Claims
- 1. A method for supplying blood to a patient's circulatory system comprising:
- a. implanting in the patient a variable volume blood pump having a variable volume blood chamber and at least one outer surface which moves as the volume of the blood chamber varies; and
- b. positioning at least a portion of the moving outer surface adjacent a portion of a lung such that the lung can move with the moving outer surface whereby compliance for the variable volume blood pump can be provided by the lung.
- 2. The method of claim 1 further comprising:
- c. receiving position signals from a position sensor connected to the variable volume blood pump, the position signals indicative of at least a relative fall condition and a relative empty condition of the blood chamber; and
- d. initiating pumping action responsive to the position signals indicating a relative full condition of the blood chamber.
- 3. The method of claim 2 wherein the condition of the blood chamber is determined comprising:
- a. determining a reference signal indicative of a preferred condition of the blood chamber to initiate the pumping action;
- b. calculating a first derivative of the position signals;
- c. detecting when the sign of said first derivative is negative;
- d. comparing the position signal to the reference signal responsive to the detection of said negative sign; and
- e. adjusting the speed of the variable volume blood pump in proportion to the difference between the position signals and the reference signal to cause the position signals to generally correspond to the reference signal.
Parent Case Info
This application is a divisional application of U.S. patent application Ser. No. 09/014,894, filed Jan. 28, 1998 now U.S. Pat. No. 5,980,448, which is hereby incorporated herein by reference.
US Referenced Citations (21)
Foreign Referenced Citations (1)
Number |
Date |
Country |
WO 9507109 |
Mar 1995 |
WOX |
Divisions (1)
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Number |
Date |
Country |
Parent |
014894 |
Jan 1998 |
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