respiratory physiology

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njshibby

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Random q's that have been bothering me... When a patient hyperventilates there will be just a minor change HCO3 correct? compensation only happens when pco2 elevated over a day or so.
when a patient hyperventilates how high can PaO2 rise?
Does the A-a gradient change in a cafe coronary?
 
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When a patient hyperventilates there will be just a minor change HCO3 correct? compensation only happens when pco2 elevated over a day or so.

HYPERventilation will cause a respiratory ALKALOSIS. You'll blow off a ton of CO2, dropping pCO2, and pH will rise. HCO3 doesn't fall (significantly) until renal compensation kicks it, which you are correct - can take a day or so. That is the difference between an "acute" and "chronic" respiratory acid/base disturbance. Acute implies before renal compensation, chronic implies with.
 
A-a gradient remains normal in a "cafe coronary." The patient is not able to get air into his alveoli to undergo gas exchange with the alveolar capillaries. The gradient between the alveolar and arterial gas only increases in situations where there's a problem with optimally getting air that's already in the alveoli to undergo exchange with alveolar capillaries (such as in a shunt situation, diffusion issues, and V/Q mismatches.) In the cafe coronary situation, if air was able to make its way into the alveoli, it'd undergo optimal exchange with the alveolar capillaries-however, there's a chunk of filet mignon in the way.
 
A-a gradient remains normal in a "cafe coronary." The patient is not able to get air into his alveoli to undergo gas exchange with the alveolar capillaries. The gradient between the alveolar and arterial gas only increases in situations where there's a problem with optimally getting air that's already in the alveoli to undergo exchange with alveolar capillaries (such as in a shunt situation, diffusion issues, and V/Q mismatches.) In the cafe coronary situation, if air was able to make its way into the alveoli, it'd undergo optimal exchange with the alveolar capillaries-however, there's a chunk of filet mignon in the way.

Ok so depends on where it is in the airway...if it's further down maybe in a bronchus then the rest of the lung perfused then the A-a would change im guessing. BRS phys and goljan differed on this.
 
Ok so depends on where it is in the airway...if it's further down maybe in a bronchus then the rest of the lung perfused then the A-a would change im guessing. BRS phys and goljan differed on this.

Oh, good point. I guess if there's some food in the distal airways, then you'd have perfusion without ventilation (i.e. a shunt) and there'd be an increase in the A-a gradient.
 
Could someone break down the relevance of the various respiratory tests?

Like egophony, fremitus, hyperresonance, etc. etc. and what they signify?

Thanks.
 
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