Rocuronium 0.3 or 0.9 mg/kg comparing onset time, duration of action, and intubating conditions in patients 80 years and older: A randomized study

Background Limited data exist about the optimal dose of rocuronium for intubation in elderly patients. We hypothesized that rocuronium 0.9 mg/kg would lead to a shorter onset time than 0.3 mg/kg in patients above 80 years. Methods Thirty-four patients were randomized to either rocuronium 0.3 or 0.9 mg/kg. The primary outcome was onset time defined as time to train-of-four (TOF) count of 0. Other outcomes included duration of action (time to TOF ratio >0.9), proportion of excellent intubating conditions using the Fuchs-Buder scale and tracheal intubating conditions using the Intubating Difficulty Scale (IDS). Results Rocuronium 0.9 mg/kg resulted in shorter onset time compared to rocuronium 0.3 mg/kg; 108 s (SD 40) vs. 228 s (SD 140) (difference: 119 s [95% CI: 41-196], p = .005), respectively. However, in 66% of the patients receiving rocuronium 0.3 mg/kg a TOF count of 0 was not obtained. Duration of action was longer after rocuronium 0.9 mg/kg: 118 min (SD 43) vs. 46 min (SD 13) (difference: 72 min [95% CI: 49-95] p < .0001), and a greater proportion of excellent intubating conditions (Fuchs-Buder) was obtained; 11/16 (69%) vs 4/18 (22%) (p = .006). No difference was found regarding IDS score. Conclusion Rocuronium 0.9 mg/kg resulted in a shorter onset time compared to rocuronium 0.3 mg/kg in patients above 80 years of age. In 66% of the patients receiving rocuronium 0.3 mg/kg a TOF count of 0 was not obtained.