Comparison of ANI Between Preoperative and Postoperative Ultrasound-guided TAP Block in Laparoscopic Cholecystectomy

Comparison of Perioperative Analgesia Nociception Index (ANI) Between Preoperative and Postoperative Ultrasound-guided Transversus Abdominis Plane Block(TAP Block) in Laparoscopic Cholecystectomy

The goal of this clinical trial is to learn if the timing of ultrasound-guided transversus abdominis plane block (US-TAP block) administration (preoperative vs. postoperative) affects the perioperative analgesia nociception index (ANI) in adult patients undergoing laparoscopic cholecystectomy. The main questions it aims to answer are:

• Does the timing of the US-TAP block significantly influence intraoperative ANI values?
• Does the difference in US-TAP block timing and subsequent ANI values correlate with actual patient recovery, postoperative pain scores (VAS), and complication rates?

If there is a comparison group: Researchers will compare the experimental group (Group A: US-TAP block before surgical incision) to the control group (Group B: US-TAP block after wound closure) to see if early block administration provides superior intraoperative pain suppression and reduces postoperative pain or analgesic consumption.

Participants will:

• Undergo standard general anesthesia induction and maintenance.
• Receive a bilateral US-TAP block with a total of 30 mL of 0.2% ropivacaine, administered either before incision (Group A) or after closure (Group B).
• Be monitored via standard monitoring devices alongside an ANI monitor.
• Use an intravenous patient-controlled analgesia (IV-PCA) pump for 24 hours after surgery.
• Participate in postoperative assessments to measure pain scores (VAS), rescue analgesic consumption, satisfaction, and complications at specific intervals up to 24 hours post-surgery.

Inclusion Criteria:

• Patients scheduled to undergo laparoscopic cholecystectomy.
• Aged 19 years or older.
• American Society of Anesthesiologists (ASA) physical status I, II, or III.

Exclusion Criteria:

• Patients who lack the capacity to understand the study examinations or perform the assessment procedures.
• Patients with coagulation deficiencies or bleeding disorders.
• Patients with cardiac arrhythmias or those with an implanted cardiac pacemaker.
• Patients taking medications that affect the autonomic nervous system, including beta-blockers and opioid analgesics.
• Patients with surgical scars, active lesions, or anatomical abnormalities at the block site.
• Patients with pre-existing neurological deficits or impairment at the block site.
• Patients with a known history of allergic reactions or hypersensitivity to ropivacaine or other local anesthetics.
• Pregnant or lactating individuals.