Patent Application
20220151876
The present invention relates to a feeding tube, and in particular to a gastric feeding (gastrostomy) tube (eg a G-tube).
Adequate nutrition and medication are essential for patients recovering from surgery, illness or suffering from chronic conditions or congenital problems. In many cases, patients may be unable to suck or swallow and are therefore unable to take adequate nutrients or medicines orally. In these situations, patients may be fitted with a gastrostomy tube (also known as a feeding tube, gastric feeding tube or G-Tube). The gastrostomy tube provides a means to introduce a nutrient and/or medication directly into the stomach.
Gastrostomy tubes are usually fitted to a patient through percutaneous endoscopic gastrostomy (PEG). A gastroscopy is performed to determine the location and anatomy of the stomach. This is typically performed by transillumination using a light source on an endoscope within the stomach. An incision is then made in the abdominal wall and a guidewire is inserted and then pulled out of the mouth. The gastrostomy tube is then attached to the guide wire and pulled in through the mouth, oesophagus and stomach and then out through the incision. In certain cases the gastrostomy tube may be positioned surgically. Once positioned, the gastrostomy tube remains in position and a stoma tract is established through the abdominal wall and into the stomach.
Once fitted, gastrostomy tubes may remain in position for a variable amount of time depending on the needs of the patient. For short-term recovery or respite the tube may only remain in place for a few days or weeks. For patients experiencing long-term chronic or congenital conditions such as problems of the mouth, oesophagus, stomach or intestines the tube may remain in place for several months or longer and may be replaced multiple times.
A conventional gastrostomy tube is typically a flexible tube composed of silicone or polyurethane. A bolster is positioned at the internal end of the tube (i.e. the end intended to be positioned within the stomach). A bolster helps to retain the tube in position whilst sealing the stomach wall. In recent times balloons tend to be used on replacement gastrostomy tubes in preference to bolsters due to ease of removal. Balloon gastrostomy tubes have a bulb which can be inflated once inside the stomach (using sterile water or another fluid) to prevent the tube being pulled out through the stoma tract. The balloon can be deflated again when the tube needs to be removed.
To enable in situ inflation and deflation of the balloon, the tube requires two channels or lumens: a main channel to carry a nutrient and/or medicine into the stomach (or to drain the contents of the stomach) and a secondary channel to carry fluid to inflate the balloon. It is important to ensure that these channels remain separate to prevent stomach fluids escaping, or premature deflation (or over-inflation) of the balloon. The two channels (or lumens) are usually positioned within the same tube and are separated by an internal wall.
In addition to the balloon (or bolster), an external retention device is positioned on an external portion of the tube (i.e. a portion positioned or intended to be positioned outside the body of the patient). In use, the external retention device is positioned against the patient's abdomen. It supports the tube and prevents the tube from being drawn further into the stomach. Together with the balloon (or bolster) within the stomach, the external retention device limits longitudinal movement of the tube once in place.
Balloon gastrostomy tubes can be replaced by simply deflating the balloon and then pulling the tube out through the stoma tract. A new tube with a deflated balloon can then be inserted through the stoma tract and the balloon inflated once inside the stomach. This simple procedure can often be carried out at home without assistance from a clinician. In comparison, gastrostomy tubes with rigid bolsters or bumpers must be removed by a clinician.
The external end of the tube (i.e. the end intended to be positioned outside the body) typically has a Y-port. The Y-port has two connection ports: a feed connection port to allow food or medicine supplies such as a feeding bag to be connected to the main channel; and a balloon inflation port to allow a pressurised fluid supply to be connected to the secondary channel to inflate or deflate the balloon.
The Y-port is typically secured to the external end of the tube via an adhesive and/or by mechanical attachment. Bonding a silicone tube to a hard plastic Y-port is not straightforward: the low relative surface energy of silicone rubber means that it does not readily interact with adhesives or other surfaces. Chemical alteration to improve adhesion of the silicone is not necessarily an option for medical grade silicone tubing as it must remain bioinert and not cause irritation to the patient. Typically the tubing at the connection to the Y-port has to be textured (e.g. with a “Chrisonas tree” type connection) used in combination with a specific adhesive. This attachment is a common cause of tube failure.
