NCT Number: NCT07592091
This randomized controlled trial aims to compare the analgesic efficacy of rectus sheath block (RSB) and transversus abdominis plane block (TAPB) in patients undergoing laparoscopic bariatric surgery. Both techniques are regional anesthesia methods used as part of multimodal analgesia to reduce postoperative pain and opioid requirements.
Eligible participants will be randomly assigned to receive either a RSB or a TAPB after general anesthesia. Postoperative pain scores, opioid consumption, recovery outcomes, area of sensory loss, time to first rescue analgesia, and block-related adverse events will be assessed and compared between the two groups.
This study will help determine which regional anesthesia technique provides more effective postoperative analgesia for laparoscopic bariatric surgery
Trial opening soon.
Get Notified20 year–60 year
All sexes
Interventional
Not applicable
Chiang Mai, Mueang, 50200, Thailand
Artid Samerchua, MD
CONTACT
Artid Samerchua, MD
PRINCIPAL_INVESTIGATOR
Kittitorn Supphapipat, MD
CONTACT
Kittitorn Supphapipat, MD
PRINCIPAL_INVESTIGATOR
Laparoscopic bariatric surgery provides sustained weight loss for patients with obesity and is associated with improved metabolic outcomes and increased life expectancy. Despite its minimally invasive approach, laparoscopic bariatric surgery is often associated with moderate-to-severe postoperative pain, which may require significant opioid use. Postoperative opioid administration may increase the risk of opioid-related adverse effects, including opioid-induced ventilatory depression and postoperative nausea and vomiting. These concerns are particularly important in patients with obesity, who may have an increased risk of obstructive sleep apnea and opioid-related respiratory complications.
Enhanced Recovery After Surgery principles recommend opioid-sparing strategies, including regional anesthesia and local anesthetic techniques, as part of multimodal analgesia for bariatric surgery. Several regional analgesic techniques have been used for laparoscopic bariatric surgery, including local infiltration analgesia, transversus abdominis plane block, rectus sheath block, and other fascial plane blocks.
Transversus abdominis plane block is commonly used for abdominal surgery and provides somatic analgesia to the anterolateral abdominal wall. However, its analgesic efficacy in laparoscopic bariatric surgery remains variable, partly due to differences in block technique, injection site, local anesthetic regimen, and technical challenges in patients with obesity. Excessive subcutaneous tissue may make identification of the target fascial plane more difficult and may increase the risk of inaccurate needle placement or incomplete sensory blockade.
Rectus sheath block is another regional anesthesia technique used for abdominal surgery. It involves the injection of local anesthetic between the rectus abdominis muscle and the posterior rectus sheath, providing analgesia to the anterior abdominal wall, particularly around the midline and periumbilical region. Rectus sheath block may be technically easier to perform than transversus abdominis plane block in patients with obesity because of its more superficial needle trajectory. Previous studies suggest that rectus sheath block may reduce postoperative pain and opioid consumption compared with systemic analgesia alone or local infiltration analgesia.
Although both rectus sheath block and transversus abdominis plane block may improve postoperative analgesia after laparoscopic bariatric surgery, their relative efficacy remains unclear. No previous study has directly compared these two techniques for postoperative analgesia in this surgical population.
This randomized controlled trial will compare the analgesic efficacy and opioid-sparing effects of ultrasound-guided rectus sheath block (RSB) and ultrasound-guided transversus abdominis plane block (TAPB) in patients undergoing laparoscopic bariatric surgery. Eligible participants will be randomly assigned to receive either RSB or TAPB as part of perioperative multimodal analgesia.
The study will assess postoperative pain intensity, opioid consumption, quality of recovery, rescue analgesic requirements, and block-related adverse events. The primary analysis will evaluate whether one technique provides superior analgesia. If superiority is not demonstrated, equivalence will be assessed. The findings may help guide the selection of regional anesthesia techniques for postoperative analgesia in patients undergoing laparoscopic bariatric surgery.
Healthy volunteers accepted: No
Only the study team can determine whether someone qualifies for participation.
Inclusion criteria
Exclusion criteria
Bilateral rectus sheath block will be performed by an anesthesiologist experienced in ultrasound-guided regional anesthesia. The ultrasound probe will be positioned at the midpoint between the xiphoid process and the umbilicus along the mid-clavicular line. After aseptic preparation of the puncture site and ultrasound probe, a needle will be advanced using an in-plane, lateral-to-medial approach under continuous ultrasound guidance. After correct needle-tip placement between the rectus abdominis muscle and the posterior rectus sheath, 30 mL of 0.25% bupivacaine with epinephrine 5 µg/mL will be injected on each side after negative aspiration. Local anesthetic spread will be monitored in real time, and the procedure will be repeated on the contralateral side using the same technique.
