NBME1 spoiler, please help

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shiv

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An adult's hemoglobin is 98% saturated with oxygen, but arterial oxygen content is decreased. Cause:
A anemia
B an arteriovenous shunt
C hemoglobinopathy
D high-altitude hypoxia
E pulmonary diffusion defect

I was thinking High altitude hypoxia, bc with high altitude ur PA02 goes down and consequently Pa02 goes down., now body response would be to increase the Hb to compensate for the low 02. what do u guys think?? thanks
 
hmmm...it could be anemia. you can still have a high Hb saturation but the total amount of oxygen carrying capacity will drop since the Hb count is low.
 
pretty sure that tx is right....you could have 100% saturated Hg (and from the question you can pretty much assume the Hg is fine b/c its well saturated), but if you barely have any red blood cells (low total Hg) you're not going to have very much arterial oxygen...I could be wrong though....haven't studied cv med since last year....
 
see one thing that i am not clear abut is the arterial O2 content is that the total oxygen or just P02(dissolved 02)?? if arterial 02 is total then anemia would be the right answer i would think.. any suggestions??
 
Its anemia... goljan only explains it about 10 times in the first lecture. All the other choices have a decreased saturation owing to a decreased pao2 (or bad hemoglobin)

http://www.lakesidepress.com/pulmonary/ABG/PO2.htm
scroll all the way down to the answer for clinical problem 5.5... then scroll back up and read the explanations. This website helped me understand o2 tension/saturation/content before we even did resp phys, so its worth a look if you're weak in the subject.
 
Hey!! Thanks for the website it really helped me out..Do you kno of any other website or resource that explains murmurs? i have been having hard time with this.. Thanks
 
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