Estimation of oxygen utilization by dual oximetry.

Total body oxygen utilization coefficient was estimated using continuous pulse and pulmonary artery oximetry (dual oximetry) in 17 patients with respiratory failure. Change in arterial and mixed venous oxygen saturations was induced by altering airway pressure. Continuous measurement of mixed venous oxygen saturation provided an accurate and linear estimate of oxygen utilization coefficient (r = -0.92), the true values being overestimated by 0.05 +/- 0.06 (mean +/- SD). Addition of pulse oximetry improved the correlation (r = 0.93) and decreased the difference between absolute values (0.02 +/- 0.06). Oxygen utilization coefficient can be estimated reliably in an online fashion using pulmonary artery oximetry. However, the use of dual oximetry will further improve the estimate.