Lewis S M
J Appl Physiol Respir Environ Exerc Physiol. 1978 Mar;44(3):424-30. doi: 10.1152/jappl.1978.44.3.424.
Changes in the nitrogen concentration seen during the single-breath nitrogen washout reflect changes in relative flow (V) from units with differing ventilation/volume ratios (V/V0). The multiple-breath washout provides sufficient data for the V for units with varying V/V0 to be plotted as a function of the volume expired. Flow from the dead space may also be determined. In young normals the emptying patterns are narrow and unimodal throughout the alveolar plateau with little or no flow from the dead space at the end of the breath. Older normals show more flow from the dead space, particularly toward the end of the breath, and some show a high V/V0 mode early in the breath. Patients with obstructive lung disease have a high flow from the dead space which is present throughout the breath. A well ventilated mode at the end of the breath is seen in some obstructed subjects. Patients with cystic fibrosis showed a poorly ventilated mode appearing at the end of the breath as well as a very high dead space.
单次呼吸氮洗脱过程中观察到的氮浓度变化反映了来自具有不同通气/容积比（V/V0）的单位的相对流量（V）的变化。多次呼吸洗脱提供了足够的数据，以便将具有不同V/V0的单位的V绘制为呼出容积的函数。也可以确定来自死腔的流量。在年轻正常人中，在整个肺泡平台期排空模式狭窄且呈单峰，呼气末来自死腔的流量很少或没有。老年正常人显示来自死腔的流量更多，尤其是在呼气末，一些人在呼气早期显示出高V/V0模式。阻塞性肺疾病患者在整个呼吸过程中都有来自死腔的高流量。在一些阻塞性受试者中，呼气末可见通气良好的模式。囊性纤维化患者在呼气末出现通气不良的模式以及非常高的死腔。
