Effectiveness of post operative analgesia of ultrasound guided transversus abdominis plane block after lower segment cesarean section - A randomized control trail

Pain is an unpleasant emotional and sensory experience, substantial pain and discomfort are anticipated after cesarean delivery by most of the patients. After a cesarean section, good post-operative analgesia is important for the mother to optimally care for her neonate, effective breastfeeding, and also reduce the risk of thromboembolic disease, respiratory complications and reduce hospital stay due to early mobility of the patient. At present multimodal analgesia is used with iv/im- opioids, NSAIDs, PCA, and neuraxial blocks with opioids. However unwanted side effects like sedation, nausea, vomiting, pruritus, occasionally respiratory depression remain a major drawback for opioids.

Ultrasound-guided TRANSVERSUS ABDOMINIS PLANE BLOCK - a regional anesthesia technique, one of the most effective methods for providing analgesia after lower abdominal surgeries. TRANSVERSUS ABDOMINIS PLANE BLOCK – block the neural afferents of the anterior abdominal wall after spreading the local anesthetic agent in the neuro fascial plane between the internal oblique and transversus abdominis muscle containing thoracolumbar nerves from T10 to L1. The ultrasound-guided block technique is relatively safe and associated with minimal complications.

The purpose of the study is to compare the postoperative analgesic effectiveness of ULTRASOUND GUIDED TRANSVERSUS ABDOMINIS PLANE BLOCK after lower segment cesarean section overuse of another mode of intravenous analgesic drugs. 68 patients of ASA (American Society of anesthesia) II to ASA III physical status who are undergoing nonurgent lower segment cesarean section via Pfannenstiel incision will be recruited to participate in the study. We are considering a moderate effect size of 0.7. We require 27 patients in each group to achieve 80% power allowing for 5% type I error. Total 54 participants, 27 in each group will be divided randomly into GROUP T and GROUP C using winpepi software. A randomized envelope will be opened just before the cesarean section and the participants will be assigned either group T or group C.

All participants either in group T or in group C will be receiving spinal anesthesia under all aseptic precautions with INJ BUPIVACAINE 0.5% (heavy) 1.8 -2.0 ml, after completion of the surgery, skin closure, and dressing participants in group T will receive ultrasound-guided bilateral TAP block with hyperbaric INJ BUPIVACAINE 0.25%,40 ml with the addition of INJ DEXAMETHASONE 8mg (adjuvant). 4mg of INJ DEXAMETHASONE with 20ml of INJ BUPIVACAINE 0.25% will be given on both sides respectively and this combination would prolong the analgesic effect of TAP block for approximately 12 to 24 hours. Participants in group C will be receiving i/v diclofenac 75 mg at the end of surgery.

Ultrasound-guided TAP block will be performed by a senior resident and/or consultant who is experienced for ultrasound-guided regional anesthesia, while performing the block patient is positioned supine and with a linear array transducer placed in a transverse plane to the lateral abdominal wall at the midaxillary line, between the lower costal correct neurovascular plane. The image produced shows (from above downwards) skin, subcutaneous tissue, fat, external oblique, internal oblique, transversus abdominis. The peritoneum and bowel loops may also be visualized deeper into the muscles. A long 7-10 cm needle is inserted in the plane of the transducer directly under the probe and advanced until it reaches the plane between the internal oblique and transversus abdominis muscles. The needle also introduced a few centimeters medial to the probe (a distance equivalent to the depth of the plane as viewed on ultrasound image). The probe will have to follow the needle entry point medially in its superficial path and then return to its original position as the needle is directed deeper. Upon reaching the plane 2ml of normal saline is injected to confirm the correct needle placement, following careful negative aspiration (non-appearance of the blood) 20 ml of the local anesthetic solution is injected observing for an elliptical separation between the two fascial layers. The transversus abdominis plane is visualized expanding with the injection (as a hypoechoic space).

The assessment of the intensity of the pain post-operatively after transfer of patients from Operation Theatre to PACU (POST OPERATIVE ANESTHESIA CARE UNIT). Each patient will be assessed at 0, 2, 4, 6, 8, 12, and 24 hours by an independent observer who will be unaware of the group allocation for the degree of pain using the VAS score (0-10 scale). Also, the time for first rescue analgesia will be noted and compared in both the groups, rescue analgesia in the form of inj tramadol 1mg/kg iv will be given if the vas score will be more than 4. A total number of rescue analgesia during a period of 24 hours will also be noted.