['To evaluate the efficacy and safety of a new device (BreatheMAX) that humidifies and oscillates inspired air to increase secretion clearance in mechanically ventilated patients.', 'Poor secretion clearance is a serious problem for intubated patients leading to lung complications and delayed weaning.', 'Double blinded crossover; fifteen patients, median age 60 years, range 16-75. Interventions consisted of spontaneous deep breathing with (treatment) and without (sham) humidification and oscillation of inspired air. Airway secretions were aspirated for 3\xa0h before and after each intervention and wet weight and viscosity determined.', 'The sham intervention caused no change in secretion clearance (95% CI:\xa0-1.8, 1.8\xa0g) but after treatment secretions increased by 4.0\xa0g (95% CI: 1.3, 6.7; p\xa0<\xa00.05). Viscosity decreased 30% after treatment and was unchanged after sham. Changes in cardiopulmonary function were not clinically significant and the patients reported only mild perceptions of breathlessness.'] Does breathing exercise using a new breathing device increase airway secretion clearance in mechanically ventilated patients?