Reproducibility of cardiac output measurement by the nitrous oxide rebreathing technique

Abstract

Techniques for the measurement of cardiac output from soluble gas uptake by the lungs include the rebreathing method using nitrous oxide. The accuracy of this technique is well accepted, but its repeatability of measurement (precision) has not been well documented. We assessed the repeatability of measurements of pulmonary blood flow by the Innocor, a device employing the nitrous oxide rebreathing method. Successive paired measurements of pulmonary blood flow were made separated by a 5 min interval by the nitrous oxide rebreathing method, in 8 patients pre- or post cardiac surgery, and in 8 healthy volunteers. The standard deviation of the difference between first and second measurements was..