Rocuronium infusion: A higher rate is needed in diabetic than nondiabetic dogs

Objective

To determine the infusion rates that maintain the train-of-four (TOF) ratio within 20–70% in dogs and compare the infusion rates between diabetic and nondiabetic dogs.

Study design

Prospective clinical study.

Animals

In total, 47 dogs scheduled for phacoemulsification were included with a median (80% central range) bodyweight of 10.6 (5.7–35.5) kg and age of 7 (1–11) years. Diabetes mellitus was previously diagnosed in nine dogs.

Methods

After premedication using acepromazine and methadone, anaesthesia was induced by intravenous (IV) propofol and maintained by isoflurane and fentanyl or remifentanil. The TOF ratio was monitored by stimulating the peroneal nerve and the response quantified by accelerometry. Rocuronium 0.5 mg kg^?1 was administered IV, and further infused to maintain the TOF ratio between 20% and 70%. The infusion rates of rocuronium were compared by the Mann–Whitney test between diabetic and nondiabetic dogs, and the influence of age, sex, bodyweight, body temperature, end-tidal carbon dioxide, end-tidal isoflurane concentration, mean arterial blood pressure, pulse rate and time from induction and time from rocuronium bolus to stable rocuronium infusion rate were investigated in a stepwise, forward regression model.

Results

A stable infusion rate was found in 42 dogs. A higher median (80% central range) infusion rate was found in diabetic 0.43 (0.35–0.50) mg kg^?1 hour^?1] compared with nondiabetic dogs 0.30 (0.20–0.50) mg kg^?1 hour^?1] (p = 0.013). None of the other variables investigated were found to significantly influence the infusion rate.

Conclusions and clinical relevance

There is a quite large individual variation in the infusion rates of rocuronium needed to maintain a stable neuromuscular block in a varied population of dogs. Of the variables investigated, diabetes mellitus was the only one found to significantly influence the infusion rate of rocuronium.