A 2-year-old 22.3-kg (49.1-lb) neutered male English Springer Spaniel was referred for surgical treatment of a left elbow joint fracture. The owner reported an acute onset of non-weight-bearing lameness in the left forelimb with no history of trauma. Swelling in the region of the left elbow joint was seen on physical examination. A lateral condylar fracture of the left humerus was evident on radiographs provided by the referring veterinarian.Open reduction and internal fixation of the condylar fracture was scheduled for the day after admission. Results of the preanesthetic assessment were otherwise normal; therefore, the patient was classified as American Society of Anesthesiologists physical status II (mild systemic disease). The anesthesia protocol consisted of premedication with methadone (0.2 mg/kg [0.09 mg/lb], IV) in combination with acepromazine (0.01 mg/kg [0.0045 mg/lb], IV). Meloxicam (0.2 mg/kg, IV) was added for its antiinflammatory effects as part of a multimodal analgesia protocol. General anesthesia was induced with propofol (2 mg/kg [0.9 mg/lb]) administered IV to effect (total dose, 44.6 mg). The patient was orotracheally intubated, and anesthesia was maintained with isoflurane in oxygen administered via a circle breathing system. Monitoring a included an ECG and measurement of oxygen saturation by means of pulse oximetry, end-tidal partial pressure of CO 2 , end-tidal isoflurane concentration, and blood pressure (measured noninvasively with an oscillometric method). End-tidal isoflurane concentration was maintained at 1.3% throughout surgery. Baseline cardiorespiratory parameters included heart rate of 100 beats/min, respiratory rate of 12 breaths/min, and systolic, mean, and diastolic blood pressures of 110, 68, and 51 mm Hg, respectively. With the patient anesthetized, repeated radiography confirmed a fracture of the left lateral humeral condyle and incomplete ossification of the humeral condyle, consistent with the lack of a history of trauma.An ultrasound-guided brachial plexus block was performed for intraoperative analgesia. The patient was positioned in right lateral recumbency for clipping and standard aseptic preparation of the lateral