Bilateral transversus abdominis plane block will be performed by an anesthesiologist experienced in ultrasound-guided regional anesthesia. The ultrasound probe will be placed on the lateral abdominal wall between the costal margin and iliac crest at the mid-axillary line. Depth, frequency, and gain will be adjusted to clearly visualize the fascial plane between the internal oblique and transversus abdominis muscles. After aseptic preparation of the puncture site and ultrasound probe, a needle will be advanced using an in-plane approach under continuous ultrasound guidance. After correct needle-tip placement in the transversus abdominis plane, 30 mL of 0.25% bupivacaine with epinephrine 5 µg/mL will be injected on each side after negative aspiration. Local anesthetic spread within the fascial plane will be monitored in real time, and the procedure will be repeated on the contralateral side using the same technique.
Time frame: 6 hours postoperatively
Pain intensity will be assessed using the Numerical Rating Scale (NRS), an 11-point scale ranging from 0 to 10, where 0 indicates no pain and 10 represents the worst pain imaginable. Patients will be asked to rate their pain intensity by selecting the number that best reflected their level of pain during movement at 6 h postoperatively. Patients will be instructed to perform a standardized movement (including coughing, deep breathing, or changing position from supine to sitting) and then rate the pain intensity experienced during that movement.
Time frame: 0, 2, 6, 12, 24, and 48 hours postoperatively
Postoperative pain intensity will be assessed using the NRS. Pain scores will be recorded both at rest and movement at 0, 2, 6, 12, 24, and 48 hours (except for movement at 6 hours which was defined as primary outcome) (Pain-rest-0hour, Pain-rest-2hour, Pain-rest-6hour, Pain-rest-12hour, Pain-rest-24hour, Pain-rest-48hour and Pain-move-0hour, Pain-move-2hour, Pain-move-12hour, Pain-move-24hour, Pain-move-48hour) postoperatively. For pain at rest, patients will be asked to rate their pain while lying comfortably without active movement. For pain during movement, patients will be instructed to perform a standardized movement (including coughing, deep breathing, or changing position from supine to sitting) and then rate the pain intensity experienced during that movement.
Time frame: During intraoperative period
Total intraoperative fentanyl consumption will be recorded for each patient and expressed in microgram. Fentanyl will be administered to standard clinical practice. The cumulative dose of fentanyl administered from induction of anesthesia until the end of surgery will be extracted from the anesthesia record
Time frame: 30 minutes postoperatively
The area of sensory loss will be assessed by testing for loss of cold sensation using a cold stimulus (ice). Sensory testing will be performed over the anterior abdominal wall, and dermatomal coverage will be recorded and mapped according to patient-reported loss of cold sensation compared with the contralateral or adjacent non-blocked area.
Time frame: within 48 hours postoperatively
Time to first rescue analgesia will be defined as the interval, in minutes, from the end of surgery to the first activation (buttom press) of the patient-controlled analgesia (PCA) device. Data will be extracted from the PCA device electronic record
Time frame: 0-24 hours and 24-48 hours postoperatively
Postoperative opioid consumption will be defined as the cumulative dose of opioids administered during the postoperative period and will be expressed as intravenous morphine milligram equivalents (MME). All opioid doses administered via patient-controlled analgesia (PCA) will be extracted from PCA device logs and converted to MME using standard conversion factors
Time frame: 24 and 48 hours postoperatively
Postoperative quality of recovery will be assessed using the Thai version of the 14-item Quality of Recovery questionnaire (QoR-14), a validated patient-reported outcome measure. The QoR-14 evaluates multiple domains of postoperative recovery, including physical comfort, emotional state, physical independence, psychological support, and pain. Each item is scored on an 11-point numerical scale ranging from 0 to 10, yielding a total score from 0 to 140, with higher scores indicating a better quality of recovery.
Time frame: 0-2, 2-6, 6-12, 12-24 and 24-48 hours postoperatively.
The incidence and severity of postoperative nausea and vomiting will be assessed using a four-point numerical scale, where 0 = no nausea and vomiting, 1 = mild nausea, 2 = severe nausea or a single episode of vomiting, and 3 = more than one episode of vomiting.
Time frame: Perioperative period
Block-related complication will include the occurrence of hematoma, intra-abdominal puncture, and local anesthetic systemic toxicity (LAST).
Contact information is provided by the study sponsor or research team.
Artid Samerchua, MD
CONTACT
Kittitorn Supphapipat, MD
CONTACT
Chiang Mai University
Other
Comparison of Rectus Sheath Block and Transversus Abdominis Plane Block for Analgesia in Laparoscopic Bariatric Surgery: A Randomized Controlled Trial
Acronym: RSB-TAPB
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