1

Introduction

Pediatric subglottic stenosis is increasingly treated with conservative methods including single- or serial balloon dilation with or without additional procedures. The challenge is to restore the airway to an adequate size with minimal damage and to avoid tracheotomy.

The Inspira AIR Balloon Dilation System (Acclarent Inc, California) is designed to safely dilate airway strictures with minimal mucosal trauma achieved through controlled radial pressure through precise inflation and pressure regulation. Currently, there are 4 different balloon sizes. Balloon diameters of 5 and 7 mm are commonly used to dilate pediatric subglottic stenoses. The success rate is satisfactory while dependent on proper patient selection. Severity of the stenosis, length of stenotic segment, and pulmonary status seem to be important predictors of success. Combining balloon dilation with endoscopic anterior cricoid split and repeat serial dilations are reported to be effective in difficult or persistent stenoses. The safety of the procedure has been attested to since early publications . This case report will serve the purpose of increasing awareness of a serious adverse event that happened during balloon dilation and is, to the best of our knowledge, the first in the literature so reported.

2

Case report

A 24-week-old premature baby boy (birthweight, 900 g) was seen at age 2 months for increasing episodes of apneas, bradycardia, and desaturations observed at the neonatal intensive care unit. He was intubated after birth for 10 days but has not had required intubation since. Increased respiratory effort and desaturations with feeds prompted a modified Ba swallow test that showed no aspiration or penetration into the airway. Additional problems include umbilical hernia, bilateral hydroceles, and gastro-esophageal reflux. A short neck was noted. An airway evaluation was soon scheduled and performed. The base of tongue was mildly obstructive; supraglottic larynx and vocal cords were normal. A narrow subglottis was visualized. A 2.5 Endotracheal Tube was used to size the airway and provided no leak at 15 cm H ₂ O. His subglottic stenosis was determined to be less than 50% and thus cotton grade 1. Considering his prematurity, tongue position, reflux, and short neck, tracheotomy was recommended but was rejected by the parents. Conservative management continued with mixed success and frequent admissions due to respiratory problems over the next 12 months. Mild failure to thrive, leukopenia, and neutropenia were observed. Approximately a year after the initial ENT evaluation, he experienced acute respiratory failure at home with reported desaturation to 50%, was cyanotic, and possibly had seizure activity. Emergency Medical Services made several attempts for intubation, and the patient was eventually intubated with a 3.0 uncuffed tube on site and rushed to a local emergency room to be airlifted to our pediatric intensive care unit.

His 3.0 Endotracheal Tube started showing a leak at day 10, and he was taken to the operating room for an airway evaluation. His tongue base, supraglottic larynx, and vocal cords were normal. The subglottis had 60% stenosis with fresh avulsion scars and torn mucosa. His stenosis was determined to be Cotton grade 2. A tracheotomy was performed. A re-evaluation 3 months later showed the subglottis to have a 70% obstruction and mature scar of about 4 to 5 mm in length. At this time, balloon dilation was performed with Inspira AIR Balloon Dilation System using a 7-mm balloon. The balloon was inflated to 14 atm and kept inflated for 3 minutes. After proper deflation and withdrawal, endoscopic examination with a telescope showed a complete obstruction of the lumen by edema that developed within seconds after withdrawal of the balloon. At this time, the presence of a tracheotomy ensured continued safety of the patient, and the procedure was terminated after another 15 minutes of observation of the occluded subglottic lumen through the telescope. No resolution of the edema was visualized in response to an intravenous dose of 1 mg/kg dexamethasone or topical xylometazoline spray. No repeat dilation or probing was attempted to avoid further injury.

A repeat examination 4 months later showed the subglottis to have 70% stenosis (cotton grade 2), with mature scar of 4 to 5 mm in length. Balloon dilation with a 7-mm balloon was performed, and the balloon was inflated to 14 atm for 5 minutes. The subglottis diameter increased to normal size without subsequent edema or obstruction. A repeat dilation followed by decannulation is planned in the next few months.