Comparison between CDI-100 continuous SO2, Hb, and Hct monitoring, intermittent ABL-4 saturation and Hb monitoring, and lab Hb and Hct monitoring

: During extracorporeal circulation (ECC) a continuous monitoring of venous oxygen saturation yields a quantitative impression of the equilibrium of oxygen supply and oxygen consumption in steady state conditions. The aim of the investigation was to study whether the measurements of venous oxygen saturation and haemoglobin of a continuous on-line monitor (CDI-100) agree with those of the ABL-4 bloodgasmonitor or the haemoglobincyanid method in hospital laboratory. The study group consisted of 21 patients, with comparable conditions of anesthesia and ECC set-up. Measurements of saturation and haemoglobin were compared at three moments, resulting in a total of 189 measurements. Analysis was based on the Bland Altman method, using the differences between correspondent measurements, which contain all the information needed to decide whether the methods agree. Bias of saturation measurement (CDI-100 versus ABL-4) is -3.4, 3.0 and -3.5% at times 1,2 and 3. All values are situated within the limits of agreement. Bias of haemoglobin measurement (CDI-100 versus ABL-4) is 0.3, 0.3, and 0.2 gr/dl at times 1, 2 and 3. All values (except one value) are situated within the limits of agreement. Bias of hemoglobin measurement (CDI-100 versus hospital laboratory) is 0.2, 0.0 and 0.1 gr/dl, and all values are situated within the limits of agreement. The results confirm that the CDI-100, in the set-up as described, can be used as a reliable instrument to monitor venous oxygen saturation and haemoglobin during ECC.