A novel method for the noninvasive estimation of cardiac output with brachial oscillometric blood pressure measurements through an assessment of arterial compliance

Abstract

Objective To propose and validate a new method for estimating cardiac output based on the total arterial compliance (Ct) formula that does not need an arterial waveform and to apply it to brachial oscillometric blood pressure measurements (OBPMs). Methods One hundred subjects with normal heart anatomy and function were included. Reference values for cardiac output were measured with echocardiography, and Ct was calculated with a two-element Windkessel model. Then, a statistical model of arterial compliance (Ce) was used to estimate cardiac output. Finally, the measured and estimated cardiac output values were compared for accuracy and reproducibility. Results The model was derived from the data of 70 subjects and prospectively tested with the data from the remaining 30 individuals. The mean age of the whole group was 43.4 ± 12.8 years, with 46% women. The average blood pressure (BP) was 107.1/65.0 ± 15.0/9.6 mmHg and the average heart rate was 67.7 ± 11.4 beats/min. The average Ct was 1.39 ± 0.27 mL/mmHg and the average cardiac output was 5.5 ± 1.0 L/min. The mean difference in the cardiac output estimated by the proposed methodology vs. that measured by Doppler echocardiography was 0.022 L/min with an SD of 0.626 L/min. The intraclass correlation coefficient was 0.93, and the percentage error was 19%. Conclusion Cardiac output could be reliably and noninvasively obtained with brachial OBPMs through a novel method for estimating Ct without the need for an arterial waveform. The new method could identify hemodynamic factors that explain BP values in an ambulatory care setting.

Hemodynamic profiles of arterial hypertension with ambulatory blood pressure monitoring

“…In a previous study, we developed and validated a mean systolic pressure (MSP) method for estimating C t and CO without a BP waveform analysis through a two-element Windkessel (2-WK) model) [ 14 ]. MSP is a measurement of the volume transfer to the aorta in each heartbeat in terms of pressure, which is estimated as (MAP+SBP)/2.…”

“…MSP is a measurement of the volume transfer to the aorta in each heartbeat in terms of pressure, which is estimated as (MAP+SBP)/2. This formula is obtained with a trapezoid built under the systolic area of an arterial pressure curve and employing SBP, MAP and systolic time (T s ) [ 14 ].…”

“…The possibility of deriving hemodynamic features with the same BP values obtained during a 24 h ABPM study would refine this method by adding complementary pathophysiological information about the function of the arterial system in hypertensive patients [ 14 ]. We aimed to describe the hemodynamic profiles of different HT subtypes derived from this new C t estimation method obtained from the average ambulatory BP and heart rate (HR) values in a large group of individuals undergoing 24 h ABPM.…”

Differences in blood pressure control based on hypertension subtype in patients with a de novo diagnosis: a retrospective cohort study

“…Using the BP and heart rate in the o ce and anthropometric variables, the following hemodynamic variables were estimated: i) cardiac output; ii) total SVR; and iii) arterial compliance, as previously described [28,31].…”