Valve means for enteral therapy administration set

A one way valve means for incorporation into a fluid administration set for enteral therapy which arrests retrograde movement of fluid into the set to avoid flow rate interruption or, in the event of extreme fluid back pressure, rupturing of the tubing in the set. The one way valve means is responsive to fluid back pressure and is incorporated in a male connector disposed on a distal end of the administration set tubing. As a result retrograde fluid movement caused by either irrigation or patient originated, fluid back pressure is immediately arrested before fluid enters the administration set.

DESCRIPTION 
1. Technical Field 
The present invention generally relates to the field of enteral therapy, 
and, in particular, to a one way valve means for preventing fluid backflow 
or retrograde fluid movement through an enteral fluid administration set. 
2. Background Art 
Enteral therapy is achieved through intubation of a nasogastric feeding 
tube. Typically, the feeding tube is joined at a proximal end to a 
container, which provides a source of nutritional solution. Interposed 
between the proximal end of the feeding tube and the container is a fluid 
administration set. For gravity feeding of enteral solutions the set 
typically comprises a segment of tubing linking the feeding tube with the 
container. Usually the tubing segment has an inner diameter larger than 
the inner diameter of the feeding tube. In addition, the tubing segment 
includes a male connector on a distal end for seating in a female 
connector disposed on the proximal end of the feeding tube. A tube clamp 
for regulating fluid flow may also be interposed along the tubing segment. 
A drip chamber may also be carried on the tubing segment near the 
container. The drip chamber may also include a hollow spike for connecting 
to the container of enteral nutritional solution. 
Where pumping of enteral fluid is desired a pump administration set is 
connected to the proximal end of the feeding tube. A pump administration 
set comprises essentially the same elements of a gravity feeding set 
except that a pump set also includes a portion of specially selected 
tubing, often made from silicone, which is interposed along the tubing 
segment. This portion of silicone tubing is wrapped around the rotor of a 
peristaltic pump and is sequentially occluded by the rotor to achieve a 
pumping action. 
To irrigate, aspirate or administer oral medications through a nasogastric 
enteral feeding tube, a "Y" connector may be inserted between the proximal 
end of the feeding tube and the male connector of the administration set. 
More recently, Y connectors have been integrally formed on the proximal 
end of the feeding tubes to eliminate the need for separate Y connector 
sets. By using a Y connector, the feeding tube can be irrigated, aspirated 
or injected with medication without disconnecting the feeding tube from 
the administration set. A side arm of the Y connector receives a luer tip 
syringe or may be adapted to receive a cath tip syringe. 
A problem with Y connectors is that if the feeding tube is occluded, the 
pressure of irrigating fluid, for example, is directed in a retrograde 
direction into the administration set. Prior to Y connectors, this 
pressure was released when the feeding tube was disconnected from the 
administration set. The fluid pressure created by a 50-60 ml. irrigating 
syringe can exceed 20-30 psi. In the case of pump administration sets, the 
fluid pressure travels through the set until it meets the resistance of 
the occluded tubing wound around the pump rotor and bursts the tubing. To 
avoid this costly result, which requires replacement of the fluid 
administration set and an interruption in patient therapy, a pinch clamp 
may be used distal to the connection of the administration set with the 
feeding tube. In the alternative, the user may pinch the tubing at this 
same point. However, if the user neglects to do this or the pinch clamp 
fails, then rupture of the administration set will likely result during 
irrigation or medication administration. 
In addition to retrograde fluid movement created by irrigation backflow, it 
has been observed that retrograde movement of fluid within the feeding 
tube and into the administration set also results when an intubated 
patient moves, coughs, laughs or belches. That is, the source of fluid 
back pressure within the administration set is the patient himself. Such 
patient-originated retrograde fluid movement disrupts accurate fluid flow 
rate which is important to effective enteral therapy. 
Hence, prior to the development of the present invention a need existed for 
a one way valve means to be incorporated preferably into a distal segment 
of a fluid administration set which would respond to fluid backflow 
pressure and automatically arrest retrograde movement into the tubing of 
an administration set. 
