Diffusion disorders. Diffusion capacity of the lungs/Repetitorium

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.

Related articles

 * Examination of pulmonary diffusion and perfusion