Comparison of Pain ReliefofBupivacaineWith Dexmedetomidine and Bupivacaine Alone in TransversusAbdominisPlane Block For Postoperative Anelgesia in Patients Undergoing Abdominal Surgeries

Introduction:

Pain is defined as, "an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage" by the international association for the study of pain. Postoperative suboptimal analgesia has very pronounced effects on the wellbeing of the patient. Patients have experienced delayed mobility, thromboembolic phenomenon, and pulmonary complications.It not only leads to prolonged stay due to delayed ambulation but also basal lung atelectasis and collapse from limited chest expansion after abdominal incision. The abdominal wall is a significant source of pain after abdominal surgery. Expected pain prevalence after hernia repair was determined as 54% and postoperative 2-year cumulative prevalence was found to be 30%.

Many methods to efficiently combat post-operative pain have been tried in the past. The multimodal approach of pain management as defined by the American Society of Anaesthesiology (ASA2012) is the administration of two or more drugs that act by different mechanisms via the same route or different route to provide optimal analgesia.Patient-controlled thoracic epidural, intravenous patient-controlled analgesia the intraperitoneal injection of local anesthetics, non-steroidal anti-inflammatory drugs, and opioids have all been part of it in different combinations.

Over the past years, the ideology of pain management has evolved from mere decreasing pain intensity to optimizing a patient's condition. The mainstay of this is to work particularly in two areas; decreasing pain scores and stress response, together with a decrease in analgesic-related side effects like nausea vomiting, and sedation. Systemic opioids have been the mainstay for postoperative analgesia for a long; but at the expense of adverse effects of nausea, vomiting, pruritus, sedation, and respiratory depression. All these issues have led to the continuous search for a better,safer, and long-lasting alternative for post-op analgesia. Though much work has been done for better understanding of the pathophysiology of postoperative pain along with the introduction of modern analgesics and delivery techniques;yet approximately 80% of the patients continue to suffer acute postoperative pain and among them, 75% experienced moderate to severe pain.

TAP block provides regional analgesia in dermatome area over T6-L1. It was initially started with the landmark technique, through lumber triangle of petit formed by external oblique muscle anteriorly, latissimussdorsi posteriorly, iliac crest inferiorly and is usually identified as a defect as 1 cam above the iliac crest in mid-axillary line. Quite several previous studies on TAP block have shown favourable results in terms of post-op pain relief, but the duration of analgesia remains an unsolved concern.Different adjuncts have been tried with bupivacaine to achieve this desired goal of long-lasting post-op analgesia with minimal side effects. Among those many studies have been done using dexamethasone,midazolam,ropivacaine, anddexmedetomidine.

Rationale:

The rationale of the study is to find out the effect of the addition of dexmedetomidine to bupivacaine on pain relief, and the demand for rescue analgesia on patients undergoing abdominal surgeries in Sheikh Zayed Hospital Rahim Yar Khan, when used in TAP block.

Past studies have shown encouraging results with the use of TAP block with or without dexmedetomidine; however, we lack local data concerning especially the patients undergoing abdominal procedures. Despite many studies performed on postoperative pain control we still have not attained gold standard criteria of multi-modal pain relief with minimal undesired effects on patients. This experimental study will pick the difference in postoperative pain relief by adding this adjunct to bupivacaine.