Measurement of mixed venous oxygen saturation (SvO2) may be helpful in the care of critically ill patients. Serial determinations of SvO2 give an index of the relationship between oxygen delivery and tissue oxygen consumption. Continuous monitoring of SvO2 is now readily available with the Shaw Oximetrix pulmonary artery catheter (Oximetrix Inc., Mountain View, CA). This system has provided useful information in the high risk cardiac surgery patient. Continuous monitoring of mixed venous saturation may be helpful in high risk or critically ill general and peripheral vascular surgery patients both in the intensive care unit and in the operating room. The following clinical report is presented to illustrate the usefulness of continuous SvO2 monitoring in a high risk vascular surgery patient.