Comparison Of Dexamethasone Versus Dexmedetomidine As An Adjuvant To 0.25% Bupivacaine In Ultrasound Guided Tap Block On Post-Op Analgesia Duration In Patients Undergoing Laparotomy

After approval of synopsis by the research board and ethical committee and Research department CPSP Karachi, the data collection process will begin. The study will be conducted in the Anesthesia Department of Sahiwal Teaching Hospital Sahiwal. Written informed consent will be obtained from all the patients included in the study. Patients aged between 25 to 65 years, belonging to ASA class-I and class-II, scheduled for laparotomy will be divided into 2 groups of 48 patients each:

• Group A: Patients who will receive transversus abdominis plane block with - 18ml Bupivacaine 0.25%+ 2 ml Dexamethasone 8mg.
• Group B: Patients who will receive transversus abdominis plane block with - 18ml Bupivacaine 0.25%+ 2ml Dexmedetomidine (1µg/Kg diluted in 2ml saline).

At the end of the surgery, bilateral Ultrasound (U/S) guided TAP block will be performed in both groups using ultrasound machine. The patient will be in supine position and a high frequency linear probe will be placed transverse to abdominal wall between the costal margin and iliac crest at mid axillary line. The needle will be introduced in plane of the ultrasound probe directly under the probe and advanced until it reaches the plane between the internal oblique and transverse abdominis muscles. Upon reaching the plane and after negative aspiration test for blood, 2ml of saline will be injected to confirm correct needle position, after which the patient will receive the TAP block as per the group allocation. Patients will be observed for any complication like signs of local anesthetic toxicity or hematoma formation at site of block. In PACU and surgical unit, Visual Analogue Scale Score (VAS) will be recorded at arrival to PACU 2, 4, 6, 12 and 24 hours post-operative. A VAS score of ≤3 will be considered satisfactory pain relief. If patients have inadequate analgesia, supplementary rescue analgesia will be given in the form of IV ketorolac 30mg at VAS ≥4. The time of first request for rescue analgesic will be recorded. Post-operative nausea and vomiting will be documented according to a categorical scale: 0 none, 1 nausea, 2 vomiting, 3 nausea and vomiting. Hemodynamic variables such as heart rate and mean arterial pressure will be recorded. The primary outcome will be to compare the time for first rescue analgesia. The secondary outcome will be assessment of postoperative pain using VAS score at 2, 6, 12, 18 and 24 hrs.