WO1995016477A1

WO1995016477A1 - Catheters

Info

Publication number: WO1995016477A1
Application number: PCT/GB1994/002604
Authority: WO
Inventors: Michael Norman Collins
Original assignee: Smiths Industries Public Limited Company
Priority date: 1993-12-18
Filing date: 1994-11-29
Publication date: 1995-06-22
Also published as: AU1112595A; GB9325918D0

Abstract

A haematuria catheter has a main drainage lumen (10), which is closed at the patient end tip (15) of the catheter and opens through drainage openings (16, 18 and 19) just rearwardly of the tip and forwardly of an inflatable balloon (22) by which the catheter is secured in the bladder. An inflation lumen (11), extending in an internally projecting rib (13), opens into the balloon (22) and is sealed closed by a plug (17) at one of the drainage openings (16). An irrigation lumen (12) along a second rib (14) extends beyond the drainage openings and opens through an opening (21) at the tip of the catheter so that irrigation liquid emerges from the catheter at a point spaced from the drainage openings.

Description

CATHETERS

This invention relates to catheters of the kind having a drainage lumen closed at the patient end of the catheter by a rounded tip of the catheter, an opening in the wall of the catheter into the drainage lumen rearwardly of the tip and an irrigation lumen.

Haematuria catheters have a patient end inserted in the bladder via the urethra. The catheter has several openings, or eyes, in its wall close to the tip through which fluid can drain out of the catheter. The tip of the catheter is rounded and closed so that it can be inserted without trauma. Irrigation liquid is supplied to the bladder via a lumen extending along the catheter within its wall. The irrigation lumen is usually interrupted by one of the drainage openings so that irrigation liquid can flow out of the catheter via the opening. The irrigation liquid is used to remove clots and post-surgery debris left in the bladder so that they can be drained through the main lumen of the catheter.

The problem with these previous catheter is that a large proportion of the irrigation liquid can flow immediately back into the catheter through the drainage eye. This reduces the effectiveness of the catheter in breaking up clots and can result in treatment being prolonged.

According to one aspect of the present invention there is provided a catheter of the above-specified kind, characterised in that the irrigation lumen extends beyond the drainage opening, and that the irrigation lumen has an opening at the tip of the catheter so that irrigating liquid emerges from the catheter at a point spaced from the drainage opening.

The catheter preferably has a balloon located close to the patient end of the catheter and an inflation lumen opening into the balloon. The inflation lumen may be cut by the drainage opening and sealed at the drainage opening. The irrigation lumen and the inflation lumen are preferably located diametrically opposite one another and the catheter preferably has a pair of drainage openings located opposite one another and between the two lumens. The or each lumen is preferably extruded with the wall of the catheter and may be extruded in a rib projecting inwardly of the wall of the catheter. The opening of the irrigation lumen is preferably located centrally of the tip of the catheter.

According to another aspect of the present invention there is provided a method of making a catheter according to the above one aspect of the invention, characterised in that the patient end of the catheter is heat formed closed and rounded about a bent pin.

A haematuria catheter and its method of manufacture in accordance with the present invention, will now be described, by way of example, with reference to the accompanying drawing, in which:

Figure 1 is a partly sectional side elevation of the catheter;

Figure 2 is an enlarged sectional view of the patient end of the catheter; and

Figure 3 illustrates the method of manufacture of the patient end of the catheter;

Figures 4 illustrate alternative methods of manufacture, and 5

With reference to Figures 1 and 2, the catheter is a urological, haematuria catheter and is about 400mm long with an external diameter of about 7mm. The catheter comprises a main tubular shaft 1 bonded at its proximal or machine end 2 into a coupling 3. The tubular shaft 1 is extruded from a flexible plastics material and has a main bore or lumen 10 and two minor lumens 11 and 12. The minor lumens 11 and 12 extend along the wall of the shaft within respective internally-projecting ribs 13 and 14 located diametrically opposite one another and extruded integrally with the shaft.

At its distal, patient end 15 the shaft 1 is moulded with a rounded tip. A drainage eye or opening 16 is formed through the side wall of the shaft 1 just rearwardly of the tip 15 and cutting through one of the minor lumens 11, which is sealed by a plug 17 on the proximal side of the eye. A pair of two further drainage openings 18 and 19 open into the main lumen 10, rearwardly of the forward opening 16, these openings being arranged diametrically opposite one another between the minor lumens 11 and 12.

The second minor lumen 12 continues forwardly beyond the drainage openings 16, 18 and 19 to the tip 15 of the catheter. The lumen 12 communicates via an extension passage 20 with an irrigation opening 21 formed axially, in the centre of the tip 15, as shown in Figure 2.

An inflatable latex balloon or cuff 22 is mounted on the shaft 1 just to the rear of the eyes 18 and 19, and is bonded to the shaft at opposite ends 23 and 24. The minor lumen 11 opens into the cuff 22 through an opening 25 cut into the wall of the shaft from the outer surface, overlying the lumen.

