A Comparison of Three Pulmonary Artery Oximetry Catheters in Intensive Care Unit Patients (14)

Light of appropriate wavelength(s) is generated by light-emitting diodes and delivered to the PA by a fiberoptic bundle contained in the catheter. The light is backscattered off the hemoglobin in the red blood cells present in the circulation, and the reflected light is collected by a detecting fiberoptic bundle also contained in the PA catheter. Analysis of the reflected light and the application of appropriate algorithms permit the calculation of the relative proportions of oxyhemoglobin and deoxyhemoglobin.
Previous studies have evaluated the clinical performance of PA oximetry catheters in various settings, including animal models and human studies. Those studies, which did not employ periodic recalibration of the PA oximetry catheters, showed that the Oximetrix system produced closer agreement to bench oximetry than did the Edwards Critical Care device; however, these studies all evaluated the older SAT-1 version of the Edwards system. Only one of these studies undertook a three-way comparison of the available oximetry systems. This study also showed that the Oximetrix system produced closer agreement to bench oximetry than did the Edwards Critical Care device or the Spectramed device. It has been hypothesized that the previously reported differences in performance were attributable to inherent differences in two- vs three-wavelength catheter systems.