|Publication number||WO1999058187 A1|
|Publication date||18 Nov 1999|
|Filing date||10 May 1999|
|Priority date||13 May 1998|
|Publication number||PCT/1999/245, PCT/IL/1999/000245, PCT/IL/1999/00245, PCT/IL/99/000245, PCT/IL/99/00245, PCT/IL1999/000245, PCT/IL1999/00245, PCT/IL1999000245, PCT/IL199900245, PCT/IL99/000245, PCT/IL99/00245, PCT/IL99000245, PCT/IL9900245, WO 1999/058187 A1, WO 1999058187 A1, WO 1999058187A1, WO 9958187 A1, WO 9958187A1, WO-A1-1999058187, WO-A1-9958187, WO1999/058187A1, WO1999058187 A1, WO1999058187A1, WO9958187 A1, WO9958187A1|
|Inventors||Nimrod Lev, Talmon Rabinovitz|
|Applicant||Infutec Medical Systems Ltd.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Classifications (5), Legal Events (7)|
|External Links: Patentscope, Espacenet|
A CLAMPING SYSTEM FOR INFUSION PUMPS, A CLAMP AND A CLAMP MAGAZINE FOR USE THEREWITH
FIELD OF THE INVENTION
The present invention is in the field of devices used in aclministering fluids to patients.
More specifically, the present invention provides a clamp, a magazine for holding a multiplicity of such clamps, and a device for feeding said clamps for sealing a fluid supply tube and for prevention of free flow on disconnection of said tube from a peristaltic pump.
BACKGROUND OF THE INVENTION
The use of infusion sets and the need for clamps in such sets has been well explained by Winterer et al. in his foreword to U.S. Patent No. 5,704,584.
The use of infusion sets to administer medical solutions to patients is well known and higher in use in the medical arts. Infusion sets are used for both enteral and parenteral applications. Enteral feeding pumps are used to provide patients with nutrition and medication when they are unable to eat normally. Parenteral (intravenous) solutions are provided to patients to ensure adequate hydration and to provide needed nutrients, minerals and medication in a variety of instances. When precise flow control is not required, the infusion set may be placed in a freestanding arrangement in which gravity drives the fluid into the patient. Rough flow control can be achieved by use of roller-type clamps or by other types of clamps, which are commercially available. When more precise flow control is required, for example when the fluid being administered contains medicines, a regulating pump such as a peristaltic pump is used. Typically, an infusion set comprises flexible tubing fitted with an inlet for connecting to a fluid container, an outlet for connecting to a needle or a catheter, and also a manually operated clamp, in most cases a roller-type clamp. Thus, when using peristaltic pumps, the clamps which are typically provided with the infusion set, are manually opened or altogether removed, as such clamps would interfere with the normal functioning of the pump and would influence the flow rate. However, at times infusion sets are not provided with a clamp whatsoever. When provided, the roller clamp may be closed to stop flow through the infusion set with the intention that the medical personnel connect the pump or other regulating device to the infusion set. However, emergencies or other distractions may prevent these persons from properly attaching the pump or other regulating device or properly operating the clamp. When the infusion set is not properly positioned in the pump, a free- flow situation may develop. Gravity then causes the solution to flow freely over the floor, or if the infusion set is already connected to the patient, the solution may freely flow into the patient, not controlled by the pump or other regulating device, resulting in the patient receiving an overdose. This can be particularly dangerous if the solution contains a potent medicine and if the patient is too weak to adjust to a large inflow of whatever solution is being administered.
Kent in U.S. Patent No. 4,585,441 proposes to solve this problem by adding a flow sensor to the IV set, and by providing an interlock which prevents removal of the IV set from the pump or other controller unless flow has stopped. Thus the pump operator closes a clamp before removing the IV set.
A simpler system, variations of which are found in a number of U.S. patents, uses a clip which is inserted in some form of holder and held in its open position as long as the pump door is closed or the pump mechanism is operating. Removal of the IV set from the pump automatically releases the clip to its closed position to prevent free flow. The clip is assembled to the IV set, so a new clip needs to be inserted into the pump for successive use. Examples of such systems are seen in U.S. Patents Nos. 5.017,192, 5,401,256, 5,437,642 and 5,704,584.
The finding, handling and insertion into the pump of this small item is a bothersome task for the medical personnel. Failure to insert such a clamp will render the pump inoperative if an interlock is provided. If no interlock is provided, the pump will operate without the clamp and the danger of a free-flow situation remains.
