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

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.