Urinary catheters

Abstract

An intermittent urinary catheter (101) with a tip (105), a tubular portion (102) and a drainage end (106), the tubular portion defining a longitudinal axis and having an inner lumen (109) which defines a portion of a drainage flow path. The tubular portion having a plurality of eyelets (108A-108E) arranged along the longitudinal axis, which vary in cross-sectional area in a gradient along the longitudinal axis.

Description

[0001] Urinary Catheters

[0002] Technical Field of the Invention

[0003] The present invention relates to urinary catheters, in particular to intermittent urinary catheters.

[0004] Background to the Invention

[0005] A urinary catheter is a medical device comprising a hollow catheter tube designed for use for insertion into a user’s bladder via the urethra to drain the bladder. Typically, the catheter tube is provided with one or more eyelets - holes through the catheter tube to allow fluid communication between the bladder and an interior of the catheter tube, which allow the urine to be drained.

[0006] In use, these eyeleets may become blocked by the bladder wall, the reduction in, or stoppage of, the flow may cause a negative pressure differential to occur within the catheter tube drawing the bladder wall into the eyelet.

[0007] Furthermore, depending upon the positioning of the catheter tube within the bladder an incomplete draining of the bladder may occur with teh eyelets positioned above the urine such that the flow stops.

[0008] Stoppage of the flow can either lead the user to assume that the bladder is properly drained or require intervention to reposition the catheter and continue draining the bladder, neither of which is desirable.

[0009] In an attempt to address these issues, urinary catheters with a greater number of small eyelets provided on the catheter tube have been developed.

[0010] However, in Panesar, S. & Oliveira, F. 2024. Study of Laboratory Evaluation of Sediment and Mucus Flow through Intermittent Catheters. [Poster]. BAUN Annual Conference, 19-21 Nov 2023, Liverpool UK, testing (as outlined in detail below) of Luja™ (as manufactured by Coloplast A / S of Denmark, an example of a urinary catheter with a large number of small eyelets) it has been found that small eyelets are more susceptible to blockage from sediment and mucus which can be found within the bladder. Furthermore, the inclusion of a plurality of small eyelet can reduce the rigidity of the catheter tube. In WO 2022 / 221509 Al, this effect is applied proximate to the tip to increase tip flexibility. However, as will be appreciated by those skilled in the art, applying this type of eyelet over an extended portion of the catheter tube could make insertion of the catheter more difficult as it may flex and deform outside the urethra.

[0011] It is an aim of an embodiment or embodiments of the invention to overcome or at least partially mitigate one or more problems with the prior art and / or provide an improved catheter tube.

[0012] Summary of the Invention

[0013] According to a broad aspect of the disclosure, there is provided a catheter, preferably a urinary catheter. The catheter may comprise a tip. The catheter may comprise a tubular portion. The tubular portion may define a longitudinal axis. The catheter may comprise a drainage end. The tubular portion may comprise an inner lumen. The inner lumen may define a portion of a drainage flow path. The tubular portion may comprise a plurality of eyelets. The eyelets may be arranged along the longitudinal axis. The cross-sectional area of the eyelets may vary along the longitudinal axis. The cross-sectional area of the eyelets may vary in a gradient along the longitudinal axis.

[0014] According to a first aspect of the disclosure, there is provided a urinary catheter comprising, a tip, a tubular portion and a drainage end, the tubular portion defining a longitudinal axis and comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises a plurality of eyelets arranged along the longitudinal axis, and wherein the cross-sectional area of the eyelets varies in a gradient along the longitudinal axis.

[0015] Advantageously, the provision of eyelets with cross-sectional areas varying in a gradient improves drainage of the bladder, eyelets with a larger cross-sectional area clear sediment and mucus from the urine adjacent to the catheter whilst the eyelets with smaller cross-sectional areas reduce the risk of large pressure differentials. The, one or more, or each eyelet with the largest cross-sectional area may be arranged adjacent to the tip. The, cross-sectional area of the other eyelets may decrease in cross-sectional area away from the tip. Advantageously, by providing larger eyelets closer to the tip, sediment and mucus can be cleared upon insertion into the bladder and the smaller eyelets are closer to the urethra, where if blocked (as is likelier close to the urethra) they cause less of a pressure differential within the inner lumen.

