Comparison Of Perineural Dexamethasone And Dexmedetomedine Vs Dexamethasone Only As An Adjuvant In Ultrasound Guided Sciatic Nerve Block Via Popliteal Approach In Orthopaedic Below Knee Surgeries A Double Blind Randomised Controlled Trial

Postoperative pain after orthopedic lower limb surgery is a very distressing symptom and a major component of the postoperative morbidity.Considering the extensive number of orthopaedic surgeries undertaken every day and finding an opioid sparing and convenient options for analgesia, this study aims to investigate whether the adjuvant combination of dexamethasone and dexmedetomidine could additively provide a longer duration of blockade and superior analgesia compared to using Ropivacaine alone in a peripheral sciatic nerve block performed by the popliteal approach. An ultrasound machine with a high frequency 9-13 MHz linear probe will be used considering the minimal penetration of tissues required. A 22G, 100 mm needle will be used to administer the block. Although approachable by the patient in the supine, lateral, or prone position, in order to minimize patient discomfort, especially when awake, patient is placed in the supine position with the legs elevated with folded blankets or an adjustable table. The skin is prepared with 0.5% chlorhexidine. The transducer is positioned in a transverse orientation at the popliteal fossa. At this level, the popliteal artery is identified and confirmed with colour flow or power doppler. Once the artery is visualized, the hyperechoic nerves are located superficially. To visualize where the TN and CPN eventually come together to form the sciatic nerve and separate distally, with the CPN travelling laterally and the TN staying medially, it is traced proximally. The optimal image is the configuration of the nerves just as they begin to separate, giving a peanut or figure 8 shape.

. HR, NIBP, SpO2 at 30 mins, 1hour, 2 hours, 4 hours, 8 hours, 12 hours and 24 hours postoperatively

ii. Postoperative pain at rest and on movement as assessed by Numeric Rating Scale at 30mins, 1hour, 2 hours, 4 hours, 8 hours, 12 hours, and 24 hours postoperatively

iii. Time to first rescue analgesic is noted in the post operative room as time of administration of morphine via epidural or Intravenous tramadol in case of SAB