CO-oximetry interference by perflubron emulsion: comparison of hemolyzing and nonhemolyzing instruments

Perflubron emulsion is expected to be in clinical use soon as a non-hemoglobin blood substitute. A preliminary report indicates that this new oxygen-carrying fluorocarbon interferes with the measurements of CO-oximeters. Therefore, we have quantified the interference that perflubron causes in the measurements of eight widely used oximeters and CO-oximeters. The AVL Omni 6, CC270, IL482, IL682, and OSM3 are conventional CO-oximeters that hemolyze blood samples before analyzing them. In contrast, the AVOXimeters 1000 and 4000 and the IL Synthesis 35 make their measurements without hemolyzing the samples. Because perflubron is expected to be used most frequently on surgical patients in a hemodiluted state, we conducted all tests on human erythrocytes suspended in plasma at a hemoglobin concentration standardized to 70 g/L (7 g/dL) and with oxyhemoglobin saturation set at 97%. When perflubron was added to the blood samples, the nonhemolyzing CO-oximeters were not seriously affected by perflubron concentrations in and above the therapeutic range. In contrast, some of the hemolyzing CO-oximeters experienced concentration-dependent interference in their measurements of all analytes except total hemoglobin concentration. Thus, we conclude that the nonhemolyzing CO-oximeters provide an effective means for determining whether a hemolyzing CO-oximeter is experiencing clinically important interference in blood from patients receiving perflubron.