[0016] The one, or more, or each eyelet with the smallest cross-sectional area may be arranged adjacent to the tip. The cross sectional area of other eyelets may increase away from the tip. Advantageously, providing the largest eyelets away from the tip allows for improved sediment removal during drainage of the bladder. Sediment accumulates at the lowest point in the bladder (which is adjacent to the opening to the urethra) and its removal is improved with increased rates of flow. With this arrangement, the larger eyelets will be more closely aligned with this sediment and allow for the effective removal of it due to their increased flow rates as compared to smaller eyelets.

[0017] The eyelets may be arranged in rows. The rows may extend along the longitudinal axis. The rows may extend longitudinally and circumferentially (i.e. they may be helictical). There may be at least 2 rows. There may be at least 4 rows. There may be at least 6 rows. The rows may be equally spaced about the catheter tube.

[0018] Each row may comprise at least 2 eyelets. Each row may comprise at least 4 eyelets. Each row may comprise at least 6 eyelets. Each row may comprise at least 10 eyelets. Each row may comprise at least 15 eyelets.

[0019] Eyelets in each row may be longitudinally offset from the eyelets in the adjacent row(s).

[0020] One, or more than one, or each eyelet may have an oval shape. One, or more, or each eyelet may have a stadium shape (that is a rectangular where two opposing sides are replaced by semicircles). The longest axis of one, or more, or each eyelet may extend longitudinally along the tubular portion. One, or more, or each eyelet may have a length measured along the tubular portion. One, or more, or each eyelet may have a length of at least 1 mm, preferably at least 1.5 mm, more preferably at least 2 mm, such as at least 3 mm. One, or more, or each eyelet may have a length of between 0.5 and 6 mm, preferably between 1 and 5 mm, more preferably, between 2 and 4 mm. The length of each eyelet in a row may increase by the same amount relative to the adjacent eyelet. That is the difference in eyelet length between each adjacent row is equal. Excluding the eyelets at the ends of their respective rows, every eyelet in a row is larger than a longitudinally adjacent eyelet and smaller than another longitudinally adjacent eyelet. The difference in length between each eyelet and the larger longitudinally adjacent eyelet, and between said eyelet and the smaller longitudinally adjacent eyelet may be the same.

[0021] One, or more than one, or each eyelet may have a width measured circumferentially around the tubular portion. One, or more than one, or each eyelet may have a width of at least 0.5 mm, preferably at least 0.7 mm, more preferably at least 0.9 mm, for example at least 1 mm. One, or more than one, or each eyelet may have a width of between 0.5 and 1.5 mm, preferably between 0.7 and 1.3 mm, more preferably between 0.9 and 1.1 mm, for example between 0.95 and 1.05 mm, such as 1 mm.

[0022] The one, or more than one, or each eyelet may have a cross-sectional area of between 1 and 5 mm2, preferably between 1.5 and 4 mm2, more preferably between 1.7 and 3.9 mm2, for example, between 1.8 and 3.8 mm2.

[0023] One, or more than one, or each eyelet may have a circular shape. One, or more than one, or each eyelet may have a diameter of at least 1 mm, preferably at least 1.2 mm, more preferably at least 1.4 mm.

[0024] One, or more than one, or each eyelet may have a diameter of between 0.2 and 1 mm, preferably between 0.25 and 0.95 mm, more preferably, between 0.3 and 0.9 mm, for example, between 0.35 and 0.85 mm, such as between 0.4 and 0.8 mm.

[0025] The tip may define a proximal end of the catheter. The eyelets may be longitudinally arranged in a region between 3 and 50 mm, preferably between 4 and 40 mm, more preferably between 5 and 25 mm, from the tip.

[0026] Some, or each eyelet may have a cross-sectional area of between 0.05 and 1 mm2, preferably between 0.08 and 0.7 mm2, more preferably between 0.1 and 0.6 mm2, for example, between 0.13 and 0.5 mm2. The eyelet proximate to the tip may be arranged between 2 and 8 mm from the tip, preferably between 3 and 7 mm, more preferably between 4 and 6 mm, for example 5 mm.

[0027] The tubular portion may comprise or be coated in a hydrophilic material.

[0028] The urinary catheter may be an intermittent urinary catheter. The urinary catheter may be a female urinary catheter. The urinary catheter may be a male urinary catheter.

