Finapres arterial pulse wave analysis with Modelflow® is not a reliable non-invasive method for assessment of cardiac output

Abstract

Non-invasive continuous monitoring of cardiac output could be very useful in clinical care and in research settings, particularly in elderly subjects. We studied whether Finapres arterial pulse wave analysis with Modelflow is a reliable non-invasive method for the assessment of cardiac output in healthy elderly subjects. We compared Modelflow cardiac output (MFCO) with thermodilution cardiac output (TDCO) in 28 healthy subjects, aged 70+/-4 years (mean+/-S.D.). TDCO was measured during right-sided heart catheterization, while MFCO was calculated with Modelflow(R) software from non-invasive arterial Finapres blood pressure, which was measured simultaneously. The two methods were compared using a paired t-test, by Pearson correlation, and by Bland-Altman analysis. TDCO was 6.4+/-1.1 litres/min (mean+/-S.D.) and MFCO was 4.7+/-1.3 litres/min (P<0.001). There was no significant correlation between MFCO and TDCO (r=0.28, P=0.13). Mean difference (bias) was -1.7 litres/min (S.E.M. 0.27 litres/min), with an S.D. (precision) of 1.5 litres/min. The 95% limits of agreement were -4.6 to +1.1 litres/min. In conclusion, non-invasive MFCO values differed significantly from and showed no significant correlation with invasively determined TDCO values in the normal range. Although simple, non-invasive and patient-friendly, the Modelflow method is inaccurate for assessment of cardiac output without invasive calibration.

Stroke volume monitored by modeling flow from finger arterial pressure waves mirrors blood volume withdrawn by phlebotomy

“…However, in a study performed in the elderly, the validity of Modelflow has been questioned [24]. It has been shown that a calibration factor using one concomitant thermodilution cardiac output measure should be used to obtain accurate estimates of cardiac output with the Modelflow [24]. One consideration which may affect stroke volume estimation by the Modelflow is the effect of HR on the aortic impedance, which reflects cardiac afterload faced by the left ventricle.…”

“…Under our conditions the within-subject changes in stroke volume closely mirrored the blood withdrawal. However, in a study performed in the elderly, the validity of Modelflow has been questioned [24]. It has been shown that a calibration factor using one concomitant thermodilution cardiac output measure should be used to obtain accurate estimates of cardiac output with the Modelflow [24].…”

Validation of a Semi-Classical Signal Analysis Method for Stroke Volume Variation Assessment: A Comparison with the PiCCO Technique

“…Approaches that consider the nonlinear aspects of the arterial system have also been proposed, as Modelflow, 29 but the latter is not very efficient in a number of cases. 22 Other methods, resulting from distributed arterial models, have been developed. They use the pressure area so that SV is supposed to be proportional to the area under the systolic part of the pressure curve (see Fig.…”

“…Figure 8 represents the crosscorrelation coefficients for the 20 subjects (dashed lines). As homogeneity was verified, averaged values were also plotted (22). The vertical axis depicts the correlation coefficients.…”

Orthostatic tolerance in older patients with vitamin B12 deficiency before and after vitamin B12 replacement

“…However, this also appears to be unlikely given the objective nature of the haemodynamic evidence obtained. The validity of the Modelflow software function of the Portapres, which allowed non-invasive measurement of SVR in this study, has recently been called into question [14]. Remmen et al reported that measurement of cardiac output (and, therefore, SVR) with Modelflow failed to correlate with thermodilution measurements in healthy older volunteers who had undergone right heart catheterization.…”