Therefore, it is a primary object of the present invention to obviate the disadvantages of prior art infusion systems and to provide a system which obviates the need for handling individual clamps.
It is a further object of the present invention to provide a system which automatically assures tube clamping before removal of the infusion set from the pump, also when a set is not originally provided with an integral clamp.
SUMMARY OF THE INVENTION The present invention achieves the above objects by providing a clamping system for a peristaltic pump used in combination with a flexible tube segment of a medical liquid infusion set. The system comprises a clamp magazine for holding a plurality of stacked clamps urged towards a clamp expelling opening, a first clamp being located proximal to said expelling opening. Each clamp is formed with a slot having a neck portion oriented to face the flexible tube. An urging mechanism is arranged for expelling the first clamp through the expelling opening towards the flexible tube into clamping engagement therewith so as to interfere with fluid flow through the lumen of the tube.
In a preferred embodiment of the present invention there is provided a clamping system wherein the urging mechanism comprises a solenoid-activated feeding arm projecting into the magazine for engagement with the first clamp. Alternatively, the urging mechanism comprises an electric motor or a spring biased feeding arm. In accordance with a most preferred embodiment of the present invention there is provided a clamping system wherein said urging mechanism is triggered to expel the first clamp upon movement of a release latch retaining a tube-retaining door of said pump, or upon opening of the pump's door. Alternatively or in addition, the urging mechanism may be triggered to expel the first clamp by a suitable switch.
Preferably the system is also fitted with a detection system for detecting and alerting when the clamp magazine is about to empty.
According to another aspect of the present invention there is provided a clamp for closing a flexible tube segment of a medical liquid infusion set, said clamp being a flat element formed with clamping slot having a widened neck portion for facilitating engagement with said tube segment, a continuation of said slot being sufficiently narrow to close the lumen of said tube segment when engaged therewith. Preferably, the clamp is made of a plastic material which renders it some flexibility for facilitating engagement with the tube on the one hand, and on the other hand it is of sufficient rigidity to ensure tight clamping of the tube and closing the lumen.
According to still another aspect of the invention, there is provided a clamp magazine for use in conjunction with a clamping system with which the invention is concerned, said clamp magazine retaining a plurality of clamps and being formed with a clamp expulsion opening, said opening when assembled in said pump facing said flexible tube segment; said plurality of clamps being biased towards said expulsion opening, and said neck portion of said first clamp being oriented to face said flexible tube segment. Preferably the plurality of clamps are stacked.
By a specific design, the clamp magazine comprises a first end wall and an opposite second end wall, and configured for storing therebetween and dispensing a multiplicity of stacked clamps as defined hereinabove, a compression spring being disposed between said second end wall and said stack urging said stack towards said first end wall, said magazine being configured to be removably loadable into a peristaltic pump. Typically the magazine and the clamps are disposable.
It will thus be realized that the novel device of the present invention serves to eliminate the danger of free-flow conditions in infusion sets, yet without reliance on the attention of medical personnel who may be distracted by other tasks, the device being useful also in minimal cases where the infusion set is not a priori fitted with a clamp. Furthermore, the magazine holding a large number of clamps eliminates individual handling of these small items, which enables medical staff to concentrate their attention on more important matters.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to understand the invention and to see how it may be carried out in practice, a preferred embodiment will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:
Fig. 1 is a perspective view of a peristaltic pump used to adiriinister fluid from an TV set to a patient;
Fig. 2 is a perspective view of the same pump, the door being opened to reveal a tube clamping system according to the present invention;
Fig. 3 is a perspective, partial view of a mechanical embodiment of the clamping system; Figs. 4, 5 and 6 are perspective, partial views of electrical embodiments of the clamping system;
Fig. 7 is a perspective view of a clamp for use with the system;
Figs. 8 and 9 are perspective views of magazines for holding clamps; and
Figs. 10A and 10B are views of a magazine fitted with a last clamp alert system, at a full state and at a last clamp, alerting state, respectively.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
There is seen in Fig. 1 a peristaltic pump 10, used in combination with a flexible tube segment 12 of a medical liquid infusion set 14. The pump 10 is in flow adjustment according to medically-determined need as known per se. Tube segment 12 is an extension of a flexible tube 16 which leads from the infusion bag 18 through the pump 10 which regulates flow through the segment 12 according to the chosen flow setting. A tube continuation 20 extends from the segment 12 and is in turn connected to a patient 22 (i.e., by a needle or a catheter).
