Quick Review: Winter's Formula
T Fujii, B Phillips
Citation
T Fujii, B Phillips. Quick Review: Winter's Formula. The Internet Journal of Academic Physician Assistants. 2002 Volume 3 Number 1.
Abstract
This brief review will discuss when to administer bicarbonate.
When is it productive to administer Bicarbonate ?
Case # 1: 60 yr. old Male, Septic Shock
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Pulse 116 BP 96/42
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pH = 7.15
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pO2 = 80
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pCO2 = 30
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HCO3- = 16
Should you give Bicarb ?
Case # 2: 66 yr. old Female, 2 hours s/p CABG
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Pulse 98, NSR BP 98/56
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pH = 7.18
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pO2 = 74
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pCO2 = 31
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HCO3- = 10
Should you give Bicarb ?
Acid/Base Buffering:
H2CO3.........................H+ + HCO3-.................... H+ + CO2
The Winter's Formula: A Guide to Bicarb Administration
pCO = (HCO3-) x 1.5 + 8 (+/- 4)
If the observed pCO2 is HIGHER than the calculated pCO2, then the body is not handling intercellular CO2 well & extracellular bicarbonate will not be able to enter the cellular environment
Figure 1
Figure 2
Case # 1: 60 yr. old Male, Septic Shock
-
Pulse 116 BP 96/42
-
pH = 7.15
-
pO2 = 80
-
pCO2 = 30
-
HCO3- = 16
Should you give Bicarb ?
-
pCO2 = (HCO3-) x 1.5 + 8 (+/- 4)
-
pCO2 = (16) x 1.5 + 8 (+/- 4)
-
pCO2 = 24 + 8 (+/- 4)
-
pCO2 = 32 +/- 4
* Observed pCO2 is 30: the body is buffering the CO2 well - it is physiologically a good idea to administer bicarbonate !
Case # 2: 66 yr. old Female, 2 hours s/p CABG
-
Pulse 98, NSR BP 98/56
-
pH = 7.18
-
pO2 = 74
-
pCO2 = 31
-
HCO3- = 10
Should you give Bicarb ?
-
pCO2 = (HCO3-) x 1.5 + 8 (+/- 4)
-
pCO2 = (10) x 1.5 + 8 (+/- 4)
-
pCO2 = 15 + 8 (+/- 4)
-
pCO2 = 23 +/- 4
observed pCO2 is 31: the body is NOT buffering the CO2 well - it is physiologically wrong to administer bicarbonate !