Читать книгу Manual of Equine Anesthesia and Analgesia - Группа авторов - Страница 213

 The surface area available for diffusion.

 The physical properties of the gas.

 The thickness of the air‐blood barrier.

  The driving pressure of the gas between the alveolus and capillary blood as described by Fick's law of diffusion.Fick's Law Vgas = the volume of gas transferred across a membrane or barrier.A = the area available for diffusion.T = the membrane thickness.D = a diffusion constant that is dependent on the physical properties of the gas.P1‐P2 = the partial pressure difference of the gas across the membrane.Note: CO2 is approximately 20 times more soluble than O2, and therefore its diffusion across a membrane is less likely to be impaired, relative to O2, by a change in membrane thickness.

 In the normal lung, equilibration of O2 and CO2 across the alveolar capillary membrane occurs within 0.25 seconds; approximately one third of the time the blood is in the capillary.