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* NBME 5 block 4 Q47
 #600428  
  happydoctor - 07/19/11 19:15
 
  exam in three weeks...

http://www.usmleforum.com/files/forum/2011/1/577797-3.php

can someone helps explain why the answer is A not B? I'm weak in pulmonary.

I think the question is trying to ask you the difference between chronic bronchitis and emphysema. I think chronic bronchitis is blue puffer(lots of CO2 retention), whereas emphysema is pink puffer (less CO2 retention due to equal damage of alveoli and blood vessel). Therefore, the y-axis should show less CO2...
pls correct me if I"m wrong.

also, can some one guild me how to improve respiratory physiology quickly? I"m so worried about it. Many thanks!
 
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* Re:NBME 5 block 4 Q47
#2433634
  happydoctor - 07/19/11 20:39
 
  anyone please?  
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* Re:NBME 5 block 4 Q47
#2433650
  sarim - 07/19/11 21:38
 
  what's ur Dx?  
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* Re:NBME 5 block 4 Q47
#2433665
  happydoctor - 07/19/11 22:02
 
  I am confused with my diagnosis: I would say emphysema, but the patient also has hypercapnia. all the other signs are symptoms are consistent with this...but why he also has CO2 retention? I just don't get it.  
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* Re:NBME 5 block 4 Q47
#2433707
  happydoctor - 07/19/11 23:01
 
  come on guys, anyone give me a explanation or correct me please...

PS: I want to thank Maraym and other people provided such good explanations. that saved lots of time for me to find out the correct answers.
 
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* Re:NBME 5 block 4 Q47
#2433923
  happydoctor - 07/20/11 08:51
 
  anyone, please help me out. thanks!  
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* Re:NBME 5 block 4 Q47
#2689529
  drmufti - 07/02/12 11:41
 
  Here is my solution:


Given values:
Patient has got Hypoxia & Hypercapnia (Pco2 > 40mmHg)
Gas exchange rate 15% of healthy individual
Patient breathing air @ sea level, so Po2 = 150mmHg


now letís calculate PAO2 (partial pressure of O2 @ alveolar air) using the formula
PAO2=150-(PaCo2/.8)
(Here, PaCo2= partial pressure of arterial CO2)

PAO2= 150-{(>40mmHg)/.8} = 150 Ė {>50mmHg} =
 
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* Re:NBME 5 block 4 Q47
#2689531
  drmufti - 07/02/12 11:42
 
  Here is my solution:
Given values:
Patient has got Hypoxia & Hypercapnia (Pco2 > 40mmHg)
Gas exchange rate 15% of healthy individual
Patient breathing air @ sea level, so Po2 = 150mmHg
now letís calculate PAO2 (partial pressure of O2 @ alveolar air) using the formula
PAO2=150-(PaCo2/.8)
(Here, PaCo2= partial pressure of arterial CO2)
PAO2= 150-{(>40mmHg)/.8} = 150 Ė {>50mmHg} =
 
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* Re:NBME 5 block 4 Q47
#2689543
  kocharov777 - 07/02/12 12:25
 
  for simplification-just look at PO2 valuesin BCDe variants-its >100  
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* Re:NBME 5 block 4 Q47
#2689939
  drmufti - 07/03/12 01:51
 
  ya. nice.  
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