Diabetes mellitus affects the duration of action of vecuronium in dogs

Objective To compare the duration of action of vecuronium in diabetic dogs with a control group. Study design Prospective clinical study. Animals Forty client-owned diabetic (n = 20) and non-diabetic dogs. Methods Dogs were considered free from other concurrent disease based on clinical examination and laboratory data. After pre-anaesthetic medication with acepromazine and methadone, anaesthesia was induced with intravenous (IV) propofol and maintained with isoflurane-nitrous oxide in oxygen. Neuromuscular blockade (NMB) was achieved with vecuronium, 0.1 mg kg-1 IV and its effects recorded by palpation (pelvic limb digital extension) and electromyography (m. tibialis cranialis) of responses (twitches; T) to repeated train-of-four (TOF) nerve stimulation. Time to onset of NMB was the period between vecuronium injection and loss of fourth twitch (T4) in the TOF pattern recorded by EMG and palpation. Duration of NMB was defined as the time from drug administration to return of T1 by palpation (T1tactile) and EMG (T1EMG). Times to return of T2-4 were also recorded. Time from induction of anaesthesia to vecuronium injection was recorded. Heart rate, non-invasive mean arterial pressure, body temperature, end-tidal isoflurane and end-tidal CO2 concentrations were recorded at onset of NMB and when T1EMG returned. Loss and return of palpable and EMG responses for diabetic and non-diabetic dogs were compared using t-tests and Mann Whitney U-tests. Results There were significant (p < 0.05) differences between diabetic and non-diabetic dogs for the return of all four palpable and EMG responses. Times (mean +/- SD) for return of T1tactile were 13.2 +/- 3.5 and 16.9 +/- 4.2 minutes in diabetic and non-diabetic dogs respectively. There were no differences between diabetic and non-diabetic dogs in the time to onset of vecuronium with EMG or tactile monitoring. Conclusions and clinical relevance The duration of action of vecuronium was shorter in diabetic dogs as indicated by both tactile and EMG monitoring.