Increase in pulmonary ventilation-perfusion inequality with age in healthy individuals
Increase in pulmonary ventilation-perfusion inequality with age in healthy individuals
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DOI：
10.1164/ajrccm.156.2.9606016
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发表时间：
1997-08-01
影响因子：
24.7
通讯作者：
Wagner, PD
中科院分区：
文献类型：
--
作者：
Cardus, J;Burgos, F;Wagner, PD
已知动脉氧分压（Pa-O2）会随着年龄的增长而降低，这伴随着肺部机械特性的许多变化，包括弹性回缩的丧失和闭合容积的增加。随着年龄的增长，呼吸力学的变化可能会导致通气/灌注（（V）超过点A/（Q）超过点）不匹配，从而解释Pa-O2的降低。在64名年龄在18 ~ 71岁的正常受试者中（终生不吸烟，肺功能正常），我们测量了（V）在点A/（Q）在点不平等和动脉呼吸血气（Pa-O 2和Pa-CO 2）。(V)由血流和通气分布的二阶矩（logSDQ和logSDV）表示的过点A/（Q）过点失配随年龄增加，但仅轻微增加（20岁时平均logSDQ为0.36，70岁时为0.47）。Pa-O2相应下降了6 mm Hg。证实了先前在20岁受试者中建立的log SDQ（0.60）和log SDV（0.65）的95%置信上限。在70岁时，log SDQ的参考上限为0.70，log SDV为0.75。研究表明，随着年龄的增长，肺泡-动脉氧分压差增加是由于（V）超过点A/（Q）超过点的不平等，而不是分流。
Arterial oxygen tension (Pa-O2) is known to decrease with age, and this is accompanied by a number of changes in mechanical properties of the lungs, including loss of elastic recoil and increase in closing volume. The changes in respiratory mechanics with age could induce greater ventilation/perfusion ((V) over dot A/(Q) over dot) mismatch and thus explain the decrease in Pa-O2. In 64 normal subjects aged 18 to 71 yr (lifetime nonsmokers with normal spirometry), we measured (V) over dot A/(Q) over dot inequality and arterial respiratory blood gases (Pa-O2 and Pa-CO2) at rest in the seated position. (V) over dot A/(Q) over dot mismatch, represented by the second moments of the blood flow and ventilation distributions (log SDQ and log SDV) increased with age, but only slightly (mean log SDQ was 0.36 at age 20 yr and 0.47 at age 70 yr). Pa-O2 fell by a correspondingly small amount of 6 mm Hg. Previously established upper 95% confidence limits for log SDQ (0.60) and log SDV (0.65) in subjects at age 20 yr were confirmed. At age 70 yr, the upper limits of reference for log SDQ are 0.70 and for log SDV 0.75. The study shows that an increased alveolar-arterial O-2 gradient with age is due to (V) over dot A/(Q) over dot inequality rather than to shunting.