Drug bolus delivery system

• US 6,635,049 B1
• Filed: 04/30/1999
• Issued: 10/21/2003
• Est. Priority Date: 04/30/1999
• Status: Expired due to Fees

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Christiansen, Chris C., Lent, Mark, Robinson, Reginald D.
• Primary Examiner(s): Hayes, Michael J.
• Application Number:
  US09/303,790
• Time in Patent Office: 1,635 Days
• Field of Search: 604/93, 604/65, 604/66, 604/67, 604/891.1, 604/890.1, 604/242, 604/151, 604/241, 604/132, 604/133, 604/141, 604/142, 128/DIG.12, 128/DIG.1, 128/DIG.13
• US Class Current: 604/891.1
• CPC Class Codes: A61M 2230/04 Heartbeat characteristics, e.g. ECG, blood pressure modulation
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/16809 by repeated filling and emptying of an intermediate volume pressure infusion using positive displacement pumps A61M5/142
• CPC Class Codes: A61M 5/1723 using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00

Abstract

An bolus delivery system includes an implantable pump, a sensor for sensing an adverse patient condition, such as atrial fibrillation, and a catheter for delivery of a bolus of drug to a target area of a living body. The pump is provided with a bolus metering assembly which includes, in a preferred embodiment, an auxiliary bellows defining a bolus reservoir in addition to the main reservoir of the pump. The auxiliary bellows is selectively placed in fluid communication with the pressurized main supply of drug via an inlet valve to refill the bolus reservoir. An outlet valve is provided to permit egress of the bolus to the catheter from the bolus reservoir. A drive train including a stepper motor and a face cam selectively opens and closes the inlet and outlet valves to effect accumulation or metering and delivery of the bolus. The auxiliary bellows is preferably provided as a collapsible element resiliently biased to an expanded position and is collapsed under pressure in the main reservoir to expel the bolus.

Claims

1. A pumping mechanism, entirely implantable in a living body, for delivering a bolus of a beneficial drug agent to a preselected location in said living body, said living body having a known body pressure, said mechanism comprising:

(a) a channel in said living body interconnecting said pumping mechanism with said preselected location in said living body, said channel providing a flow path for said bolus of said drug agent;

(b) a sensor in said living body for sensing an adverse condition in said living body and transmitting a signal of said adverse condition;

(c) a normally enclosed first reservoir onboard said pumping mechanism for storing a bolus amount of said beneficial drug agent at a preselected first pressure level which is greater than said body pressure, said first reservoir comprising a flexible deformable bellows member being movable between an expanded position and a collapsed position, said bellows member having an interior portion for storing said bolus drug and also having an exterior portion defining said interior portion, said bellows member being at said expanded position when storing said bolus amount of said drug agent at said first pressure level;

(d) a second reservoir onboard said pumping mechanism and containing a supply of said drug agent in an amount greater than said bolus amount, said supply of said drug agent in said second reservoir normally being in pressurized communication with said exterior portion of said bellows member at said first pressure level;

(e) a valve onboard said pumping mechanism and interconnected in said flow path and being positioned between said first reservoir and said channel, said valve having a first valve position and a second valve position and being moveable between said first valve position and said second valve position, said drug agent being maintained at said first pressure level in said interior storage chamber when said valve is in said first position;

(f) a power supply onboard said pumping mechanism; and

(g) a metering and drive assembly, onboard said pumping mechanism, said metering and drive assembly being operatively connected to said sensor and being capable of receiving said signal of said adverse condition, said metering and drive assembly also being operatively connected to said power supply for driving said valve from said first valve position to said second valve position upon receiving said signal, said channel thereby openly communicating with said first reservoir as said valve is being moved to said second valve position, the drug agent in said second reservoir acting against said bellows of said first reservoir for driving said bellows to the collapsed position and thereby driving said bolus drug agent in said first reservoir through said flow path from said first reservoir past said valve, said bolus drug amount thereby being delivered to said living body, said passage of said drug agent being in response to said greater pressure in said first reservoir relative to said body pressure.

2. The pumping mechanism of claim 1 including a control module operatively associated with said sensor and with said power supply, the control module causing said power supply to activate said metering and drive assembly in response to said signal of said adverse patient condition.

3. The pumping mechanism of claim 1 wherein said second reservoir comprises a bellows surrounding said first reservoir and which is normally biased toward an expanded position.

4. The pumping mechanism of claim 3, which further includes stop members for limiting the expansion of both said bellows of both said first and second reservoirs.

5. The pumping mechanism of claim 1 which includes a flow passage for conveying a bolus amount of said drug agent from said supply of said drug agent in said second reservoir to said first reservoir after said bolus amount of said drug agent is delivered from said first reservoir to said second reservoir.

6. The pumping mechanism of claim 5 wherein said bellows of said first reservoir is self biased to said expanded position as said bolus of said drug agent is being delivered from said second reservoir to said first reservoir thereby refilling a bolus amount of said drug agent in said first reservoir.

7. The pumping mechanism of claim 5 wherein said valve comprises a flow restrictor for permitting a predetermined rate of ingress of said drug agent from said second reservoir to said first reservoir.

8. The pumping mechanism of claim 1 wherein said metering and driving assembly includes a cam mechanism for selectively and rotatably operating said valve between said first valve position and said second valve position.