Clinical Evaluation of Continuous Venous Oxygen Saturation Monitoring During Anesthesia

Abstract

A new pulmonary artery flow-directed balloon catheter combined a fiberoptic reflectometry system (Oximetrix, Opticath) provides a continuous digital display of mixed venous oxygen saturation (Sv̄O₂) together with the usual intermittent blood sampling, and pressure and flow measurement capabilities of the thermodilution pulmonary catheter. Some reports-^1–3 have described a good correlation between on-line Sv̄O₂ and hemodynamic changes, although one concluded that there was no significant correlation between Sv̄O₂ and cardiac index⁴. This study therefore was designed to evaluate this fiberoptic reflectometry system in patients during anesthesia by comparing in vivo Sv̄O₂ measurements with those obtained in vitro Sv̄O₂ using a Radiometer ABL-300. We hoped to be able to correlate on-line Sv̄O₂ measurements with intermittently measured and derived oxygen transport variables.