A Guide to ABG Interpretation

Arterial Blood Gases (ABGs) are simpler than you think.

Use the ROME (Respiratory Opposite, Metabolic Equal) method. First, check the pH. Is it acidotic (<7.35) or alkalotic (>7.45)? Next, look at the PaCO2 (respiratory component) and HCO3 (metabolic component). Which one matches the pH direction? That's your primary cause. If the other value is moving to compensate, you have compensation. We'll walk through several examples to make it crystal clear.