What is the normal ratio of bicarbonate to dissolved carbon dioxide (HCO3-:dCO2) in arterial blood?

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Multiple Choice

What is the normal ratio of bicarbonate to dissolved carbon dioxide (HCO3-:dCO2) in arterial blood?

Explanation:
In arterial blood, pH is governed by the Henderson–Hasselbalch relationship, which uses the ratio of bicarbonate to dissolved CO2. The normal values are roughly bicarbonate about 24 mEq/L and dissolved CO2 about 1.2 mmol/L (since dissolved CO2 equals 0.03 × PCO2, with PCO2 around 40 mmHg). So the ratio of bicarbonate to dissolved CO2 is 24 / 1.2 ≈ 20, i.e., about 20:1. Unit-wise, bicarbonate is in mEq/L and dissolved CO2 is in mmol/L, but for these singly charged species the numerical ratio works out to 20:1. This 20:1 balance supports a normal arterial pH near 7.40; deviations in this ratio reflect acid-base disturbances—smaller ratios indicate acidosis, larger ratios indicate alkalosis.

In arterial blood, pH is governed by the Henderson–Hasselbalch relationship, which uses the ratio of bicarbonate to dissolved CO2. The normal values are roughly bicarbonate about 24 mEq/L and dissolved CO2 about 1.2 mmol/L (since dissolved CO2 equals 0.03 × PCO2, with PCO2 around 40 mmHg).

So the ratio of bicarbonate to dissolved CO2 is 24 / 1.2 ≈ 20, i.e., about 20:1. Unit-wise, bicarbonate is in mEq/L and dissolved CO2 is in mmol/L, but for these singly charged species the numerical ratio works out to 20:1.

This 20:1 balance supports a normal arterial pH near 7.40; deviations in this ratio reflect acid-base disturbances—smaller ratios indicate acidosis, larger ratios indicate alkalosis.

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