Propofol Effect-Site Target Controlled Infusion in the Obese: Characterization of the Time Profile of Bispectral Index Response

Propofol Effect-Site Target Controlled Infusion in the Obese: Characterization of the Time Profile of Bispectral Index Response.

The aim of this study is to characterize the Pharmacokinetic/Pharmacodynamic relationship of a single bolus dose of propofol in obese patients and to extract a time to peak effect (t-peak) from the estimated model parameters.

Target controlled infusion (TCI) is a technique to administer intravenous drugs that allows rapid achievement and maintenance of predetermined drug concentrations, either in plasma (Cp) or at the site of effect (Ce).

To characterize the time profile of propofol effect an additional parameter, the equilibration half time between plasma and effect site (T1/2keo) needs to be incorporated in the pharmacokinetic (PK) model.

Inclusion Criteria:

• IMC > 35 kg m-2
• Scheduled for laparoscopic bariatric surgery
• ASA I-II patients
• Between 20 and 60 yr of age.

Exclusion Criteria:

• Patients with allergy to study drugs
• Uncontrolled hypertension
• Heart block greater than first degree
• Take any drug acting in the central nervous system