A Novel Triple-Bladder Cuff Method for Blood Pressure Estimation Based on Pulse Wave Dynamics in Brachial Artery: Theoretical and Experimental Analyses

Objective: The objective of this study was to develop a novel triple-bladder cuff method for accurate and automated estimation of systolic (SBP) and diastolic (DBP) blood pressure and validate its reliability in animal experiments. Methods: The cuff is composed of three bladders each measured one-third the width of a conventional BP cuff, which are designed to measure oscillatory pulsation at the proximal, middle, and distal segments of the upper arm. This structure allows evaluation of the pulse wave propagation in the brachial artery under the cuff. SBP is estimated (SBPe) by detecting resumption of systolic arterial flow based on statistical similarity in oscillatory pulse traces between the proximal and distal segments. DBP is estimated (DBPe) based on the relation between pulse wave velocity and transmural pressure at diastole in the brachial artery. In 7 anesthetized goats, we compared SBPe and DBPe to reference SBP and DBP, respectively, measured by an intra-arterial catheter. BP was perturbed by infusing nitroprusside or noradrenaline. Results: SBP correlated strongly with SBPe in each animal [mean coefficient of determination (R-2) = 0.98 +/- 0.01]. Mean +/- standard deviation of errors between SBP and SBPe was 0.0 +/- 4.9 mmHg. DBP correlated strongly with DBPe in each animal (R-2 = 0.96 +/- 0.03). Mean +/- standard deviation of errors between DBP and DBPe was 0.0 +/- 6.3 mmHg. Conclusion: This method estimates SBP and DBP with acceptable accuracy. Significance: Accurate and automated BP estimation by this method may potentially optimize antihypertensive treatment in patients with hypertension.