Free flow prevention system for infusion pump

• US 5,017,192 A
• Filed: 10/20/1989
• Issued: 05/21/1991
• Est. Priority Date: 10/20/1989
• Status: Expired due to Term

• Current Assignee: Graseby Medical Limited (ICU Medical Incorporated)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Dodge, Larry H., Stone, Stanford C.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Lelois, Ralph A.
• Application Number:
  US07/424,386
• Time in Patent Office: 578 Days
• Field of Search: 604/250, 604/246, 604/245, 604/34, 251/4.7, 137/637
• US Class Current: 604/250
• CPC Class Codes: A61M 39/281 Automatic tube cut-off devices, e.g. squeezing tube on detection of air
• CPC Class Codes: A61M 39/287 Wedge formed by a slot having varying width, e.g. slide clamps
• CPC Class Codes: A61M 5/14228 with linear peristaltic action, i.e. comprising at least three pressurising members or a helical member

Abstract

A free flow prevention system for preventing free flow of fluid through IV tubing when the tubing is disconnected from an infusion pump. A flexible clamp is provided having a pair of clamping arms, which define a variable width slot for receiving the IV tubing. The IV tubing may be moved along the slot between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width of the slot at the first position. The clamping arms are resiliently biased to a closed position wherein the IV tubing is squeezed when in its second position to close the lumen to prevent fluid flow. A clamp-receiving passageway and clamp-opening wedge are provided on the infusion pump. The clamp-opening wedge is movable relative to a clamp received in the passageway to an operating position, wherein the wedge moves the arms of the flexible clamp against their bias to an open position wherein the lumen of the IV tubing is allowed to open to permit fluid flow during operation of the pump.

Claims

1. A free flow prevention system comprising:

IV tubing having a lumen through which fluid may be pumped for administration to a patient;

a pumping assembly including pumping means for pumping fluid through the IV tubing, and releasable holding means for holding the IV tubing during operation of the pumping assembly;

a flexible clamp associated with the IV tubing and having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width of the slot at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when in its second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted;

clamp-receiving means on the pumping assembly for releasably receiving the flexible clamp; and

releasable clamp-opening means for separating the clamping arms of the flexible clamp and moving the arms from their closed position to the open position before operation of the pumping assembly;

the clamp-receiving means and clamp-opening means being mounted on the infusion pump for movement of the clamp-opening means relative to the flexible clamp received in the clamp-receiving means between an unloading position, wherein the clamp-opening means does not hold the arms of the flexible clamp in their open position, and an operating position, wherein the clamp-opening means moves the arms of the flexible clamp to their open position and holds the arms in the open position.

2. A free flow prevention system according to claim 1 wherein the clamp-opening means includes a wedge mounted on the pumping assembly for separating the clamping arms of the flexible clamp, the wedge and the flexible clamp being movable relative to one another between the operating position, wherein at least a portion of the wedge is positioned between the clamping arms to separate and hold the arms in their open position, and the unloading position, wherein the wedge is not opening the clamping arms from their closed position so that the lumen of the IV tubing is closed to fluid flow when the IV tubing is removed from the pumping assembly.

3. A free flow prevention system according to claim 2 wherein the clamp-receiving means is mounted or formed on the releasable holding means, and the releasable holding means is movable between a loading and unloading position, wherein the IV tubing may be loaded into or unloaded from the pumping assembly and the wedge and flexible clamp are in their unloading position, and the operating position wherein the flexible clamp is moved to the operating position relative to the wedge and the clamp and IV tubing are held for operation of the pumping assembly.

4. A free flow prevention system according to claim 2 wherein the flexible clamp has a bridging portion defining an inner end of the slot, the clamping arms of the clamp extending outwardly from the bridging portion and terminating in free ends that define the outer end of the slot, the free ends of the arms being tapered inwardly toward the slot and bridging portion to guide the wedge into the outer end of the slot between the clamping arms.

5. A free flow prevention system according to claim 4 wherein the clamping arms define a portion of the slot generally adjacent the inner end of the slot as the second position having a width normally less than the width of the slot at the first position, and the clamping arms have portions generally adjacent their free ends that define an open area generally adjacent the free ends as the first position wherein the width of the slot is sufficient to permit the clamp to move longitudinally along the IV tubing.

6. A free flow prevention system according to claim 5 wherein the flexible clamp comprises a body formed of thermoplastic or synthetic resin material, and a resilient spring member biasing the clamping arms to their closed position.

