Mechanical ventilators are medical devices that assist or replace spontaneous breathing in patients who cannot breathe adequately on their own. They deliver a controlled flow of air and oxygen into the lungs, ensuring that the patient receives the necessary oxygen while removing carbon dioxide. These devices are commonly used in hospitals for patients with respiratory failure, severe pneumonia, or during surgery. The operation of mechanical ventilators can be adjusted based on the patient's needs, allowing healthcare providers to set parameters such as pressure, volume, and oxygen concentration. They are essential tools in critical care settings, helping to stabilize patients until they can breathe independently again.