TECHNICAL FIELD

The present invention relates to improvements in the method of removing catheters. The present invention also relates to devices that assist in the removal of catheters, which also alleviate the pain associated with the removal of catheters. Particularly, the present invention relates to a device that assists in the removal of renal catheters, including supra-pubic catheters and a method of using the device in the removal of renal catheters, including supra-pubic catheters.

BACKGROUND ART

A catheter is a flexible tube made of latex, silicone or Teflon that can be inserted into the body creating a channel for the passage of fluid or the entry of a medical device. There are many specialized catheter designs. The three major types of catheters are coronary, renal, and infusion. This invention is particularly concerned with renal catheters, including suprapubic renal catheters, which are renal catheters that are inserted into a patient's bladder directly through the patient's abdominal wall.

The best-known renal catheters are Foley catheters, which are equipped with an inflatable balloon and are used for patients with urine incontinence, terminally ill patients, and bladder drainage of patients following surgery or following an incapacitating injury or illness. The Foley catheter is relatively easy to use and is used throughout the world in hospitals, nursing homes, healthcare facilities and home-care settings. These catheters are usually left in place in the body but do need to be replaced periodically to reduce the possibility of infections. Typically, these catheters are replaced on a monthly basis by trained medical personnel. Commonly, when these catheters are removed and a new catheter is inserted, the patient experiences discomfort ranging from mild irritation up to excruciating pain and often there is also associated attendant bleeding, which in some cases may last up to several days and often results in hematuria (blood in the urine). Infections and hospitalisation are common experiences for patients using renal catheters, particularly when they are removed and inserted from the body in a conventional manner. A report by the National Health Service (UK) (NHS), Centre for Evidence-based Purchasing (CEP) Evidence Review, Bardex IC Foley Catheter, CEP 06001: Nov, 2006, pg 4 states that up to 40 per cent of all hospital acquired infections (HAI's) are due to Catheter Associated Urinary Tract Infections (CAUTI).

When inserted into a patient's bladder, renal catheters are retained by means of a balloon at the tip, which is inflated with sterile water or some other sterile solution. When the renal catheter is removed from a patient's bladder, the balloon is deflated by removing the sterile solution to allow the catheter to be removed. Conventionally, in order to drain the sterile solution from the balloon, a syringe is attached to a valve at the end portion of the minor y-branch of the catheter and the plunger of the syringe is pulled along inside a cylindrical tube (the barrel), allowing the syringe to take in the sterile solution through an orifice at the open end of the tube of the syringe.

One common reason for the pain associated with removing renal catheters in a conventional manner is that the inflatable balloon that is located at the tip of the catheter does not properly deflate when the sterile solution is removed from the balloon by a syringe. This is because of the vacuum pressure that is created in the catheter and the balloon when the plunger is pulled along inside the cylindrical tube (the barrel) of the syringe. As a result of this pressure, the side walls of the balloon can become stuck together, forming a relatively stiff, ridge-like surface. This problem is exacerbated where, in order to provide an alternative for patients with allergies, the Foley catheter, along with its components are made of silicone rubber rather than Latex rubber. Silicone rubber does not have the same elastic properties as Latex rubber. As a result, balloons of Foley catheters, and particularly those made from silicone rubber can exhibit "cuffing".

Cuffing refers to the situation in which the inflatable balloon tends to fold over on itself or shift toward the bladder end of the catheter. As the balloon is attached at its end to the shaft of the catheter, a cuff forms when the outer expanded portion of the balloon pushes over the inner attached end of the balloon. This cuff can remain when the balloon is deflated before withdrawal of the catheter from the bladder and possibly also the abdomen of a patient. The cuff results in the deflated balloon having a larger diameter than it did when it was first inserted. The increased diameter can result in discomfort and injury to patients when the catheter is removed from the patient.

When the renal catheter is removed from the patient's bladder, and particularly when removing a supra-pubic catheter from a patient's abdomen, the ridge-like formation and/or the cuff of the deflated balloon can cause movement or even rip and tear the sub-cutaneous tissue of the patient, resulting in excruciating pain for the patient and more often than not, attendant bleeding. The pain experienced by the patient leads to anxiety and fear surrounding the procedure, which decreases the quality of life and in some cases results in depression in the patient who may require the administration of anti-anxiety and/or anti-depressant drugs due to the ongoing trauma experienced during the regular catheter replacement procedures. In turn, the negative experience of the patient leads to increased stress levels for the medical clinicians carrying out the procedure.

Whilst it is generally not possible to eliminate the incidence of cuffing when the Foley balloon is deflated because of the increased surface area of the deflated balloon, it is desirable to minimise the trauma that can be caused to a patient when the catheter is removed as a result of the cuffed deflated balloon. One such approach would be to minimise the stiffness and rigidity of the ridges that are formed in the cuffed deflated balloon. In other words, it would be advantageous to provide a cuffed deflated balloon having soft, pliant and moveable ridges. This would reduce the trauma associated with the removal of a catheter from a patient.