7. A free flow prevention system according to claim 1 wherein the clamp-receiving means comprise walls in the releasable holding means defining an elongate passageway having an open end for receiving the flexible clamp, the releasable holding means being movable between a loading and unloading position, wherein the IV tubing may be loaded into and unloaded from the pumping assembly, and an operating position, wherein the IV tubing is held for operation of the pumping assembly, the clamp-opening means being positioned in the elongate passageway such that the clamping arms are moved from their closed position to their open position when the releasable holding means is moved to the operating position.

8. A free flow prevention system according to claim 7 further comprising abutment means on the clamp for limiting insertion of the clamp into the elongate passageway to a first predetermined distance, the slot of the flexible clamp defining a longitudinal axis of the clamp, with the first and second positions of the IV tubing being spaced apart along the longitudinal axis of the clamp a second predetermined distance substantially equal to the first predetermined distance, the pumping assembly including a wall substantially preventing movement of the IV tubing into the elongate passageway as the flexible clamp is inserted into the elongate passageway so that the IV tubing is moved from the first to the second positions when the flexible clamp is inserted in the elongate passageway the first predetermined distance.

9. A free flow prevention system according to claim 8 wherein the clamp-receiving means includes a pivotable arm for releasably retaining the flexible clamp in the passageway when the clamp is inserted the first predetermined distance.

10. A free flow prevention system according to claim 9 wherein the releasable holding means of the pumping assembly includes a door having a pivotable projecting portion spring biased to a holding position for pressing or holding the arm against the flexible clamp when the door is moved to a closed position, the projecting portion being movable against the spring bias by the pivotable arm when the clamp is partially inserted in the passageway and the door is closed to prevent jamming of the door when the clamp is only partially inserted in the passageway.

11. A free flow prevention system according to claim 10 wherein the IV tubing includes a pumping cassette having flexible walls defining fluid pumping chambers that may be compressed by the pumping means to regulate fluid flow through the IV tubing, the door of the pumping assembly being adapted to hold the pumping cassette in the pumping assembly.

12. A free flow prevention system according to claim 10 wherein the flexible clamp includes two bridging portions joining the clamping arms and defining opposite ends of the variable width slot, the bridging portions and/or clamping arms being sufficiently flexible to permit the clamping arms to be moved against the bias to their open position.

13. A free flow prevention system according to claim 8 wherein the releasable clamp-opening means includes a wedge on the pumping assembly that separates the clamping arms of the flexible clamp when the releasable holding means of the pumping assembly is moved to its operating position such that the arms are held in their open position, the releasable holding means of the pumping assembly including a door having a projecting portion adapted for releasably retaining the flexible clamp in the elongate passageway when the clamp is inserted the first predetermined distance and the door is moved to a closed position whereby the flexible clamp is held against longitudinal movement by the projecting portion when the wedge separates the clamping arms of the flexible clamp.

14. An infusion pump for regulating fluid flow through a lumen of IV tubing to a patient and being adapted for use with a flexible clamp that prevents free flow of the fluid through the IV tubing after the tubing is disconnected from the infusion pump, the clamp being of the type having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when in the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted;

the infusion pump comprising;

a pumping assembly including pumping means adapted for pumping fluid through the IV tubing, and releasable holding means adapted for holding the IV tubing during operation of the pumping assembly;

clamp-receiving means on the pumping assembly adapted for releasably receiving the flexible clamp; and

releasable clamp-opening means adapted for separating the clamping arms of the flexible clamp and moving the arms from their closed position to the open position before operation of the infusion pump;

the clamp-receiving means and clamp-opening means being mounted on the infusion pump for movement relative to one another between an unloading position, wherein the clamp-opening means does not hold the arms of a flexible clamp received in the clamp-receiving means in their open position, and an operating position wherein the clamp-opening means moves the arms of a flexible clamp received in the clamp-receiving means to their open position and holds the arms in the open position.

15. An infusion pump according to claim 14 wherein the clamp-receiving means further comprises walls in the pumping assembly defining a passageway having an open end adapted for releasably receiving the flexible clamp, and the clamp-opening means comprises a wedge mounted on the pumping assembly, the wedge and the walls being movable relative to one another between the operating position, wherein at least a portion of the wedge is positioned between the clamping arms of a flexible clamp received in the passageway to separate and hold the arms in their open position, and the unloading position, wherein the wedge is not opening the clamping arms of a flexible clamp received in the passageway from their closed position so that the lumen of the IV tubing is closed to fluid flow when the IV tubing is removed from the pumping assembly.

