Clinical Pearls: VBG vs ABG

There is a legitimate reason why ER providers consistently order a VBG over an ABG and the ICU provider then may or may not believe the VBG choosing to tack on an ABG instead.

Many patients in the hospital require assessment of their acid base balance and oxygenation/ventilation status which is best quantified from serum arterial samples. Additionally, the ABG provides expedited lab results such as hemoglobin, potassium and other electrolytes, and lactic acid. These values are very helpful in making a rapid diagnosis and treatment plan. A venous blood gas seems to be the standard replacement for an arterial blood gas in the emergency department. It does offer some benefits, but has limitations as well which should be acknowledged.

The focus of this article is to describe the pros/cons of using a VBG as a surrogate, the exclusion criteria, and the method of converting a VBG to an ABG.