Ventilator-associated pneumonia (VAP) is a type of lung infection that occurs in people who are on mechanical ventilation. It typically develops 48 hours or more after a patient has been intubated and connected to a ventilator. The infection can be caused by bacteria that enter the lungs through the breathing tube, leading to inflammation and difficulty in breathing. Symptoms of VAP may include fever, cough, and increased production of sputum. Diagnosis is usually confirmed through chest X-rays and laboratory tests. Treatment often involves antibiotics and supportive care to help the patient recover and prevent further complications.