Term
| How much oxygen does the lung tissue itself consume during the gas exchange process? |
|
Definition
| Very little, as the lung tissue itself does no work |
|
|
Term
| Carbon dioxide levels are proportional or inversely proportional to the level of alveolar ventilation? |
|
Definition
|
|
Term
| If there is a true shunt (V/Q=0), what will the alveolar PO2 and PCO2 levels be? |
|
Definition
| They will be the same as the mixed venous PO2 and CO2 perfusing the compartment |
|
|
Term
| In the case of physiologic dead space (V/Q=infinity), what will the alveolar PO2 and PCO2 levels be? |
|
Definition
| The alveolar gas tensions will be identical to inspired gas with a PO2 of 150 mm Hg and a PCO2 of 0 |
|
|
Term
| In a two compartment model, if alveoli 1 is hypoventilated, how will this affect the alveoli 2? |
|
Definition
| Alveoli 2 will be hyperventilated with an increased V/Q ration and a PO2 that is higher than normal and a PCO2 that is less than normal |
|
|
Term
| What can cause regional decreases in ventilation? |
|
Definition
| A decrease in compliance in alveoli or an increase in resistance in the conducting airways |
|
|
Term
| In a two compartment model, if alveoli 1 has a perfusion of 0, how will this affect alveoli 2? |
|
Definition
| Blood flow will be diverted to alveoli 2; ventilation can go up as well, but its effect will depend on how much perfusion rises |
|
|
Term
| In most clinical settings, regional loss of perfusion is associated with an increase in what? How does this affect V/Q? |
|
Definition
| Increase in both minute and alveolar ventilation, such that the V/Q ratio of the perfused compartment remains approximately 1 or greater |
|
|
