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

Abstract

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 L7–S1 interspaces (sternal recumbency) or the L5–6/L6–7 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 (L7–S1 vs L5–6/L6–7) 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 (T0) and 10 mins after (T1) 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 L5–6/L6–7 interspaces and low postoperative complications. Hypotension and bradycardia were the most common side effects.

Incidence of dural sac puncture during neuraxial anesthesia in cats: an observational, retrospective study

“…Although no clinical consequences of intended dural puncture have been reported in cats, it seems that the use of a needle gauge <22 G may be more protective of neural structures, minimizing the risk of adverse clinical effects. The use of a 25 G needle for spinal anesthesia in cats was proposed by Sarotti et al, 2 but it was associated with a procedure failure rate of 27%. Further studies are warranted to weigh the efficacy of the technique vs the protection of the neural structures and to investigate the short- and long-term clinical consequences of dural puncture.…”

“…After initial stabilization, the lumbosacral region was clipped and aseptically prepared. In all cases, needle advancement was guided by the pop sensation, 1,2 and neuraxial injections were performed by two experienced anesthetists. Cats were positioned in sternal recumbency, with the pelvic limbs extended cranially.…”

“…3,4 Commonly, final confirmation of needle tip epidural or intrathecal location relies on the absence or presence of cerebrospinal fluid (CSF) outflow, respectively. 1,2 However, unlike in human medicine in which the occurrence and adverse clinical consequences of dural puncture are well documented, 5 no reports evaluating the occurrence and outcome of this event have been published in the veterinary literature.…”

“…1 In cats, neuraxial injections are usually performed via a lumbosacral access. 1,2 At this level, the spinal cord and surrounding meningeal membranes occupy the majority of the vertebral canal, and the distance between the ligamentum flavum and the dura mater is smaller than the length of the bevel of the recommended needles for both epidural and intrathecal approaches. 3,4 Commonly, final confirmation of needle tip epidural or intrathecal location relies on the absence or presence of cerebrospinal fluid (CSF) outflow, respectively.…”