This app calculates the four equations that make up the simplified Stewart approach to bedside interpretation of blood gas values as presented by Story ( PubMed ): Stewart Acid-Base: A Simplified Bedside Approach. Anesth Analg. 2016 Aug;123(2):511-5.

Data Input

The BE_ecf (standard base excess) as calculated by the blood gas machine is entered in mmol/L (equivalent to mEq/L). Sodium, chloride and lactate are also entered in mmol/L (same as mEq/L). Albumin is input as g/L (ten times g/dL).

An approximate correction to the base excess can be applied in the setting of chronic respiratory changes:
0.4 mmol/L for every 1.0 mm Hg chronic change in CO₂ partial pressure.

If not all values are available, values that might be expected in the clinical situation can be tried to see what effect they would have. The "Reset" button will return all inputs to their reference values.

Calculated Values

Four contributions to the base excess are calculated: the sodium minus chloride effect, the lactate effect, the albumin effect, and the effect of other ions. These, like the base excess, are expressed in mEq/L. Negative values represent acidotic contributions, and positive values alkalotic.

Equations

Na−Cl effect = (Na−Cl)−35
Lactate effect = 1−lactate
Albumin effect = 0.25×(42−albumin)
Other Ions effect = BE−(sum of above effects)

Other systems

ABG Formulas

About

Bedside Stewart 2.4
2016, 2023
Contact: John Friesen
slumbersoftware@gmail.com

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