CDI Blood Parameter Monitoring System 500--a new tool for the clinical perfusionist

Sarns/3M Health Care has recently introduced the CDI 500 Blood Parameter Monitoring System. In addition to parameters previously available, this system now offers continuous monitoring of the patient's oxygen consumption (VO2/min) and potassium concentration ([K+]). The purpose of this study was: (1) to compare the [K+] from the CDI 500 with the [K+] derived from our hospital's laboratory; and (2) to compare the VO2/min from the CDI 500 with the results obtained utilizing the "gold-standard" Fick equation. The mean absolute difference in [K+] was 0.10 mEq/L with a mean percentage error of only 3.93%. The mean absolute difference in VO2/min was 18.78 ml O2/min, with a mean percentage error of 11.63%. We concluded that the [K+] correlated well and that 9.13% of the oxygen consumption percentage error was attributable to the exclusion of dissolved oxygen in the calculation used by the CDI 500, with the remaining 2.5% attributable to differences in technology. We recommended that future upgrades to the CDI 500 should include dissolved O2 when measuring oxygen consumption and consideration should be given to increasing the operating range for [K+].