High efficiency external counterpulsation apparatus and method for controlling same
The present invention provides a method for applying external counterpulsation to a patient, including detecting a blood-flow impedance signal, self-adaptive filter processing the detected blood-flow impedance signal, and adjusting inflation of an inflatable member based on the self-adaptive filter processing in order to optimize counterpulsation timing. The present invention further includes an external counterpulsation apparatus providing a high-frequency current source applied to the patient to produce an electrocardiographic signal and a blood flow impedance signal, as well as an amplifier-filter circuit to operably condition the electrocardiographic signal and a heart impedance signal amplifier receiving the blood flow impedance signal. A computer processes the signals and controls a fluid distribution device to distribute compressed fluid to a plurality of inflatable members based on said processed signals.
1. An external counterpulsation apparatus for use with a patient, comprising:
a plurality of inflatable members adapted to be received about a limb of the patient;
a source of compressed fluid in fluid communication with said plurality of inflatable members;
a fluid distribution device connected to said inflatable members and operable to distribute compressed fluid from said source of compressed fluid to said inflatable members;
a high-frequency current source operably applied to the patient to produce an electrocardiographic signal and a blood flow impedance signal;
an amplifier-filter circuit operably conditioning said electrocardiographic signal received from the patient;
a heart impedance signal amplifier operably receiving said blood flow impedance signal from the patient; and
a computer operably processing said electrocardiographic signal and said blood flow impedance signal and operably associated with the fluid distribution device for controlling distribution of compressed fluid to said plurality of inflatable members based on said processed electrocardiographic signal and blood flow impedance signal.
2. The external counterpulsation apparatus of claim 1 , wherein said amplifier-filter circuit includes a low-pass differential amplifier and a band-pass filter for amplifying and filtering said electrocardiographic signal received from the patient.
3. The external counterpulsation apparatus of claim 1 , wherein said computer detects a QRS wave from said electrocardiographic signal.
4. The external counterpulsation apparatus of claim 1 , wherein said computer performs adaptive processing of said impedance blood flow signal.
5. The external counterpulsation apparatus of claim 4 , wherein said computer uses an impedance reference signal to adaptively process said impedance blood flow signal.
6. The external counterpulsation apparatus of claim 1 , wherein said computer determines electrocardiographic characteristic points from a group comprising: aortic valve closure, diastolic amplitude and systolic amplitude.
7. The external counterpulsation apparatus of claim 1 , further comprising a drive circuit electrically controlled by said computer to inflate and deflate said plurality of inflatable members.
8. The external counterpulsation apparatus of claim 1 , further comprising a pulse transducer electrically connected to said computer and operably detecting a pulse wave.
9. The external counterpulsation apparatus of claim 8 , further comprising a pressure transducer electrically connected to said computer for detecting a maximum arterial pressure.
10. The external counterpulsation apparatus of claim 9 , wherein said computer processes said pressure and pulse signals.
11. The external counterpulsation apparatus of claim 10 , wherein said computer controls counterpulsation based on said processed pressure and pulse signals.
12. The external counterpulsation apparatus of claim 10 , wherein said computer calculates oxygen saturation based on said processed pressure and pulse signals.