Do PaCO2 and peripheral venous PCO2 become comparable when the peripheral venous oxygen saturation is above a certain critical value?

The difference in sample site chosen for blood gas analysis between European and Australian centres has been notable for members of our author group, prompting discussion and review of the literature. In the absence of significant anaerobic metabolism, the amount of CO2 formed in any tissue is proportional to tissue oxygen delivery via the respiratory quotient. Peripheral venous and arterial blood gas analysis in adults: are they comparable? A systematic review and metaanalysis.