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A program to calculate Winter's formulas for the interpretation of the blood gas analysis
Winter's empirical formulas calculate the optimal compensation for blood pH disturbances (see Berend K. Diagnostic use of base excess in acid-base disorders, New Engl. J. Med. 2018; 378: 1419-1428). If the patient's measured values fall within a + or -2 interval from the calculated parameter, the patient is considered to have only one disease; if not, a secondary disease is superimposed to the primary one.
Winter's formulas are as follows:
expected optimal compensation of metabolic acidosis: PCO2 = 1.5x[HCO3-] + 8
expected optimal compensation of metabolic alkalosis: PCO2 = 0.7x([HCO3-]-24) + 40
expected optimal compensation of chronic respiratory acidosis and alkalosis: [HCO3-] = 24+0.4x(PCO2−40)
The program will initially propose an example case; you may change the input parameters at will, or take the parameters from a real case.
The primary disease is identified by the following set of rules:
| pH | PCO2 | HCO3- | |
| 7.4 | 40 mmHg | 24-26 mM | health |
| <= 7.4 | >> 40 mmHg | (> 26 mM) | Respiratory (hypercapnic) acidosis |
| < 7.4 | (<< 40 mmHg) | < 24 mM | Metabolic (hypocapnic) acidosis |
| >= 7.4 | << 40 mmHg | (< 24 mM) | Respiratory (hypocapnic) alkalosis |
| > 7.4 | (>> 40 mmHg) | > 26 mM | Metabolic (hypercapnic) alkalosis |
pH: 7.3; PCO2: 26 mmHg; HCO3-: 12.4 mM; total CO2: 13.2 mM; SBE: -13.6 mEq/L.
Condition: metabolic acidosis.
Expected PCO2: 27 mmHg.
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