The aims of this study are to determine population PK parameters of bupivacaine in children following TAP block using a population-based PK approach, and to evaluate the influence of patient covariates on drug disposition.
The number of published pediatric studies on the use of transversus abdominis plane (TAP) block has increased in recent years. The transversus abdominis plane (TAP) block has been used for postoperative analgesia for surgery to the abdominal wall and involves the injection of local anesthetic solution into a plane between internal oblique (IO) and transversus abdominis (TA) muscles. The TAP block has the advantage of providing unilateral analgesia in instances of non-midline abdominal incision and is particularly useful in cases where epidural blockade is either contraindicated or technically or logistically not feasible. Bupivacaine and ropivacaine have been used as local anesthetics for TAP blocks in published studies to date. However, no data exist regarding the pharmacokinetics of bupivacaine after TAP block in children. The aims of this study are to determine population pharmacokinetic (PK) parameters of bupivacaine in children following a TAP block, using a population-based PK approach.
Study Type
OBSERVATIONAL
Enrollment
20
Bupivacaine levels will be measured with an assay developed on the 4000 QTrap Tandem Mass Spectrometer (Applied Biosystems/ MDS Sciex). Data will be collected and analyzed using the Agilent ChemStation software (Rev A.10.02). The analytical column is an Agilent Zorbax Eclipse XDB-C8 (4.6 x 150mm, 5µm).Quantification of bupivacaine is based on analyzing a six point calibration curve (0 to 4.0 mg/L). An internal standard (Prilocaine 221.2/86.1) is included with each calibrator, quality control or patient sample. Instrumentation and Chromatographic conditions: The HPLC system consists of a Specta-System P1000 Isocratic Pump and an AS3000 Autosampler (Thermo Electron Corporation, Waltham MA).
The Hospital for Sick Children
Toronto, Ontario, Canada
Population pharmacokinetics of bupivacaine and the influence of patient covariates on drug disposition
Blood will be drawn from an indwelling intravenous catheter. Each patient will have a total of 6 samples collected during each of the following time blocks: 0 - 10 minutes, 11 - 20 minutes, 21 - 30 minutes, 31 - 60 minutes, 61 - 180 minutes and 181 - 360 minutes after the TAP block is performed. Age, weight, sex, concomitant drugs (intravenous and inhalation anesthetics, muscle relaxants, and opioids), and kidney function data will be investigated as co-variables for each of the primary parameters. We will obtain estimates of total clearance (CL), volume of distribution, elimination half life (t1/2), estimates of clearance, and absorption rate constant.
Time frame: 0 - 360 minutes after the TAP block is performed
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