Comparison of values of traditionally measured venous bicarbonate with calculated arterial bicarbonate in intensive care unit patients of a hospital in a third-world country.

Background: Measurement of serum or plasma bicarbonate (HCO3 (-)) from a sample of peripheral venous blood is routinely practiced in hospital patient managements. HCO3 (-) status can also be obtained by a simple calculation during blood gas analysis requiring arterial blood as sample which is cumbersome for both patient and doctor. This study compared the measured bicarbonate levels with calculated arterial values in intensive care unit (ICU) patients to determine whether traditionally measured venous HCO3 (-) and calculated HCO3 (-) values [from arterial blood gas (ABG) analyzers] can be used interchangeably.