Relation between initial blood distribution volume and propofol induction dose requirement

• Published in: Anesthesiology (Philadelphia) Vol. 94; no. 2; pp. 205 - 210
• Main Authors: KAZAMA, Tomiei, IKEDA, Kazuyuki, MORITA, Koji, IKEDA, Takehiko, KIKURA, Mutsuhito, SATO, Shigehito
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott 01.02.2001
• Subjects: Adolescent; Adult; Age Factors; Aged; Anesthetics, Intravenous - pharmacology; Anesthetics. Neuromuscular blocking agents; Biological and medical sciences; Blood Volume; Cardiac Output - drug effects; Child; Female; Humans; Liver Circulation; Male; Medical sciences; Metabolic Clearance Rate; Middle Aged; Neuropharmacology; Pharmacology. Drug treatments; Propofol - administration & dosage; Propofol - pharmacokinetics; Heart; Human; Distribution volume; General anesthetic; Blood volume; Induction; Liver; Prediction; General anesthesia; Propofol; Posology; Blood flow
• ISSN: 0003-3022; 1528-1175
• DOI: 10.1097/00000542-200102000-00007

Propofol induction dose is variable and depends on many factors, including initial volume of distribution and early disposition. The authors hypothesized that preadministration blood distribution volumes, cardiac output (CO), and hepatic blood flow (HBF) could be examined to establish a propofol induction dose. Propofol dose required to reach loss of consciousness, when infused at infusion rate per lean body mass (LBM) of 40 mg x kg(-1) x h(-1), was determined in 75 patients aged 11-85 yr. CO, blood volume (BV), central blood volume (CBV), and HBF were measured with indocyanine green pulse spectrophotometry. Univariate least squares linear regression analysis was used to individually analyze the relation between propofol induction dose and patient characteristics, including LBM, baseline distribution volumes, CO, and HBF. Stepwise multiple linear regression models were used to select important predictors of induction dose. Although there was a significant correlation between the induction dose and each of the eight variables of age, sex, LBM, hemoglobin, CO, BV, CBV, and HBF, only factors of age (partial r = -0.655), LBM (partial r = 0.325), CBV (partial r = 0.540), and HBF (partial r = 0.357) were independently associated with the induction dose (R2 = 0.85) when all variables were included in a multivariate model. At a constant propofol infusion rate of 40 mg x kg(-1) x h(-1) as a function of LBM in patients with American Society of Anesthesiologists physical status I or II, the induction dose can be determined from four variables: age, LBM, CBV, and HBF.