PES: Is High Resolution Endotracheal Tube Leak Data Indicative of the Development of Post-extubation Stridor in Children?

Post extubation stridor (PES) is a common and possibly serious complication of invasive ventilation via endotracheal tube (ETT) in pediatric intensive care (PICU) patients. The source of the PES is either temporary in the case of post-intubation laryngeal edema, or long-term in the case of subglottic stenosis.

Patients with PES could be in acute respiratory distress and failure requiring: 1. Medical Intervention (i.e. nebulized adrenaline, steroids or need for re-intubation), 2. Diagnostic Procedures (direct laryngoscopy) or 3. Temporary or permanent surgical airway - all leading to longer admissions and possible long term complications.

Several studies have tried to determine whether the development of PES is predictable using a airleak test (ALT) where a standardized test - measuring ETT leakage after deflating the ETT cuff- is performed once or multiple times just prior to extubation. Results have been contradictory to say the least (ref).

Based on current literature two questions arise. First; do we need to look at ETT leakage with a deflated - as is common practice in airleak tests - cuff? Or is the presence or absence of ETT leakage with an inflated cuff predictive for the development of PES? Second; airleak tests provide merely a snapshot -a trend measurement can possibly offer greater insight - especially using high resolution data. Would looking at the ETT leak trend for a longer period prior to extubation provide a clearer predictive value for the development of PES? The aim of our study is to answer these question and to determine if high resolution endotracheal tube leak data is predictive of the development of post-extubation stridor in children.

Analysis Airleak (% inspiratory tidal volume - expiratory tidal volume) will be calculated every minute in the 12 hours prior to extubation. Both magnitude (airleak %) and exposure (time) will be examined and plotted for patients with and without post-extubation stridor (primary outcome).