There have been attempts in the past to provide a solution to the balloon deflation problem of Foley catheters by providing alternative types of balloons. For example, International PCT patent application no. PCT/US2006/023401 (WO/2007/005234) in the name of Rochester Medical Corporation describes a cuff resistant Foley catheter including a catheter shaft and an inflatable balloon. The catheter shaft defines a first lumen and a second lumen, the first lumen being in fluid communication with an opening located at a distal end of the catheter shaft. The inflatable balloon is positioned in fluid communication with the second lumen of the catheter shaft. The inflatable balloon has a length defined between a first end of the balloon attached to the catheter shaft and a second end of the balloon attached to the catheter shaft. The length of the balloon is about 0.40 inches or less.

As conventional supra-pubic catheters are less expensive to manufacture and are commonly used within the health care industry around the world, it would be preferable to continue to utilise conventional renal catheters in healthcare situations.

United States patent no. US 4610660 (Rosenberg) discloses a method of performing a nephrostomy procedure. The comprises the steps of establishing a pathway to the renal calyces, inserting an inflatable sleeve catheter with a proximal connector and an inflation valve a catheter into a patient's body until a distal portion of the catheter is located in the renal calyces, inflating a sleeve of the catheter in the renal calyces, removing a proximal connector and valve of the catheter such that the sleeve deflates, telescopically passing a sheath of a scope over a shaft of said catheter located in the patient's body, removing the catheter through the sheath and inserting a telescope of the scope through the sheath. However, the connector assembly 64 does not include an aperture which is open to the atmosphere. Thus, the cuffing problem associated with the inflatable balloon is not likely to be overcome by using the connector assembly 64 of US 4610660 (Rosenberg).

United States patent no. US 5002558 (Klein) discloses a urethral catheter having an adjustable dilating balloon length for dilating a prostatic urethra and a method for using same. The device includes a catheter to which a Foley balloon is affixed at the distal end, and to which a dilating balloon is annularly affixed, and includes means to independently expand and contract the balloons. Concentrically encompassing the catheter is a sheath or ring, which in one embodiment slides along the outside of the catheter. In other words, the catheter of US 5002558 (Klein) has both a Foley balloon affixed to the distal end thereof and a dilating balloon annularly affixed to the shaft of the catheter.

United States patent no. US 6093191 (Porter) discloses A urethral valve system includes a fixation balloon that is positioned in and contoured to the geometry of the bladder near the opening to the urethra. The fixation balloon, which is narrower at an end that is closest to the urethra and wider at an opposite end, includes a channel through which urine is directed to flow from the bladder to the urethra. A valve balloon is positioned in the channel and inflates to prevent urine flow through the channel and deflates to allow urine to flow around the balloon and out the end of the channel.

The fixation balloon is inflated and deflated with fluid via a pump 18. The use of the pump 18 does not address the cuffing problem associated with the inflatable balloon.

International PCT publication no. WO 2007/022050 (Vance et al) discloses a Foley catheter with a retention balloon, which includes an elongated inflation tube so that the Inflation port used to inflate and deflate the balloon may be manoeuvred away from the drainage port of the Foley catheter. If the Foley catheter was placed using a urethral access sheath, the elongated inflation tube allows the surgeon to easily remove the access sheath from the patient.

International PCT publication no. WO 2007/027216 (the USA as represented by the secretary of the army) discloses a safety adaptor having attachment components and reservoir components for use with balloon anchored catheters such that if the catheter is forcibly removed the reservoir components will act as a safety valve and allow the anchoring balloon to deflate. The safety adaptor acts to minimize damage caused to a patient due to the removal of an inflated anchor balloon of a catheter. The safety adaptor attaches to any existing catheter having a fluid balloon and does not require re-engineering or re-tooling of the catheter or adaptor. It is the pressure of the tension membrane that causes the fluid from the balloon to drain into the reservoir of the safety adaptor rather than atmospheric pressure.

Therefore, it would be advantageous to provide a device that assists in the removal of conventional renal catheters and a method of using the device in the removal of conventional renal catheters. Such a device would overcome at least some of the disadvantages of previously known approaches in this field, or would provide a useful alternative.

DISCLOSURE OF INVENTION

According to a first aspect of the invention there is provided a device for the removal of a renal catheter from a patient. The catheter includes an inflatable balloon, which is inflated by a fluid that is drained therefrom via a drainage lumen of the catheter. The device comprises:

a first end, which is adapted to fluidly engage with the drainage lumen of the catheter; a first aperture, which is located at or near the first end of the device; and

a second aperture, which is open to the atmosphere.

