Neuromuscular blockade effects of cisatracurium in 11 cats undergoing ophthalmological surgery anaesthetised with isoflurane

Case series summary This case series describes the neuromuscular blockade (NMB) following 0.15 mg/kg intravenous (IV) cisatracurium administration in 11 cats undergoing ophthalmological surgery and anaesthetised with isoflurane. Anaesthetic records were analysed retrospectively. Neuromuscular function was assessed by a calibrated train-of-four (TOF) monitor. Cats were 73 +/- 53 months old, weighed 4 +/- 1 kg and were of American Society of Anesthesiologists' physical classification 2. Duration of anaesthesia and surgery were 144 +/- 27 and 94 +/- 24 mins, respectively. The lowest TOF count was zero in four cats, four in six cats and for one cat the TOF ratio never decreased below 31%. The time of onset was between 1 and 6 mins after the administration of cisatracurium and the mean duration of action was 20.4 +/- 10.1 mins. Relevance and novel information Cisatracurium at a dose of 0.15 mg/kg IV did not consistently induce a TOF count of zero in all cats. The dose used in these cats did not produce any remarkable cardiovascular side effects. Although the NMB was not complete, the dose given was sufficient to produce central eyeball position, which was the goal of the ophthalmic surgeries.