With reference to the rest of the figures, similar reference numerals have been used to identify similar parts.
Fig. 2 shows the pump 10 with its door 24 open to reveal the addition of a clamping system 26 according to the present invention, assembled inside the pump 10.
As seen in Fig. 2, prior to the opening of the pump door 24, the clamping system 26 has pushed a clamp 28 onto the flexible tube segment 12 to close the lumen 30 thereof, thereby preventing a free-flow condition occurring through the infusion set (owing to gravity force) which could be damaging to the patient 22 and unpleasant if flowing on the floor.
The open door 24 allows removal and replacement of the infusion set 14. In addition, if flow is to be resumed through the set 14, then the clamp may be easily manually removed and the set is then ready for use again.
An embodiment of a mechanically operated clamping system 32 is shown in Fig. 3 without the pump 10. A clamp magazine 34 holds a plurality of stacked clamps 36 urged towards a clamp expelling opening 38, facing the tube 12.
A first clamp 40 is located proximal to opening 38, thus being a so-called duty or stand-by clamp, i.e., the clamp to be next utilized. Each clamp 36 is formed with an open slot 42, seen to better effect in Fig. 7, and a widened neck portion 44 is oriented to face the flexible tube segment 12.
An urging mechanism 46 is arranged for expelling the first clamp 40 through opening 38 towards flexible tube segment 12 into clamping engagement therewith, as seen in Fig. 2. In the present embodiment the urging mechanism 46 includes a helical compression spring 48 which is released by a catch 50 when the spring catch handle 52 is turned down, before the pump door 24 can be opened. The catch handle 52 in its upper position as shown prevents opening of the pump door 24. A feed arm 54 ejects first clamp 40 from the magazine 34. The user returns the feed arm 54 to its starting position and re-compresses the spring 48 by pressing in feed arm extension 56, then lifting the spring catch handle 52 to retain the spring 48 in its compressed state.
As the handle in its upper position obstructs the door 24, door 24 cannot be inadvertently opened before lowering the handle 52, which activates the clamping system 32 and thus ensures that the tube lumen is closed and so prevents free-flow conditions in the infusion set 14.
Reference is now made to Fig. 4 of the drawings in which a clamping mechanism 58 comprises an electrical urging member 60. The urging member includes a solenoid-activated feeding arm 62 projecting into clamp magazine 63 for engagement with the first clamp 40.
Starting to open the pump door 24 operates a micro-switch 64 which immediately triggers the urging member 60 to expel first clamp 40 and to engage the clamp 40 with flexible tube segment 12 of the medical liquid infusion set. The magazine 63 comprises also a last clamp alert system 65, which will be referred to in more detail with reference to Fig. 10.
Referring now to Fig. 5, there is depicted a flexible tube clamping system 66 similar to that described with reference to Fig. 4.
However, in the embodiment of Fig. 5 the pump door 68 has a release catch 70 which must be unlocked before the pump door 68 can be opened. When the release catch 70 is turned clockwise before the door 68 can be opened, the micro-switch 72 triggers a momentary electric pulse to activate the solenoid 74 and so to expel first clamp 40. Thus activation of the clamping mechanism 66 is assured before the flexible tube segment 12 loosens the support of the door 68. Fig. 6 shows a further clamping system 76, again similar to that described with reference to Fig. 4.
The urging member is a solenoid 60 triggered to expel first clamp 40 upon operation of a manual switch 78. Advantageously a door activated switch 80 and an electrical interlock circuit 82 are provided which switch on a red warning light 84 if the pump door 86 is opened before the manual switch 78 has been operated to clamp the tube segment 12.
Fig. 7 illustrates a clamp 88 for closing flexible tube segment 12 of a medical liquid infusion set 14 seen in Fig. 1. The clamp 88 is a flat element, typically 1-2 mm thick. The clamp provides several advantages - tube cutting is prevented owing to its shape, the clamp does not skew when pushed onto the tube, and potential clamp feeding difficulties are eliminated. The essentially thin clamps enable stacking a large quantity of clamps within a magazine. The clamp 88 is formed with a clamping slot having a widened neck portion 44 for facilitating engagement with tube segment 12. A continuation 42 of the slot is sufficiently narrow to securely close the lumen 30 of tube segment 12 when engaged therewith. Preferably, the slot is chamfered to prevent sharp edges from injuring the tube. There is no need for the clamp 88 to deform elastically during application, as the tube is being clamped, typically made of a silicon or PVC, deforms sufficiently for closure of the tube lumen 30.