The connection between the tubing and the Y-port may become loose over time, leading to leaks or a loss of balloon pressure. The Y-port itself may also become damaged or require changing to enable attachment of different or updated devices. Regular manipulation of the Y-port is necessary to attach, change and remove medicine or nutrient supplies. The Y-port may fail as a result of repeated pulling, tugging or snagging on clothes. The seals or threads may become damaged through wear after repeated use. This wear may be exacerbated through contact with corrosive stomach acids, particularly if the gastrostomy tube is used to drain stomach contents.
Given the complexity of the connection between the tube and the Y-port, it is not possible to fix the connection or replace the Y-port without removing and replacing the entire gastrostomy tube. This increases costs, results in more wastage and is inconvenient for the patient.
Often a clamp is placed on the external portion of the tube between the external retention device and the Y-port. The clamp can be used to close the main channel of the tube to prevent gastric fluids escaping during (for example) changing of the feeding bag. However the clamp also closes the secondary channel. This can cause the pressure of fluid within the balloon to increase, potentially leading to failure of the balloon. The clamp can also damage the internal wall separating the two channels of the tube over prolonged and repeated use. Failures of the internal wall and balloon are not possible to rectify without removing and replacing the entire gastrostomy tube, again resulting in increased costs and wastage as well as inconvenience and discomfort to the patient.
The present invention seeks to improve the performance of gastrostomy tubes, in particular by reducing the risk of component failure.
Viewed from a first aspect the present invention provides a gastrostomy tube for enteral nutrition or medication of a subject, comprising:
The substantially Y-shaped connector may be a connector having three arms which extend radially from a juncture. The three arms may be substantially coplanar. The three arms may have the same length or different lengths. The arms may extend substantially equiangularly from the juncture. For example, each of the angles between adjacent arms may be about 120°. Alternatively two of the three angles between adjacent arms may be the same or the three angles may be different.
Preferably an angle between a first arm (having the first port) and a second arm (having the second port) is about 180° (ie the first and second ports are substantially coaxial). Preferably an angle between the first arm and a third arm (having the third port) is larger than an angle between the second arm and the third arm.
The gastrostomy tube of the present invention has the substantially Y-shaped connector at an intermediate position along the delivery channel remote from an outer terminus of the delivery channel at the second end of the second flexible tube. This configuration offers several advantages. The Y-shaped connector is positioned closer to the body of the patient and is less likely to be damaged through snagging or pulling. By positioning the Y-shaped connector at an intermediate position along the delivery channel, the length of the first flexible tube can be reduced. This decreases manufacturing costs because a shorter length of the more complex, expensive dual lumen tube is required. As only the first flexible tube (and the internal retention device) is intended to be positioned within the stoma tract and stomach, this means that a smaller proportion of the gastrostomy tube must be made of high-grade material suitable for use in vivo.
By providing a second flexible tube, a feed connection port (which may be attached to the second end of the second flexible tube) can be longitudinally distanced from the Y-shaped connector. In use, this reduces the need to manipulate the Y-shaped connector as it is only actively used when inflating or deflating the balloon. This reduces the risk of failure of the Y-shaped connector and in particular the connection between the first flexible tube and the first port of the Y-shaped connector. If a feed connection port fails (for example as a result of repeated use), it can be removed from the second flexible tube and replaced without having to replace the entire gastrostomy tube.
Typically the conduit is a single conduit.
The second flexible tube provides a convenient site for clamping or otherwise shutting off flow along the delivery channel without the need to clamp the dual channel (lumen) first flexible tube.
The optimum length of the first flexible tube will vary depending on the patient. Larger patients will typically require a longer first flexible tube. As the second flexible tube is positioned entirely ex vivo its length is not dependent on the size of the patient. The first flexible tube may therefore be longer than, the same length as or shorter than the second flexible tube. Preferably the first flexible tube is between 5 cm and 15 cm in length. Preferably the length of the first flexible tube is minimised, i.e. the length is equal to or up to 2 cm longer than the length of the patient's stoma tract. This reduces the required amount of high grade material suitable for in vivo use.
Preferably a longitudinal distance between the substantially Y-shaped connector and the second end of the second flexible tube is equal to or greater than a longitudinal distance between the substantially Y-shaped connector and the internal retention device. In the context of this invention, “longitudinal distance” should be interpreted as a distance measured along the delivery channel (i.e. the main channel of the first flexible tube, an intermediate channel extending between the first and second ports of the Y-shaped connector and the conduit of the second flexible tube).
