Comparison of noninvasive continuous arterial waveform analysis (Nexfin) with transthoracic Doppler echocardiography for monitoring of cardiac output

Study Objectives: To compare the Nexfin cardiac output (CO) with the CO obtained from transthoracic Doppler echocardiography (TTE) during routine cardiac function screening. Design: Observational clinical study. Setting: Echocardiography laboratory. Patients: 40 ASA physical status 1 and 2 patients scheduled for routine TTE examination. Interventions: None. Measurements and Main Results: In 40 patients scheduled for routine TTE examination, we obtained simultaneous CO measurements with Doppler ultrasound and derived from Nexfin blood pressure measurements. Correlation and level of agreement between Nexfin and TTE were analyzed using Pearson correlation coefficient and Bland-Altman plots. The Pearson correlation coefficient for Nexfin versus TTE was 0.68 (CI: 0.46 - 0.82, P < 0.0001). Bland-Altman analysis showed a bias of 0.51 +/- 1.1 L/min and limits of agreement of -1.6 to 2.6 L/min, with a percentage error of 39%. Conclusions: Considering limits of precision of CO measurements with Doppler echocardiography (+/- 30%), the agreement between noninvasive CO measurement with the Nexfin and TTE is reasonable. (C) 2012 Elsevier Inc. All rights reserved.