Measuring the oscillometric method contribution to the measurement uncertainty of automated sphygmomanometers using a patient simulator

摘要

The sphygmomanometer is a widely used device for non-invasive blood pressure measurement. Systematic measurement errors and uncertainties can affect measurements, consequently, impacting diagnosis or medication. In order to maintain the conformity of the instruments, sphygmomanometers are usually under control of legal metrology demanding periodical verifications. Automated sphygmomanometers are based on the oscillometric method, measuring small changes of arterial blood pressure occurring in the cuff. Once pressure working standards are unable to generate the oscillometric pulses, verifications are performed on the sphygmomanometer on its manometer mode, disregarding the contribution of the oscillometric mode to the uncertainties. The present study investigates the contribution of the oscillometric method to the expanded measurement uncertainty. We used a patient simulator in four sphygmomanometers available in the market for consumers. The results show that the contribution of the oscillometric mode to the expanded uncertainty can be significant, varying from 0.16 to 1.56 mmHg and from 0.12 to 1.55 mmHg, for 100 and 150 mmHg, respectively. We also observed different contributions to the uncertainty for systolic and diastolic blood pressure.