Preferably the second flexible tube is at least 5 cm in length. Even more preferably the second flexible tube is between 8 cm and 12 cm in length This provides spare material to allow the second flexible tube to be cut to a shorter length as required, and/or a new or replacement feed connection port to be attached.
The size (external diameter) of the first flexible tube will vary depending on the specific needs of the patient. Preferably the first flexible tube has a French size of between 10 and 22 inclusive.
Preferably a cross-sectional area of the main longitudinal channel is larger than a cross-sectional area of the secondary longitudinal channel. Preferably the cross-sectional area of the main longitudinal channel is between 2 and 20 times larger than the cross-sectional area of the secondary longitudinal channel. More preferably the cross-sectional area of the main longitudinal channel is between 7 and 12 times larger than the cross-sectional area of the secondary longitudinal channel.
Preferably the cross-sectional area of each of the main and secondary longitudinal channels remains substantially constant along the length of the first flexible tube.
The main longitudinal channel may have any suitably shaped cross-section to enable the transfer of the nutrient or medicine in liquid, suspension, paste or pulp form. Preferably the main longitudinal channel has a substantially circular, oval or substantially D-shaped cross-section. A substantially circular cross-section reduces the risk of blockages through the build-up of material in corners. A substantially D-shaped cross-section balances the advantages of the circular cross-section whilst ensuring an adequate minimum thickness of an internal separating wall between the main and secondary longitudinal channels.
Preferably the secondary longitudinal channel has a substantially circular cross-section. A substantially circular cross-section ensures that pressure forces from the balloon inflation fluid are distributed more evenly. This minimises forces exerted on the internal separating wall.
Preferably a cross-sectional area of the conduit is the same size or larger than the cross-sectional area of the main longitudinal channel. Where the cross-sectional area of the conduit is larger than the cross-sectional area of the main longitudinal channel, the intermediate channel of the Y-shaped connector extending between the second and first ports preferably tapers to gradually adjust the diameter of the delivery channel between the second and first flexible tubes. This helps to limit blockages.
The gastrostomy tube may further comprise a feed connection port attached to the second end of the second flexible tube. The feed connection port may be attached to the second flexible tube permanently. For example the feed connection port may be attached to the second flexible tube using an adhesive or a physical connector such as a “Christmas-ree” type connector, a friction fit or a clamp or grip-type connector. Where a permanent connection is used, the feed connection port can be replaced by cutting the second flexible tube to remove the feed connection port, and then fitting a new feed connection port using adhesive or a physical connection to the cut end of the second flexible tube. The feed connection port is preferably compatible with ENFit type connectors.
The first flexible tube and the substantially Y-shaped connector are preferably composed of a first material and the second flexible tube is preferably composed of a second material which is different from the first material. The first material is preferably silicone of a grade suitable for use in vivo. By forming the substantially Y-shaped connector and the first flexible tube from the same material, an appropriate adhesive can be selected to improve the strength of the bond between the first port and the first flexible tube. The first flexible tube may be connected to the Y-shaped connector by an adhesive and/or a physical connector such as a “Christmas tee” type connector or friction fit. Alternatively the first flexible tube and the substantially Y-shaped connector may be formed as a single continuous part. The second material is preferably polyurethane.
The gastrostomy tube may further comprise an external retention device adjustably mounted on the first flexible tube. The external retention device may be mounted to be adjustable longitudinally along the length of the first flexible tube. The external retention device may be mounted permanently (i.e. so it cannot be removed from the first flexible tube without breaking or cutting) or it may be mounted removably. The external retention device may be composed of a rigid plastic (such as polyvinyl chloride) or may be composed of a flexible material such as polyurethane or silicone. Preferably the external retention device is composed of a thermoplastic polyurethane.
The external retention device may retain its longitudinal position on the first flexible tube frictionally (for example through a tight friction fit around the circumference of the first flexible tube). Alternatively the external retention device may have a locking mechanism which is operable to grip the first flexible tube and prevent movement of the external retention device along the first flexible tube.
Preferably the external retention device has a main body and a locking arm hingedly connected at or near to the perimeter of the main body. The main body may have an aperture at or near to an end through which the first flexible tube may be snugly fitted. The first flexible tube may pass through a duct extending substantially perpendicularly away from the aperture along the main body. The duct may at least partially enclose the first flexible tube. By virtue of the aperture and duct, the external retention device may be slidable longitudinally along the first flexible tube to allow selective positioning.
