An endotracheal tube is a medical device used to maintain an open airway in patients who are unable to breathe on their own. It is a flexible tube inserted through the mouth or nose and into the trachea, allowing for ventilation and oxygen delivery. This procedure is often performed during surgeries or in emergency situations. Endotracheal tubes are typically made of plastic and come in various sizes to accommodate different patients, including children and adults. They are secured in place to prevent movement and are connected to a ventilator or other breathing apparatus to assist with respiration.