The lungs are the vital organs of respiration. Their main function is to oxygenate the blood by placing the inspired air close to the venous blood in the pulmonary capillaries. While cadaver lungs are retracted, firm or hard to the touch, and change color, healthy lungs in living people are normally light, soft and spongy, and fully occupy the lung cavities. They are also elastic and retract to approximately one third of their original size when the chest cavity is opened. The lungs are separated from each other by the mediastinum. Intensive Care Units (ICUs) were created out of the need to care for critically ill patients. These patients could be submitted to invasive mechanical ventilation (IMV) due to changes in respiratory mechanics. The physiotherapeutic approach using the ZEEP maneuver in IMV patients aims to enhance airway hygiene, promote more effective aspiration and improve lung ventilation.