Preferably the duct has a substantially circular cross-section of a size suitable to receive snugly the first flexible tube. Preferably the duct has an elongate slot in an outer wall. The first flexible tube may be able to pass through the aperture and the duct.
Preferably the locking arm is pivotal in an arc between an open position and a closed position. The closed position may be locked.
Preferably in the closed position, a locking rod on the free end of the locking arm is captured within a correspondingly-shaped groove on the main body.
The inner wall of the locking arm preferably has one or more teeth configured to pass through the elongate slot to contact and grip the first flexible tube positioned within the duct. This serves to prevent longitudinal movement of the first flexible tube in the locked position.
The gastrostomy tube may further comprise a clamp mounted to the second flexible tube. The clamp may be operable to shut off a fluid pathway between the first and second ends of the second flexible tube. By providing the clamp on the second flexible tube, an internal end of the delivery channel is selectively isolable from the feed connection port (for example when no nutrient or medicine source is connected). This prevents leakage of stomach acids through the feed connection port which could damage the seals and threads on the feed connection port as well as being unpleasant for the subject.
The clamp is advantageously mounted exclusively on the second flexible tube. By avoiding clamping the first flexible tube, the likelihood of the internal separating wall of the first flexible tube failing is reduced.
Preferably the internal retention device comprises a balloon having an elastic body with an interior void in fluid communication with the secondary longitudinal channel. The balloon may be inflated by passing fluid through the third port and secondary channel into the interior void. The balloon may be composed of a suitable material such as silicone. The fluid is preferably a liquid such as sterile water or a saline solution. The fluid may be applied from a syringe attached to the third port. The third port may be configured to attach directly a syringe. For example the third port may be provided with a thread which is engageable with a corresponding thread on the nozzle of a syringe. Alternatively a separate adapter may be attached to the third port to enable a syringe to be attached.
Viewed from a second aspect the present invention provides a kit of parts comprising: a gastrostomy tube as hereinbefore defined; and a nutrient/medicine container attachable or attached to the gastrostomy tube via the second flexible tube or the feed connection port.
The kit of parts may further comprise one or more adapters attachable to the second end of the second flexible port or the feed connection port. The adapter may permit various nutrient/medicine containers, syringes or other items to be connected.
The kit of parts may further comprise a syringe adapter attachable to the third port. The syringe adapter may permit a syringe to be attached to the third port.
The kit of parts may further comprise a first syringe attachable to the third port to supply fluid to and/or to remove fluid from the internal retention device. The first syringe may be preloaded with a predetermined quantity of sterile fluid. This prevents errors by ensuring that the internal retention device is charged with a sufficient quantity of fluid to prevent it being pulled out through the stoma tract of the subject prematurely, whilst avoiding over inflation of the balloon.
The kit of parts may further comprise a second syringe attachable to the delivery channel via the second flexible tube or the feed connection port. This second syringe advantageously enables the stomach contents of the patient to be periodically tested (for example pH measurement) or a test to be performed prior to removing and replacing a gastrostomy tube.
A specific implementation of the present invention will now be described, by way of example only, and with reference to the accompanying drawings in which:
Referring initially to
As best illustrated by
Referring now to
Each of the first, second and third ports 41, 42, 43 are shaped and sized differently to ensure correct assembly. The third flexible port 43 may be fitted with a suitable adapter (not shown) to enable attachment of a syringe. The first port 41 has a protruding wedge 46 which corresponds to a cutting in the external end 22 of the first flexible tube 2. The inflation channel 45 opens into the first port 41 at the protruding wedge 46. This ensures correct alignment of the first flexible tube 2 in the first port 41 so that the secondary channel 24 is aligned and in fluid communication with the inflation channel 45 and the main channel 23 is aligned and in fluid communication with the intermediate channel 44. The separating wall 25 and body of the Y-shaped connector 4 ensure that the intermediate channel 44 and main channel 23 are completely separated from and are not in fluid communication with the secondary channel 24 and the inflation channel 45. The Y-shaped connector 4 is composed of medical grade silicone. The external end 22 of the first flexible tube 2 is bonded to the first port 41 with a silicone adhesive.
