An observational study in Abdominal Surgery Patients, Transversus Abdominis Plane (TAP) Block and Pharmacokinetic Analysis, sponsored by University of Liege. Not yet recruiting. Open to participants aged 18 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-05-12.
Sponsored by University of Liege · Observational
This prospective single-center observational pharmacokinetic study will evaluate plasma levobupivacaine concentrations after ultrasound-guided transversus abdominis plane (TAP) block in adult patients undergoing elective abdominal surgery under general anesthesia at CHU Liège. Participants receiving TAP block as part of standard clinical care (levobupivacaine 0.375%, total volume 40 mL, maximum dose 150 mg) will undergo serial blood sampling at 3, 7, 15, 30, 60, 120, and 180 minutes after block completion. Plasma levobupivacaine concentrations will be measured using validated LC-MS/MS methods. The primary objectives are to estimate maximum plasma concentration (Cmax) and time to maximum concentration (Tmax). Secondary objectives include characterization of the concentration-time profile, AUC0-180, interindividual variability, and exploratory associations with clinical factors (age, sex, BMI, type of surgery). The study also aims to inform a pragmatic safety window for subsequent intravenous lidocaine infusion used in multimodal analgesia protocols. Approximately 26 participants will be enrolled. No modification of routine anesthesia or analgesic care is required apart from study-related blood sampling.
This prospective single-center pharmacokinetic observational study is designed to characterize systemic exposure to levobupivacaine after ultrasound-guided transversus abdominis plane (TAP) block performed as part of routine perioperative analgesia for elective abdominal surgery under general anesthesia.
TAP block is widely integrated into multimodal analgesic pathways because it may reduce postoperative pain and opioid requirements. However, administration of relatively large volumes of local anesthetic into fascial planes can result in measurable systemic absorption. Although levobupivacaine has a favorable safety profile compared with racemic bupivacaine, understanding peak plasma concentrations and their timing remains clinically relevant, particularly when additional analgesic strategies such as intravenous lidocaine may be considered during the perioperative period.
Eligible adult participants scheduled for abdominal surgery and already planned to receive TAP block according to institutional practice will be enrolled after informed consent. No changes to standard anesthetic or surgical management are mandated by the study. The TAP block will be performed by experienced anesthesiologists using the institutional standard technique with levobupivacaine 0.375% (total volume 40 mL; maximum dose 150 mg).
The reference time (T0) will be defined as completion of local anesthetic injection. Serial blood samples will be obtained during the early postoperative period at predefined time points up to 180 minutes after T0 to capture the expected absorption phase and early elimination profile. Plasma levobupivacaine concentrations will be quantified using a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay.
The primary pharmacokinetic parameters of interest are maximum observed plasma concentration (Cmax) and time to maximum concentration (Tmax). Secondary analyses will include concentration-time profiles, area under the curve from 0 to 180 minutes (AUC0-180), interindividual variability, and exploratory evaluation of associations between exposure metrics and selected demographic or clinical variables such as age, body mass index, sex, and surgical category.
Results are expected to provide real-world pharmacokinetic data for levobupivacaine after TAP block and may help inform safer sequencing of multimodal analgesic approaches, including timing of intravenous lidocaine administration after fascial plane block. Safety monitoring will follow routine perioperative standards, and any suspected local anesthetic systemic toxicity will be managed immediately according to institutional protocols.
University of Liege is the lead sponsor of 251 studies on the registry; 50 are open to participants now.
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Adult patients treated at CHU Liège who are scheduled for elective abdominal surgery under general anesthesia and for whom an ultrasound-guided transversus abdominis plane (TAP) block with levobupivacaine is planned as part of routine perioperative analgesic care. The study population consists of clinically stable surgical patients able to provide informed consent and undergo serial perioperative blood sampling for pharmacokinetic analysis.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adult participants undergoing elective abdominal surgery under general anesthesia at CHU Liège who receive an ultrasound-guided transversus abdominis plane (TAP) block with levobupivacaine 0.375% (total volume 40 mL; maximum dose 150 mg) as part of standard perioperative analgesic management. This is a single observational cohort. The intervention of interest is the routine TAP block, after which serial blood samples are collected up to 180 minutes to characterize plasma levobupivacaine pharmacokinetics. No experimental treatment is assigned by the study.
Procedure: Ultrasound-Guided Transversus Abdominis Plane Block with Levobupivacaine
Ultrasound-guided transversus abdominis plane (TAP) block performed as part of routine perioperative analgesia after induction of general anesthesia for elective abdominal surgery. Levobupivacaine 0.375% is injected into the transversus abdominis fascial plane under real-time ultrasound visualization, using a total volume of 40 mL (typically bilateral administration, adjusted to surgical indication), with a maximum total dose of 150 mg. The block is performed by an experienced anesthesiologist according to institutional standard practice.
Maximum Plasma Levobupivacaine Concentration (Cmax)
Maximum observed plasma concentration (Cmax, µg/mL) of levobupivacaine after TAP block, determined from serial plasma samples collected during the first 180 minutes after completion of the block.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
Time to Maximum Plasma Levobupivacaine Concentration (Tmax)
Time to maximum observed plasma concentration (Tmax, minutes) of levobupivacaine after TAP block, determined from serial plasma samples collected during the first 180 minutes after completion of the block.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
Area Under the Plasma Concentration-Time Curve From 0 to 180 Minutes (AUC0-180) of Levobupivacaine
Area under the plasma concentration-time curve (AUC0-180, µg·min/mL) of levobupivacaine following TAP block, calculated from serial plasma concentration measurements obtained during the first 180 minutes after completion of the block.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
Plasma Levobupivacaine Concentration at Each Sampling Time Point
Measured plasma concentration (µg/mL) of levobupivacaine at predefined sampling time points after TAP block.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement.
Interindividual Variability of Maximum Plasma Levobupivacaine Concentration (Cmax)
Interindividual variability of maximum plasma levobupivacaine concentration (Cmax), assessed using descriptive dispersion measures including standard deviation and coefficient of variation.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
Association Between Area Under the Plasma Concentration-Time Curve (AUC0-180) and Clinical Factors
Association between levobupivacaine AUC0-180 (µg·min/mL) and predefined clinical factors including age, sex, body mass index (BMI), and type of surgery.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
Time to Reach Plasma Levobupivacaine Concentration Below Prespecified Safety Threshold
Time required for plasma levobupivacaine concentrations to decrease below the predefined safety threshold considered compatible with initiation of intravenous lidocaine administration after TAP block.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
Interindividual Variability of Area Under the Plasma Concentration-Time Curve (AUC0-180)
Interindividual variability of levobupivacaine AUC0-180, assessed using descriptive dispersion measures including standard deviation and coefficient of variation.
Time frame: From completion of TAP block (T0) to 180 minutes post-block placement
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Plan to share: No
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