Venous Bicarbonate Correlates Linearly With Arterial Base Deficit Only If pH Is Constant

Martin et al¹ retrospectively studied more than 2000 nontrauma-related surgical ICU admissions and reported that serum bicarbonate (HCO₃) might provide information equivalent to the arterial base deficit (BD). This conclusion is a bit surprising, as is their determination that the normal BD of 0 is associated with an HCO₃ level of 22 mEq/L rather than the typical level of 24.