The Relationship Between Assessment of Laryngeal Edema in Intensive Care Patients Using Cuff Leak Test and Ultrasound-Guided Laryngeal Air Column Width Difference and Weaning Success

Endotracheal intubation is one of the life-saving procedures used to support the respiratory system of critically ill patients on mechanical ventilation. In intubated patients, mechanical ventilation support is frequently applied in conditions such as acute respiratory failure or acute exacerbation of chronic respiratory failure where adequate oxygenation and/or ventilation cannot be achieved, loss of consciousness or airway reflexes, upper airway obstruction, and advanced life support in cardiac arrest; with the aim of improving gas exchange, reducing the work of breathing, or maintaining airway patency (1).

Airway complications may occur as a result of mechanical effects such as friction between the endotracheal tube and anatomical structures and prolonged compression. Prolonged intubation may cause partial airway obstruction, which can lead to laryngeal edema and post-extubation stridor (2). In patients receiving mechanical ventilation for 4 days or longer, mucosal ulcerations and laryngeal edema can be observed in almost all cases (3). Factors associated with post-extubation edema include advanced age, female gender, endotracheal tube size, presence of a cuffed endotracheal tube, prolonged duration of intubation, underlying airway disease, traumatic intubation, tracheal aspiration, tube mobility, and patient resistance to the tube (4). This may lead to sore throat, cough, dysphonia, dysphagia, and even respiratory failure requiring reintubation due to airway narrowing. Consequently, laryngeal edema in intensive care units (ICUs) is associated with longer durations of mechanical ventilation, increased hospital stay, higher morbidity and mortality, and significant economic costs (5).

"Weaning" is defined as the gradual reduction and discontinuation of mechanical ventilation support (6). The weaning process begins with the resolution of the cause of respiratory failure and results in the patient eventually breathing spontaneously. Weaning trials may fail due to increased work of breathing, laryngeal edema caused by prolonged intubation, electrolyte imbalances, malnutrition, hypothyroidism, major organ failure, and critical illness neuropathy (6).

Laryngeal edema causing post-extubation respiratory distress is usually the result of edema in the subglottic region and vocal cords (7). Examination of the vocal cords is typically performed using direct or indirect laryngoscopy. However, the presence of the endotracheal tube before extubation prevents direct visualization of the upper airway, making it difficult to detect laryngotracheal injury and edema.

The endotracheal tube cuff leak test is one of the most commonly used non-invasive and easily applicable bedside methods to assess airway anatomy and patency before extubation (6,8).