A Comparison of Three Pulmonary Artery Oximetry Catheters in Intensive Care Unit Patients (1)

A Comparison of Three Pulmonary Artery Oximetry Catheters in Intensive Care Unit Patients (1)Considerable controversy exists as to the clinical utility of pulmonary artery (PA) mixed venous oxygen saturation (SvOJ catheters as a continuous monitor for patient treatment. Significant impediments to the clinical use of Sv02 oximetry systems include both the reported inaccuracy of some systems and the absence of clinical data defining acceptable levels of agreement when compared with a criterion standard.
The published “accuracy specifications” contained in the product information for all three instruments supplied by their respective manufacturers are ±2 percent saturation (±2 SDs) when compared with a bench oximeter such as a CO-oximeter. These figures are presumably based on manufacturers’ studies using flow bench preparations, animal data, and clinical trials. Studies to date, however, have failed to confirm these levels of performance clinically. Nevertheless, Sv02 oximetry is a widely used clinical measurement that has been advocated as a means of providing information about the adequacy of oxygen supply relative to demand and of assessing the adequacy of cardiorespiratory function in certain disease states.
Few studies, however, have systematically compared the performance of the three mixed venous oximetry catheters available, and the analyses of catheter performance have frequently been flawed by incomplete or inappropriate statistical analysis. Further, recent changes by the manufacturers in catheter design, computer algorithms, and optical modules have led to potentially improved clinical accuracy and performance of these devices. This study was designed to ascertain the accuracy of the three available oximetry PA catheters compared with conventional bench oximetry (CO-oximetry). The study population consisted of patients in the intensive care unit (ICU) who required hemodynamic monitoring for medical management.