16. An infusion pump according to claim 15 wherein the walls defining the passageway comprise walls in the releasable holding means, and the releasable holding means is movable between a loading and unloading position, wherein the IV tubing may be loaded into or unloaded from the pumping assembly and the walls and flexible clamp are in their unloading position, and the operating position wherein the walls are moved to the operating position relative to the wedge so that the clamping arms of the flexible clamp are moved to their open position for operation of the pumping assembly.

17. An infusion pump according to claim 16 wherein the clamp-receiving means includes a pivotable arm for releasably retaining the flexible clamp in the passageway when the clamp is inserted the first predetermined distance, the releasable holding means of the pumping assembly including a door having a pivotable projecting portion spring biased to a holding position for pressing or holding the arm against the flexible clamp when the door is moved to a closed position, the projecting portion being movable against the spring bias by the pivotable arm when the clamp is partially inserted in the passageway and the door is closed to prevent jamming of the door when the clamp is only partially inserted in the passageway.

18. An infusion pump according to claim 16 wherein the releasable holding means of the pumping assembly includes a door having a projecting portion adapted for releasably retaining the flexible clamp in the passageway when the door is moved to a closed position whereby the flexible clamp is held against longitudinal movement by the projecting portion when the wedge separates the clamping arms of the flexible clamp.

19. A flexible clamp for preventing undesired free flow of fluid through IV tubing when the IV tubing is disconnected from an infusion pump regulating fluid flow to a patient, the clamp having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width of the slot at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when at the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted, the clamp further comprising a bridging portion defining an inner end of the slot, the clamping arms of the clamp extending outwardly from the bridging portion and terminating in free ends that define the outer end of the slot, the clamping arms and bridging portion being formed of thermoplastic or synthetic resin material and a resilient spring member biasing the clamping arms to their closed position.

20. A flexible clamp according to claim 19 for use in an infusion pump including a pumping assembly having a wedge for opening the clamping arms of the flexible arms before operation of the pumping assembly;

the free ends of the arms being tapered inwardly toward the slot and bridging portion to guide the wedge into the outer end of the slot between the clamping arms.

21. A flexible clamp according to claim 20 wherein the clamping arms define a portion of the slot generally adjacent the inner end of the slot as the second position having a width normally less than the width of the slot at the first position, and the clamping arms have portions generally adjacent their free ends that define an open area generally adjacent the free ends as the first position wherein the width of the slot is sufficient to permit the clamp to move longitudinally along the IV tubing.

22. A flexible clamp according to claim 21 wherein the clamping arms extend in a longitudinal direction of the clamp and the slot is elongate in the longitudinal direction of the clamp, the clamp further comprising at least one laterally outwardly extending ledge for limiting the distance the flexible clamp can be inserted into the infusion pump to a first predetermined distance, the first and second positions being spaced apart along the slot a second predetermined distance substantially equal to the first predetermined distance.

23. A flexible clamp according to claim 22 wherein the at least one ledge includes two ledges extending laterally outwardly from opposite clamping arms at substantially the same longitudinal position along the arms, the ledges and the free ends of the clamping arms being separated by a longitudinal distance substantially equal to the second predetermined distance that the first and second positions are spaced apart along the slot.

24. A flexible clamp for preventing undesired free flow of fluid through IV tubing when the IV tubing is disconnected from an infusion pump regulating fluid flow to a patient, the clamp having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width of the slot at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when at the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted, the clamp being adapted for use in an infusion pump including a pumping assembly having a wedge for opening the clamping arms of the flexible arms before operation of the pumping assembly;

the clamp further comprising a bridging portion defining an inner end of the slot, the clamping arms and bridging portion being formed of thermoplastic or synthetic resin material and a resilient spring member biasing the clamping arms to their closed position, the clamping arms of the clamp extending outwardly from the bridging portion and terminating in free ends that define the outer end of the slot, the free ends of the arms being tapered inwardly toward the slot and bridging portion to guide the wedge into the outer end of the slot between the clamping arms;

the clamping arms defining a portion of the slot generally adjacent the inner end of the slot as the second position having a width normally less than the width of the slot at the first position, and the clamping arms have portions generally adjacent their free ends that define an open area generally adjacent the free ends as the first position wherein the width of the slot is sufficient to permit the clamp to move longitudinally along the IV tubing.

25. A flexible clamp for preventing undesired free flow of fluid through IV tubing when the IV tubing is disconnected from an infusion pump regulating fluid flow to a patient, the clamp having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width of the slot at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when at the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted, the clamp further comprising two bridging portions joining the clamping arms and defining opposite ends of the slot, the bridging portions and/or clamping arms being sufficiently flexible to permit the clamping arms to be moved against the bias to their open position.

