A low cost, high sensitivity, non-invasive bedside monitoring system for vital signs and measuring changes in lung water content.


Chronic heart failure, pulmonary hypertension, ARDS, and Kidney failure are leading causes of deaths in the United States. The cornerstone for managing these diseases is assessing patients’ volume fluid status in lungs. Currently, there are 5 million Americans suffering from heart failure and there are 500,000 new patients every year. Unfortunately, current measurement methods use inaccurate surgical implants, invasive catheterization, expensive scans, and unreliable daily weighing of patients. Furthermore, in the $1.5 billion small portable medical devices market, there is no non-invasive and accurate method for monitoring changes in lung water content on a continuous basis.

The Cardio-Pulmonary (CP) Wireless Stethoscope technology, a Lung Water Content Measurement System and Calibration Method, is an improvement of a previous invention, the Microwave Stethoscope for Measuring Cardio-Pulmonary Vital Signs and Lung Water Content. Together, these two inventions overcome many of the challenges that are plaguing existing modalities.

The CP Wireless Stethoscope combines a lung water detection and vital sign monitor with Radio Frequency (RF) technology. Using a “Chest Patch” with two sensors and a RF receiver, the non-invasive, wearable sensor system uses low level RF signals (lower than those used in cell phones) to monitor vital signs and provide real time assessment of changes in lung water content. Data may be remotely monitored using an electronic tablet or sent to designated observers using cloud application via Bluetooth connection ().

Researchers at the University of Hawaii’s Hawai’i Advanced Wireless Technologies Institute have developed a revolutionary, low cost, high sensitivity, non-­invasive bedside monitoring system for vital signs and measuring changes in lung water content. Data is monitored on mobile devices and/or transmitted to a cloud database for remote monitoring ().

The researchers collaborated with Queen’s Medical Center, and conducted a highly successful, NIH funded, clinical trial on heart failure and dialysis patients. Results from these trials are published in the IEEE Transactions on Biomedical Engineering.

Further Details
Microwave Stethoscope: Development and Benchmarking of a Vital Signs Sensor Using Computer-Controlled Phantoms and Human Studies, IEEE Transactions on Biomedical Engineering, Vol. 61, No. 8, August 2014.

Key Benefits

Low Cost

High Sensitivity


Real time assessment

Mobile device accessible

Accessible via Cloud

Remote monitoring


The CP Stethoscope can be used for noninvasively measuring water in the lungs, which is critical for detecting early heart failure and monitoring burns, dehydration, sepsis, pulmonary edema, and other pulmonary diseases.

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