When the first end of the device is fluidly engaged with the drainage lumen of the catheter, a pressure differential is created between the inflatable balloon and the atmosphere, thereby causing the fluid to flow from the balloon via the drainage lumen of the catheter and through the first aperture of the device.

The device preferably further includes an elongate body extending from the first end of the device towards a distally located second end. Most preferably, the first end of the body further includes a male Luer connector, which is adapted to engagingly connect with a one-way valve in an end portion of the catheter.

Preferably, the body further includes a scale of incrementally marked intervals, which allows for the measuring of the amount of fluid which is drained from the inflatable balloon of the catheter via the first aperture into the body of the device when the first end of the device is engaged with the drainage lumen of the catheter. Most preferably, the scale commences with a first marked interval located at or near the second end of the body and the scale finishes with a last marked interval located at or near the first end of the body. The marked intervals of the scale preferably incrementally increase in units of 1.OmL, commencing at 0.OmL and finishing at 10.OmL.

The second end of the body is preferably sealed with the second aperture being located at or near the first end of the body.

The renal catheter is preferably a Foley catheter inserted into a patient's bladder.

The body is preferably a substantially rectangular elongate receptacle. According to a second aspect of the present invention there is provided a method of removing a renal catheter from a patient, the catheter including an inflatable balloon, which is inflated by a fluid that is drained therefrom via a drainage lumen of the catheter, and wherein the method comprises the steps of:

engaging a first end of a device with the drainage lumen of the catheter, the device including a first end, which is adapted to fluidly engage with the drainage lumen of the catheter; a first aperture, which is located at or near the first end of the device; and a second aperture, which is open to the atmosphere;

depressing a one-way valve in an end portion of the catheter with the first end of the device, the one-way valve being in fluid communication with the drainage lumen of the catheter, thereby creating a pressure differential between the inflatable balloon and the atmosphere;

causing the fluid in the inflatable balloon to flow therefrom via the drainage lumen of the catheter and through the first aperture of the device; and

after the fluid, which is drained from the inflatable balloon of the catheter via the first aperture of the device substantially ceases, disengaging the first end of the device from the drainage lumen of the catheter.

Preferably, the device referred to in step (a) further includes an elongate body extending from the first end of the device towards a distally located second end.

The body preferably further includes a scale of incrementally marked intervals, which allows the amount of fluid which is drained from the inflatable balloon of the catheter via the first aperture into the body of the device to be observed and measured.

The method of removing a catheter from a patient preferably comprises the further steps of:

utilising the scale of incrementally marked intervals to observe and, optionally, record the quantity of fluid which is drained from the inflatable balloon of the catheter via the first aperture into the body of the device; and subsequently to observing and/or optionally recording the volume of fluid which is drained from the inflatable balloon of the catheter via the first aperture into the body of the device, removing the catheter from the patient.

Preferably, the renal catheter is a Foley catheter in the patient's bladder and the catheter is removed by withdrawing the catheter therefrom.

According to a third aspect of the present invention there is provided a device for removing a catheter from a patient, the catheter including an inflatable balloon, which is inflated by a fluid that is drained therefrom via a drainage lumen of the catheter, the device comprising:

a first end, which is adapted to fluidly engage with the drainage lumen of the catheter;

a first aperture, . which is located at or near the first end of the device; and

a second aperture, which is open to the atmosphere.

When the first end of the device is fluidly engaged with the drainage lumen of the catheter, a pressure differential is created between the inflatable balloon and the atmosphere, thereby causing the fluid to flow from the balloon via the drainage lumen of the catheter and through the first aperture of the device. As the fluid is drained from the balloon and it deflates, the ridges that are formed because of the cuffing of the balloon are substantially soft, pliable and moveable, thereby minimising trauma to the patient when the catheter is removed.

According to a further aspect of the present invention there is provided a device for the removal of a renal catheter from a patient, the catheter including an inflatable balloon, which is inflated by a fluid that is drained therefrom via a drainage lumen of the catheter. When the device is engages with a portion of the catheter, a pressure differential is created between the inflatable balloon and the atmosphere, thereby causing the fluid to drain from the balloon via the drainage lumen.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

FIG 1 depicts a front perspective view of the device of the present invention;

FIG 2 depicts a rear perspective view of the device shown in FIG 1 engaging with an end portion of a catheter.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention generally relates to a device 1 that assists in the removal of renal catheters 9 from a patient's bladder. The invention particularly relates to a device for the removal of Foley catheters from a patient. FIGS 1 and 2 show that the device 1 comprises a receiving body 2, which has a first end 3 and a second end 6. The first end of the body 3 includes a male Luer connector 5 with a first aperture 4. Key features of Luer connectors are defined in the ISO 594 standards. In summary, Luer connectors are a standardised system of small-scale fluid fittings used for making leak-free connections between a male-taper fitting and its mating female part on medical and laboratory instruments, including hypodermic syringe tips and needles or stopcocks and needles. The Luer connector 5 of the device 1 of the present invention is therefore adapted to engage with an end portion of the catheter 9 in a conventional manner. When the Luer connector 5 is engaged with the end portion of the catheter 9, the Luer connector depresses a one-way valve in the end portion of the catheter, thereby allowing fluid to flow from the catheter, through the first aperture 4 of the body and into the receiver 2.

