Assessment of Stroke Volume From Brachial Blood Pressure Using Arterial Characteristics

Goal: The goal of this study is to present a modified pulse contour method to estimate the stroke volume (SV) based on an oscillometric sphygmomanometer. Methods: The pulse contour was extracted from the pulse signal of the cuff pressure. The characteristics of the brachial artery, as well as the compliance (Cartery) and time constant τ of the Windkessel model, could be determined and used to estimate the SV once the apparatus finished the blood pressure measurement. Results: Assessments of the SV by echocardiography and our method were carried out in 55 subjects. The change in the brachial arterial volume obtained by our method was significantly correlated with that of the two-dimensional ultrasound method (r_v = 0.871). The estimated SV values by our method for male and female groups, SV_estimate, were also significantly correlated with the echocardiography results, SV_ref (r_male = 0.680, r_female = 0.706). The Bland-Altman plot showed agreement between SV_ref and SV_estimate, with all data points contained within the limits of agreement (± 2 SD). The mean difference and standard deviation (mean ± SD) were 0.101 ± 14.880 ml and 0.650 ± 11.990 ml for the male and female groups, respectively. Conclusion: The blood pressure, SV, and cardiac output were measured simultaneously, making our method well suited for home use. Significance: Our method was embedded in an oscillometric sphygmomanometer.