Inclusion Criteria:  admission to one of the participating ICUs; intubated with an endotracheal tube containing a cuff; receiving invasive mechanical ventilation; and expected to need invasive ventilation beyond the following calendar day at the moment of inclusion.  Exclusion Criteria:  age < 18 years; known or suspected tracheal damage, e.g., after inhalation trauma, thorax trauma, or intubation trauma; any condition for which deflation of the endotracheal cuff is deemed detrimental, e.g., in case high airway pressures are needed; and any infection, or colonization with pathogens that require strict single isolation of the patient (cohort isolation is allowed).