Accuracy of Estimating Resting Oxygen Uptake and Implications for Hemodynamic Assessment

The Fick principle (cardiac output [Qc ] = oxygen uptake [V o2 ]/arteriovenous oxygen difference) can be used to calculate Qc , with VO2 frequently estimated by derived equations. To compare the accuracy of measured versus estimated VO2 , data were analyzed from 2 studies in which VO2 at rest was measured using the Douglas bag technique. One study comprised adults with diabetes, and the other was an exercise study of healthy adults. VO2 at rest was estimated as VO2 (ml/min) = 125 ml/min/m2 × body surface area (m2 ), with sensitivity analyses evaluating 2 other commonly used equations. Mean absolute difference (milliliters per minute) and ordinary least products regression were used to assess agreement between measured and estimated VO2 . Overall, mean measured versus estimated VO2 differed significantly (307.2 ± 75.2 vs 259.9 ± 36.7 ml/min, p