A Pneumatic Low-Pass Filter for High-Fidelity Cuff-Based Pulse Waveform Acquisition
Abstract
Cuff-based pulse waveform acquisition (CBPWA) devices are reliable solutions for non-invasive cardiovascular diagnostics. However, poor signal resolution has limited clinical applications. This study aims to demonstrate the improved signal quality of CBPWA devices by implementing passive pneumatic low-pass filters (pLPF). Conventionally, pressure sensor output resolution is a percentage of the operating range. Therefore, measurement of small pressure changes in a large range must sacrifice signal resolution to accommodate for the large mean pressures. We design a pLPF to obtain the running mean pressure and combine it with a high-resolution differential pressure sensor for isolating the signal’s pulsatile component. Thirty-one volunteers participated in a device proof-of-concept study at Caltech. Volunteers were measured at rest in the supine position on the left arm. The filtering behavior is mathematically modeled and experimentally verified, showing good agreement between measured and predicted cutoff frequencies. In the human study, the device successfully captured high-fidelity pulse waveform measurements for all volunteers: a blood pressure (BP) reading was followed by inflate-and-hold acquisition in diastolic BP (DBP), mean arterial pressure (MAP), and supra systolic BP (sSBP). The study demonstrated the reliability and high signal resolution of pLPF for CBPWA. Considering the widespread use of the brachial cuff, a system for high-resolution CBPWA motivates the clinical implementation of non-invasive pulse waveform analysis (PWA).
Copyright and License
© The Author(s) under exclusive licence to Biomedical Engineering Society 2023.
Acknowledgement
The authors of this paper would like to acknowledge David Jeon for the technical support, Prof. John E. Sader for the scientific discussions, and Dr. Francisco Padilla for the data collection during the IRB study.
Funding
This work was supported in part by the Cherng Fellowship from the Andrew and Peggy Cherng Department of Medical Engineering at Caltech and in part by the Gakenheimer Fellowship.
Conflict of Interest
A. Tamborini and M. Gharib have a pending patent with the USPTO and PCT for the system described. Caltech is in negotiation for potentially licensing the patent to a biomedical company.
Additional details
- ISSN
- 1573-9686
- Gakenheimer Fellowship
- Andrew and Peggy Cherng Department of Medical Engineering Fellowship
- Caltech groups
- GALCIT