GB2532212A

GB2532212A - Urinary catheter

Info

Publication number: GB2532212A
Application number: GB1420030.7A
Authority: GB
Inventors: Lindsey Denman Clive; Al-Zebari Nawar; Gautrot Julien
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-11-11
Filing date: 2014-11-11
Publication date: 2016-05-18
Also published as: GB201420030D0

Abstract

The invention relates to a urinary catheter 1. Catheter 1 has an elongate catheter tube 10 having a proximal end 11 and a distal end 12 for insertion though the urethra X into the bladder Y, and a memory shape tip member 20 at the distal end of the tube, said tip member having a first elongate shape to allow the tip member to pass through the urethra and into the bladder, and said tip member changing to a second shape once inserted into the bladder to prevent the distal end of the catheter tube from being withdrawn through the bladder entrance. The tip will preferably create a drainage channel that allows urine in the bladder to drain through the catheter to prevent build up of a sump of urine around the bladder entrance. The catheter will preferably be constructed from a memory shaped polymer that is sensitive to temperature.

Description

TITLE: Urinary Catheter The present invention relates to a urinary catheter.

A standard "Foley Type" catheter is well known. It comprises an inflatable balloon towards the distal end of the catheter tube. The balloon is in the deflated state when the catheter is introduced through the urethra into the bladder, and is then inflated with water through a lumen in the catheter tube. Once inflated, the balloon acts a blockage at the entrance to the bladder to prevent the catheter from being withdrawn accidentally. The design of this catheter requires the placement of eyelets which serve to drain urine from the bladder to be placed above the balloon at the distal end. This creates a sump of urine which is neither drained nor exchanged within the bladder. This sump of urine is a breeding ground for the naturally present bacteria which leads to the formation of urease, encrustation of the catheter, potential blockage of the catheter, and a greatly increase likelihood of a bladder infection. Another problem is that this type of catheter is relatively expensive to produce.

The invention seeks to provide a solution to this problem.

According to the present invention there is provided a urinary catheter comprising: a) an elongate catheter tube having a proximal end and a distal end for insertion though the urethra into the bladder, b) a memory shape tip member at the distal end of the tube, said tip member having a first elongate shape to allow the tip member to pass through the urethra and into the bladder, and said tip member changing to a second shape once inserted into the bladder to prevent the distal end of the catheter tube from being withdrawn through the bladder entrance.

Preferably the tip member creates a drainage channel allowing urine in the bladder to drain through the catheter to prevent build-up of a sump of urine in the bottom of the bladder around the bladder entrance.

Preferably the tip member is a memory shape polymer. The memory shape polymer may be sensitive to temperature having its first shape under normal room temperature and changing to said second shape at body temperature.

In one embodiment the tip member is in the form of two or more elongate members forming a split tube shape in the first position, and the elongate members curling to form a widened end to the distal end of the tube to prevent the distal end of the catheter tube from being withdrawn through the bladder entrance. Preferably there are four or six elongate members.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a catheter inserted into a bladder with a tip member in a first shape, and Figure 2 shows the catheter inserted into a bladder with a tip member in a second shape.

Referring to Figures 1 and 2 the drawings there is shown a urinary catheter 1.

Catheter 1 has an elongate catheter tube 10 having a proximal end 11 and a distal end 12 for insertion though the urethra X into the bladder Y through the bladder entrance Z. A memory shape tip member 20 is provided at the distal end 12 of the tube 10.

As shown in Figure 1, tip member 20 initially has a first elongate shape to allow the tip member to pass through the urethra and into the bladder. Tip member is formed of four elongate members 21A,21B,21C,21D forming a split tube shape in the first position.

As shown in Figure 2 tip member 20 changes it shape once inserted into the bladder as the elongate members 21A,2113,21C,21D curl to form a widened end to the distal end of the tube to prevent the distal end of the catheter tube from being withdrawn through the bladder entrance.

Tip member 20 may be formed of a memory shape polymer which has its first shape at room temperature, and changes to a second shape at body temperature.

It will be seen that in the tip member second shape, the curled elongate members 21A,21B,21C,21D support the distal end 12 of the tube 10 just at the bladder entrance. This creates a drainage channel allowing urine in the bladder to drain through the catheter to prevent build-up of a sump of urine in the bottom of the bladder around the bladder entrance.

In order to remove the catheter, it is envisaged that cold water could be passed up the catheter into the bladder which would cause the tip member to return to the first position allowing the catheter to be removed.

The catheter tip member may be made from polyurethane / poly(lactic acid) blend with inherent anti-bacterial effect through the incorporation of biocompatible medical grade chitin/chitosan polymer. For example a medical grade polyurethane/ poly(caprolactone) co-polymer will be used as the main polymer for the catheter blended with a medical grade poly(lactic acid) and highly tuned to a specific molecular weight to achieve a narrower transition temperature and closer to body temperature. Poly(lactic acid) may be used as a hard phase polymer that provides the memory for the polymer. The transition temperature may be around 60-65 °C. This transition temperature may be reduced by introducing poly(ethylene glycol), which acts as a plasticizer, and therefore lowers the transition temperature to around 40 °C. Poly(lactic acid) may also reduce the encrustation effect, as it can provide an acidic environment that dissolves or prevents the encrustations. Medical grade chitosan polymer may then be blended within this mixture to provide inherent anti-bacterial effect. The polymer is derived from chitin which is the second most abundant polymer after cellulose, therefore the material can be obtained relatively cheaply and copiously. Chitin:Chitosan 50:50 molar ratio will be protonated (positively charged) and is homogenously distributed within the catheter and provides a slow release of positively charged polyelectrolyte that can bind to negatively charged bacterial membranes and disrupt the structure and releasing the inner content of the bacteria, therefore breaking them down. The added benefit of this polymer is to provide a lubricant effect upon contact with water. The polymer is widely used in medical material applications from sutures and skin patches to scaffolds for tissue engineering and regenerative medicine.

The invention may take a form different to that specifically described above. For example there may be other than four elongate members in the tip member, e.g. six. The tip member may be formed as a different structure without elongate members.

Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

CLAIMS1. An urinary catheter comprising: a) an elongate catheter tube having a proximal end and a distal end for insertion though the urethra into the bladder, and b) a memory shape tip member at the distal end of the tube, said tip member having a first elongate shape to allow the tip member to pass through the urethra and into the bladder, and said tip member changing to a second shape once inserted into the bladder to prevent the distal end of the catheter tube from being withdrawn through the bladder entrance.
2. A catheter according to claim 1, wherein the tip member creates a drainage channel allowing urine in the bladder to drain through the catheter to prevent build-up of a sump of urine in the bottom of the bladder around the bladder entrance.
3. A catheter according to claim 1 or 2, wherein the tip member is a memory shape polymer.
4. A catheter according to claim 3, wherein the memory shape polymer is sensitive to temperature, and having its first shape under normal room temperature and changing to said second shape at body temperature.
5. A catheter according to any preceding claim, wherein the tip member is in the form of two or more elongate members forming a split tube shape in the first position, and the elongate members curling to form a widened end to the distal end of the tube to prevent the distal end of the catheter tube from being withdrawn through the bladder entrance.
6. A catheter according to claim 5, wherein there are four or six elongate members.
7. An urinary catheter substantially as hereinbefore described with reference to and as shown in the accompanying drawings.