The foundation of Cheetah Medical’s BIOREACTANCE-based NICOM approach is the discovery that when blood flows out of the heart, Phase Shifts are created in alternating radiofrequency electrical currents applied across the patients’ chest wall. Such phase shifts are conceptually similar to a Frequency Modulation, or FM, as used in FM radio transmissions. The phase shifts are measured continuously and have been shown to relate almost linearly to blood flow in the aorta.

BIOREACTANCE is often compared with bioimpedance, an older technology used to determine cardiac output. BIOREACTANCE builds on bioimpedance, and both technologies use electrodes placed on the patient’s chest to deliver an electrical current of known amplitude and frequency across the thorax. But the major difference between BIOREACTANCE and bioimpedance is analogous to that between FM and AM radio: With FM radio, detection of the radio signal is based on changes in signal frequency rather than changes in signal amplitude, allowing for greater fidelity in the obtained signal. FM enables significant advantages in filtering noise, for example noise coming from other electronic or physiologic emitters. This is why FM-based systems offer superior performance compared to AM.

Another key advantage of BIOREACTANCE stems from the fact that detection of frequency modulations are insensitive to distance between the sensing electrodes, which is in sharp contrast to the situation with the detection of amplitude changes. Therefore, BIOREACTANCE has the important advantage of flexibility in sensor location. Thus, with BIOREACTANCE, electrodes can be placed anywhere on the thorax or even on the patient’s back.