Gas Exchange and Regulation of Respiration Flashcards Preview

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Flashcards in Gas Exchange and Regulation of Respiration Deck (30):

What happens to hemoglobin's affinity for O2 as pH drops (acidemia)?

it DECREASES (aka more readily enters the tissues)


What happens to hemoglobin's affinity for O2 as temperature increases (fever)?

it DECREASES (aka more readily enters the tissues)


Does fetal hemoglobin have a greater or lesser affinity for O2?

GREATER (aka it holds onto it more tightly)


What is the effect of 2,3 BPG on hemoglobin/O2 affinity?

because it is a byproduct of glycolysis (which is an anaerobic process), it will DECREASE hemoglobin's affinity for O2 (aka allowing it to more readily enter the tissues).


What parameters will pulmonary function tests tell us?

- frequency
- tidal volume
- compliance= change in volume/change in pressure
- inspiratory reserve
- expiratory reserve
- vital capacity


What is the equation for compliance?

change in volume/change in pressure


What is the equation for minute ventilation?

frequency x tidal volume


*** What will the pressure/volume loop curve look like with a prematurely born baby with low surfactant levels?

the slope (compliance) will be LOW due to less surfactant able to increase the compliance.


What pts have a difficult time exhaling?

those with asthma or COPD


What is hysteresis?

- the difference in pressure-volume curves of the lung during inflation and deflation.
*The lung volume at any given pressure during DEFLATION is LARGER than during inflation.


Do certain therapeutic regimens exist that involve the use of liquid to ventilate a patient, rather than air?

YES via bronchiolar lavage and developing techniques.


What is the benefit of using a helium and oxygen gas mixture in certain situations?

this is called heliox and is less dense air, that requires less energy to move the air.


Why do pts with a high level of CO2 (i.e. COPD) breath a certain rate?

due to a hypoxic drive


What is the equation for oxygen content in the BLOOD (CaO2)?

- CaO2= Hb x 1.34 x SaO2 + PaO2 x 0.003
- it is either in the plasma or the hemoglobin (and the amount in the plasma is barely anything)!


What is the equation for oxygen content in the ALVEOLI (PA O2)?

PA O2= (0.21)(760-47) - (PaCO2/R) or
PA O2= FIO2(760-47) - PaCO2(1.2)
*Remember 760 torr= atmospheric pressure, and 47 torr= water vapor pressure.
*CHEAT METHOD: PA O2= 150 - (40/0.8)


What happens to oxygen saturation of barometric pressure drops?

it can also DROP :(
*Think climbing a mountain with high altitude.


What percent of the gas that we inhale normally is O2?

21% or 0.21


What will the brain tell the body to do when PaCO2 levels go up?

increase respiratory rate


What is the henderson-hasselbach equation?

pH= pk + log (base/PaCO2*k)


What happens to respiratory drive when you drop CO2 levels?

it also goes down
*Respiratory drive keeps CO2 levels down and O2 levels up


What happens in a respiratory acidosis?

you breathe less and therefore blow off less CO2. This allows for more carbonic acid in the blood leading to an acidemia.


What can type of acid/base disturbance will ischemia cause?

metabolic acidosis via anaerobic metabolites


What can cause a respiratory alkalosis?

breathing off too much CO2, and therefore decreased blood CO2 levels


What will happen to bicarb in a RESPIRATORY acidosis?

it will also go UP somewhat (because if CO2 goes up, so does carbonic acid, and therefore H+ and bicarb).


What happens to bicarb in a METABOLIC acidosis?

it will go DOWN and therefore you will increase respiration in an attempt to decrease CO2 levels in the blood as compensation


If respiratory rate went down and therefore minute ventilation went down, what would happen to CO2 levels in the blood?

they would go UP and pH would go down= respiratory acidosis


What is alveolar ventilation?

a component of normal ventilation


Can cervical spine injuries cause a respiratory acidosis?



Where are the respiratory centers (apneustic and pneumotaxic centers)?

at the base of the brain in the medulla


What is metabolic alkalosis?

increased bicarb levels