Surgical Fluid Management

• US 20070078370A1
• Filed: 06/13/2006
• Published: 04/05/2007
• Est. Priority Date: 06/13/2005
• Status: Active Grant

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew PLC
• Inventors: Hedstrom, Petter, Shener, Cemal, Loreth, Brian, Krause, Kenneth
• Granted Patent: US 7,604,610 B2
• Time in Patent Office: Days
• US Class Current: 604/8
• CPC Class Codes: A61B 17/00234 for minimally invasive surgery A61B17/0218, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence
• CPC Class Codes: A61B 17/3474 Insufflating needles, e.g. Veress needles
• CPC Class Codes: A61M 2205/12 with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 3/0201 Cassettes therefor
• CPC Class Codes: A61M 3/0202 with electronic control means or interfaces
• CPC Class Codes: A61M 3/0216 Pressure
• CPC Class Codes: A61M 3/022 Volume; Flow rate
• CPC Class Codes: A61M 3/0258 by means of electric pumps
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A fluid flow device includes a housing configured to releasably mate with a surgical control unit for controlling fluid flow during a surgical procedure. First and second ports measure fluid pressure within a fluid path provided within the housing. The fluid flow device includes a restrictor for restricting fluid flow at a restriction location along the fluid path. The first port is located upstream of the restriction location and the second port is located downstream of the restriction location. A fluid pump is provided within the housing.

Claims

1. A fluid flow device, comprising:

a housing configured to releasably mate with a surgical control unit for controlling fluid flow during a surgical procedure;

a fluid path within the housing;

first and second ports for measuring fluid pressure within the fluid path;

a restrictor for restricting fluid flow at a restriction location along the fluid path, the first port being located upstream of the restriction location and the second port being located downstream of the restriction location; and

a fluid pump within the housing.

2. The fluid flow device of claim 1, wherein the restrictor comprises a region of decreased cross-sectional area along the fluid path.

3. The fluid flow device of claim 1, wherein the ports are openings defined in a wall of the housing.

4. The fluid flow device of claim 1, further comprising a flexible membrane covering the first port and a flexible membrane covering the second port.

5. The fluid flow device of claim 1, wherein the pump comprises a non-contact, magnetic coupling configured to be operatively driven by a motor external to the housing.

6. The fluid flow device of claim 1, further comprising a second fluid path within the housing.

7. The fluid flow device of claim 6, further comprising a valve configured to selectively control fluid flow through the second fluid path.

8. The fluid flow device of claim 1, further comprising the surgical control unit.

9. The fluid flow device according to claim 1, further comprising day-tubing operatively connected to the housing, the day-tubing including a valve for limiting backflow.

10. The fluid flow device of claim 9, wherein the surgical control unit includes a first pressure sensor and a second pressure sensor.

11. The fluid flow device of claim 10, wherein the sensors align with the ports when the housing is mated with the surgical control unit.

12. The fluid flow device of claim 10, wherein the surgical control unit defines a slot for receiving the housing.

13. The fluid flow device of claim 12, wherein the slot includes a guide track and the housing includes one or more protrusions configured to matingly engage the guide track.

14. The fluid flow device of claim 13, wherein the guide track comprises a linear track section and an angled track section.

15. The fluid flow device of claim 8, further comprising a valve configured to impart a pulsating action to a fluid conduit within the housing.

16. The fluid flow device of claim 12, wherein the control unit comprises a processor configured to selectively control pump speed based on a measured pressure drop across the flow restrictor.

17. The fluid flow device of claim 16, wherein the processor is configured to selectively control pump speed based on a calculated flow rate, a setpoint surgical site pressure, and a calculated surgical site pressure.

18. The fluid flow device of claim 17, wherein the processor is operatively connected with a proportional-integral-derivative controller configured to provide closed-loop feedback with respect to a comparison between the setpoint surgical site pressure and the calculated surgical site pressure.

19. The fluid flow device of claim 17, wherein the processor is configured to control pump outlet pressure, flow rate and pump speed based on a three-dimensional system model defined by the function RPM=f(P2, Q).

20. The fluid flow device of claim 19, wherein the controller is configured to provided open-loop feed forward control with respect to a comparison between the setpoint surgical site pressure and the calculated surgical site pressure.

21. A method for controlling fluid pressure within a body cavity, comprising:

pumping fluid to the body cavity through a flow restrictor located between the body cavity and a fluid pump;

measuring a pressure change across the flow restrictor;

calculating the fluid pressure within the body cavity based on the measured pressure change; and

controlling fluid flow to the body cavity based on the calculated fluid pressure.

22. The method according to claim 21, further comprising:

setting a setpoint body cavity pressure; and

comparing the calculated fluid pressure in the body cavity with the setpoint body cavity pressure; and

adjusting pump operating speed based on the comparison.

23. The method according to claim 21, further comprising controlling pump outlet pressure (P2), flow rate (Q) and pump speed (RPM) based on a three-dimensional system model defined by the function RPM=f(P2, Q).

24. The method according to claim 22, further comprising providing open-loop feed forward control based on the comparison and closed loop feedback control with respect to pump speed.

25. A computer-readable recording medium in which computer-executable program codes are stored, the program codes being configured to cause a computer to perform a method for controlling fluid pressure within a body cavity, the method comprising:

pumping fluid to the body cavity through a flow restrictor located between the body cavity and a fluid pump;

measuring a pressure change across the flow restrictor;

calculating the fluid pressure within the body cavity based on the measured pressure change; and

controlling fluid flow to the body cavity based on the calculated fluid pressure.

26. A pump cassette for releasably mating with a surgical control unit that defines a cassette receiving slot with a guide track and has first and second pressure transducers, the pump cassette comprising:

a housing having a protrusion configured and arranged to mate with the guide track during introduction into and final placement within the slot such that the housing is spaced from the pressure transducers during introduction into the slot and contacts the pressure transducers when in final placement within the slot.

27. The pump cassette of claim 26 further comprising first and second ports positioned for alignment with the first and second pressure transducers when the cassette is in final placement within the slot.

28. A method of mating a pump cassette to a surgical control unit, the surgical control unit defining a cassette receiving slot with a guide track and having first and second pressure transducers, comprising:

aligning a protrusion on the cassette with the guide track and pushing the cassette into the guide track such that the cassette moves from a position spaced from the pressure transducers during introduction into the slot to a final placement in contact with the pressure transducers.

29. An apparatus for controlling fluid pressure within a body cavity comprising:

means for pumping fluid to the body cavity through a flow restrictor located between the body cavity and a fluid pump;

means for measuring a pressure change across the flow restrictor;

means for calculating the fluid pressure within the body cavity based on the measured pressure change; and

means for controlling the fluid flow to the body cavity based on the calculated fluid pressure.