Critical Care · Pulmonology

Arterial pH (Henderson–Hasselbalch) calculator

Enter the published formula inputs below to calculate and interpret this score.

Clinical inputs

Serum bicarbonate (mmol/L)

Partial pressure of arterial carbon dioxide (PaCO2) (mm Hg)

Result

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Formula inputs

Serum bicarbonate (mmol/L)Accepted range: 5 to 45
Partial pressure of arterial carbon dioxide (PaCO2) (mm Hg)Accepted range: 10 to 100

Primary source

Henderson LJ. The theory of neutrality and its application to blood and to aqueous solutions of biological importance. J Biol Chem. DOI: 10.1016/S0021-9258(18)85243-4. PMID: 19974646. Scope: arterial pH = 6.1 + log10([HCO3−] / (0.03 × PaCO2)) with bicarbonate in mmol/L and PaCO2 in mm Hg using the standard solubility coefficient 0.03. (1908)

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