The Effect of Unilateral Subcostal Transversus Abdominis Plane Block Applied as Single or Multiple Injections on Pain in Laparoscopic Cholecystectomy Operations

A total of 90 patients, aged 18 to 65 years, with American Society of Anesthesiologists (ASA) physical status I-III, scheduled for laparoscopic cholecystectomy, will be enrolled in this study. Exclusion criteria encompasse a history of allergy to local anesthetics, chronic analgesic use, psychiatric disorders, renal or hepatic dysfunction, coagulopathy, a body mass index (BMI) > 40 kg/m², and pregnancy. Patients in Group S receive a subcostal TAP block with a single injection, patients in Group T receive a subcostal TAP block with multiple injections, and patients in Group C will not receive any form of block.

Standard monitoring protocols will be implemented upon arrival in the operating theatre and heart rate (HR), mean arterial pressure (MAP), and peripheral oxygen saturation (SpO2) will be recorded during operation. Anesthesia will be induced using propofol (2 mg/kg) and fentanyl (1 μg/kg) and muscle relaxation is achieved with rocuronium (0.5 mg/kg). and maintained using sevoflurane in a 50:50 air/oxygen mixture at a flow rate of 1 L/min. Intraoperative analgesia will be provided through a remifentanil infusion at a rate of 0-0.2 μg/kg/min.

Prior to the initiation of surgery, the subcostal TAP block will be administered in Groups S and T under sterile conditions using ultrasound guidance. A single injection of 20 mL of 0.25% bupivacaine will be administered above the transversus abdominis muscle adjacent to the linea semilunaris to the left sides of the patients in Group S. The patients in Group T will be given three distinct injections to their left sides: 10 mL of 0.25% bupivacaine above the transversus abdominis muscle adjacent to the linea semilunaris, 5 mL of 0.25% bupivacaine between the transversus abdominis and internal oblique muscles in the subcostal region above the midclavicular line and 5 mL of 0.25% bupivacaine between the transversus abdominis and internal oblique muscles in the subcostal region above the anterior axillary line.

Laparoscopic cholecystectomy will be performed using four trocar placements on the right side of the abdomen. Postoperative analgesia was managed with a patient-controlled analgesia (PCA) device containing tramadol.

Postoperative remifentanil concumption will be estimated at the end of the operation. Assessments will be conducted at 30th minute, 1st, 3rd, 6st and 24th hours postoperatively, with parameters including pain, nausea, and total PCA consumption. Pain intensity will be measured using the Visual Analogue Scale (VAS; 0 = no pain, 10 = worst imaginable pain). Postoperative nausea and vomiting (PONV) will be evaluated using a verbal descriptive scale (VDS) (0: No PONV, 1: Mild PONV, 2: Moderate PONV, 3: Severe PONV) [10]. Patient satisfaction will beevaluated at discharge using a five-point Likert scale (1 = strongly unsatisfied, 5 = strongly satisfied). Complications, including infection, bleeding, and subcutaneous emphysema will be documented.