Saunders N A, Kreitzer S M, Ingram R H
J Appl Physiol Respir Environ Exerc Physiol. 1979 Jun;46(6):1071-5. doi: 10.1152/jappl.1979.46.6.1071.
Patterns of rib cage (RC) deformation were studied in six normal subjects during moderate static inspiratory efforts such that esophageal pressure (Pes) as an index of transthoracic pressure fell to between -30 and -60 cmH2O during each maneuver. At lung volumes below 50% inspiratory capacity (IC), static inspiratory efforts deformed RC to a more elliptical shape; RC lateral diameter became smaller and RC lateral diameter became larger. However, at high lung volumes (greater than 50% IC) the opposite change in RC dimensions occurred despite similar changes in Pes, i.e., the RC became more circular. These differences in RC deformation did not appear to be a possive consequence of increased lung volume because the RC could be voluntarily deformed to a more circular shape at low lung volume when a) subjects performed static inspiratory efforts mainly with their intercostal and accessory muscles rather than their diaphragm as judged by a smaller change in transdiaphragmatic pressure for the same Pes; or b) subjects statically contracted their diaphragm with it held in a relatively flattened configuration as assessed by a large abdominal AP dimension. We suggest that deformation of the RC during static inspiratory efforts is not as predictable as has previously been suggested but depends on the pattern of contraction and configuration of the respiratory muscles.
在六名正常受试者进行适度静态吸气努力时，研究了胸廓（RC）变形模式，使得在每次操作过程中，作为跨胸压指标的食管压力（Pes）降至-30至-60 cmH₂O之间。在肺容积低于吸气容量（IC）的50%时，静态吸气努力使RC变形为更椭圆的形状；RC横向直径变小，RC前后直径变大。然而，在高肺容积（大于IC的50%）时，尽管Pes有类似变化，但RC尺寸出现相反变化，即RC变得更圆。RC变形的这些差异似乎不是肺容积增加的被动结果，因为当：a）受试者主要通过肋间肌和辅助肌而非膈肌进行静态吸气努力时（根据相同Pes时跨膈压变化较小判断），或者b）受试者静态收缩膈肌且膈肌保持相对扁平形态时（根据较大的腹部前后径评估），RC在低肺容积时可自愿变形为更圆的形状。我们认为，静态吸气努力期间RC的变形不像以前认为的那样可预测，而是取决于呼吸肌的收缩模式和形态。
