ANTI-FREE FLOW MECHANISM FOR ENTERAL FEEDING PUMPS
An anti-free-flow mechanism includes an occluder mechanism which is disposed along a segment of tubing and a mounting structure. The occluder mechanism is normally in a biased closed position, but may be moved into an open position by placement in the mounting structure. However, unless force is applied to keep the occluder mechanism in the mounting structure, the occluder will move relative to the mounting structure and return to the first, closed position.
This application claims priority to U.S. Provisional Patent Application No. 61/041,561, filed Apr. 1, 2008, which is incorporated herein by reference in its entirety
The present invention relates to mechanisms for preventing free-flow in an infusion pump. More particularly, the present invention relates to methods and associated devices for preventing free-flow in an infusion pump while minimizing nuisance alarms.
The use of anti-free-flow devices with medical pumps is well known in the art. When a fluid is being infused into a patient, it is usually desirable for the rate of flow to be regulated. It is disadvantageous in many circumstances to have a condition, commonly referred to as free-flow, in which flow into the patient is controlled solely by the force of gravity. Such conditions can result in a large volume of solution being infused into a patient over a very short period of time. Due to medical conditions or medication contained in the infused solution, a free-flow condition can pose health concerns to a patient. In some situations it can even result in the death of the patient.
Because of these concerns, numerous devices have been developed to regulate free-flow in medical pumps. For example, several different anti-free-flow devices are shown in U.S. Pat. No. 7,150,727, which is incorporated herein by reference.
One challenge with the use of anti-free-flow devices is retrofitting presently existing pumps. While newer pump models are typically designed to accommodate anti-free-flow devices, pumps that are already in existence may lack such structures. One concern with occluders used with some existing pumps is that a free-flow condition can occur if the infusion set is not properly mounted in the pump. For example, if the occluder is mounted in a mounting structure and moved into an open position to allow flow but the infusion set is not properly wrapped around the rotor of the pump, there is nothing to control the rate of flow through the infusion set.
One solution to this problem has been the use of in-line occluders such as that shown in the '727 patent. An in-line occluder is placed and designed to prevent free-flow unless sufficient force is developed to expand the tubing sufficiently to allow flow past the occlude, or for an external structure to apply force to the infusion set and thereby open a channel between the infusion set and the occluder.
One problem with in-line occluders is that many older enteral feeding pumps develop relatively low pumping pressures. Because of this, the pumping pressure is occasionally inadequate to overcome the occluder or requires sufficient force that the pump inaccurately determines that there is an undesired occlusion downstream from the pumping mechanism. This causes the generation of an alarm which requires the response of medical personnel to determine that the tubing is in fact not occluded. These nuisance alarms waste the time and effort of medical personnel and unnecessarily disrupt the infusion process.
For example, as shown in
The occluder 1 is advantageous over many other occluders because it will prevent flow through the infusion tubing if the tubing is inadvertently removed from the pump rotor. Other occluders, such as some pinch clip occluders, are opened when the tubing 2 is mounted on the pump and will not close if the tubing becomes loose.
One issue with the occluder 1 configuration is nuisance occlusion alarms. Many older pumps, such as the pump 3, have relatively low pumping power and will detect on undesired occlusion downstream based simply on the pressure needed to bypass the in-line occluder. Thus, it is desirable to have an occluder mechanism which will allow flow without nuisance alarms when the infusion set is properly mounted on the pump, and which will prevent a free-flow condition through the line if the tubing comes off the pump rotor or is otherwise not properly engaging the rotor.
While consideration has been given to simply opening the occluder when the infusion set is mounted on the pump, this still leaves open the risk of a free-flow situation. If the infusion line were inadvertently removed from around the rotor, the rotor would no longer act on the infusion line to control fluid flow. Thus, a free-flow situation could develop, potentially injuring the patient. Thus, there is a need for an apparatus and method for providing protection against a free-flow condition while avoiding nuisance alarms.
An anti-free-flow mechanism for use with a medical pump and associated methods of use is disclosed. Embodiments of an anti-free-flow mechanism may include an occluder mechanism mounted on or in the infusion line which is biased into a closed position and which, when mounted on the pump, is opened as the infusion set is wrapped in tension around the rotor of the pump. The occluder mechanism may be configured to allow flow through the infusion tube as long as the tubing around the pump is in tension. In the event that tension is no longer present in the infusion pump around the tube, the occluder mechanism closes once again and prevents fluid from flowing through the tubing. Thus, flow through the tubing is not prevented as long as the tubing is properly mounted on the pump, but is terminated in the event that the tubing becomes loose.
