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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Obesity

Intervention / Treatment
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* Drug: Propofol


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Propofol<br>14 obese patients(IMC>35 kg m-2) scheduled for laparoscopic bariatric surgery | Drug: Propofol<br>* Propofol was administered by plasma TCI and a bolus dose was given by setting the initial plasma target between 12-16 μg/ml according to the anesthesiologist criteria. The protocol target range was selected based on previous experience using this model in the obese. After the patients reached this target, propofol infusion was stopped until the patients woke up (BIS>75). No other drugs were given during this period. Facemask ventilation was assisted only if necessary to maintain SpO2 > 90%. BIS data and propofol infusion data were automatically recorded every five seconds using the AnestFusor© program. Arterial blood samples of 4 ml for propofol assays were collected at 1, 2, 3, 5, 7 and 10 minutes after the initial bolus dose or until BIS > 75. After the patient woke up the study was considered finished and propofol infusion was restarted according to the anesthesiologist plan.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Profile of Pharmacokinetic and Pharmacodynamic of an induction bolus dose of propofol in obese patients. | Pharmacokinetic parameters (V1, V2, V3, CL, Q) Pharmacodynamic parameters (E0, Emax, C50, Gamma, t1/2Ke0, T peak ) | 1, 2, 3, 5, 7 and 10 minutes after the initial bolus dose or until BIS > 75 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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anaesthetics iv, propofol, pharmacokinetics, pharmacodynamic