Interpreting ABGs (Arterial Blood Gases) Made Easy

Arterial blood gasses, or ABGs, are among the more complex assessments performed by clinical healthcare professionals.

Fortunately, there are some easy ways to remember how to decipher these important results.

When interpreting ABG results, it is essential to know what ABG values are considered ‘normal’. From this baseline, you can then begin to recognise significant variations in a patient’s results, which could indicate clinical deterioration.

The first value is the pH, which measures how many hydrogen ions (H+) are in the sample. This determines if the blood is acidotic or alkalotic. Normal values for pH range from 7.35 - 7.45.

The next value is the carbon dioxide level, and this will tell you if the problem is respiratory in origin, as CO2 is regulated by the lungs (Berman et al. 2017). The normal range for PaCO2 is 35 to 45 mmHg.

Finally, bicarbonate ions, or HCO3-, will tell you if the problem is related to metabolic changes in your patient and refers to the renal system (Berman et al. 2017). Normal is considered to be from 22 to 26 mmol/L.