Referring again to
The second flexible tube 5 has the same outer diameter as the first flexible tube 2. However, as the first flexible tube 2 has two internal channels and the second flexible tube 5 only has one internal channel, the cross-sectional area of the main channel 23 is smaller (and a different shape) to the cross-sectional area of the conduit 51. The intermediate channel 44 of the Y-shaped connector 4 is therefore tapered to gradually adjust the diameter and shape of the delivery channel. This gradual transition between the larger circular cross-section of the conduit 51 and the smaller substantially D-shaped cross-section of the main channel 23 aids the smooth movement of fluids along the delivery channel and prevents pressure build-ups or blockages.
As best illustrated by
The feed connection port 6 also has a cap 65 which can be screwed into the male port 63 to seal the open end of the central tube 67 and delivery channel. This may be advantageous to prevent backflow and leakage of stomach acids through the delivery channel when, for example, no nutrient or medicine source is connected to the gastrostomy tube 1. The cap 65 is attached to the main body 60 of the feed connection port 6 via a flexible arm 66.
Referring now to
A locking arm 72 is hingedly connected to the perimeter of the main body 70. The locking arm is pivotal in an arc between an open position (shown in
The gastrostomy tube 1 also has a clamp 8 positioned around the second flexible tube 5. The clamp 8 provides a convenient means to isolate the feed connection port 6 from the rest of the gastrostomy tube 1, for example when a nutrient or medicine source is attached or removed from the feed connection port 6. This prevents stomach acid backflowing up the main channel 23 and conduit 51 and leaking.
The clamp 8 has a first shoulder 81 and a second shoulder 82. The two shoulders are displaced longitudinally relative to each other at either end of a main body 84 and each have an aperture through which the second flexible tube 5 is passed. The second shoulder 82 has an arm 80 which is resiliently biased in an open position (shown) and can be moved into a locked position (not shown) to press the second flexible tube 5 against the main body 84 to close the conduit 51 and prevent fluid flow. The first shoulder 81 is also resiliently deformable and has a protrusion 83 which acts to retain the arm 80 in the locked position as required. The arm 80 can be released from the locked position by pulling the first shoulder 81 outwards (i.e. away from the second shoulder 82).
A patient being fitted with gastrostomy tube 1 will typically already have an established stoma tract owing to an earlier fitted gastrostomy tube or PEG procedure. As shown in
Once the internal retention device 3 is positioned against the stomach wall 93 as shown in
Once the gastrostomy tube 1 is in position, a nutrient or medicine source can be connected to the feed connection port 6. A nutrient or medicine can then be delivered into the stomach through the delivery channel along the entire length of the gastrostomy tube 1.
Where a nutrient or medicine source needs to be attached to the feed connection port 6, removed or changed, the clamp 8 around the second flexible tube 5 is first moved into the locked position to block the delivery channel. This prevents any backflow of stomach acids out through the feed connection port 6. By providing the clamp 8 on the single lumen second flexible tube 5 (rather than the dual lumen tube as in the prior art), the risk of damage to the separating wall 25 of the first flexible tube 2 is reduced. This reduces the overall failure rate of the gastrostomy tube 1 compared to existing tubes. During periods where no nutrient or medicine is required, the clamp 8 is typically retained in an open position to prevent permanent deformation or damage of the second flexible tube 5. In this situation the cap 65 can be screwed into the male part 63 of the feed connection port 6. This provides a seal to prevent backflow and leakage of stomach acids.
During use, it may be necessary to replace the feed connection port 6, for example to enable attachment of a nutrient or medicine source with a differently shaped connector, or because of damage to the feed connection port 6. In this case, the feed connection port can be replaced by simply cutting the second flexible tube 5 between the clamp 8 and the feed connection port 6 (when the clamp 8 is in the locked position). A new feed connection port 6 can then be fitted to the cut end of the second flexible tube 5.
It may also be necessary to use the gastrostomy tube 1 to drain the contents of a patient's stomach. This can be achieved by simply removing the nutrient or medicine source from the male port 63 of the feed connection port 6 (or opening the cap 65). With the clamp 8 open, the contents can then be drained through the gastrostomy tube 1. If rapid draining is required then the second flexible tube 5 can be cut to remove the feed connection port 6 entirely.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018212.7 | Nov 2020 | GB | national |
