To address this hypothesis, we will conduct a clinical study evaluating the pharmacokinetics and pharmacodynamics of propofol in 20 morbidly obese subjects scheduled to undergo laparoscopic gastric banding or another elective procedure. Full PK/PD profiles will be obtained during surgery and the Bispectral index monitor will be used as a validated approach for PD monitoring, a measure of depth of anesthesia (5). The population nonlinear mixed effect modeling (NONMEM) approach will be used with extensive covariate analysis to account for observed inter- and intraindividual variability (6, 7). The potential covariates affecting propofol PK (and PD) we will explore include total body weight, lean body mass, Body Mass Index (BMI), Body Surface Area (BSA), height, age, gender, type of procedure, and duration of procedure.