Advantageously the clamp 88 is sized for use in combination with the clamping system 26 seen in Fig. 2. Reference is now made to Fig. 8 of the drawings in which a clamp magazine 90 is seen. The magazine 90 is configured for use in conjunction with the clamping system seen in Fig. 2.
The magazine 90 retains a plurality of stacked clamps 92 and is formed with a clamp expulsion opening 94. The opening 94, when the magazine 90 is assembled in the pump 10, faces the flexible tube segment 12. A plurality of clamps 92 are biased towards the expulsion opening 94. The neck portions 96 of the clamps are oriented to face the opening 94.
In the present embodiment the magazine is oriented with the clamp stack above the opening 94. A weight 98 (or a spring), suitably of metal, above the stack ensures that the clamps 92 feed out in an orderly manner.
Preferably the clamp magazine 90 is disposable. The clamps 92 and weight 98 are sealed in the magazine 90 during manufacture and no clamp refill opening is provided or needed.
Referring now to Fig. 9, there is depicted a clamp magazine 100 which can be operated with the clamp stack 102 below the opening 104. Such magazine orientation could be useful where there is no room inside the pump for a magazine 90 shown in Fig. 8.
Magazine 100 has a first end wall 106 and an opposite, second end wall 108, and is configured for storing therebetween and dispensing a multiplicity of stacked clamps 110.
A compression spring 112 is disposed between second end wall 108 and the stacked clamps 110, urging the stack towards first end wall 106. Thus the magazine can be used in any orientation, whichever is most suitable for the peristaltic pump into which it is to be loaded. The clamp magazine 100 is preferably configured for use in combination with a clamping system 26 as described with reference to Fig. 2.
By a preferred embodiment of the invention, the system may also be fitted with a detection system for detecting and alerting when the clamp magazine is about to empty. Such a system is illustrated in Fig. 10. The detection system comprises a light emitting diode 120 and a corresponding light receiver diode 122, both located adjacent the expelling opening 124 of a magazine 126, at a predetermined height, i.e. corresponding with the thickness of one clamp (or few more). When the magazine is loaded with more than the predetermined number of clamps, as illustrated in Fig. 10A, the light emitted from diode 120 is blocked by clamp 128 and receiving diode 122 does not issue a warning signal. However, when the level of clamps within the magazine drops below the predetermined level (see Fig. 10B), light issued from diode 120 is received by diode 122, the latter issuing an alarm signal, which may be a visual signal, an audio signal or a combined signal. Alternatively, or in combination, the alert signal may activate a security mechanism such as an alternative clamping mechanism.
While preferred embodiments have been shown and described, it is to be understood that it is not intended thereby to limit the disclosure, but rather it is intended to cover all modifications and arrangements falling within the spirit and scope of the invention, mutatis mutandis. For example, solenoids may be replaced by motors (typically electric motors) or pneumatic actuators, and switches may be replaced by suitable sensors, such as optic sensors.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|FR2345141A1 *||Title not available|
|US4434963 *||22 Dec 1982||6 Mar 1984||Baxter Travenol Laboratories, Inc.||Slide clamp including elevation stabilizer|
|US4585441||17 Sep 1984||29 Apr 1986||Minnesota Mining And Manufacturing Company||IV fluid control system with fluid runaway prevention|
|US5017192||20 Oct 1989||21 May 1991||Minnesota Mining And Manufacturing Company||Free flow prevention system for infusion pump|
|US5401256||14 Jan 1994||28 Mar 1995||Minnesota Mining And Manufacturing Company||Flexible clamp for use in IV tubing set|
|US5437642||1 Jun 1993||1 Aug 1995||Minnesota Mining And Manufacturing Company||Free flow prevention system for infusion pump|
|US5704584||10 May 1996||6 Jan 1998||Zevex, Inc.||Pinch clip occluder for infusion sets|
|Cooperative Classification||A61M39/281, A61M2209/06, A61M39/287|
|18 Nov 1999||AL||Designated countries for regional patents|
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