Comparative Study Between Dexmedetomidine & Neostigmine as an Adjuvant to Local Anesthetic Mixture in Peribulbar Block in Vitreoretinal Surgeries

The majority of patients undergoing ophthalmic surgeries are elderly, with multiple chronic diseases, with increased risk of morbidity and mortality under general anesthesia. Peribulbar anesthesia is widely practiced now as a first-choice local block for ophthalmic surgeries. Dexmedetomidine is a highly selective alpha-2 adrenoceptor. It increases central and peripheral nerve blockade and when added to local anesthetic as an adjuvant, it will provide better anesthetic quality as well as prolongation of postoperative analgesia . Neostigmine is a parasympathomimetic drug that increase the level of acetylecholine at peripheral muscarinic receptors present in the peripheral nerve endings . Many researches examined the analgesic effects of peripherally administered neostigmine as in intravenous regional anesthesia reporting that addition of neostigmine to the local anesthetic solution accelerated the onset of anesthesia \& prolong duration .