Onset and duration of action of vecuronium in the elderly: comparison with adults.
The onset and duration of action of vecuronium were studied in young adult (n = 30; mean age 34 +/- 11.1 (s.d.) yr), middle-aged (n = 20; mean age 60 +/- 5.8 yr) and elderly patients (n = 30; mean age 80 +/- 4.6 yr) anaesthetised with thiopentone, nitrous oxide in oxygen and halothane. Neuromuscular block was monitored by applying the train-of-four (TOF) stimulation at 2 Hz to the ulnar nerve every 12 s. Half the patients in each group received 0.08 and the other half 0.12 mg kg-1 of the relaxant. The time to return of T1 (first response in the TOF sequence) to 25% of control was 28 +/- 5.2 (s.d.), 34 +/- 7.1 and 39 +/- 10.2 min following 0.08 mg kg-1 dose (P less than 0.05 between the elderly and young adults) and 45 +/- 9.2, 48 +/- 6.2 and 69 +/- 19.2 min following 0.12 mg kg-1 dose, respectively, in the three age groups (P less than 0.05 between the elderly and the other two groups). The recovery indices (time for 25-75% recovery of T1) after the 0.08 mg kg-1 was 9.6 +/- 3.4, 13.6 +/- 5.1 and 17.4 +/- 6.1 min, respectively (P less than 0.05 between the elderly and young adults). There was no significant difference in any of the parameters between the young adults and the middle-aged. The onset of block at each dose was not significantly different between the three age groups; however, the time to maximum effect was significantly shorter with the higher dose in the young and the middle-aged, but not in the elderly. Regression analysis of the data between age and the duration of action and recovery index suggested a significant prolongation (P less than 0.05) of these parameters in the elderly.
Department of Anaesthetics, Queen's University, Belfast, N. Ireland.
G
G
McCarthy
P
P
Elliott
R K
RK
Mirakhur
R
R
Cooper
T D
TD
Sharpe
R S
RS
Clarke
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D000769:Anesthesia, Inhalation; D006801:Humans; D008875:Middle Aged; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D013508:Ophthalmologic Surgical Procedures; D013997:Time Factors; D014673:Vecuronium Bromide / Q000494:pharmacology*
D014673:Vecuronium Bromide