Abstract: An accumulator for an implantable infusion system employs a pair of separated diaphragms movable in unison by a transfer fluid disposed therebetween. A first chamber receives infusate in metered amounts and dispenses the contents as a function of toggled valve operation. During filling, the first diaphragm deflects upward and by pressure transfer causes a corresponding deflection in the second diaphragm. The second diaphragm is biased by springs, gas under pressure or the like. Hence, when the outlet valve opens, the pressure differential across the diaphragm causes downward deflection. No mechanical stops are needed in the infusate chamber for the first diaphragm since its movement is controlled by the pressure differential across the second diaphragm.

Abstract: A fluid metering device useful in implantable drug delivery systems is coupled between a pressurized fluid source and an outlet conduit to provide discrete flow pulses at a predetermined rate. The metering device consists of a first movable member constrained within a housing and a second movable member retained in a cavity by the first. Alternate positioning of the first member simultaneously fills and empties the cavity in which the second resides, discharging fluid through the conduit. The first movable member can be a planar slider, an axially translatable cylinder or a rotatable cylinder. The second movable member may be a flat shuttle, a sliding bar or a diaphragm.

Abstract: An implantable infusion reservoir having a resilient foam member in a rigid housing to urge fluid to an implantation site. The foam member compresses upon charging and then expands to maintain a predetermined pressure characteristic within the fluid. The foam replaces the previously used two-phase propellent and eliminates the need for a hermetic metal bellows. The foam may be either closed celled or open celled, with or without a barrier skin. The device can be conformal to any desired shape and employ various metering techniques to deliver accurate quantities of fluid.

Abstract: An implantable device uses shape memory alloy (SMA) as the driver to compress a reservoir thereby providing a constant pressure source fluid delivery device. The SMA may form either the reservoir itself by appropriate shaped sheets or it may form bands around a flexible reservoir member. The reservoir may also be formed of rigid members pivoted or clamped using SMA actuators to bias the rigid members together.

Abstract: A variable flow constant pressure implantable pump employs an in-line needle restrictor having a variable insertion distance in a capillary. The degree of insertion determines the effective restriction within the capillary. The restrictor may be repositioned following implantation to vary the drug delivery rate by changing the effective restriction in the capillary. Various couplings may be used such that an auxiliary or bolus port delivers infusate directly into the outlet catheter so that medication from the main chamber does not pass through the auxiliary chamber. A combination of double lumen catheters and T-connectors are employed to provide parallel infusion paths.

Abstract: An implantable valve accumulator pump for the delivery of medication is disclosed. The implantable pump comprises a drug reservoir maintained a constant pressure vapor. The medication metering assembly comprises a fixed volume accumulator positioned between a pair of valves. The valves alternately open and close to admit medication from the reservoir into the accumulator and to dispense a precise volume spike to an outlet catheter. In order to minimize dead volume and insure complete discharge, the accumulator employs a titanium diaphragm seated in one position by a recessed stop and in the discharge position by a spacer plate having a groove pattern. The unit is externally programmed.

Abstract: Implantable variable flow infusion apparatus comprises a collapsible infusate chamber having an outlet conduit leading to the infusion site by way of series-connected fixed and variable fluid flow restrictors. The infusate in the chamber is maintained under substantially constant pressure by a nonelectric energy storage cell to establish flow from the chamber to the site. The variable restrictor is controlled by commands from a preprogrammed microprocessor and programmable memory powered by a small long-lived battery. The processor sets the variable restrictor to the proper setting to establish the correct infusate flow for the particular time of day. A pressure transducer connected across the fixed restrictor senses the pressure differential across the fixed restrictor which differential indicates actual infusate flow from the chamber.

Abstract: A programmable implantable infusion pump includes a housing containing a variable volume infusate chamber and variable volume control fluid pressure and displacement reservoirs. A conduit conducts infusate from the chamber exteriorly of the housing. A restricted fluid path exists between the two reservoirs which are filled with an incompressible control fluid. A loaded spring applies a constant force to the pressure reservoir causing fluid flow between the two reservoirs. The differential pressure across the flow restriction is sampled by a microprocessor which computes the fluid flow rate, that rate being proportional to the infusate flow rate from the chamber. When the fluid flow rate deviates from a programmed value, the processor issues an error command to a battery-driven motor which reloads the spring to reestablish the constant force on the pressure reservoir.