winters_formula: Winter's Formula for Metabolic Acidosis Compensation

In cliot: Clinical Indices and Outcomes Tools

Winter's Formula for Metabolic Acidosis Compensation

Description

Calculates the expected partial pressure of carbon dioxide (PaCO2) in the setting of metabolic acidosis to determine if the respiratory compensation is appropriate. If the measured PaCO2 falls outside the calculated range, a concomitant respiratory disorder exists.

Usage

winters_formula(bicarbonate, measured_paco2 = NULL)

Arguments

bicarbonate	Numeric. The serum bicarbonate (HCO3) level in mEq/L or mmol/L.
measured_paco2	Numeric (Optional). The measured arterial PaCO2 in mmHg. If provided, the function evaluates whether a mixed acid-base disorder is present.

Details

The formula used is:

Expected PaCO_2 = (1.5 \times HCO_3) + 8 \pm 2

Interpretation of results when PaCO2 is provided:

• Within Range: Pure metabolic acidosis with appropriate respiratory compensation.

• < Lower Limit: Concomitant Respiratory Alkalosis.

• > Upper Limit: Concomitant Respiratory Acidosis.

Value

A list containing:

Expected_PaCO2_Range_mmHg	The range of expected PaCO2 values.
Interpretation	Analysis of the compensation status based on the measured PaCO2.

References

Albert MS, Dell RB, Winters RW. Quantitative displacement of acid-base equilibrium in metabolic acidosis. Ann Intern Med. 1967;66(2):312-322. doi:10.7326/0003-4819-66-2-312

Examples

# Example 1: Compensated Metabolic Acidosis
# HCO3 = 14, PaCO2 = 29
# Exp = (1.5 * 14) + 8 = 29 +/- 2 = 27-31
winters_formula(14, 29)

# Example 2: Concomitant Respiratory Acidosis
# HCO3 = 14, PaCO2 = 35 (Higher than expected range 27-31)
winters_formula(14, 35)

cliot documentation built on Dec. 1, 2025, 1:06 a.m.