27.通氣時所需之經肺壓力差(transpulmonary pressure,PL ),可以用下列那個描述來代表?
(A)係為肺泡壓力(alveolar pressure)減去氣道出口之壓力(pressure at the airway opening)
(B)係為肺泡壓力(alveolar pressure)減去體表壓力(pressure at the body surface)
(C)係為肺泡壓力(alveolar pressure)減去肋膜腔內壓力(intrapleural pressure)
(D)係為肋膜腔內壓力(intrapleural pressure)減去體表壓力(pressure at the body surface)