Estimation of Cardiac Index: Validation of the Mobil-O-Graph NG in Comparison with the FloTrac/Vigileo

ABSTRACT

OBJECTIVE: Although the reference value of cardiac index (CI) is derived by pulmonary arterial pressure, the use of pulmonary arterial catheterization is limited by low cost effectiveness and many concerns regarding complications. Therefore, relatively noninvasive indirect measurement is used widely perioperatively. The goal of this study was to determine the accuracy of the CI derived by Mobil-O-Graph NG (cCI) noninvasively in patients undergoing general anesthesia by comparing that measured by FloTrac/Vigileo (fCI), the minimal invasive method. METHODS: The Bland-Altman method was used to quantify agreement. Bias (mean difference between fCI-cCI) represents the systematic error between methods and precision (standard deviation of the bias) represents the random error or variability between techniques. The percentage error was considered clinically acceptable, and the tested method (Mobil-O-Graph NG) was regarded as interchangeable with the reference method (FloTrac/Vigileo), if it was below 30%. RESULTS: One hundred and ninety-five patients were included in this study, and CI, measured in the 121 patients. The Bland-Altman analysis revealed a bias −0.01 and the percentage error of 32.4%. And the difference is inversely increased according the mean CI. CONCLUSION: Results showed that CI measured by Mobil-O-Graph NG had a wide limit of agreement with that measured by FloTrac/Vigileo, therefore regarded as not interchangeable.