SUMMARY OF THE INVENTION 
According to the present invention, a one way valve means for incorporation 
into a fluid administration set for enteral therapy has been developed 
which responds to fluid backflow pressure and arrests retrograde movement 
of fluid into the set thereby avoiding any rupturing of the tubing in the 
set. In the broader aspects of the present invention, the one way valve 
means may be interposed in a pump administration set anywhere between the 
portion of administration set tubing which is wound around the rotor of a 
peristaltic pump and the proximal end of the feeding tube. In a gravity 
fed administration set the one way valve means may be interposed anywhere 
along the tubing distal to the clamp which regulates fluid flow. In the 
preferred embodiment of the present invention, the one way valve means is 
incorporated in a male, luer type connector disposed on a proximal end of 
the administration set tubing. As a result, retrograde fluid movement 
caused by either irrigation or patient-originated fluid back pressure is 
immediately arrested before fluid enters the administration set. 
Broadly, the one way valve means of the present invention may embody duck 
bill valves, ball check valves, flap valves or any one way valve known in 
the medical fluid administration art which responds to a selected level of 
fluid pressure. In the preferred embodiment of the present invention, a 
ball check valve is carried within the male luer type connector near the 
distal end of the tubing segment. Hence, any significant fluid backflow 
pressure causes the ball to seat to prevent any fluid flow into the 
administration set. 
Other advantages and aspects of the invention will become apparent upon 
making reference to the specification, claims, and drawings to follow.

DETAILED DESCRIPTION 
While this invention is susceptible of embodiment in many different forms, 
there is shown in the drawings and will be described in detail a preferred 
embodiment of the invention. The present disclosure is to be considered 
only as an exemplification of the principles of the invention and is not 
intended to limit the broad aspect of the invention to embodiment 
illustrated. 
Referring now to the drawings, FIG. 1 discloses enteral therapy fluid 
delivery system utilizing a peristaltic pump 10, a nasogastric feeding 
tube 12, a pump administration set generally referenced by 14 and a 
container 16 providing a source of therapeutic fluid. Feeding tube 12 
carries a Y connector 18 on a distal end of the tube. Connector 18 
includes a primary arm 20 and a side arm 22. Primary arm 20 embodies a 
female connector to join feeding tube 12 to pump administration set 14. 
Side arm 22 may receive a syringe tip for aspirating, irrigating or 
administering oral medications into feeding tube 12. 
Pump set 14 is exemplary of prior art pump sets and includes a segment of 
tubing 24 which generally has an inner and outer diameter larger than 
feeding tube 12. Disposed on a distal end of tubing segment 24 is a male 
connector 26 which seats within the primary arm 20 of feeding tube 12. As 
will be explained later in greater detail, in the preferred embodiment of 
the present invention, male connector 26 carries a one way valve means 
responsive to fluid back pressure to arrest retrograde fluid movement from 
feeding tube 12 through tubing segment 24. 
Distal to male connector 26, pump set 14 also includes a separate portion 
of tubing spliced in tubing segment 24 which functions as a pump body 28. 
As disclosed in FIG. 1, pump body 28 is stretched and wound around a rotor 
30 of pump 10 to thereby sequentially compress pump body 28 to generate a 
peristaltic pumping action. For durability, pump body 28 is formed from 
silicone. 
Immediately distal to pump body 28 is a drip chamber 32 which acts to 
evenly deliver fluid in the pump body 28. Finally, near the distal end of 
the tubing segment 24 is a clamp 34 for regulating fluid flow to drip 
chamber 32. 
FIG. 2 discloses an administration set 14' which is utilized for gravity 
fed enteral therapy. Set 14' includes a segment of tubing 24' on a distal 
end of which is a male connector 26'. In a preferred embodiment of the 
present invention, male connector 26' carries a one way valve means 
responsive to fluid back pressure to arrest retrograde fluid movement from 
feeding tube 12 through tubing segment 24'. 
