V d V t = P A C O 2 − P e C O 2 P A C O 2 Ī common step is to then presume that the partial pressure of carbon dioxide in the end-tidal exhaled air is in equilibrium with that gas' tension in the blood that leaves the alveolar capillaries of the lung. The original formulation by Bohr, required measurement of the alveolar partial pressure P A. The original notation used by Fowler has been retained. defines Vds, the anatomical dead space volume. The Bohr equation is used to quantify the ratio of physiological dead space to the total tidal volume, and gives an indication of the extent of wasted ventilation. Hence during heavy exercise the Bohr estimate of dead space utilising measurements of end-tidal CO 2 yields an inappropriately high value because the end-tidal CO 2 consistently exceeds the mean alveolar (and arterial). It differs from anatomical dead space as measured by Fowler's method as it includes alveolar dead space. Chapter 68 Respiratory Physiology: Breathing Mechanics ANATOMIC & PHYSIOLOGIC DEAD SPACE /anatomic-physiologic-dead-space Dead space: air volume enters airways, lungs no gas exchange occurs ANATOMIC DEAD SPACE Air inaccessible to body for gas exchange (due to anatomical structure) Air contained in conducting zone (nose terminal bronchioles) Conduit for air movement in/out of lungs. This is given as a ratio of dead space to tidal volume. The Bohr equation, named after Danish physician Christian Bohr (1855–1911), describes the amount of physiological dead space in a person's lungs. Not to be confused with the Bohr model or the Bohr effect.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |