Stam H, Hrachovina V, Stijnen T, Versprille A
Department of Pulmonary Diseases, Erasmus University, Rotterdam, The Netherlands.
J Appl Physiol (1985). 1994 Jun;76(6):2356-63. doi: 10.1152/jappl.1994.76.6.2356.
In this study we determined reference values of total diffusing capacity of carbon monoxide (DLCO) and DLCO per liter alveolar volume (DLCO/VA) at total lung capacity (TLC) and at lung volumes below TLC in sitting position. In 55 healthy nonsmoking volunteers (20-85 yr old), we determined reference values at TLC level in which age was the only parameter. In a subgroup (n = 16) these references did not change by correction for normal variability in hemoglobin concentration. In all volunteers DLCO decreased and DLCO/VA increased with decreasing VA. The increase in DLCO/VA was linear and less in older subjects. We derived equations to calculate reference values of DLCO/VA for lung volumes at and below TLC with two methods: 1) "random coefficients linear" model, which calculates the reference values directly, and 2) a conversion method, which calculates DLCO/VA for lower VA levels from reference values at TLC. An advantage of the conversion method is the suitability of DLCO/VA reference values at TLC of other populations. A disadvantage is the greater standard deviation of these reference values compared with those obtained by the random coefficients linear method. DLCO can be found by multiplying DLCO/VA with VA.
在本研究中，我们测定了坐位时肺总量（TLC）以及低于TLC的肺容积下一氧化碳总弥散量（DLCO）和每升肺泡容积的DLCO（DLCO/VA）的参考值。在55名健康非吸烟志愿者（年龄20 - 85岁）中，我们测定了以年龄为唯一参数的TLC水平下的参考值。在一个亚组（n = 16）中，校正血红蛋白浓度的正常变异性后，这些参考值没有变化。在所有志愿者中，随着肺容积（VA）降低，DLCO下降而DLCO/VA升高。DLCO/VA的升高呈线性，且在老年受试者中升高幅度较小。我们用两种方法推导了用于计算TLC及低于TLC的肺容积下DLCO/VA参考值的方程：1）“随机系数线性”模型，可直接计算参考值；2）一种转换方法，根据TLC时的参考值计算较低VA水平下的DLCO/VA。转换方法的一个优点是适用于其他人群TLC时的DLCO/VA参考值。缺点是与随机系数线性方法获得的参考值相比，这些参考值的标准差更大。DLCO可通过将DLCO/VA与VA相乘得出。
