alveolar ventilation as function of tidal volume and dead space

The ratio of physiologic dead space to tidal volume is usually about 1/3. Defines the standard lung volumes and understands their measurement. With the subsequent development of a simple measurement of anatomical dead space, it became apparent that the alveolar dead space component was substantially increased in a range of pulmonary diseases, and that its original interpretation as ventilation delivered to unperfused alveolar surfaces was not adequate to explain the pathophysiology of. PA refers to alveolar partial pressure of a gas, while Pa refers to the partial pressure of that gas in arterial blood. Alveolar dead space is the volume of gas within unperfused alveoli (and thus not participating in gas exchange either) it is usually negligible in the healthy, awake patient. The alveolar ventilation rate changes according to the frequency of breath, tidal volume, and amount of dead space. Anatomic dead space is the volume of gas within the conducting zone (as opposed to the transitional and respiratory zones) and includes the trachea, bronchus, bronchioles, and terminal bronchioles it is approximately 2 mL/kg in the upright position. Doubling the depth of respiration (tidal volume would double his alveolar ventilation) 4. Physiologic or total dead space is the sum of anatomic dead space and alveolar dead space. Dead space is the volume of a breath that does not participate in gas exchange.

Alveolar ventilation as function of tidal volume and dead space