Oppenheimer Beno W, Berger Kenneth I, Hadjiangelis Nicos P, Norman Robert G, Rapoport David M, Goldring Roberta M
Division of Pulmonary and Critical Care Medicine, Bellevue Hospital Chest Service, Department of Medicine, New York University School of Medicine, 462 First Ave 7W54, New York, NY 10016, USA.
Respir Med. 2006 Jul;100(7):1247-53. doi: 10.1016/j.rmed.2005.10.015. Epub 2006 Jan 11.
We examined pulmonary diffusing capacity (D(LCO)) and its partition in pulmonary vascular diseases without evident parenchymal disease to assess the pattern and proportionality of change in membrane diffusion (D(m)) and capillary blood volume (V(c)). Disproportionate reduction in D(m) relative to V(c) (low D(m)/V(c)) in these diseases has been attributed to associated alveolar membrane/parenchymal disease, thus providing a potentially important diagnostic tool.
Diseases included: idiopathic pulmonary arterial hypertension (n=6), chronic thromboembolic disease (n=5), and intravenous drug use (n=14), providing a spectrum of pulmonary vascular diseases. V(c) and D(m) were determined as described by Roughton and Forster.
All diseases showed a reduced V(c) (59+/-10, 69+/-14, 71+/-21 % predicted, respectively) and D(m) (76+/-22, 53+/-19, 63+/-16 % predicted, respectively) with no differences between groups (p>0.05). Disproportionate reduction of D(m) (D(m)/V(c) % predicted <1) was seen in all diseases (range 0.36-1.89). A mathematical analysis is presented to illustrate that changes in vascular geometry may additionally influence the proportionality of changes in D(m) and V(c). The mathematical analysis suggests that when reduction in patency of some vessels co-exits with compensatory dilatation of the remaining vasculature, a disproportionate reduction in D(m) relative to V(c) may result.
The balance between vascular curtailment and compensatory dilatation may contribute to the variability of the D(m)/V(c) relationship seen in pulmonary vascular disease. Disproportionate reduction in D(m) relative to V(c) may result from this imbalance and need not imply subclinical alveolar membrane and/or parenchymal disease.
我们研究了无明显实质疾病的肺血管疾病中的肺弥散能力（D(LCO)）及其在肺血管中的分布，以评估膜弥散（D(m)）和毛细血管血容量（V(c)）的变化模式和比例关系。这些疾病中D(m)相对于V(c)的不成比例降低（低D(m)/V(c)）被归因于相关的肺泡膜/实质疾病，因此这提供了一种潜在的重要诊断工具。
疾病包括：特发性肺动脉高压（n = 6）、慢性血栓栓塞性疾病（n = 5）和静脉药物滥用（n = 14），涵盖了一系列肺血管疾病。V(c)和D(m)按照Roughton和Forster所述的方法测定。
所有疾病的V(c)均降低（分别为预测值的59±10%、69±14%、71±21%），D(m)也降低（分别为预测值的76±22%、53±19%、63±16%），组间无差异（p>0.05）。所有疾病均出现D(m)的不成比例降低（预测的D(m)/V(c)%<1）（范围为0.36 - 1.89）。进行了数学分析以说明血管几何形状的变化可能会额外影响D(m)和V(c)变化的比例关系。数学分析表明，当一些血管的通畅性降低与其余血管系统的代偿性扩张同时存在时，可能会导致D(m)相对于V(c)的不成比例降低。
血管缩减与代偿性扩张之间的平衡可能导致肺血管疾病中D(m)/V(c)关系的变异性。D(m)相对于V(c)的不成比例降低可能源于这种失衡，并不一定意味着存在亚临床肺泡膜和/或实质疾病。
