ACCURATE FLOW CONTROL IN DRUG PUMP DEVICES

• US 20130184640A1
• Filed: 11/19/2012
• Published: 07/18/2013
• Est. Priority Date: 04/20/2010
• Status: Abandoned Application

• Current Assignee: MiniPumps, LLC
• Original Assignee: MiniPumps, LLC
• Inventors: Li, Po-Ying
• Application Number:
  US13/680,990
• Publication Number:
  US 20130184640A1
• Time in Patent Office: Days
• US Class Current: 604/67
• CPC Class Codes: A61M 2005/14204 with gas-producing electrochemical cell
• CPC Class Codes: A61M 2205/3523 using telemetric means
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3584 using modem, internet or bluetooth
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2210/0612 Eyes
• CPC Class Codes: A61M 5/14248 of the skin patch type
• CPC Class Codes: A61M 5/14276 specially adapted for implantation
• CPC Class Codes: A61M 5/14526 the piston being actuated by fluid pressure
• CPC Class Codes: A61M 5/14593 the diaphragm being actuated by fluid pressure
• CPC Class Codes: A61M 5/1684 by detecting the amount of infusate remaining, e.g. signalling end of infusion
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: A61M 5/172 electrical or electronic A61M5/16804, A61M5/16831 take precedence

Abstract

The accuracy of drug delivery with drug pump devices may be improved by a combination of pump operation at high flow resistances and pump pressures, pressure-relief mechanisms, and sensor-based feedback for pump control.

Claims

1. A drug pump device comprising:

a drug reservoir;

an exit member for fluidically connecting the reservoir with a drug injection site;

an electrolysis pump comprising a pump chamber in mechanical communication with the drug reservoir via an intervening displacement member, the electrolysis pump being operable to exert a pressure to drive the displacement member toward the exit member and thereby force therethrough fluid in the drug chamber; and

a pressure sensor disposed within the pump chamber for measuring a pressure therein;

a direct-measurement flow sensor disposed within the exit member for measuring a flow rate of fluid flow therethrough; and

control circuitry for (i) calculating a flow rate from the measured pressure, (ii) comparing the calculated flow rate with the measured flow rate, and (iii) if the measured flow rate is within 5% of the calculated flow rate, continuing fluid flow through the exit member by operating the pump to generate a pressure, and otherwise initiating a safety protocol.

2. The device of claim 1, wherein the safety protocol comprises interrupting pump operation.

3. The device of claim 1, wherein the safety protocol comprises re-starting pump operation.

4. In a drug pump device comprising a drug reservoir, an exit member for fluidically connecting the reservoir with a drug injection site, and an electrolysis pump operable to exert a pressure on the reservoir to thereby force fluid from the drug reservoir into the exit member, a method of controlling a rate of fluid flow through the exit member, the method comprising:

measuring a pressure in a pump chamber of the electrolysis pump;

measuring a flow rate of fluid flow through the exit member;

calculating a flow rate from the measured pressure;

comparing the calculated flow rate with the measured flow rate, and, if the measured flow rate is within 5% of the calculated flow rate, continuing fluid flow through the exit member by operating the pump to generate a pressure, and otherwise executing a safety protocol.

5. The method of claim 4, wherein executing the safety protocol comprises interrupting pump operation.

6. The device of claim 5, wherein executing the safety protocol further comprises re-starting pump operation.

7. A drug pump device comprising:

a drug reservoir;

an exit member for fluidically connecting the reservoir with a drug injection site;

a flow restrictor downstream of the drug reservoir for restricting fluid flow through the exit member;

an electrolysis pump comprising a pump chamber in mechanical communication with the drug reservoir via an intervening displacement member, the electrolysis pump being operable to exert a pressure to drive the displacement member toward the exit member and thereby force therethrough fluid in the drug chamber; and

a pressure sensor for measuring a pump pressure within the pump chamber;

a pressure sensor for measuring a reservoir-outlet pressure between the drug reservoir and the flow restrictor; and

control circuitry for monitoring a difference between the pump pressure and the reservoir-outlet pressure and, based thereon, operating the electrolysis pump to achieve a substantially constant rate of fluid flow through the exit member.

8. In a drug pump device comprising a drug reservoir, an exit member for fluidically connecting the reservoir with a drug injection site, and an electrolysis pump operable to exert a pressure on the reservoir to thereby force fluid from the drug reservoir into the exit member, a method of controlling a rate of fluid flow through the exit member, the method comprising:

measuring a pump pressure within the pump chamber;

measuring a reservoir-outlet pressure between the drug reservoir and the flow restrictor; and

monitoring a difference between the pump pressure and the reservoir-outlet pressure and, based thereon, operating the electrolysis pump to achieve a substantially constant rate of fluid flow through the exit member.