Influences of age and gender on dose response and time course of effect of atracurium in anesthetized adult patients.
OBJECTIVE
To determine the influences of age and gender on the dose response and the time course of effect of atracurium.


METHODS
Prospective, nonrandomized, clinical comparison.


METHODS
Operating room, Plastic Surgery Hospital of the Chinese Academy of Medical Sciences and Peking Union Medical College.


METHODS
72 adult ASA physical status I patients (38 male and 34 female), aged 15 to 59 years, scheduled for elective plastic surgery.


METHODS
Patients were divided into the three groups on the basis of age: Group 1, patients aged 15-29 years (n = 32); Group 2, patients aged 30-40 years (n = 21); and Group 3, patients aged 41-59 years (n = 19). Anesthesia was maintained with 60% nitrous oxide in oxygen, thiopental, and incremental doses of fentanyl as required. The dose-response relationship of atracurium was determined by a cumulative dose-response technique.


RESULTS
Neuromuscular function was assessed mechanomyographically with train-of-four stimulation at the wrist every 12 seconds and the percentage depression of first twitch (T1) response was used as the study variable. Age and gender significantly affected the dose-response relationship and time course of recovery of atracurium. Advancing age was associated with a reduced effective doses (ED50, ED90, and ED95) of atracurium and a longer duration of action. The effective doses of atracurium were greater, and its duration of action was shorter in men than in women. There were significant differences in the 50%, 90%, and 95% effective dose (ED50, ED90, and ED95) of atracurium, and clinical duration and total duration following administration of atracurium 400 micrograms/kg among the three age groups, and between men and women.


CONCLUSIONS
Age and gender have significant effects on the dose response and time course of effect of atracurium. Older patients and women are more sensitive to atracurium-induced neuromuscular block than are young patients and men.
Xue
F S
FS
Department of Anesthesiology, Plastic Surgery Hospital, Beijing, People's Republic of China. angangbj@263.net
Zhang
Y M
YM
Liao
X
X
Liu
J H
JH
An
G
G
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000758:Anesthesia; D001279:Atracurium / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D003473:Neuromuscular Nondepolarizing Agents / Q000494:pharmacology*; D011446:Prospective Studies; D012737:Sex Factors; D013997:Time Factors
D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium