Check for a Cuff Leak in Patients who Might have Tracheal EDEMA Before Extubation
E. David Bravos MD
Critically ill patients often require intubation and mechanical ventilation. Along with the morbidities of intubation, problems following extubation can occur. Airway obstruction from laryngeal or tracheal edema is a significant risk and can result in respiratory distress that may require emergent reintubation. Risk factors for airway edema include traumatic or difficult intubation, duration of intubation, high balloon cuff pressure or large endotracheal tube size, inhalational injuries including burns or caustic substances, and recent self-extubation.
What to Do
The gold standard for detection of airway edema is direct visualization. However, the presence of an endotracheal tube obscures the view, making this sometimes difficult. Indirect methods of determining airway edema such as the cuff-leak test are commonly used. This test measures whether air is able to pass around the outside of the endotracheal tube through the patient’s airway when the cuff of the tube is deflated and the patient exhales. This can be assessed qualitatively and quantitatively. Qualitatively, cooperative patients should breathe when the cuff is deflated with assessment for the presence of stridor. This is more commonly done in pediatric patients with croup. More recently, quantitative measurements are done by comparing the returned tidal volume of patients on volume-control ventilation when the cuff is inflated as well as deflated. The difference in the two values is the cuff leak. In practice, several tidal volumes are recorded (usually five to six) with the cuff deflated and the values averaged. Additionally, the size of the cuff leak has been hypothesized to be inversely proportional to the amount of edema and potential obstruction.