The intrapulmonary percussive ventilator is an airway clearance device that simultaneously delivers aerosolized solution and intrathoracic percussion. This modified method of intermittent positive pressure breathing superimposes high-frequency minibursts of gas (at 50–550 cycles/min) on the patient’s own respiration. This creates a global effect of internal percussion of the lungs, which can promote clearance of the peripheral bronchial tree. The high-frequency gas pulses expand the lungs, vibrate and enlarge the airways, and deliver gas into distal lung units, beyond the accumulated mucus [11].

Intrapulmonary percussive ventilation can be delivered through a mouthpiece, a face mask, or through endotracheal and tracheostomy tubes. The primary aims of this technique are to reduce secretion viscosity, promote deep lung recruitment, improve gas exchange, deliver a vascular “massage,” and protect the airway against barotrauma. The main contraindications are the presence of diffuse alveolar hemorrhage with hemodynamic instability. Relative contraindications include active or recent gross hemoptysis, pulmonary embolism, subcutaneous emphysema, bronchopleural fistula, esophageal surgery, recent spinal infusion, spinal anesthesia or acute spinal injury, presence of a transvenous or subcutaneous pacemaker, increased intracranial pressures, uncontrolled hypertension, suspected or confirmed pulmonary tuberculosis, bronchospasm, empyema or large pleural effusion and acute cardiogenic pulmonary edema [12].

During high-frequency chest wall oscillation, positive pressure air pulses are applied to the chest wall through a vest or under a chest shell. This technique provides oscillation at 5–25 Hz. Mechanical vibration is performed at frequencies up to 40 Hz. Vibration is applied during the entire breathing cycle or during expiration only. The adjustable inspiratory/expiratory ratio permits asymmetrical inspiratory and expiratory pressure changes (e.g., +3–6 cmH₂0), which favors higher exsufflation flow velocities to mobilize secretions. The average length of time spent in each treatment session will vary according to patient tolerance, amount and consistency of secretions, and the phase of the patient’s illness (acute or chronic). Simultaneous use of an aerosolized medication or saline is recommended throughout the treatment. This humidifies the air to counteract the drying effect of the increased airflow [13]. High-frequency chest wall oscillation may act like a physical mucolytic, reducing both the spinnability and viscoelasticity of mucus and enhancing clearance by coughing [9, 11].

Contraindications for this therapy are mostly the same as for intrapulmonary percussive ventilation, with the addition of head or unstable neck injury, burns, open wounds, infection or recent thoracic skin grafts, osteoporosis, osteomyelitis, coagulopathy, rib fracture, lung contusion, distended abdomen, and chest wall pain [9, 13].