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Pulmonary Pathophysiology

--How are alveolar ventilation and oxygenation estimated and assessed?
--What pathophysiological factors might alter ventilation-perfusion matching in the lungs?
--What are the clinical manifestations and common causes of acute airway obstruction?
--What is the rationale for using drugs such as β2 agonists, acetylcholine antagonists, corticosteroids, and mast cell stabilizers to manage obstructive pulmonary disorders?
--What pulmonary function test abnormalities are characteristic of obstructive and restrictive pulmonary disorders?

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Alveolar ventilation refers to the volume of air that reaches the alveoli per unit time. This can be calculated using tidal volume (the total volume exchanged in inspiration/expiration with no conscious effort) and dead space volume (inspired air that does not participate in gas exchange either because it's in the airway and not the alveoli, or in alveoli not perfused). The calculation is simply: Tidal volume - dead space.

Alveolar oxygenation is a little more convoluted in calculation. It's obviously not practical to measure the partial pressure of oxygen in the alveoli in a patient directly, thus it has to be calculated from easily measurable variables. These variables are:

The amount of oxygen in atmospheric air
The amount of O2 taken in, CO2 expelled - CO2/O2 = RQ or respiratory quotient
Atmospheric pressure
Vapor pressure of water at body temperature
Arterial partial pressure of CO2

These variables can ...

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The solution discusses questions related to pulmonary pathophysiology.