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

Abstract

A B S T R A C TNon-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 Modelflow2 is a reliable non-invasive method for the assessment of cardiac output in healthy elderly subjects. We compared Modelflow2 cardiac output (MFCO) with thermodilution cardiac output (TDCO) in 28 healthy subjects, aged 70p4 years (meanpS.D.). TDCO was measured during right-sided heart catheterization, while MFCO was calculated with Modelflow2 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 6.4p1.1 litres/min (meanpS.D.) and MFCO was 4.7p1.3 litres/min (P 0.001). There was no significant correlation between MFCO and TDCO (r l 0.28, P l 0.13). Mean difference (bias) was k1.7 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 k4.6 to j1.1 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 Modelflow2 method is inaccurate for assessment of cardiac output without invasive calibration.

Evaluation of two methods for continuous cardiac output assessment during exercise in chronic heart failure patients

“…In a study using a different pulse contour analysis method, it was shown that this method is not suitable for measuring absolute cardiac output values during exercise in healthy individuals (33). However, it was also demonstrated that initial calibration with another method improved the accuracy substantially (38).…”

Compression leggings modestly affect cardiovascular but not cerebrovascular responses to heat and orthostatic stress in young and older adults

“…Several studies have validated the ModelFlow method compared with the standard invasive techniques (thermodilution and pulse dye densitometry) and indicate that this method provides a reliable estimate of changes in cardiac output in healthy exercising humans (Matsukawa et al 2004), patients with septic shock (Jellema et al 1999) or during prolonged tilt testing (Harms et al 1999). However, the validity of absolute ModelFlow estimates are uncertain during initial changes in posture or with ageing (Remmen et al 2002). Therefore, the emphases of these data are on comparative changes because ModelFlow-derived estimates of SV and Á Q track group-averaged changes reliably (Leonetti et al 2004).…”

Noninvasive continuous arterial pressure measurements in the assessment of acute, severe central hypovolemia

“…Our study is in line with their observation. The method of pulse wave analysis for assessment of stroke volume, without invasive calibration may be imprecise (21), however, in emergency medicine the distinctive capacity of a parameter is important, rather than its precisity, compared to a "gold standard". The scarce availability of stroke volume analysis is a limitation yet.…”