Technical evaluation of a simulator for accurate reproduction of oscillometric blood pressure pulses, providing traceability for automated oscillometric sphygmomanometers

Abstract

Oscillometric blood pressure measurement devices are not directly traceable to primary standards. Currently, device accuracy is measured by comparison between a sample device and reference measurements in a clinical trial. We researched in this study the potential for an alternative evaluation with a simulator. Our research simulator was studied for repeatability and accuracy in delivering simulated blood pressure pulses. Clinical cuff pressure measurements were obtained, along with simultaneous recordings of oscillometric pulse waveforms, spanning the clinical range of cuff pressures, pulse intervals and pulse shapes. Oscillometric pulse peak amplitudes ranged from 1.1 to 3.6 mmHg. Simulated repeatability results showed an average Standard Deviation (SD) for pulse peaks of 0.018 mmHg; 1.0% of peak amplitudes. Comparing simulated pulse shapes, the average repeat SD was 0.015 mmHg; 0.8% of the normalised pulse shapes. The simulated accuracy results had a mean error of − 0.014 ± 0.042 mmHg with a mean accuracy of 97.8%. For pulse shape the corresponding values were − 0.104 ± 0.071 mmHg with a mean accuracy of 95.4%. The correlation between the reference and simulated pulse shapes ranged from 0.991 to 0.996 (all p < 0.00003), with a mean 0.994. We conclude that oscillometric pulses can be reproduced with high repeatability and high accuracy with our research simulator. The extended uncertainty U(p sim ) = 0.3 mmHg for the simulated pulses is dominated by the uncertainty (64%) of the clinical reference data. These results underpin the potential of the simulator to become a secondary standard for millions of oscillometric sphygmomanometers.