In vitro evaluation of continuous mixed venous oxygen saturation and hematocrit monitors.

Four venous hemoglobin oxygen saturation monitors, two of which provide hemoglobin monitoring, were evaluated and compared to a performance standard (control) during cardiopulmonary bypass (CPB). The CDI 100 Hematocrit/Saturation Monitor, CDI 400, Cobe Hematocrit/Saturation Monitor, and the Baxter Bentley OxySat values were compared to the Radiometer Copenhagen OSM3 Hemoximeter and the Damon International Equipment Company Microbore Centrifuge Hematocrit. The Bentley OxySat meter was found to be the most accurate venous oxygen saturation monitor, with the CDI 100 and the Cobe Hct/Sat monitors correlating closely with the control. Only the CDI 400 failed to correlate with the control. The hematocrit monitors, although useful as trending devices, demonstrated inaccuracies in measurements requiring further refinement.