Combined spinal and general anaesthesia in 58 cats undergoing various surgical procedures: description of technique and retrospective perioperative evaluation

Objectives The aim of this retrospective study was to describe the spinal anaesthesia (SA) technique and evaluate the incidence of perioperative complications in cats. Methods The anaesthetic records of cats of American Society of Anaesthesiologists physical status I, II and III, which received general and SA for different surgeries between 2012 and 2016, were examined. SA was administered through a 25 G Quincke needle, using an isobaric solution of bupivacaine and morphine at the level of either the L-7-S-1 interspaces (sternal recumbency) or the L-5-(6)/L-6-(7) interspaces (lateral recumbency). Procedural failure rate (PFR), drugs and dose used, heart rate (HR), arterial blood pressure, incidence of bradycardia (HR <100 bpm) and hypotension (mean arterial pressure [MAP] <60 mmHg for at least 5 mins), intraoperative rescue analgesia (iRA) and any other detrimental events and their treatment until discharge were recorded. Abdominal surgery cases were excluded from the intraoperative evaluation. Results A total of 58 anaesthetic records met the inclusion criteria and were analysed. PFR related to the space of injection (L-7-S-1 vs L-5-(6)/L-6-(7)) was 3/11 (27%) and 1/47 (2%), respectively (P = 0.017). The total median dose of intrathecal bupivacaine and morphine was 0.8 (range 0.5-1.6 mg/kg) and 0.10 (0.05-0.18 mg/kg), respectively. Nine of 46 (20%) cats received iRA, and no iRA cases were reported with a dose of bupivacaine higher than 0.8 mg/kg. Median HR and MAP before intrathecal injection (T-0) and 10 mins after (T-1) were, respectively, 118 bpm (range 74-190 bpm) and 106 bpm (67-160 bpm) (P = 0.005), and 65 mmHg (range 50-94 mmHg) and 52 mmHg (range 35-85 mmHg) (P = 0.003). Bradycardia was reported in 18/46 (39%) cats and hypotension in 23/46 (50%) cats. No complications were recorded during the observation period. Conclusions and relevance SA was characterised by a low PFR when performed at the L-5-(6)/L-6-(7) interspaces and low postoperative complications. Hypotension and bradycardia were the most common side effects.