What type of ventilation is performed using a bag-valve-mask (BVM)?

The correct choice is positive pressure ventilation, which is delivered through a bag-valve-mask (BVM) setup. In this method, air is pushed into the patient's lungs by squeezing the bag, creating a pressure that forces air into the airway and into the lungs, thereby aiding in respiration. This technique is particularly important during emergencies, where it can be used to assist or control breathing in patients who are unable to breathe adequately on their own.

Negative pressure ventilation refers to a different approach, such as with an iron lung, where the pressure around the thorax is decreased to draw air into the lungs. Assisted ventilation typically implies that a patient initiates their breaths, but the machine helps them by providing additional support, which is not the case with BVM as it is primarily an operator-driven technique. Spontaneous ventilation involves the patient breathing on their own without assistance, which does not apply when utilizing a BVM, as the device actively provides breathing assistance.