title: Continuous S-vO2 measurement and oxygen transport patterns in cardiac surgery patients.
abstract: Twenty adult cardiac surgery patients with impaired ventricular function by contrast ventriculography at cardiac catheterization were monitored from before anesthesia until the time of extubation up to 12 h postoperatively. A thermodilution pulmonary artery catheter with fiberoptic channels for continuous measurement of mixed-venous oxygen saturation (S-vO2) by reflection oximetry was substituted for the usual catheter. The S-vO2 was recorded continuously along with blood pressure, cardiac filling pressures, and heart rate. Thermodilution cardiac output determinations were used to derive hemodynamic and oxygen transport indices. There was a consistently high and significant negative correlation (r = -.84) between S-vO2 and the percentage of oxygen extracted from blood. Thus, S-vO2 reflects oxygen extraction and continuous S-vO2 provides continuous quantification of global oxygen extraction. None of the other oxygen transport variables including cardiac index showed significant correlation with S-vO2. The oximetry system provides a continuous and reliable indication of mixed-venous blood oxygenation which is a continuous reflection of oxygen extraction.
mesh_terms: D000368:Aged; D006328:Cardiac Catheterization; D002302:Cardiac Output; D006348:Cardiac Surgical Procedures; D006801:Humans; D007432:Intraoperative Period; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D011184:Postoperative Period
chemical_list: D010100:Oxygen