Diffusion disorders. Diffusion capacity of the lungs/Repetitorium

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Concepts assumed

• factors affecting diffusion
• differences in the diffusion of O 2 , CO 2 and N 2

Diffusion disorders

1. Reduction of the diffusion area (morphological and functional changes of the lungs, pulmonary edema, changes in the ratio of ventilation and perfusion).
2. Changes in the diffusion path (pulmonary fibrosis, pulmonary edema - asthma cardiale ), "alveolar block".
3. Reduction of the alveolo-capillary pressure gradient (changes in the partial pressures of gases, alveolar hypoventilation, uneven ventilation).

Diffusion capacity of the lungs (D L ) – transfer factor

• The amount of diffusion per unit time relative to a unit pressure gradient (for oxygen , carbon dioxide or carbon monoxide).

Measurement methods

1. for oxygen: D LO2 = V O2 / Pa O2 (norm. 25–30 ml/min/mmHg)
2. for carbon monoxide : D LCO = V CO / PA CO , D LO2 = D LCO · 1.23

• Advantages of determining diffusion capacity using CO.
• Clinical interpretation of lung diffusion capacity values.
• Dependence of lung diffusion capacity values ​​on V'/Q' unevenness.

Links

Related articles

• Examination of pulmonary diffusion and perfusion

Source

• VÍZEK, Martin. Repetitorium [online]. [cit. 2012-01-11]. <https://web.archive.org/web/20130512032641/http://pf.lf2.cuni.cz/vyuka/repetitorium.html>.