According to some embodiments, the safety occluder is formed as a pinch clip which is biased so that the exterior of the tubing is pinched closed to prevent flow. Mounting the infusion set on the pump causes the pinching mechanism to be moved open. However, if the tubing is somehow removed from the rotor so that the infusion set is no longer in tension, the biasing element will return the pinching mechanism to an occluding orientation and thereby prevent fluid flow.
In other embodiments, a pinching mechanism is used to apply force to the tubing and thereby open a flow path past an in-line occluder when the infusion set is properly mounted in an infusion pump. However, when tension is released from the infusion set, the force on the tubing is released and flow through the infusion set is again stopped.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments are shown and described in reference to the numbered drawings wherein:
It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The various elements in the illustrated embodiments are exemplary and not comprehensive of all possible variations and embodiments. It is appreciated that not every element can be clearly displayed in a single drawing, and as such every drawing may not show each and every element of each embodiment.
The drawings will now be discussed in reference to the numerals provided therein so as to enable one skilled in the art to practice the present invention. The drawings and descriptions are exemplary of various aspects of the invention and are not intended to narrow the scope of the appended claims.
Turning now to
The occluder mechanism 10 may include a plunger or slider 24 which engages the tubing 14. A biasing element 28, such as a spring, may bias the slider 24 into engagement with the tubing 14 so as to pinch the tubing closed and thereby occlude the tube and prevent flow therethrough. Thus, the occluder mechanism 10 may be biased in a closed position which prevents flow.
An actuator 32, typically in the form of a pivot clip, may be disposed in engagement with the slider 24. Movement of the actuator 32, e.g. rotation of the pivot clip about an axis 34 (
The occluder mechanism 10 has at least one sloped sidewall 36 which is configured to allow the occluder mechanism to nest in the mounting structure 20 so that the sloped sidewall 36 engages a sloped sidewall 40 of the mounting structure 20 or some other structure in the sidewall. As the tapered occluder mechanism 10 slides into the tapered opening in the mounting structure 20, the wall 40 helps to center the occluder mechanism.
The wall 40 or a portion thereof may also engage the actuator 32 and push it inwardly into the occluder mechanism 10. This causes the slider 24 to move out of the closed, pinching position and into an open, non-occluding position where flow through the tubing 14 is enabled. Thus, mounting the occluder mechanism 10 in the mounting structure 20 opens flow through the tubing, as shown in
The engagement of actuator 32 and the sidewall 40 of the mounting structure 20, however, prevents the occluder mechanism 10 from remaining in the mounting structure in the event that the tubing 14 is not properly loaded. The biasing element 28 provides a force against the slider 24, and thus against inward movement of the actuator 32. If an external force is not applied to the occluder mechanism 10, the biasing element 28 will cause the occluder mechanism (via the slider 24 and actuator 32) to push against the mounting structure 20 to move upwardly, thereby returning the slider 24 into the occluding position. To overcome this biasing, the tubing 14 is placed in tension when it is wrapped around the rotor of the pump as represented by the arrow 50 in
If the tension on the tubing 14 is relieved, i.e. if the tubing inadvertently comes off the pump rotor, the lack of downward pull on the tubing represented by arrow 50 disappears and the bias of the biasing element 28 on the slider 24 and actuator 32 overcomes the effect of gravity on the occluder mechanism 10 and the pushes the occluder mechanism 10 upwardly in the mounting structure 20. This returns the actuator 32 to its original position and allows the slider 24 to occlude flow. It will be appreciated that the actuator 32 need not return the occluder mechanism 10 to the top of the mounting structure. Rather, the actuator 32 need only push the occluder mechanism upwardly sufficiently for the slider 24 to occlude flow through the tubing. This can be assisted by a void 48 in the sidewall 40 of the mounting structure 20.
