Acid-Base Balance Lab (2D)

Respiratory Component

pCO2 40 mmHg

Metabolic Component

Plasma HCO3- 24 mEq/L

Normal acid-base balance — pH held near 7.40 by the bicarbonate buffer.

Live Readout

Blood pH

7.40

HCO3-/pCO2

20 : 1

Classification

Normal

Compensation

None needed

How it works

Blood pH is set by the ratio of bicarbonate to dissolved CO2, per the Henderson-Hasselbalch equation: pH = 6.1 + log([HCO3-] / (0.03 × pCO2)). The lungs control pCO2 (the respiratory component) breath-to-breath; the kidneys control HCO3- (the metabolic component) over hours to days. A healthy ratio of about 20:1 keeps pH in the narrow 7.35-7.45 range.

Raise pCO2 (hypoventilation) and pH falls — respiratory acidosis. Lower it (hyperventilation) and pH rises — respiratory alkalosis. Drop HCO3- (e.g. diarrhea, ketoacidosis) and pH falls — metabolic acidosis. Raise it (e.g. vomiting, antacid excess) and pH rises — metabolic alkalosis.

With compensation ON, the healthy system opposite the primary disorder partially corrects it: the kidneys retain or excrete HCO3- to offset a respiratory problem, while the lungs hyper- or hypoventilate to offset a metabolic one — pulling pH back toward normal without fully restoring it. Turn compensation OFF to see the uncompensated, textbook single-variable disorder instead.

Normal zone Compensation range Current state