Influence of age and gender on the pharmacodynamic parameters of rocuronium during total intravenous anesthesia.

Aims: To compare the pharmacodynamics of 0.6 mg kg(-1) rocuronium in young and older patients of both genders during total intravenous anesthesia.

Methods: Following local ethics committee approval and informed consent, patients scheduled for surgery under total intravenous anesthesia (propofol/sufentanil) were divided into 4 study groups: 37 males aged 20-40, 40 males aged 60-75 yrs, 43 females aged 20-40 and 38 females aged 60-75 yrs. Neuromuscular block following rocuronium (0.6 mg kg(-1)) was monitored: train-of-four [TOF] stimulation of the ulnar nerve at 15-s intervals, EMG of the adductor pollicis muscle. The onset time (from application of rocuronium to maximum depression of T(1)), clinical duration (from application to 25% recovery of T(1)), and time to full spontaneous recovery (from application to TOF-ratio ≥ 0.9) were determined for each patient. The Kruskal-Wallis test was used to compare differences between groups; P<0.05 was considered statistically significant.

Results: The onset time (median [interquartile range]) in the respective groups was 90 [80-110](BCD), 135 [116-165](AC), 75 [60-90](ABD), and 120 [90-146](AC) seconds. The clinical duration was 30 [25-42](BCD), 58 [53-67](AD), 50 [40-65](AD), and 85 [70-90](ABC) min. Interval to full spontaneous recovery was 59 [51-67](BCD), 102 [75-106](A), 76 [66-91](AD), and 128 [94-137](AC) min. ((A)P<0.05 vs. young males, (B)P<0.05 vs. elderly males, (C)P<0.05 vs. young females, (D)P<0.05 vs. elderly females).

Conclusion: Females and older patients were more sensitive to rocuronium.