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Kaplan Qbank USMLE



Author10 Posts
  #1

A 54-year-old woman with a long history of emphysema presents because of an exacerbation of her cough and dyspnea. On physical examination, her blood pressure is 126/64 mm Hg, pulse is 82/min, and respirations are 24/min. On lung examination, there are loud expiratory wheezes and rhonchi. The cardiac examination is normal. An arterial blood gas is performed. Which of the following results would most likely be expected?


A. pH of 7.20, pCO2 of 60, and pO2 of 46

B. pH of 7.30, pCO2 of 50, and pO2 of 94

C. pH of 7.35, pCO2 of 45, and pO2 of 60

D. pH of 7.46, pCO2 of 25, and pO2 of 76

E. pH of 7.52, pCO2 of 30, and pO2 of 82


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  #2

B. Chronic respiratory acidosis.

  #3

C


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Prepare as if you're the worst, Perform as if you're the best! As you dream, so you manifest. So, DREAM BIG!! When you face hardship, remember, God never gives you more than you can handle. Keep your face to the sunshine and you cannot see the shadows.

  #4

B? with no repiratory distress, the O2 would be near-normal i wud guess!

  #5

C. pH of 7.35, pCO2 of 45, and pO2 of 60


___________________
FORUM RULES-- Those who believe in telekinesis, raise my hand. I get enough exercise just by pushing my luck --P4U World.." The pure and simple truth is rarely pure and never simple."

  #6

SURVIVOR wrote:
B? with no repiratory distress, the O2 would be near-normal i wud guess!


she is dyspneic, inc resp rate, wheezes, rhonchi


___________________
Prepare as if you're the worst, Perform as if you're the best! As you dream, so you manifest. So, DREAM BIG!! When you face hardship, remember, God never gives you more than you can handle. Keep your face to the sunshine and you cannot see the shadows.

  #7

Oh yeah! I should've read it more carefully!

  #8

D????




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Great works are performed not by strength, but by perseverance.

  #9

The correct answer is C.

This patient has an acute exacerbation of her chronic obstructive pulmonary disease (COPD). On the basis of the history and physical examination, she would be expected to have a compensated respiratory acidosis because CO2 retention. Furthermore, she would be expected to have evidence of mild hypoxia. With respirations of 24/min, which is high but not extremely high, she would not be expected to show the severe levels of acidosis and CO2 retention illustrated in choice A. The patient is sufficiently symptomatic that the near normal pO2 of 94 seen in choice B would be unlikely. Although asthmatics may present during an acute exacerbation with a respiratory alkalosis (choices D and E), in a patient with underlying COPD, there is usually a baseline respiratory acidosis

FROM WHAT I UNDERSTAND

Some patients with COPD may have a mild respiratory acidosis with mild to moderate hypoxemia without hypercapnia . For these patients to have Hypercapnia , the FEV 1 would have to fall below 1 L / s or 30 % of the predicted value . Remember , COPD is cronic condition where the kidney are partially ( NOT TOTALLY ) trying to compensate that acid base disturbance reving up bicarbonate ( metabolic alkalosis )

That 's why you would see a BODERLINE RESPIRATORY ACIDOSIS ( ALMOST NORMAL ) and besides as the explanation said above : Choice A is for a SEVERE RESPIRATORY ACIDOSIS in extreme case of hypoxemia and you would find the respiratory rate even higher than 24 / min


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The elevator to succes is broke ,you must take the stairs

  #10

Hi guys,It s known that COPD is associated with respiratory acidosis. But, i read in Goljan pathology Textbook that Emphysema gives RESPIRATOTY ALKALOSIS.

May someone explain why this patient with emphysema presents with RESPIRATORY ACIDOSIS.

Don t want to make the same mistake in the real thing.Please help me.

Thanks in advance.


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Great works are performed not by strength, but by perseverance.







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