Published in:
01-06-2013 | Reports of Original Investigations
In non-obese patients, duration of action of rocuronium is directly correlated with body mass index
Published in: Canadian Journal of Anesthesia/Journal canadien d'anesthésie | Issue 6/2013
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Background
Administration of neuromuscular blocking agents using a dose calculated on actual body weight carries a risk of prolonged duration of action in obese patients whose body mass index (BMI) is > 30 kg·m−2. In the present study, we hypothesized that there could be a correlation between BMI and the duration of action of rocuronium administered according to actual body weight in non-obese patients, in particular, overweight (BMI 25-30 kg·m−2) and underweight patients (BMI < 18.5 kg·m−2).
Methods
Sixteen female patients (BMI 15-30 kg·m−2, aged 45-60 yr) scheduled for elective surgery under total intravenous anesthesia were included in this study. Rocuronium 0.9 mg·kg−1 was administered, and adductor pollicis train-of-four responses following ulnar nerve stimulation were monitored every minute with acceleromyography. The times from the injection of rocuronium until spontaneous recovery of first twitch to 5% (5% Duration) and 25% (25% Duration) of baseline were measured, and the correlation with BMI was analyzed.
Results
A significant correlation between 5% Duration and BMI (r2 = 0.56; P < 0.001) was found by linear regression analysis. A significant correlation was also found between 25% Duration and BMI (r2 = 0.49; P = 0.003).
Conclusion
In adult female patients with a BMI in the range of 15-30 kg·m−2, the duration of action of rocuronium increases with BMI when the drug is administered on the basis of mg per actual kg body weight.