Korean J Anesthesiol.  2000 Feb;38(2):231-236. 10.4097/kjae.2000.38.2.231.

Determinants of Effective Dose of Thiopental Sodium, Propofol and Etomidate in Elderly

• Kang YJ
• Kim DW

• KMID: 1936343
• DOI: http://doi.org/10.4097/kjae.2000.38.2.231

Abstract

BACKGROUND: Many drugs are commonly administered according to total body weight or age basis. However, drugs are primarily distributed to the lean body mass. This study was undertaken to find out the best determinant for drug requirements during induction in elderly.
METHODS
Forty-five ASA 1 to 3 male and female patients older than 65 years scheduled for elective surgery were divided into 3 groups and received thiopental sodium 62.5 mg/min (group T, n = 15), propofol 25 mg/min (group P, n = 15), or etomidate 5 mg/min (group E, n = 15) respectively. Kendall's tau test for correlations was used to describe the relationship between drug requirements for induction and total body weight, lean body mass determined by Weisburg's modification of Gubner's formula, ideal body weight calculated by Devine's method, and body surface area.
RESULTS
Loss of consciousness was obtained with a thiopental sodium dose of 128.4 +/- 29.3 mg, propofol 59.8 +/- 13.6 mg, and etomidate 9.8 +/- 1.4 mg. Kendall's tau correlation test showed that requirements of drugs were related to lean body mass (group T, r = 0.490*, group P, r = 0.433*, group E, r = 0.493*, global P < 0.05) and ideal body weight (group P, r = 0.426*, group E, r = 0.434*, p < 0.05), but not to total body weight or body surface area.
CONCLUSIONS
Our results indicate that drug requirements for induction of anesthesia correlate better with lean body mass and ideal body weight than with total body weight or body surface area in elderly patients.

Keyword

Anesthetics, intravenous: etomidate; propofol; thiopental sodium; Pharmacokinetics: body surface area; ideal body weight; lean body mass; total body weight

MeSH Terms

Aged*
Anesthesia
Body Surface Area
Body Weight
Etomidate*
Female
Humans
Ideal Body Weight
Male
Propofol*
Thiopental*
Unconsciousness
Etomidate
Propofol
Thiopental