The present study aims to evaluate the effect of mechanical insufflation-exsufflation on airway mucus clearance among mechanically ventilated ICU patients. A parallel group randomized clinical trial will be conducted in a single mixed medical-surgical ICU of a tertiary hospital in Southern Brazil. Adult ICU patients with a length of mechanical ventilation >24 hours will be evaluated for eligibility. Patients will be randomized in a 1:1 ratio to receive respiratory physiotherapy using a mechanical insufflation-exsufflation device (intervention group) or standard respiratory physiotherapy without the use of the mechanical insufflation-exsufflation device (control group). The primary outcome is the amount of aspirated respiratory mucus (weight in grams) 5 minutes after the finish of respiratory physiotherapy.

Inclusion Criteria:

• Age ≥ 18 years;
• Admission to the ICU
• Length of mechanical ventilation > 24 hours
• Stable ventilatory and hemodynamic status defined by positive end- expiratory pressure ≤ 8 cm H2O, inspiratory oxygen fraction ≤ 40%, ratio of arterial oxygen partial pressure to fractional inspired oxygen ≥ 150, respiratory rate ≤ 35 breaths per minute, heart rate ≤ 130 beats per minute and systolic blood pressure between 90 and 160 mmHg.

Exclusion Criteria:

• Patients with primary neuromuscular disease.
• Patients in exclusive paliative care.
• Patients with contraindications to the use of mechanical insufflation- Exsufflation device.