Efficacy of Ultrasound-guided Greater Auricular Nerve Block in Preventing Postoperative Emergence Agitation in Pediatric Patients Undergoing Microscopic Middle Ear Surgery.

Overview

This study is designed to evaluate the effectiveness of ultrasound-guided greater auricular nerve block (GAN) on the reduction of emergence agitation (EA) occurrence and EA severity in children who are receiving general anesthesia for a microscopic middle ear operation.

Emergence agitation (EA) is one of the Perioperative Neurocognitive Disorders (PND). It's defined as psychomotor agitation and delirium, that typically occurs within the first 45 minutes postoperative. It may present as non-purposeful movements such as kicking and pulling or lack of eye contact or awareness to the surroundings. EA has been linked to several risk factors, including type of surgery (ENT, ophthalmic), the use of volatile anesthetics (especially sevoflurane) . Middle earsurgeries are especially noteworthy because of their high EA risk owing to significant nociceptive stimulation of the external ear and its surrounding tissues as well. Pain is one of the modifiable risk factors, and studies have demonstrated a strong association between postoperative pain scores and incidence of EA The greater auricular nerve (GAN), originating from the cervical plexus (C2-C3), provides sensory innervation to the inferior two-thirds of the auricle, skin over the mastoid process, angle of the mandible and parotid region (5). All these areas are typically involved in or manipulated for middle ear surgery, and therefore the GAN is an easily identifiable nerve for perioperative analgesia treatment. An ultrasound-guided GAN block has been performed in both adults and pediatric populations to provide analgesia for postoperative pain after parotidectomy, auriculotemporal procedures, and mastoid surgery (6,7). The strong association between moderate to severe postoperative pain and EA, coupled with the high rate of EA in middle ear procedures, suggest that a safe, focused regional technique could address these issues in this population (8). That in mind, we hypothesize that using an ultrasound-guided technique giving 100% accuracy blocking GAN, will reduce the pain and hence the incidence of EA postoperative.