Chest physiotherapy involves techniques like postural drainage, percussion, and vibration to mobilize pulmonary secretions and clear the lungs. It aims to assist coughing, improve breathing muscle function, and enhance lung ventilation. Specific positions are used to facilitate drainage of secretions from different lung segments via gravity. The treatment is monitored closely and may require modification based on a patient's tolerance. Potential risks include hypoxemia, increased intracranial pressure, and bronchospasm.