Updates for Anesthetic Management of the Shared Airway

Abstract

Never are cooperation and communication between surgeon and anesthesiologist more important than during shared airway surgery. Maintaining, and protecting an airway in the face of abnormal anatomy and simultaneous surgical intervention can test the skills and patience of any anesthesiologist. Clearly, a thorough understanding of airway anatomy, the problems of common otorhinolaryngological and maxillofacial procedures will prove invaluable in handling these demanding anesthetic challenges. Successful intubation, ventilation, cricothyrotomy, and regional anesthesia of the larynx require detailed knowledge of airway anatomy. There are two openings to the human airway: the nose, which leads to the nasopharynx, and the mouth, which leads to the oropharynx. These passages are separated anteriorly by the palate, but they join posteriorly in the pharynx. The pharynx is a U-shaped fibromuscular structure that extends from the base of the skull to the cricoid cartilage at the entrance to the esophagus. It opens anteriorly into the nasal cavity, the mouth, the larynx, and the nasopharynx, oropharynx, and laryngopharynx, respectively. The nasopharynx is separated from the oropharynx by an imaginary plane that extends posteriorly. At the base of the tongue, the epiglottis functionally separates the oropharynx from the laryngopharynx or hypopharynx. The epiglottis prevents aspiration by covering the glottis (the opening of the larynx) during swallowing. The larynx is a cartilaginous skeleton held together by ligaments and muscle. The larynx is composed of nine cartilages: thyroid, cricoid, epiglottic, and in pairs; arytenoid, corniculate, and cuneiform. Particularly challenging to the anesthesiologist is the safe management of the pediatric patient undergoing surgery of the ear, nose, and throat. The restricted spaces in the airway of the child require an understanding and cooperative relationship between surgeon and anesthesiologist, and the use of specially adapted equipment suitable to these cramped areas. I- Pediatric shared airway surgeries: A) Pediatric congenital anomalies 1- Choanal atresia: 2- Cleft lip and palate B) Throat surgeries (i ) Pharyngeal surgeries Tonsillectomy and adenectomy (ii) laryngeal and tracheal surgeries 1- Tracheostomy 2- Subglottic stenosis C) Pediatric airway emergencies 1- Sudden Airway obstruction a) Foreign body aspiration: b) Foreign Body Ingestion: 2- Progressive Airway obstruction Supraglottitis D) Oral and Dental Surgery a) Dental Surgery: b) Oral surgery: A tonsillectomy probably is the most frequently performed airway surgical procedure. Indications for surgery include: obstructive tonsillar hyperplasia, recurrent or chronic tonsillitis, and peritonsillar abscess. Often, a combined procedure including the adenoids is performed at the same time; “Adenoidectomy” to relieve nasopharyngeal obstruction caused by adenoid hyperplasia. Significant numbers of these patients will suffer from obstructive sleep apnea syndrome “OSAS”. Posttonsillar hemorrhage may result in unappreciated large volumes of swallowed blood originating from the tonsillar fossa. These patients must be considered to have a full stomach, and anesthetic precautions addressing this situation must be taken.