Which type of ventilator uses an endotracheal tube to deliver air directly into the lungs?

The type of ventilator that uses an endotracheal tube to deliver air directly into the lungs is an invasive ventilator. This is because invasive ventilation involves the placement of an artificial airway, such as an endotracheal tube, that allows for direct access to the patient's lungs. This setup enables the ventilator to precisely control the volume and pressure of the air being delivered, ensuring effective ventilation in patients who are unable to breathe adequately on their own.

In contrast, noninvasive ventilators provide support through interfaces like masks and do not require any surgical airway interventions, while negative pressure ventilators encase the body and create pressure changes to stimulate breathing without needing an endotracheal tube. Volume cycled ventilators are a type of ventilator that can be either invasive or noninvasive, focusing on delivering specific volumes of air, but they do not define the method of airway access. Thus, the presence of the endotracheal tube is the key factor that identifies invasive ventilation in this context.