Neuromuscular effects of 600 μg·kg−1 of rocuronium in infants during nitrous oxide-halothane anaesthesia |
| |
Authors: | SUSAN K WOELFEL MD BARBARA W BRANDOM MD FRANCIS X McGOWAN Jr MD BRIAN J GRONERT MD D RYAN COOK MD |
| |
Institution: | Departments of Anesthesiology, Children's Hospital of Pittsburgh and the University of Pittsburgh, Pittsburgh, Pennsylvania 15213 USA |
| |
Abstract: | Rocuronium bromide (Zemuron) is a new steroidal nondepolarizing neuromuscular blocking drug. We were interested in determining the effect of a bolus of rocuronium in infants during halothane anaesthesia as we did previously in older children. Eighteen infants (2-11 months) received a bolus of 600 μg·kg?1, which is equal to twice the dose of rocuronium estimated to produce 95% depression of neuromuscular function (ED95) in children (2-12 yr). Neuromuscular blockade was monitored by recording the electromyographic activity of the adductor pollicis muscle resulting from supramaximal stimulation of the ulnar nerve at 2 Hz for 2 s at 10-s intervals. Time (mean ± SEM, range) from administration of 600 μg·kg?1 rocuronium to 90% (B90) and 100% (B100) neuromuscular block was 37 ± 2 (20-60) s and 64 ± 10 (20-180) s, respectively. The time to recovery of neuromuscular transmission to 10% (T10) was 35.3 ± 3.0 (20.7-57.8) min and to 25% of baseline (T25) was 41.9 ± 3.2 (24.3-67.7) min. The recovery index (T25-T75) was 26.6 ± 2.7 (11.7-44.5) min, and the time to recovery of the train-of-four ratio (T4/T1) ± 0.75 was 82.1 ± 6.9 (53.2-138.3) min. The plasma concentration of rocuronium when T1 had recovered to about 30% was 654 ± 34 (417-852) ng·ml?1 which is similar to that observed in children. Six-hundred μg·kg?1 of rocuronium has a rapid onset of effect in infants and prolonged duration of action in infants compared to children. |
| |
Keywords: | anaesthetics volatile: halothane neuromuscular relaxant rocuronium |
|
|