It will be appreciated that the mounting structure 20 may be mounted on any number of different pumps in a variety of ways. Some pumps, such as that shown in
Turning now to
The mounting structure 20′ includes a sloped wall 40′ which interacts with a sloped wall 32a′ on the actuator 32′ As the occluder mechanism 10′ is drawn down into the mounting structure 20′, the wall 32a′ interacts with wall 40′ and pushes against the biasing element 28 to move the slider 24 into the open position. Due to the force of the biasing element 28, however, a downward force must be placed on the occluder mechanism 10′ to overcome the bias. This is done by the tension on the tubing 14. If the tension is released, the biasing element 28 will push against the slider 24, which will force the actuator 32 outwardly. The sloped interaction between the mounting structure 20′ and the wall 32a′ of the actuator 32 will cause the occluder mechanism 10′ to rise sufficiently that tubing 14 is pinched closed by the slider 24′.
It will be appreciated that the housing 12 of the occluder mechanism 10 or 10′ need not be sloped. Likewise, the entire wall 40, 40′ need not be sloped. Rather, only portions may be needed on the mounting structure 20 or 20′ and the actuator 32 or 32′, which interact to allow for conversion of the force of the biasing element 28 into movement of the occluder mechanism 10, 10′ when the tubing 14′ is not in tension.
It will be appreciated that the interior of the occluder mechanism 10 or 10′ may include a wall disposed on one side of the tubing 14 to aid the slider 24 to pinch closed the tubing. In other words, one side of the tubing 14 is held by the wall and the opposing side is engaged by the slider 24 to pinch the tubing closed.
Turning now to
The occluder mechanism 110 also includes a base 118. The base 118 may be configured to nest in a mounting structure, such as mounting structure 20′ in
The base 118 may include an actuator 132 which pivotably extends from the base. As shown in
Because of the slope presented by the far end of the actuator 132 when it is extended, extending the actuator will tend to lift the base out of the mounting structure (e.g. mounting structure 20′ in
Such a configuration may be highly advantageous in the context of a medical pump. If the infusion set is not properly loaded, the occluder mechanism 110 will remain with the plunger or slider 124 in the first, occluding position, thereby preventing a free-flow situation which could cause injury to the patient. Once the infusion set is properly loaded, the occluder mechanism 110 is moved into the second, open position where it will not interfere with the pump's operation and will be less susceptible to causing false occlusion alarms. In the event the tubing 14 is accidentally removed from proper placement on the pump (i.e. the tubing is inadvertently pulled off the rotor), the occluder mechanism is lifted or otherwise moved sufficiently to enable it to return to the occluding position. Thus, free-flow is avoided even when the tubing 14 is inadvertently removed from its proper position.
The mounts 174 and 178 include a receiving portion 180 which is tapered or generally frusto-conical (excepting the openings). The receiving portions can receive the occluder mechanism 10, 10′ etc. and facilitate lifting of the occluder mechanism if tension is not maintained on the tubing. It will be appreciated that other pumps may have receiving portions which are not tapered. However, the actuator 32 or 32′ can be configured to still engage the receiving portion and lift the occluder mechanism to thereby occlude flow.
Turning now to
Opening a flow channel past the stop 230 can be accomplished in several ways. One common method is to simply provide sufficient pressure to radially expand the tubing 14 so that a flow path opens around the tubing. As mentioned in the background section, however, this method can create false alarms suggestion that the tubing is occluded downstream.
Another method to open a flow channel may be to apply force to the tubing adjacent the stop 230. When force is applied, the tubing tends to deform and open a flow channel around the stop 230. By controlling where the force is applied to the stop, the configuration of the openings can also be controlled as discussed in the '727 patent. Applying force on one side can create a single channel, while applying force on opposing sides will create a flow channel on each side perpendicular to the application of force.
While it operates with an in-line occluder rather than a pinch occluder, the occluder mechanism 210 can function similarly to those discussed above in that when the occluder mechanism 210 is disposed in the mounting structure 170 or 220 and tension is applied, the tubing is opened for fluid flow controlled by the pump. If, however, tension is not present on the tubing, the biasing of the arms 214 (like the biasing element 128) will allow the tubing to be returned to an occluded orientation. Alternatively, the occluder mechanism 210 can be configured so it nests in the mounting structure 170, 220 and remains open regardless of tension on the tubing—thereby forgoing automatic closure if the tubing 14 is not loaded properly. Whether the occluder mechanism 210 provides automatic closure will depend on the engagement between the occluder mechanism and the mounting structure.
