Comparison of Dexamethasone and Magnesium sulphate as adjuvants to Ropivacaine in ultrasound guided transversus abdominis plane block for post operative analgesia in patients undergoing Total Abdominal Hysterectomy: A Randomized Controlled Trial.

Postoperative analgesia aims to reduce the negative consequences of acute postsurgical pain and help the patient transition smoothly back to normal function. Acute postoperative pain without adequate management leads to persistent postsurgical pain or chronic pain.  Regional anaesthesia provides site specific, effective and long lasting anaesthesia.  Some of the abdominal nerve blocks are transversus abdominis plane, subcostal, rectus, ilioinguinal and iliohypogastric, transversalis fascia plane, and quadratus lumborum block. Transversus abdominis plane block is a peripheral nerve block that blocks sensation to anterior and lateral abdominal wall as well as the parietal peritoneum. The TAP anatomical compartment is located between the internal oblique and transversus abdominis muscles and contains the T6 to L1 thoracolumbar nerves.  The T9 to T11 Intercostal and T12 Subcostal (SC) nerves penetrate the transversus abdominis plane compartment posterior to the midaxillary line. It is one of the most common truncal block for post operative analgesia in lower abdominal surgeries because of its easy accessibility, safety and reliability. Ropivacaine, an enantiomer of Bupivacaine, is a long-acting amide and less likely to penetrate large myelinated motor fibers so it has relatively shown lesser motor blockade with safer cardiac profile used for peripheral nerve block. Addition of adjuvant improves the efficacy of local anaesthetics by reducing the duration of onset of action, prolonging the duration of action, decrease pain intensity and reduce consumption of systemic opioids and lesser systemic side effects. Dexamethasone is a highly potent, long acting glucocorticoid. It acts by inhibiting    potassium conductance by binding to glucocorticoid receptors which decreases  the activity of nociceptive C-fibres and may also prolong the analgesia duration through systemic anti-inflammatory effects and local vasoconstrictive action. Magnesium sulphate is an N-methyl D-aspartate (NMDA) receptor antagonist. It is a non-competitive antagonist which blocks the voltage- dependent ion channels. This receptor is found in many parts of the body, including the nerve endings and plays a role in modulating inflammatory responses and pain responses by preventing central sensitisation caused by peripheral nociceptive stimulation. Hence, the aim of this study is to compare the efficacy of Dexamethasone versus Magnesium sulphate with Ropivacaine in ultrasound guided transversus abdominis plane(TAP) block for patients undergoing Total Abdominal Hysterectomy.