Multiple reservoir implantable drug infusion device and method
View Patent ↗Multiple reservoir implantable valve accumulator pump for the delivery of medication, and method of infusate delivery. The apparatus includes at least first and second infusate reservoirs in a common pressure chamber, each in fluid communication with a metering assembly. The metering assembly includes an accumulator that is preferably a fixed volume accumulator having an inlet and an outlet. A first valve is in fluid communication with the first infusate reservoir and an inlet of the accumulator, and a second valve is in fluid communication with the second infusate reservoir and an inlet of the accumulator. An outlet valve is in fluid communication with the outlet of the accumulator. The accumulator can be filled with infusate from the first and second infusate reservoirs sequentially, can be filled from the first infusate reservoir multiple times consecutively, the second infusate reservoir multiple times consecutively, or any combination or permutation thereof.
1. A method of independently introducing infusate into an accumulator from at least two separate infusate sources, comprising:
providing an implatable pressure chamber that contains a fluid having positive vapor pressure at normal body temperature;
providing a first infusate reservoir in said pressure chamber, said first infusate reservoir adapted to contain a first infusate at a constant pressure of the pressure chamber;
providing an additional infusate reservoir in said pressure chamber, said additional infusate reservoir adapted to contain an additional infusate at a constant pressure of the pressure chamber, wherein the additional infusate reservoir is oppositely disposed to the first infusate reservoir in the pressure chamber;
providing a metering assembly consisting essentially of a fixed volume accumulator having an inlet in fluid communication with said first infusate reservoir via a first valve and in fluid communication with said additional infusate reservoir via an additional valve, and an outlet valve in communication with an outlet of said accumulator, said accumulator comprising a chamber housing a flexible diaphragm that provides a barrier between a gas portion of the chamber and an infusate portion of the chamber;
introducing said first infusate into said first infusate reservoir to cause the first reservoir to expand in a first direction;
introducing said additional infusate into said additional infusate reservoir to cause the additional infusate reservoir to expand in a second direction opposite the first direction;
introducing said first infusate from said first infusate reservoir independent of said additional infusate into said infusate portion of said accumulator by opening said first valve while said additional valve and said outlet valve are in a closed position;
emptying said accumulator of said first infusate by opening said outlet valve while said first and additional valves are closed;
introducing said additional infusate from said additional infusate reservoir into said infusate portion of said accumulator by opening said additional valve while said first valve and said outlet valve are in a closed position; and
emptying said additional infusate from said accumulator by opening said outlet valve while said first and additional valves are in a closed position.
2. The method of claim 1 , wherein said first infusate reservoir is filled with said first infusate, and said accumulator is filled with and then emptied of said first infusate, multiple times before said additional infusate is introduced into said additional infusate reservoir.
3. The method of claim 1 , wherein introducing said first infusate from said first infusate reservoir independent of said additional infusate into said accumulator further comprises channeling said first infusate through said accumulator through a single trough providing a lateral flow path between said inlet and outlet of said accumulator and an annular groove intersecting said trough with a diameter less than a length of said trough providing an annular flow path.
4. The method of claim 1 , wherein introducing said second infusate from said additional infusate reservoir independent of said first infusate into said accumulator further comprises channeling said additional infusate through said accumulator through a single trough providing a lateral flow path between said inlet and outlet of said accumulator and an annular groove intersecting said trough with a diameter less than a length of said trough providing an annular flow path.