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 Really Easy Ones # 4  

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A 44-year-old HIV positive man admitted to the hospital for presumed pneumocystis carinii pneumonia. His pulse oxymetery revealed an oxygen saturation of 85%. Hypoxemia that is corrected with O2 therapy includes all of the following, except?

a- Large pulmonary arterio-venous malformation.
b- Acute pneumonia.
c- Pulmonary hemorrhage.
d- Pulmonary thromboembolism
e- Acute asthma.


D ??


a- pulmonary shunt


shunting of course... i hate these kind of questions why dont they just ask directly instead of correlating with a case , no use


ok, maybe i understand a concept incorrectly,
i thought that perfusion defects respond to 100% O2 (ie u'll see increase in blood O2..).. while the ventilation defect doesnt lead to increase in O2 secondary to administration of 100% O2

So the only vent defect i could pick from here is: .. i dont know sadB / E? Asthma sounds too weird.. Acute pneumonia.. a possibility

i am confused sad

  #6 guys are right. i muddled it up and went for D. it should be A.

can't be D cuz perfusion defects respond to oxygen therapy.

has to be A cuz supplemental oxygen will raise PaO2 slightly but NEVER produce full saturation of hemoglobin. and in fact, the lack of response to supplemental oxygen is diagnostic for pul. shunt.


I think the answer is the Asthma ... in pneumonia you dont have a ventiliation problem, rather its a diffusion problem, all the other choices may respond to a high o2 sat, even the shunt (although it might elevate it slightly)

this is what i think, waiting for the right answer ... thanks


Guys ??? Why is the forum soooo slow ??!??!


i agree with gridlock!

i know that pneumonia is one of causes of ventilation defect but maybe not in acute phase?

astma forsure is a ventilation defect

ONLY in ventilation defect we can NOT correct hypoxemia by giving 02.
why do not u paste the correct answer NNL?

Edited by doctorforever on Apr 27, 2010 - 6:33 PM

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