RESUMEN
OBJECTIVES: The aims of this study were to compare cardiac output (CO) measured by the new fourth-generation FloTrac™/Vigileo™ system (Version 4.00) (COFVS) with that measured by a pulmonary artery catheter (COREF), and to investigate the ability of COFVS to track CO changes induced by increased peripheral resistance. DESIGN: Prospective study. SETTING: University Hospital. PARTICIPANTS: Twenty-three patients undergoing cardiac surgery. INTERVENTIONS: Phenylephrine (100 µg) was administered. MEASUREMENTS AND MAIN RESULTS: Hemodynamic variables, including CO(REF) and CO(FVS), were measured before and after phenylephrine administration. Bland-Altman analysis was used to assess the discrepancy between CO(REF) and CO(FVS). Four-quadrant plot and polar-plot analyses were utilized to evaluate the trending ability of CO(FVS) against CO(REF) after phenylephrine boluses. One hundred thirty-six hemodynamic interventions were performed. The bias shown by the Bland-Altman analysis was-0.66 L/min, and the percentage error was 55.4%. The bias was significantly correlated with the systemic vascular resistance index (SVRI) before phenylephrine administration (p<0.001, r(2) = 0.420). The concordance rate determined by four-quadrant plot analysis and the angular concordance rate calculated using polar-plot analysis were 87.0% and 83.0%, respectively. Additionally, this trending ability was not affected by SVRI state. CONCLUSIONS: The trending ability of the new fourth-generation FloTrac™/Vigileo™ system after increased vasomotor tone was greatly improved compared with previous versions; however, the discrepancy of the new system in CO measurement was not clinically acceptable, as in previous versions. For clinical application in critically ill patients, this vasomotor tone-dependent disagreement must be decreased.