Post Operative Analgesic Efficacy Of Ultrasound Guided External Oblique Intercostal (EOI) Block Vs Modified Thoraco-Abdominal Nerves Block Through Perichondrial Approach (M-TAPA) After Laparoscopic Cholecystectomy

Laparoscopic Cholecystectomy is a commonly per­formed surgery in the treatment of symptomatic gallstone disease all over the world. Though minimally invasive, it can cause moderate-severe pain. Post-operative pain is a serious problem that impairs the quality of recovery and increases the risk of other postoperative complications. Many methods to treat postoperative pain such as patient controlled analgesia, epidural analgesia, intravenous analgesia, intraperitoneal local anaesthetic injection, oral and intravenous drugs including opioids are widely used. Certain  nerve blocks are also given but they provide effective analgesia  either in the midabdominal region or in the lateral abdominal region but not in both regions. Novel techniques like USG guided External Oblique Intercostal (EOI) block, Thoracoabdominal nerves block through perichondrial approach (TAPA) and then modified-TAPA (m-TAPA) block, a modification of this block are recently being used for effective analgesia in  both the anterior and lateral abdominal walls after laparoscopic surgeries. However, there is limited literature comparing EOI and M-TAPA. The primary purpose of this study is to compare the analgesic efficacy among EOI and M-TAPA  and to include as part of multimodal analgesia to reduce postoperative opioid consumption in patients undergoing Laparoscopic Cholecystectomy.

CONDUCT OF ANAESTHESIA :

After arrival in the operating room, standard monitoring including electrocardiogram (ECG), pulse oxygen saturation (SPO2), non-invasive blood pressure (NIBP) and heart rate (HR) will be monitored. An 18-gauge cannula will be secured on non-dominant hand. All patients will receive i/v fentanyl 2mcg/kg, 5 minutes before induction followed by, inj. propofol 2mg/ kg till loss of verbal command. Tracheal intubation will be facilitated by vecuronium 0.1mg/kg and mechanical ventilation will be provided using oxygen and air in ratio of 50:50 with total flow of 3L/ min along with inhalational agents (desflurane /sevoflurane) to achieve 1 MAC. Inj. Fentanyl 20mcg hourly bolus will be given to keep the mean arterial blood pressure of the patients within 20% of the baseline. IV Tramadol 1 mg/kg was given at the end of surgery. Following the completion of the sur­gery, the patients will be extubated and transferred to the post-anaesthesia care unit (PACU). The patients will be shifted to the ward when the Modified Aldreth Score ≥ 8.

Nerve Block intervention:

Following surgery, for Group EOIB, a high-frequency linear probe (6–13 MHz) is  placed at the anterior axillary line, and the external oblique muscle identified at the level of ribs 6 and 7 in line with the xiphoid process. The EOI plane is identified deep to the external oblique muscle and superficial to the sixth and seventh ribs and their associated intercostal muscles. By using the in-plane technique, a 22G, 80 mm block needle is placed in the plane and 20 ml of 0.25% Ropivacaine will be administered. The same procedure will be applied to the other side (40 ml of 0.25% bupivacaine in total).For M-TAPA group, a high-frequency linear probe (6–13 MHz) will placed in the  para sagittal direction on the 10th costal margin. The probe is angled deeply to view the lower aspect of the chondrium. By using the in-plane technique, a 22G, 80 mm block needle is placed between the transversus abdominis muscle and the lower surface of the costal cartilage and 20 ml of 0.25% Ropivacaine is injected into the lower surface of the chondrium. The same process is then repeated for the other side.

Evaluation of pain will be done using Numeric Rating Scale (NRS). It is a numerical scale in which the respondent selects an number between 0 to 10 that best reflects the intensity of the pain. In this regard, “0†meant “no pain†and “10†meant “worst pain imaginableâ€. The NRS scores at rest and in motion will recorded by an anaesthetist who did not know the group distribu­tions at postoperative hour 0, 2nd hour, 4th hour, 8th hour, 16th hour and 24th hour. Patients will be educated and familiarized with NRS scores at the preop­erative period. The primary aim is to compare the total opioid (tramadol) consumption in 24 hours in the groups. Also time of first res­cue analgesic administration will also be recorded.