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Restrictive Lung Dise

RESPIRATORY PHYSIOLOGY

Maximum Expiratory riow-Volume Curves

Total Lung _ Capacity (TLC)

TI.C and VC deoeased

Vital

- Capacity (VC)

TLC

Funclional J Residual ~ Capacity (FRC)

Restriction

Normal

J. Perkins

MS. MFA

*MDM

Figurę 5.27 Restrictive Pulmonary Disease

Rcstrictive pulmonary disease refers to a group of disorders that result in an increase in the connective tissue ot the lung (e.g.. fibrosis, alveolar wali thickening). The increasod connective tissue red u ces lung compliance, making it incrcasingly difflcult to expand the lung during inspiration. As a result, virtually all lung volumes are reduced. In particular, as shown herc. thore can be marked decreases in TLC and VC (measured as torced vital capacity 1F\^/C1>. The forced expir tory volume in the first second <FEV,> is decrcased in proportion to FVC, so the ratio of FEV,/FVC is typically normal. If the FVC is markcdly decreased. this ratio may even increase.

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