ABG

pH 7.40, CO2 40, and HCO3 24.5 are absolute normal values. Nobody’s ABGs are absolutely normal. Therefore, even if compensated, the values will lean toward the acid or alkaline side. For example, pH between 7.35 to 7.39 is compensated acid and pH between 7.41 to 7.45 is compensated alkaline.

Example:

pH 7.35 (acid), CO2 36 (alkaline), HCO3 22 (acid) = metabolic acidosis compensated

pH 7.41 (alkaline), CO2 41 (acid), HCO3 27 (alkaline) = metabolic alkalosis compensated

UNCOMPENSATED

COMPENSATED (or normal)

UNCOMPENSATED

pH ACID ←

ACID ALKALINE

7.35 ← 7.40 → 7.45

ALKALINE→

CO2 ALKALINE ← 35 ← 40 → 45 → ACID

If pH matches in acidity or alkalinity with CO2, the problem is RESPIRATORY

HCO3 ACID ← 21 ← 24.5 → 28 → ALKALINE

If pH matches in acidity or alkalinity with HCO3, the problem is Metabolic