26. An IV tubing set adapted for use with an infusion pump of the type comprising a pumping assembly including pumping means for pumping fluid through IV tubing to regulate fluid flow through the IV tubing, and releasable holding means for holding IV tubing during operation of the pumping assembly, clamp-receiving means on the pumping assembly for releasably receiving a clamp associated with the IV tubing, and releasable clamp-opening wedge mounted on the pumping assembly for moving a clamp to an open position permitting fluid flow through the IV tubing, the clamp-receiving means and clamp-opening wedge being of the type mounted on the infusion pump for movement relative to one another between an unloading position, wherein the clamp-opening wedge does not hold the arms of a flexible clamp received in the clamp-receiving means in their open position, and an operating position, wherein the clamp-opening wedge moves the arms of a flexible clamp received in the clamp-receiving means to their open position and holds the arms in the open position;

the IV tubing set comprising;

IV tubing having a lumen through which fluid may be pumped for administration to a patient; and

a flexible clamp associated with the IV tubing and being adapted to be inserted in clamp-receiving means before operation of the infusion pump, the flexible clamp having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when in the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted such that the clamp-opening wedge of the infusion pump can move the clamping arms to the open position before operation of the infusion pump;

the clamp further comprising a hinged bridging portion defining an inner end of the slot, the clamping arms of the clamp extending outwardly from the hinged bridging portion and terminating in free ends that define the outer end of the slot, the clamping arms and bridging portion being formed of thermoplastic or synthetic resin material and a resilient spring member biasing the clamping arms to their closed position.

27. An IV tubing set according to claim 26 wherein the free ends of the arms are tapered inwardly toward the slot and bridging portion to guide the clamp-opening wedge into the outer end of the slot between the clamping arms.

28. An IV tubing set according to claim 27 wherein the clamping arms define a portion of the slot generally adjacent the inner end of the slot as the second position having a width normally less than the width of the slot at the first position, and the clamping arms have portions generally adjacent their free ends that define an open area generally adjacent the free ends as the first position wherein the width of the slot is sufficient to permit the clamp to move longitudinally along the IV tubing.

29. An IV tubing set adapted for use with an infusion pump of the type comprising a pumping assembly including pumping means for pumping fluid through IV tubing to regulate fluid flow through the IV tubing, and releasable holding means for holding IV tubing during operation of the pumping assembly, clamp-receiving means on the pumping assembly for releasably receiving a clamp associated with the IV tubing, and releasable clamp-opening means for moving a clamp to an open position permitting fluid flow through the IV tubing, the clamp-receiving means and clamp-opening means being of the type mounted on the infusion pump for movement relative to one another between an unloading position, wherein the clamp-opening means does not hold the arms of a flexible clamp received in the clamp-receiving means in their open position, and an operating position, wherein the clamp-opening means moves the arms of a flexible clamp received in the clamp-receiving means to their open position and holds the arms in the open position, the infusion pump being of the type wherein the clamp-opening means comprises a wedge mounted on the pumping assembly for movement relative to the clamp-receiving means between the unloading and operating positions;

the IV tubing set comprising;

IV tubing having a lumen through which fluid may be pumped for administration to a patient; and

a flexible clamp associated with the IV tubing and being adapted to be inserted in clamp-receiving means before operation of the infusion pump, the flexible clamp having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when in the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted such that the clamp-opening means of the infusion pump can move the clamping arms to the open position before operation of the infusion pump;

the clamp further comprising a hinged bridging portion defining an inner end of the slot, the clamping arms of the clamp extending outwardly from the hinged bridging portion and terminating in free ends that define the outer end of the slot, the clamping arms and bridging portion being formed of thermoplastic or synthetic resin material and a resilient spring member biasing the clamping arms to their closed position, the free ends of the arms being tapered inwardly toward the slot and bridging portion to guide the wedge into the outer end of the slot between the clamping arms;

the clamping arms defining a portion of the slot generally adjacent the inner end of the slot as the second position having a width normally less than the width of the slot at the first position, and the clamping arms have portions generally adjacent their free ends that define an open area generally adjacent the free ends as the first position wherein the width of the slot is sufficient to permit the clamp to move longitudinally along the TV tubing.

30. An IV tubing set according to claim 29 wherein the clamping arms extend in a longitudinal direction of the clamp and the slot is elongate in the longitudinal direction of the clamp, the clamp further comprising at least one laterally outwardly extending ledge for limiting the distance the flexible clamp can be inserted into the clamp-receiving means of the infusion pump to a first predetermined distance, the first and second positions being spaced apart along the slot a second predetermined distance substantially equal to the first predetermined distance.

