Dexmedetomidine as an Adjuvant to Bupivacaine in Ultrasound-guided Pericapsular Nerve Group Block( PENG)

Patients are greatly concerned about pain that occurs shortly after shoulder surgeries. Most patients experience significant pain after shoulder surgery, with almost half reporting severe pain immediately after. Since shoulder surgeries are usually done as outpatient or one day procedures, good pain control after surgery is important for quick recovery and rehab for patient's overall recovery. Interscalene nerve blocks provide the best pain relief for shoulder surgery patients. They reduce pain for at least 8 hours and decrease the need for opioids for 8 to 12 hours after surgery. It anesthetizes most of the brachial plexus, except the ulnar nerve (C8-T1). It is useful for surgeries on the distal clavicle, shoulder, and proximal humorous .However, interscalene blocks also raise concerns about temporary and potential long-term problems with breathing, especially paralysis of the diaphragm and phrenic nerve. By targeting nerve roots in the neck rather than peripheral nerves, interscalene blocks also carry a higher risk of nerve damage.The pericapsular nerve group block has been effectively used in hip surgeries as in hip arthroplasty and it is one of the best regional anesthesia regarding many other hip operations. Recently PENG block has also shown to have strong analgesic effect on shoulder surgeries. Dexmedetomidine (DEX) is a highly selective Alpha-2 adrenergic agonist. It has sedative and analgesic properties that thought to be due to binding to both presynaptic and postsynaptic alpha-2 adrenoreceptors and inhibiting the release of norepinephrine, as a result, it terminates the propagation of pain signals and inhibits the sympathetic activity decreasing heart rate and blood pressure. The aim of our study is to compare the effect of adding dexmedetomidine to bupivacaine in ultrasound-guided Pericapsular nerve group block (PENG) with bupivacaine alone and determine its effect on duration of analgesia and post-operative opioid consumption.