Holtz B, Bake B, Winstedt P
Scand J Respir Dis. 1979 Jun;60(3):119-27.
Closing volume (CV) was measured in 64 healthy subjects aged 18--76 years, in supine position, with a bolus (helium) technique in two ways: following a maximal (CV100) and a submaximal (=50% VC; CV50) inspiration from residual volume. With increasing age CV50 increased less than CV100 according to the equation CV100(%VC)-CV50(%VC)=0.13Xage-0.6(r=0.46, P less than 0.001), e.g. at 70 years of age CV100=32(%VC) and CV50=24(%VC). Therefore, during normal breathing elderly subjects to not presumably close airways at as high a lung volume as predicted from conventional CV-measurements. A strong correlation between CV50 and CV100 was found, CV50(%VC)=0.55XCV100(%VC)+5.3(r=0.90; P less than 0.001), thus allowing a more accurate prediction of CV50 from CV100 than from age. Neither smoking habits nor body position affected the decrease of CV with reduced inspired volume.
采用团注（氦气）技术，以两种方式对64名年龄在18至76岁的健康受试者仰卧位时的闭合气量（CV）进行了测量：从残气量开始进行最大吸气量（CV100）和次最大吸气量（=50%肺活量；CV50）后测量。随着年龄的增长，根据公式CV100（%肺活量）-CV50（%肺活量）=0.13×年龄-0.6（r=0.46，P<0.001），CV50的增加量小于CV100，例如在70岁时，CV100=32（%肺活量），CV50=24（%肺活量）。因此，在正常呼吸过程中，老年受试者气道闭合时的肺容积可能不像传统CV测量所预测的那么高。发现CV50与CV100之间存在很强的相关性，CV50（%肺活量）=0.55×CV100（%肺活量）+5.3（r=0.90；P<0.001），因此与根据年龄预测相比，根据CV100能更准确地预测CV50。吸烟习惯和体位均不影响随着吸气量减少CV的下降。
