Continuous Cardiac Output Monitoring by Peripheral Blood Pressure Waveform Analysis

Abstract

Abstract-A clinical method for monitoring cardiac output (CO) should be continuous, minimally invasive, and accurate. However, none of the conventional CO measurement methods possess all of these characteristics. On the other hand, peripheral arterial blood pressure (ABP) may be measured reliably and continuously with little or no invasiveness. We have developed a novel technique for continuously monitoring changes in CO by mathematical analysis of a peripheral ABP waveform. In contrast to the previous techniques, our technique analyzes the ABP waveform over time scales greater than a cardiac cycle in which the confounding effects of complex wave reflections are attenuated. The technique specifically analyzes 6-min intervals of ABP to estimate the pure exponential pressure decay that would eventually result if pulsatile activity abruptly ceased (i.e., after the high frequency wave reflections vanish). The technique then determines the time constant of this exponential decay, which equals the product of the total peripheral resistance and the nearly constant arterial compliance, and computes proportional CO via Ohm's law. To validate the technique, we performed six acute swine experiments in which peripheral ABP waveforms and aortic flow probe CO were simultaneously measured over a wide physiologic range. We report an overall CO error of 14.6%.

Model-based data integration in clinical environments

“…The earlier work in [17] exploited beat-to-beat variability in a different way to estimate these same quantities.…”

Continuous Left Ventricular Ejection Fraction Monitoring by Aortic Pressure Waveform Analysis

“…Thus, C a may have been sufficiently constant in our study even though MAP was varied over a wide range, which is consistent with previous studies including those by Bourgeois et al 6,7 (see the Previous Related Techniques subsection below) and us. 21,25,38 Assumption 3: Three-Parameter Raised Cosine Function Representation of Left Ventricular Elastance During the Systolic Ejection Interval…”

“…Indeed, this need may be regarded as urgent due to the rapidly growing population with chronic heart disease 2 together with the projected shortage of clinical staff. 40 Based on our previous work in the field of hemodynamic monitoring, 21,25,37,38,42 our hypothesis is that EF may be accurately estimated by deciphering the information embedded in the temporal variations of blood pressure waveforms. In this way, EF may be continuously monitored in various inpatient settings with routinely employed invasive catheter systems 22 as well as automatically measured in outpatient clinics and at home with commercial noninvasive transducers (see, e.g., the Finometer and Portapres, Finapres Medical Systems, The Netherlands and the T-Line Blood Pressure Monitoring System, Tensys Medical, San Diego, CA).…”

Multimodal signal processing for the analysis of cardiovascular variability

“…Thus, over the last few years, innovative studies have aimed at reconstructing cardiac output changes from peripheral measurements of AP. Most of them are based on lumped Windkessel modelling or on TF estimate (Lu & Mukkamala 2006;Mukkamala et al 2006b;Swamy et al 2007). These techniques are now sufficiently robust to be exploited in a multimodal approach including cardiac output into the set of signals for CV monitoring.…”