Accuracy of stroke volume estimation via reservoir pressure concept and three element windkessel model

Accurate stroke volume (SV) measurements can convey large amounts of information about patient hemodynamic status. However, direct measurements are too invasive in clinical practice and current procedures for estimating SV require specialised devices. This study presents an analysis of the accuracy of SV estimation by combining pulse-wave and windkessel analyses. What makes this study different to existing pulse-contour analyses is that pressure contour variation due to altered arterial mechanical properties (resistance, characteristic impedance and compliance) were related to correct corresponding pressure zones, enabling this model to more accurately capture SV from aortic pressure measurements alone. Using data from three porcine experiments, the median difference between measured and estimated SV was 1.4 ml with a 90% range (5^th-95^th percentile) -11.3ml - 12.2ml. This result relies on an estimate of the average value of just one windkessel parameter. The presented method demonstrates that SV can be estimated from pressure waveforms alone, without the need for identification of complex physiological metrics where strength of correlations may vary from patient to patient.