zeloc
Forum Junior
Topics: 11
Posts: 53
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A patient with abdominal pain and orthostatic hypotension is described with
ph 7.28
pCO2 29
HCO3- 11
Na 135
Cl 102
BUN 31
Cr 0.8
What acid-base disorder/combination does the patient have?
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| zeloc
Forum Junior
Topics: 11
Posts: 53
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Answer: There are various answer choices describing acid-base combinations. I say that the patient has a primary metabolic acidosis with a concurrent respiratory acidosis, because the patient has an elevated anion gap metabolic acidosis, and using Winter's formula, the pCO2 should be 24.5, plus or minus 2. Since the patient's pCO2 is even higher, it appears there is a respiratory acidosis. Only the answer they give is that the patient has a metabolic acidosis with a compensatory respiratory alkalosis. Is this a mistake in USMLEWORLD?
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| gr8doc
Forum Senior
Topics: 8
Posts: 210
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No that's whateven my first impression was . That this is a clear case of Metabolic Acidosis with Respiratory compensation. I got a little worried while reading your explanation & when you mentioned about the big formulas....but was happy to see the final answer matching my thinking. Why would you think this as respiratory acidosis with the CO2 levels of 29 ?? there is no CO2 retention to call it respiratory acidosis.
Hope this helps.
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| cirus
Forum Guru
Topics: 108
Posts: 740
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thats not right..
Compensation = 1.5(HCO3)+8--->24.5(this is supposed to be the level of CO2) & since it is higher, then its both anion gap Metabolic acidosis + resp acidosis.
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| gr8doc
Forum Senior
Topics: 8
Posts: 210
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Oops !!!! I really need to check this one . In the meanwhile ,will appreciate any other views. Cirus, do you follow the same formula mentioned earlier?
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| Ivonne
Find a way or make one
Topics: 58
Posts: 1,611
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Could you please guys write the winter's formula in a case of Primary respiratory acidosis
HCO3(compensation)=?
Thanks in advance
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| Drtweetie
Forum Elite
Topics: 17
Posts: 301
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agree w/ cirus!
Winter's formula is used to determine in a case of metab acidosis to see if there's a respiratory compensation or not:
PCO2= 1.2 HCO3 + 8 (+/-2)
so if after plugging in HCO3 and PCO2 is greater than observed in lab value, then there's additional respiratory acidosis. IF PCO2 is less than observed, then there's also resp alkalosis.
In case of primary resp acidosis,
-acute: bicarb increases by 1 for every 10 increase in PCO2
-chronic: bicarb increased by 4 for every 10 increase in PCO2
Edited by Drtweetie on 08/16/07 - 03:08 PM
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| gr8doc
Forum Senior
Topics: 8
Posts: 210
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Which book does mention about the Winter's Formula?
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| Drtweetie
Forum Elite
Topics: 17
Posts: 301
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Boards & Wards
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