In gravity administration set 14', tubing segment 24' does not include a 
pump body 28. As a result, a drip chamber 32' is positioned at the 
proximal end of tubing segment 24'. Near drip chamber 32' is a clamp 34'. 
To irrigate, aspirate or administer oral medications through feeding tube 
12, a syringe tip may be inserted into side arm 22 carried on the proximal 
end of feeding tube 12. However, if feeding tube 12 is occluded or a 
syringe of an improper size is selected, fluid back pressure results in 
feeding tube 12 and travel through tubing segment 24 of, for example, pump 
administration set 14. Typically, such fluid back pressure will continue 
to move in a retrograde direction through tubing segment 24 until reaching 
the portion of tubing segment 24 which carries pump body 28. Typically, 
the fluid back pressure ruptures the splice of pump body 28 with tubing 
segment 24. At a minimum, the administration set must be replaced and, as 
disclosed in FIG. 1, where the container 16 is permanently affixed to 
administration set 14, it is also necessary to replace the container. 
Retrograde fluid movement from the feeding tube into the tubing segment 24 
of an administration set has been observed to result when an intubated 
patient moves, coughs, laughs or belches. While patient originating fluid 
back pressure may not burst or rupture any portion of the tubing segment 
of the administration set, such retrograde fluid movement disrupts 
accurate fluid flow rates which are important to effective enteral 
therapy. 
Hence, in the preferred embodiments of the present invention, a one way 
valve means responsive to fluid back pressures may be incorporated within 
the male connector 26 of pump set 14 or male connector 26' of gravity set 
14'. Although such one way valve means may embody duckbill valves, flap 
valves or other one way check valves, preferably a ball check valve may be 
embodied within male connector 26. As best disclosed in FIGS. 3 and 4, 
connector 26' has an internal axial bore 38 which joins a fluid inlet 40 
on one end of connector 26 with a fluid outlet 42 on an other end of 
connector 26'. In normal operation, fluid flows from tubing segment 24' 
and enters connector 26' at fluid inlet 40, passes through axial bore 38 
and exits connector 26' at fluid outlet 42. Connector 26' is provided with 
a luer type fitting 44 so as to seat within primary arm 20 on feeding tube 
12. Fluid inlet 40 is provided with a recessed cavity 46 for receiving the 
distal end of tubing segment 24'. 
The one way ball check valve mechanism of connector 26 includes a valve 
chamber 48 which generally has inner dimensions larger than the inner 
diameter of bore 38. One side of chamber 48 which is directed to fluid 
inlet 40 defines a valve seat 50. Likewise, an other side of chamber 48 
which is directed to fluid outlet 42 carries a plurality of fingers 52 
which project from side walls 54 of chamber 48 which fingers 52 function 
as a valve stop. 
Finally, the ball check valve mechanism of the present invention includes a 
generally spherical valve member 56 which may freely float about chamber 
48. However, movement of valve member 56 within chamber 48 is limited in 
the direction of fluid outlet 42 by valve stops 52 and is likewise limited 
in the direction of fluid inlet 40 by valve seat 50. In response to fluid 
back pressure flowing into fluid outlet 42 and in the direction of fluid 
inlet 40 urges valve member 56 to move within chamber 48 in the direction 
of fluid outlet 40. If fluid back pressure is sufficient, then valve 
member 56 is forced to abut against valve seat 50, thereby sealing any 
fluid access to fluid inlet 40 to automatically arrest retrograde fluid 
movement into tubing segment 24. It should be understood that valve member 
56 could be replaced with a flap or by valve, duckbill type arrangement 
which would likewise respond to sufficient fluid back pressure to seal any 
fluid access to fluid inlet 40 thereby arresting retrograde fluid 
movement. 
While the specific embodiments have been illustrated and described, 
numerous modifications come to mind without significantly departing from 
the spirit of the invention and the scope of protection is only limited by 
the scope of the accompanying claims.