In which of the following types of ventilation is alveolar expansion during inspiration due to a decrease in pleural pressure?
I. positive-pressure ventilation (PPV)
II. negative-pressure ventilation (NPV)
III. spontaneous ventilation

Question

In which of the following types of ventilation is alveolar expansion during inspiration due to a decrease in pleural pressure?
I.	positive-pressure ventilation (PPV)
II.	negative-pressure ventilation (NPV)
III.	spontaneous ventilation

Quizplus · Accepted Answer

II and IIIIn both negative-pressure ventilation (NPV) and spontaneous ventilation, alveolar expansion during inspiration is due to a decrease in pleural pressure. NPV mechanically decreases pleural pressure to mimic the natural inspiratory effort, while spontaneous ventilation relies on the natural decrease in pleural pressure generated by the diaphragm and chest wall muscles during inspiration. Positive-pressure ventilation (PPV), on the other hand, forces air into the lungs, increasing the pressure within the airways to expand the alveoli, which is a different mechanism.

In Which of the Following Types of Ventilation Is Alveolar