At the proximal end 2 of the shaft 1, both minor lumens 11 and 12 are occluded by heat forming the ribs 13 and 14 outwardly (in a manner described in detail in PCT/GB94/02367). Two openings 26 and 27 are cut into respective ones of the minor lumens 11 and 12 from the outside of the shaft 1 at a point about 14mm from the proximal end, that is, distally of the occlusion.

The coupling 3 is a plastics moulding of trident shape with a central tubular body 30 and two side arms 31 and 32. The central body 30 communicates with the main, drainage lumen 10 of the shaft 1; the side arms 31 and 32 communicate with the inflation and irrigation lumens 11 and 12 via the openings 26 and 27. The side arm 31 has a one-way valve 35 and a female coupling 36 into which the nose of an inflation syringe can be inserted. The other side arm 32 is used for supplying irrigating liquid to the catheter and has a female coupling 37 at its proximal end that can be connected to a suitable supply of liquid.

In use, the catheter is inserted urethrally in the bladder and the cuff 22 is inflated with saline by means of a syringe connected to the inflation arm 31. Irrigating fluid supplied via the irrigating arm 32 flows along the lumen 12 and the extension passage 20 to emerge at the tip of the catheter through the opening 21. This produces a jet of irrigating liquid directed axially of the catheter, which is highly effective in breaking up clots and dislodging debris located forwardly of the catheter. Because the irrigating liquid emerges at a location spaced from the drainage openings 16, 18 and 19, the liquid does not immediately flow back into the catheter. The irrigating opening 21 does not compromise the rounded atraumatic tip of the catheter because the opening is relatively small compared with the external diameter of the catheter.

The patient end tip 15 of the catheter is made, in the manner shown in Figure 3, by heat forming a square-cut end of the shaft in a die 50. The die 50 has a cavity 51 with a diameter equal to the external diameter of the shaft. The cavity 51 has a rounded floor 52 of semi- spherical shape from which projects a pin 53. The pin 53 is mounted centrally of the base but is of a bent, cranked shape to form the extension 20 of the irrigation lumen 12. The upper end of the pin 53 extends vertically close to the side of the cavity 53 in alignment with the lumen 12. The pin 53 has a diameter equal to that of the lumen 12 and a rounded end so that it can be introduced into the lumen as the shaft 1 is pushed down into the cavity 51. A heater 54 in the die 50 warms and softens the tip of the shaft as it enters the cavity 51. The material of the shaft 1 flows to conform to the floor of the cavity and the surface of the pin 53. The shaft 1 is allowed to cool and set slightly in the die before being removed so as to enable the pin 53 to be withdrawn without causing enlargement of the irrigation outlet. There are various alternative ways in which the tip of the catheter could be made. As shown in Figure 4, the tip of the shaft could be rounded closed first and the irrigation lumen 12 subsequently opened by cutting away a part of the material at the tip with a blade 60 to expose the lumen. A tip formed in this way would need to be smoothed subsequently to remove sharp edges. Alternatively, a heated tool 70 could be pushed through the material of the tip to form an opening into the irrigation lumen 12, as shown in Figure 5.

Claims

1. A catheter having a drainage lumen closed at the patient end of the catheter by a rounded tip of the catheter, an opening in the wall of the catheter into the drainage lumen rearwardly of the tip and an irrigation lumen, characterised in that the irrigation lumen (12) extends beyond the drainage opening (16, 18, 19) and that the irrigation lumen has an opening (21) at the tip (15) of the catheter so that irrigating liquid emerges from the catheter at a point spaced from the drainage opening.

2. A catheter according to Claim 1, characterised in that the catheter has a balloon (22) located close to the patient end (15) of the catheter and an inflation lumen (11) opening into the balloon.

3. A catheter according to Claim 2, characterised in that the inflation lumen (11) is cut by the drainage opening (16) and is sealed (17) at the drainage opening.

4. A catheter according to Claim 2 or 3, characterised in that the irrigation lumen (12) and the inflation lumen (11) are located diametrically opposite one another, and that the catheter has a pair of drainage openings (18, 19) located opposite one another and between the two lumens (11 and 12).

5. A catheter according to any one of the preceding Claims, characterised in that the or each lumen (12, 11) is extruded with the wall of the catheter.

6. A catheter according to any one of the preceding claims, characterised in that the or each lumen (12, 11) is extruded in a rib (13, 14) projecting inwardly of the wall of the catheter.

7. A catheter according to any one of the preceding claims, characterised in that the opening (21) of the irrigation lumen (12) is located substantially centrally of the tip of the catheter.

8. A method of making a catheter according to any one of the preceding claims, characterised in that the patient end (15) of the catheter is heat formed closed and rounded about a bent pin (53).