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  #1  
Old 02-24-2012
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Smile Blood gases ... This Q will make you crazy

A 44-year-old truck driver is brought to the emergency department with sudden onset dyspnea. His BMI is 31 kg/m2. He smokes two packs a day and drinks alcohol occasionally. His past medical history is insignificant except for mild swelling of the right calf over the past week. Which of the following arterial blood gas values would you expect most in this individual?

pH PaO2 (mm Hg) PaCO2 (mm Hg) Plasma HCO3- (mEq/L)
A. 7.21 101 21 11

B. 7.32 60 55 31

C. 7.38 70 40 22

D. 7.47 65 25 21

E. 7.50 96 32 15

F. 7.57 75 50 32
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Old 02-25-2012
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ok...i'll try it. that's the way i think about such qs:

1.) he is fat and smokes -> ascidosis (eliminates D,E,F)
2) he'll have a very low paO2 (eliminates A)
3)that leaves me with B and C and i'd go for B....because of the pCO2...

do y know the answer?
anyone a better idea?
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Old 02-25-2012
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Ans is D ....... its pulmonary embolism ... the pt has h/o of driving and DVT

he hyperventilates , loss of Pco2 , decrease in Pao2 , Hco3 will be normal as renal compensation takes 3 days and rise in Ph due to alkalosis ..
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Old 02-25-2012
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Quote:
Originally Posted by Hitman View Post
Ans is D ....... its pulmonary embolism ... the pt has h/o of driving and DVT

he hyperventilates , loss of Pco2 , decrease in Pao2 , Hco3 will be normal as renal compensation takes 3 days and rise in Ph due to alkalosis ..
i forgot about the sudden onset....hmm....thx
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Old 02-25-2012
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Quote:
Originally Posted by cabreravelezmd View Post
A 44-year-old truck driver is brought to the emergency department with sudden onset dyspnea. His BMI is 31 kg/m2. He smokes two packs a day and drinks alcohol occasionally. His past medical history is insignificant except for mild swelling of the right calf over the past week. Which of the following arterial blood gas values would you expect most in this individual?
What's the answer???
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  #6  
Old 02-25-2012
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Answer= D
sudden onset dyspnea = pulmonary thromboembolism
obesity(risk factor) + smoker(risk factor) + sedentary job(driver) +swollen right calf = DVT
PTE leads to low oxygen due to thrombus = low O2
to increase ventilation,pt hyperventilates = CO2 washout= low PCO2
since pt was immediately admitted,no renal compensation (takes 2-5 days) and so dont look at HCO3-
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