As discussed in the "Background Art" section, when renal catheters 9 are inserted into a patient's bladder, they are retained by means of a balloon at the tip, which is inflated with sterile water or some other sterile fluid. The fluid in the balloon exerts a pressure that is greater than atmospheric pressure and it is this property of the pressure imbalance between the fluid pressure in the balloon compared to the atmospheric pressure that is exploited by the device 1 of the present invention.

As shown in FIGS 1 and 2, the receiving body 2 further includes a second aperture 7, which is open to the atmosphere. When the Luer connector 5 is engagingly connected with the end portion of the catheter 9 and the Luer connector depresses the one-way valve, the pressure imbalance between the fluid in the balloon and the atmospheric pressure results in the fluid in the balloon flowing from the balloon of the catheter into the receiving body 2. This is because the second aperture 7 in the receiver 2 is open to the atmosphere and the fluid in the balloon is pushed from the balloon towards the receiving body 2. This occurs because the fluid pressure in the balloon is relatively higher than the atmospheric pressure.

In this way, it should be understood that the body 2 of the device 1 of the present invention could include a Luer connector 5 at one end to engage with the end portion of the catheter 9 and simply be open to the atmosphere at its other end. Whilst this non-preferred embodiment would effectively drain the fluid from the balloon of the catheter 9, the preferred embodiment of the device 1 of the present invention has some additional features that make it particularly useful for medical clinicians when performing the catheter removal procedure. These additional preferred features will now be discussed with particular reference to FIGS 1 and 2.

The receiving body 2 is preferably a rectangular form as it functions as a receptacle for the fluid that is drained from the catheter 9 before removal of the catheter from a patient's abdomen. To aid the medical clinician in effectively removing the catheter 9 from a patient, the receiving body 2 also includes a scale 8 of incrementally marked intervals, which allows for the measuring of the amount of fluid that is drained from the catheter into the receiver body.

The medical clinician is almost always required to record the amount of sterile fluid that is used to both fill and inflate the balloon of the catheter 9, as well as drain and deflate the same. In order to assist the clinician in accurately recording whether all of the sterile fluid is drained from the catheter before it is removed, the scale 8 allows for rapid, accurate and convenient visual identification of how much fluid is drained from the catheter before it is removed from a patient. The marked intervals of the scale 8 incrementally increase in units of 1.OmL, starting at OmL and increasing to 1OmL. In order to assist the clinician in taking a rapid, accurate reading of the amount of fluid in the receiver body 2, the first marked interval of the scale 8 is located at the second end of the receiver body 6 and the last marked interval of the scale is located near the first end 3 of the receiver body. Of course it should be understood that the scale 8 can also run in the opposite direction and can be for varying amounts, rather than the OmL to 1OmL that is shown in the accompanying drawings. Also, the marked intervals can incrementally increase in different amounts than those shown in the drawings.

The second aperture 7 is located at or near the first end 3 of the receiving body 2 because, to take a measurement of the fluid in the receiving body, a clinician will hold the device 1 of the present invention with the first end 3 of the receiver body 2 pointing up because of the orientation of the scale 8. However, it should be understood that in other embodiments, the second aperture 7 may be located at or near the second end 6 of the receiving body 2, or indeed it may be located at any position in the tube. So that the fluid does not leak from the receiver body 2 when the catheter 9 is being drained, the second end 6 of the receiving body is sealed in this preferred embodiment.

Whilst the embodiments of the device 1 of the present invention show that the receiving body 2 is a rectangular receptacle, it should be appreciated that any suitably shaped receptacle can be utilised. It should also be understood that any suitably sized receptacle can be utilised.

It will be apparent that obvious variations or modifications may be made which are in accordance with the spirit of the invention and which are intended to be part of the invention, and any such obvious variations or modifications are therefore within the scope of the invention.

In this specification, unless the context clearly indicates otherwise, the term "comprising" has the non-exclusive meaning of the word, in the sense of "including at least" rather than the exclusive meaning in the sense of "consisting only of". The same applies with corresponding grammatical changes to other forms of the word such as "comprise", "comprises" and so on. INDUSTRIAL APPLICABILITY

The invention can be utilised in a device that improves the method of removing a renal catheter from a patient. The device alleviates the pain and attendant bleeding or other injuries that can be associated with the removal of renal catheters.