If medical personnel need to temporarily open the occluder mechanism 10, 10′, 110, 110′, 110″, 110′″ or 210, he or she need only apply force to the actuator 32, 32′, 132, 132′, 132″, 132′″ or 232 to open flow through the tubing. As soon as the pressure is released, however, the flow past the occluder is terminated. Thus, the risk that medical personnel accidentally leave the tubing in a free-flow state is eliminated.
Turning now to
Turning now to
The stop 330 has a plurality of projections 336 which are spaced apart to leave channels 340. The ends of the projections 336 are configured to remain in contact with the tubing 14, while the channels 340 allow fluid to flow along the stop for the distance for which the projections engage the tubing.
When the tubing 14 is placed in tension by mounting on a pump, a portion of the tubing 14 distal from the connector 316 is pulled away from the connector. The elastomeric tubing will stretch and the stop 330 is pulled at least partially out of the connector 316 as shown in
Turning now to
The first body 518 also includes a channel 530 configured for receiving a projection 534 on the second body 522. The second body 522 is configured to nest in and travel helically in the first body 518 under a bias from the by the torsional spring 526. As the second body 522 moves upwardly, the projection 534 travels in the channel 530, causing the second body to rotate as shown by arrow 540 in
When the tubing 14 is mounted in a pump under tension, the downward force on the tubing 14 pulls against the bias of the torsional spring 526 (
Thus there are disclosed embodiments of an anti-free-flow mechanisms and associated methods of use. Those skilled in the art will appreciate numerous modifications which can be made in light of the present disclosure that do not depart from the scope of the invention. The appended claims are intended to cover such modifications.
21. A device comprising:
- an occluder mechanism configured to selectively occlude fluid flow in tubing of an enteral feeding infusion set, the occluder mechanism having a base and an actuator, the actuator being movable angularly towards the tubing to engage the tubing and thereby allow fluid flow through the tubing as a result of the engagement; and
- a mounting structure configured to selectively and cooperatively engage the occluder mechanism; wherein when the occluder mechanism is cooperatively engaged with the mounting structure, the actuator is moved angularly towards the tubing to engage the tubing such that the occluder mechanism allows flow through the tubing, and when the occluder mechanism is not cooperatively engaged with the mounting structure, fluid flow through the tubing is prevented by the occluder mechanism.
22. The device of claim 21, wherein the occluder mechanism is held in the mounting structure by tension in the tubing.
23. The device of claim 21, wherein the mounting device is affixed to an infusion pump.
24. The device of claim 21, wherein the occluder mechanism is biased to prevent fluid flow through the tubing.
25. A system for selectively occluding flow through a tube comprising:
- a tubing segment;
- an occluder mechanism, the occluder mechanism comprising: a base; an occlusion member which engages the tubing to selectively prevent flow through the tubing; an actuator attached to the base, the actuator being movable angularly towards the tubing to engage the tubing and thereby allow flow through the tubing as a result of the engagement.
26. The system of claim 25, wherein the actuator is biased away from the tubing to prevent flow through the tubing.
27. The system of claim 26, wherein the actuator pivots towards the tubing to engage the tubing and thereby allow flow through the tubing.
28. The system of claim 25, wherein the occlusion member comprises a slide which pinches the tubing closed to thereby prevent flow through the tubing.
29. The system of claim 28, wherein the slide is attached to the actuator such that movement of the actuator moves the slide.
30. The system of claim 25, further comprising a mounting structure, wherein the occluder mechanism is moved into the mounting structure in a direction parallel to the tubing, and wherein mounting the base of the occluder mechanism in the mounting structure causes the mounting structure to engage the actuator and move the actuator into engagement with the tubing to thereby allow flow through the tubing.
31. The system of claim 30, wherein the mounting structure has a tapered receiving structure for receiving the base of the occluder mechanism.
32. The system of claim 30, wherein the mounting structure is a tapered receptacle and wherein the occluder mechanism is tapered and fits in the tapered receptacle such that movement of the occluder mechanism into the receptacle moves the actuator into engagement with the tubing.
Filed: Sep 30, 2014
Publication Date: Jan 15, 2015
Inventors: Kent Beck (Layton, UT), Jason Bultman (Salt Lake City, UT), Jeffery T. Juretich (Herriman, UT), Philip Eggers (Salt Lake City, UT), Ryan Federspiel (Salt Lake City, UT), Blake Allen (Murray, UT)
Application Number: 14/501,272
International Classification: A61J 15/00 (20060101);