Calibration Refinement of Cuff Pressure Devices Using a Controlled, Physiologically Accurate In-vitro Systemic Circulatory Setup

Oscillometric blood pressure measurement (OBPM) devices are part of routine clinical practice. However, these devices are prone to measurement errors due to factors such as cuff characteristics, excessively fast inflation or deflation rates, and inaccurate device calibration. OBPM devices are often validated against other bench-top devices, and the standard lacks rigor. This increases the chance of absolute error accumulating with repeated validations against OBPM devices. Therefore, precise calibration of cuff pressure and its validation against invasively measured pressure waveforms across different cardiovascular conditions are essential. This can significantly improve hypertension management and the optimization of patient-specific therapies.

In this study, we designed an artificial arm with a brachial artery connected to a validated and physiologically accurate in-vitro left heart-aortic simulator, which includes major aortic branches such as the carotid, renal, femoral, and brachial vessels. The cuff pressure device was installed on the artificial arm, with a high-fidelity piezo-tip pressure catheter inside the brachial vessel for invasive validation. Comparisons were made based on both waveform morphology and calibration. We assessed the effects of various cardiovascular conditions, such as different heart rates, cardiac outputs, mean arterial pressures, and arterial stiffness levels, on the accuracy of the cuff OBPM device recordings and its calibration refinement.