Cough function during mechanical ventilation.

TOPIC IMPORTANCE: Cough is a vital physiological function that clears the tracheobronchial tree and facilitates effective gas exchange through secretion clearance. In ICU patients, ineffective cough is frequent, primarily due to respiratory muscle dysfunction and the presence of the endotracheal tube, which prevents glottic closure. Ineffective cough has been identified as an independent risk factor for extubation failure and prolonged mechanical ventilation. REVIEW FINDINGS: Current guidelines recognize ineffective cough as a key criterion for successful weaning from mechanical ventilation. Nevertheless, its clinical assessment remains challenging and lacks standardization. Accurate and objective evaluation of cough may improve the identification of patients at high risk of extubation failure. Beyond extubation failure, ineffective cough has also been associated with increased incidence of post-extubation pneumonia, longer ICU stay, and impaired long-term respiratory function. Poor outcome highlights the broader clinical impact of ineffective cough and reinforce the need for standardized assessment during ventilator weaning. SUMMARY: This narrative review aims to decipher the mechanisms underlying the cough reflex, outline the pathophysiological alterations observed in critically ill patients, particularly during the weaning process, and examine the available methods for cough quantification.