Accuracy of Cardiac Output Measured by Fourth-Generation FloTrac and LiDCOrapid, and Their Characteristics Regarding Systemic Vascular Resistance in Patients Undergoing Cardiac Surgery.

OBJECTIVES

The clinical use of less-invasive devices that calculate the cardiac output from arterial pressure waveform is increasing. The authors aimed to evaluate the accuracy and characteristics of the systemic vascular resistance index (SVRI) of the cardiac index measured by 2 less-invasive devices, fourth-generation FloTrac (CI) and LiDCOrapid (CI), compared with the intermittent thermodilution technique, using a pulmonary artery catheter (CI).

DESIGN

This was a prospective observational study.

SETTING

This study was conducted at a single university hospital.

PARTICIPANTS

Twenty-nine adult patients undergoing elective cardiac surgery.

INTERVENTIONS

Elective cardiac surgery was used as an intervention.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic parameters, CI, CI, and CI, were measured after the induction of general anesthesia, at the start of cardiopulmonary bypass, after completion of weaning from cardiopulmonary bypass, 30 minutes after weaning, and at sternal closure (135 measurements in total). The CI and CI had moderate correlations with CI (r = 0.62 and 0.58, respectively). Compared with CI CI and CI had a bias of -0.73 and -0.61 L/min/m, limit of agreement of -2.14-to-0.68 L/min/m and -2.42-to-1.20 L/min/m, and percentage error of 39.9% and 51.2%, respectively. Subgroup analysis for evaluating SVRI characteristics showed that the percentage errors of CI and CI were 33.9% and 54.5% in low SVRI (<1,200 dyne×s/cm/m), 37.6% and 47.9% in moderate SVRI (1,200-1,800 dyne×s/cm/m), 49.3% and 50.6% in high SVRI (>1,800 dyne·s/cm/m), respectively.

CONCLUSIONS

The accuracy of CI or CI was not clinically acceptable for cardiac surgery. Fourth-generation FloTrac was unreliable in high SVRI. LiDCOrapid was inaccurate across a broad range of SVRI, and minimally affected by SVRI.