Narrowing of the subglottic airway leading to respiratory distress in the neonate.
Identify the condition and describe the nature and severity of the problem; identify means to avoid subglottic stenosis; review medical and surgical treatment options for subglottic stenosis.
The subglottic airway is the narrowest portion of the childhood airway due to the complete ring of the cricoid cartilage at that site. Subglottic stenosis is defined as narrowing of the normal diameter of this area just below the vocal cords. In a full-term newborn, this is considered an airway that measures less than 4 mm in diameter. Preterm infants have normal airway diameters of 3 or 3.5 mm or larger. Stenoses can be either congenital or acquired, though at times it can be difficult to differentiate, as the airway may have been instrumented prior to discovery. Subglottic stenosis is usually suggested with either insertion of a smaller than expected endotracheal tube or failure to maintain stable respiratory status after extubation.
When the neonate presents with respiratory distress and stridor, an otolaryngology consultation is warranted to evaluate the airway for potential causes. Should intubation be needed more urgently, insert the smallest endotracheal tube to allow adequate ventilation. One should see an air leak at 20 cm H2O, and if this is not found, a smaller tube should be placed. The etiology of most acquired stenosis is from injury related to either infection or trauma. Size of the tube, duration of intubation, movement of the tube, and the need for repeated intubations are all contributing factors for stenosis. Gastroesophageal reflux disease (GERD) may play an adjuvant role in development in subglottic stenosis, as acid reflux may irritate an inflamed area further.
Full-term newborns that require intubation should be intubated with a 3.5 endotracheal tube as the first attempt. Smaller-sized tubes should be available in case there is narrowing below the vocal cords. Premature newborns should have an attempt with a 3.0 or smaller endotracheal tube as deemed appropriate.
Stridor in the neonate should warrant an otolaryngology consultation. Subglottic stenosis should be suspected with biphasic stridor that may worsen with exertion. Direct laryngoscopy and bronchoscopy under anesthesia is the gold standard for diagnosis and staging. PA and lateral neck x-rays can identify subglottic stenosis. Airway fluoroscopy can be used to identify this and other abnormalities, such as tracheal stenosis or tracheomalacia. The best test for identifying and quantifying the severity of reflux is a dual-channel pH-impedance probe.
Medical management of subglottic stenosis includes use of systemic steroids and racemic epinephrine. ...