31. An IV tubing set according to claim 30 wherein the at least one ledge includes two ledges extending laterally outwardly from opposite clamping arms at substantially the same longitudinal position along the arms, the ledges and the free ends of the clamping arms being separated by a longitudinal distance substantially equal to the second predetermined distance that the first and second positions are spaced apart along the slot.

32. An IV tubing set according to claim 31 wherein the IV tubing includes a pumping cassette having flexible walls defining fluid pumping chambers that may be compressed by the pumping means to regulate fluid flow through the IV tubing.

33. An IV tubing set adapted for use with an infusion pump of the type comprising a pumping assembly including pumping means for pumping fluid through IV tubing to regulate fluid flow through the IV tubing, and releasable holding means for holding IV tubing during operation of the pumping assembly, clamp-receiving means on the pumping assembly for releasably receiving a clamp associated with the IV tubing, and releasable clamp-opening means for moving a clamp to an open position permitting fluid flow through the IV tubing, the clamp-receiving means and clamp-opening means being of the type mounted on the infusion pump for movement relative to one another between an unloading position, wherein the clamp-opening means does not hold the arms of a flexible clamp received in the clamp-receiving means in their open position, and an operating position, wherein the clamp-opening means moves the arms of a flexible clamp received in the clamp-receiving means to their open position and holds the arms in the open position;

the IV tubing set comprising;

IV tubing having a lumen through which fluid may be pumped for administration to a patient; and

a flexible clamp associated with the IV tubing and being adapted to be inserted in clamp-receiving means before operation of the infusion pump, the flexible clamp having a pair of clamping arms defining a variable width slot along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when in the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted such that the clamp-opening means of the infusion pump can move the clamping arms to the open position before operation of the infusion pump;

the flexible clamp further comprising two bridging portions joining the clamping arms and defining opposite ends of the slot, the bridging portions and/or clamping arms being sufficiently flexible to permit the clamping arms to be moved against the bias to their open position.

34. An IV tubing set adapted for use with an infusion pump of the type comprising a pumping assembly including pumping means for pumping fluid through IV tubing to regulate fluid flow through the IV tubing, and releasable holding means for holding IV tubing during operation of the pumping assembly, clamp-receiving means on the pumping assembly for releasably receiving a clamp associated with the IV tubing, and releasable clamp-opening means for moving a clamp to an open position permitting fluid flow through the IV tubing, the clamp-receiving means and clamp-opening means being of the type mounted on the infusion pump for movement relative to one another between an unloading position, wherein the clamp-opening means does not hold the arms of a flexible clamp received in the clamp-receiving means in their open position, and an operating position, wherein the clamp-opening means moves the arms of a flexible clamp received in the clamp-receiving means to their open position and holds the arms in the open position;

the IV tubing set comprising;

IV tubing having a lumen through which fluid may be pumped for administration to a patient; and

a flexible clamp associated with the IV tubing and being adapted to be inserted in clamp-receiving means before operation of the infusion pump, the flexible clamp having a pair of clamping arms extending in a longitudinal direction and defining a variable width slot that is elongate in the longitudinal direction of the clamp and along which the IV tubing may be moved between a first position wherein the width of the slot is sufficient to permit the clamp to be positioned longitudinally along the IV tubing, and a second position wherein the width of the slot is normally less than the width at the first position, the clamping arms being resiliently biased to a closed position wherein the IV tubing is squeezed when in the second position to close the lumen to prevent fluid flow, the clamping arms being movable against the bias to an open position wherein the lumen of the IV tubing is allowed to open so that flow through the lumen is permitted such that the clamp-opening means of the infusion pump can move the clamping arms to the open position before operation of the infusion pump;

the clamp further comprising means for limiting the distance the flexible clamp can be inserted into the clamp-receiving means of the infusion pump to a first predetermined distance, the first and second positions being spaced apart along the slot a second predetermined distance substantially equal to the first predetermined distance.

35. An IV tubing set according to claim 34 wherein the means for limiting the distance the flexible clamp can be inserted into the clamp-receiving means of the infusion pump to the first predetermined distance comprises two ledges extending laterally outwardly from opposite sides of the flexible clamp at substantially the same longitudinal position along the clamp for limiting the distance the clamp can be inserted into the clamp-receiving means of the infusion pump to the first predetermined distance.

36. An IV tubing set according to claim 34 wherein the flexible clamp is formed of thermoplastic or synthetic resin material and a resilient spring member biasing the clamping arms to their closed position.