Ayers L N, Ginsberg M L, Fein J, Wasserman K
West J Med. 1975 Oct;123(4):255-64.
Six pathophysiologic mechanisms of a reduced single breath CO diffusing capacity are discussed and the usefulness of relating carbon monoxide (CO) uptake to the functioning alveolar volume (DL/VA, specific diffusing capacity) is illustrated for several pulmonary diseases. In patients with emphysema and pulmonary emboli (pulmonary vascular occlusive disease), reduced CO uptake is associated with significantly reduced DL/VA and is compatible with reduction of pulmonary capillary bed. In patients with pulmonary alveolar proteinosis, improvement in CO uptake and DL/VA follows lung lavage and suggests that lung units partially filled with proteinaceous material are responsible for hypoxemia, reduced CO uptake and reduced DL/VA. In most cases of radiation fibrosis, sarcoidosis and miscellaneous interstitial fibrosis, reduced CO uptake is associated with a normal DL/VA and suggests that loss of alveolar units, both capillaries and alveoli, has occurred. New regression equations for DL and DL/VA are established for children and adults. DL/VA is linearly related to height and independent of age and sex, while different predictive equations must be used for DL for the 5 through 17 and 18 through 76 age groups. The new regression equations for DL show better correlation in adults we studied over 50 years of age than previous regression equations which use a constant reduction of 2 to 3 ml CO per minute per mm of mercury for each 10 years of adult aging.
本文讨论了单次呼吸一氧化碳（CO）弥散能力降低的六种病理生理机制，并举例说明了在几种肺部疾病中，将一氧化碳摄取量与功能性肺泡容积（DL/VA，比弥散能力）相关联的实用性。在患有肺气肿和肺栓塞（肺血管闭塞性疾病）的患者中，一氧化碳摄取量降低与DL/VA显著降低相关，这与肺毛细血管床减少相一致。在肺泡蛋白沉着症患者中，肺灌洗后一氧化碳摄取量和DL/VA有所改善，这表明部分充满蛋白质物质的肺单位是导致低氧血症、一氧化碳摄取量降低和DL/VA降低的原因。在大多数放射性纤维化、结节病和其他间质性纤维化病例中，一氧化碳摄取量降低与正常的DL/VA相关，这表明肺泡单位（包括毛细血管和肺泡）已经丧失。为儿童和成人建立了新的DL和DL/VA回归方程。DL/VA与身高呈线性相关，与年龄和性别无关，而对于5至17岁和18至76岁年龄组的DL，必须使用不同的预测方程。我们研究的50岁以上成年人中，新的DL回归方程比以前的回归方程具有更好的相关性，以前的回归方程对于成年人每增长10岁，每分钟每毫米汞柱的一氧化碳摄取量恒定减少2至3毫升。
