicine, Ghent University. The dog had been hit by a car 2 years previously. Thoracic radiographs were taken immediately after the accident at a local veterinary clinic, and a diagnosis of pleural effusion was made. The dog was subsequently hospitalized for several days. After discharge, the dog never completely regained its former activity level. Over the months preceding referral, the dog gradually became exercise intolerant, lost weight, and started to cough. Food and water intake were normal, and neither vomiting nor diarrhea was reported. The dog was currently not receiving any medications. On physical examination, the dog was bright, alert, and responsive, with a body condition score of 2 of 5. On thoracic auscultation, muffling over the entire right and left ventral aspects of the thorax was noticed; however, in the left dorsal thoracic quarter, lung and heart sounds could be evaluated. Respiratory rate was 64 breaths/min, and heart rate was 108 beats/min. No murmurs or arrhythmias were detected. Metatarsal pulses were strong, symmetric, and regular. Mucous membranes were pink, and capillary refill time was normal. Rectal temperature was 39.1°C (102.4°F). On thoracic radiographs (laterolateral and dorsoventral views), a diaphragmatic hernia was visible, with presence of the stomach, small intestines, and liver in the thoracic cavity. Results of a preanesthetic CBC, serum biochemical analysis, and measurement of electrolyte concentrations were within reference limits. A 22-gauge catheter was placed aseptically in the right cephalic vein. The dog was hospitalized overnight for observation, and surgery (herniorraphy and elective ovariectomy) was scheduled for the next morning. Case Management Results of preanesthetic clinical examination on the morning of surgery were unchanged from the day of admission, and the dog was classified as American Society of Anesthesiologists class III (ie, severe systemic disease). The dog was preoxygenated (2 L/min via a face mask) for 5 minutes while propped up on a tilted table. Premedication consisted of fentanyl (5 g/kg [2.27 g/lb],