physiological dead air space is anatomic dead space plus

However, differences in the exact way of measuring this space result in clinically significant different results and, therefore, debate remains about the true value of this measured parameter.Ĭopyright © 2023, StatPearls Publishing LLC.

Indeed, it may serve as a prognostic factor in patients with acute repository distress syndrome (ARDS) who require ventilation.

This phenomenon has clinical significance because, both in healthy and impaired lungs, properly calculating and accounting for this non-physiological space is important for the proper respiratory care of ventilated patients. An alveolar ventilation rate is in our example 4,200 mL per minute. If this dead space is 150 mL, while tidal volume remains 500 mL we can multiply 350 mL (500 mL - 150 mL) with a breathing rate and get the value of alveolar ventilation rate. This is therefore termed anatomical dead space as it serves no respiratory function. However, a large percent of new air stays in the physiologic dead space of the lungs.

Anatomic dead space is an important phenomenon in respiratory physiology whereby, owing to the fact that upper airways do not function as locations for gas exchange, and because of the tidal nature of ventilation, there is always a fraction of the inspired air that does not perform a physiologic function of exchanging carbon dioxide for oxygen.

Physiological dead air space is anatomic dead space plus