alveolar vs anatomic vs physiologic dead space

Some apparatus dead space may actually reduce total dead space, as an ETT bypasses the majority of anatomical dead space of the patient (nasopharynx).ĭead space from the patient. Study with Quizlet and memorize flashcards containing terms like How does anatomical dead space differ from physiological dead space, What can the Bohr equation be used to calculate, What three assumptions are made when using the Bohr equation to calculate physiological dead space and more. Types of Dead Spaceĭead space from equipment, such as tubes ventilator circuitry. Glomerular Filtration and Tubular Functionĭead space is the proportion of minute ventilation which does not participate in gas exchange.

Philadelphia: Wolters Kluwer, p.116.Functional Anatomy and Control of Blood Flow We can apply these assumptions to the ideal gas law ( PV = nRT) to derive an equation for the physiological dead space:īoron, W.

The volume of the alveoli (V A) that participated in gas exchange, together with the physiological dead space (V D), will equal the volume of the expired air: V A+V D=V E.

The molar amount of CO 2 produced in the alveoli ( n A CO 2) will be the same amount that is expired ( n E CO 2).

The subject breathes in normal room air, and respiration (production of CO 2) happens everywhere, except in the volume occupied by the dead spaces. Physiological dead space is the sum of the anatomical dead space and the alveolar dead space. In the ideal healthy adult, this is zero.

However, it is quick enough that it can be approximated (averaged out) as an abrupt transition.Īlveolar dead space includes those parts of the respiratory zone that do not participate in gas exchange. Note that in practice, O 2 is replaced by N 2 more gradually, as a sigmoid curve. When the gas is expired, the pure O 2 is expired first.The gas in the anatomical dead space remains as pure O 2 because it remains up in the conducting zone.Most of the O 2 mixes with the air already in the alveoli (75% N 2).It is measured by the nitrogen washout (Fowler) technique: Dead space is the volume of ventilated air that does not participate in gas exchange.Īnatomical dead space is the volume of air that fills the conducting zone, about 150 mL (~30% of normal tidal volume).

Alveolar vs anatomic vs physiologic dead space