importance of lung water measurements hardly needs
justification since congestive heart failure, pulmonary edema
and sleep apnea are associated with changes in lung water
content. Currently used methods, rely on surrogate and
sometimes invasive techniques to quantify the lung water
content leading to late diagnosis, extended hospital stays,
and increased readmission rates. Besides the importance of
making these continuous measurements in typical surgical
settings, the significant growth in the field of homecare and
Telemedicine opened yet another market segment in which this
integrated vital signs and lung water content measurements
would be highly desirable.
address these measurement needs, our group at University of
Hawaii is developing a novel low-cost, integrated radio
frequency based vital signs monitoring device, namely the
"Cardio-Pulmonary (CP) Stethoscope". CP-Stethoscope can
continuously and non-invasively monitor the changes in lung
water content together with other vital signs such as heart
rate, respiration rate, and EKG-like waveform. CP-Stethoscope
is attached to the chest like a typical EKG-lead (as seen in
The CP-Stethoscope consists of three main components,
including; an innovative broadband radio-frequency sensor, an
advanced digital signal processing (DSP) algorithm for vital
sign parameter extraction and the low-cost integrated receiver
equipped with Bluetooth link for wireless data transmission.
The CP-Stethoscope measurement has been studied and validated
through computer simulations, phantom experiments, and also
verified using human, animal, and isolated lung experiments.
See Figs. 2 and 3.