Onset time and duration of action of rocuronium 0.6 mg/kg in patients above 80 years of age: A comparison with young adults

Background: The number of elderly is increasing, and a large proportion of these people will require surgery and anaesthesia. However, little data exist regarding rocuronium in patients above 80 years of age. The aim of this study was to determine the onset time and duration of action for rocuronium 0.6 mg/kg in patients above 80 years compared with young adults.

Methods: This prospective observational study included 16 young (18-40 years) and 16 elderly (>80 years) patients scheduled for total intravenous anaesthesia. Neuromuscular block following rocuronium 0.6 mg/kg was monitored with acceleromyography using train-of-four (TOF) stimulation. The primary outcome was onset time (from administration of rocuronium until TOF count = 0). Secondary outcomes were duration of action (from administration to TOF ratio >0.9) and intubating conditions according to Intubation Difficulty Score.

Results: Elderly patients, median age of 84 years, had significantly prolonged onset time compared to younger patients; median 135 seconds (135-158) vs 90 seconds (90-105), respectively, a mean difference of 82 seconds (40-124) and Wilcoxon Mann-Whitney odds (WMW) of 19.48 (7.48-X). Duration of action in elderly patients was significantly longer, with a median time of 81 minute (71-97) vs 53 minute (42-73), respectively, a mean difference of 31 minute (14-48), and WMW odds of 6.35 (2.59-X). There was no significant difference in intubating conditions.

Conclusions: Patients above 80 years had significantly prolonged onset time and duration of action after rocuronium 0.6 mg/kg compared with patients aged 18-40 years.