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. 2018 May;65(5):1176-1180.
doi: 10.1109/TBME.2017.2739695. Epub 2017 Aug 14.

Cardio-Pulmonary Stethoscope: Clinical Validation With Heart Failure and Hemodialysis Patients

Magdy F Iskander, Todd B Seto, Ruthsenne Rg Perron, Eunjung Lim, Farhan Qazi

Cardio-Pulmonary Stethoscope: Clinical Validation With Heart Failure and Hemodialysis Patients

Magdy F Iskander et al. IEEE Trans Biomed Eng. 2018 May.

Abstract

Objective: The purpose of this study is to evaluate the accuracy of a noninvasive radiofrequency-based device, the Cardio-Pulmonary Stethoscope (CPS), to monitor heart and respiration rates, and detect changes in lung water content in human experiments and clinical trials.

Methods: Three human populations (healthy subjects ( ), heart failure (), and hemodialysis () patients) were enrolled in this study. The study was conducted at the University of Hawaii and the Queen's Medical Center in Honolulu, HI, USA. Measurement of heart and respiration rates for all patients was compared with standard FDA - approved monitoring methods. For lung water measurements, CPS data were compared with simultaneous pulmonary capillary wedge pressure (PCWP) measurements for heart failure patients, and with change in weight of extracted fluid for hemodialysis patients.

Results: Statistical correlation methods (Pearson, mixed, and intraclass) were used to compare the data and examine accuracy of CPS results. Results show that heart and respiration rates of all patients have excellent correlation factors, r≥0.9. Comparisons with fluid removed during hemodialysis treatment showed correlation factor of to 1, while PCWP measurements of heart failure patients had correlation factor of to 0.97.

Conclusion: These results suggest that CPS technology accurately quantifies heart and respiration rates and measure fluid changes in the lungs.

Significance: The CPS has the potential to accurately monitor lung fluid status noninvasively and continuously in a clinical and outpatient setting. Early and efficient management of lung fluid status is key in managing chronic conditions such heart failure, pulmonary hypertension, and acute respiration distress syndrome.

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Figures

Fig. 1
Fig. 1
Schematic of the Cardio-Pulmonary Stethoscope system which includes RF sensors, MPU, and mobile app for real-time and remote monitoring. Also shown is a typical waveform signal from a single CP-Stethoscope measurement. Low frequency cycles correspond to respiration rate while high frequency cycles correspond to heartbeat and the change in the signal baseline indicates change in lung water content.
Fig. 2
Fig. 2
Setup of the stress test study. (a) Photo of a study participant running on a treadmill with the CPS system, ECG leads, and respiration belt.
Fig. 3
Fig. 3
Sample results of heart and respiration rate from one of the healthy participants during the stress teston the treadmill.
Fig. 4
Fig. 4
Bland – Altman analysis of heart and respiration rates from ECG and CPS.
Fig. 5
Fig. 5
Bland – Altman analysis to illustrate the differences between the measured heart rate and respiration rate from the CPS and the ECG from the HF and HD patients.
Fig. 6
Fig. 6
Regression analysis of the heart and respiration rates of HF and HD patients.
Fig. 7
Fig. 7
Sample clinical results of wedge-pressure measurements compared with changes in the CPS signal trend of a heart-failure patient. Measurements were taken in three 1-hr periods over three days.
Fig. 8
Fig. 8
Results from a hemodialysis patient comparing fluid removed and trend of the CPS signal.
See this image and copyright information in PMC

References

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