Gas Transfer Flashcards
How do you calculate pulmonary vascular resistance?
Perfusion pressure divided by cardiac output.
What are the three components of gas transfer?
Diffusion trough alveolo-capillary membrane, reaction with blood, matching ventilation to perfusion.
What effects the diffusion rate?
Partial pressure gradient, surface area, solubility of water, membrane thickness, molecular weight.
What is V/Q mismatch?
Caused by an increase/decrease in ventilation of lungs or increase/decrease in perfusion of lungs.
How may the lungs try to compensate for V/Q mismatch?
Hypoxic pulmonary vasoconstriction.
What is dead space?
When volume of inhaled air does not take part in gas exchange as it remains in conducting airways or reaches poorly perfused alveoli.
What is a pulmonary shunt?
Conduction where alveoli are perfused as normal but ventilation fails to supply perfused region.
How is capacity of lungs to transfer gas measured?
Single breath CO test.
