Holtz B, Bake B, Oxhöj H
J Appl Physiol. 1976 Nov;41(5 Pt. 1):623-30. doi: 10.1152/jappl.1976.41.5.623.
Closing volume (CV) was ?EASURED WITH THE RESIDENT GAS TECHNIQUE IN 12 HEALTHY SEATED SUBJECTS AGE 22-70 YR, AND IN 8 SUBJECTS WITH THE BOLUS TECHNIQUE. Various volumes were inspired (Vi range: 20-100% vital capacity) from residual volume and CV was assessed on the subsequent recording of expired volume versus gas concentration. The results indicate that the resident gas technique may erroneously underestimate CV at reduced Vi in conformity with calculations which predict that during expiration, after a certain reduced VI, the nitrogen concentration is identical in the most basal lung region and at the mouth. CV obtained with the bolus technique decreased linearly with reduced Vi and the effect appeared to be age dependent according to the equation CV50/CV100=0.0078 X age +1.18, where CV50 and CV100 denote the bolus CV corresponding to Vi=50% and 100% of vital capacity. Therefore, in older subjects, during tidal breathing, airways appear to close at substantially lower lung volume than previously considered.
采用残气技术对12名年龄在22至70岁的健康坐位受试者以及8名采用团注技术的受试者测量了闭合气量（CV）。从残气量开始进行不同容量的吸气（吸气量范围：肺活量的20%至100%），并在随后记录的呼出量与气体浓度时评估CV。结果表明，根据计算预测，在呼气过程中，在一定程度的吸气量减少后，最底部肺区域和口腔处的氮浓度相同，因此残气技术可能会在吸气量减少时错误地低估CV。采用团注技术获得的CV随吸气量减少呈线性下降，根据方程CV50/CV100 = 0.0078×年龄 + 1.18，这种影响似乎与年龄有关，其中CV50和CV100分别表示对应于肺活量50%和100%的团注CV。因此，在老年受试者中，在潮式呼吸期间，气道似乎在比以前认为的低得多的肺容量时就会闭合。
