Clinical use of continuous monitoring of mixed venous oxygen saturation during and after cardiovascular surgery.

This paper presents the authors' initial experience with a new technique for continuous monitoring of the mixed venous oxygen saturation (SvO2) during and after open heart Surgery. The method uses reflectometric measurements of SvO2 via a fiberoptic pulmonary artery catheter with the capability for thermodilution cardiac output estimates. Changes in SvO2 reflect changes in one or more of the three interacting factors of the Fick equation: arterial oxygen content, cardiac output, and total body oxygen utilization. Intra-and postoperative examples illustrate these various situations. The very short response time of the System allows for early diagnostic and therapeutic decisions.