[0029] The tubular portion may be uniformly rigid, that is to say the tubular portion is not configured to deform in a direction perpendicular to the tubular portion at a particular point. When viewed on a cross-section perpendicular to the longitudinal axis eyelets may comprise no more than 40%, preferably no more than 35%, more preferably no more than 30%, such as no more than 25%, for example no more than 20%, i.e. no more than 15%, of a circumference of the tubular portion.

[0030] When viewed on a cross-section perpendicular to the longitudinal axis eyelets may comprise between 8 and 40%, preferably between 10 and 35%, more preferably between 12 and 30%, of a circumference of the tubular portion.

[0031] The eyelets may extend at least 10 mm, preferably at least 15 mm, more preferably at least 20 mm, for example at least 30 mm, such as at least 40 mm along the tubular portion from the tip.

[0032] The eyelets may cover at least 20%, preferably at least 30%, more preferably at least 35%, for example at least 40%, such as at least 45% the length of the tubular portion.

[0033] According to a second aspect of the disclosure there is provided a method of manufacturing a urinary catheter comprising a tip, a tubular portion and a drainage end, the tubular portion defining a longitudinal axis and comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises a plurality of eyelets arranged along the longitudinal axis, and wherein the cross-sectional area of the eyelets varies along the longitudinal axis, the method comprising: providing a catheter tube, and providing a plurality of eyelets in the catheter tube, wherein the cross-sectional area of the eyelets varies along the longitudinal axis. The method may comprise removing portions of the tubular wall to provide the plurality of eyelets.

[0034] The method may comprise moulding the plurality of eyelets into the tubular portion.

[0035] The urinary catheter of the second aspect may be the urinary catheter of the first aspect, optionally including any optional feature thereof.

[0036] According to a third aspect of the disclosure there is provided a method a draining a bladder, the method comprising providing a urinary catheter comprising, a tip, a tubular portion and a drainage end, the tubular portion defining a longitudinal axis and comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises a plurality of eyelets arranged along the longitudinal axis, and wherein the cross-sectional area of the eyelets varies along the longitudinal axis, inserting the urinary catheter tip first into a user’ s urethra and draining the fluid in the bladder.

[0037] The method may comprise draining the bladder of a user with higher-than- average sediment and / or mucus in their urine. The method may comprise the sediment and / or mucus being drawn into the inner lumen and drained via the drainage flow path.

[0038] The urinary catheter of the third aspect may be the urinary catheter of the first aspect, including any optional features thereof.

[0039] According to a further broad aspect of the disclosure there is provided a catheter, preferably a urinary catheter. The catheter may comprise a tip. The catheter may comprise a tubular portion. The tubular portion may define a longitudinal axis. The catheter may comprise a drainage end. The tubular portion may comprise an inner lumen. The inner lumen may define a portion of a drainage flow path. The tubular portion may comprise a plurality of eyelets. The tubular portion may comprise at least four eyelets. The eyelets may be arranged in pairs. The pairs of eyelets may be arranged on opposing sides of the tubular portion. A second pair of eyelets may be longitudinally displaced from a first pair of eyelets. The first and second sets of eyelets may be circumferentially displaced from one another. The circumferential displacement may be 90 degrees. According to a fourth aspect of the disclosure there is provided a urinary catheter comprising: a tip, a tubular portion and a drainage end, the tubular portion comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises at least four eyelets, wherein the eyelets are arranged in pairs, wherein the eyelets in a pair are arranged on opposing sides of the tubular member and wherein a second pair of eyelets are longitudinally displaced and circumferentially displaced from a first pair of eyelets by 90 degrees.

[0040] Advantageously, the provision of at least four eyelets in two pairs where the two pairs are longitudinally and circumferentially displaced allows draining of the bladder from multiple eyelets reducing the effect of a blockage whilst also reducing the structural weaking of the tubular portion that leads to preferential bending at a particular point.

[0041] The urinary catheter of the fourth aspect may optionally include any features of the first aspect, including any optional features thereof. The optional features of the first aspect may be selected in isolation from essential features of the first aspect.

[0042] There may be at least 3 eyelet pairs, at least 4 eyelet pairs, at least 5 eyelet pairs.

[0043] Where there are more than two eyelet pairs the pairs may be longitudinally displaced and rotationally displaced by 90 degrees from the adjacent eyelet pair(s).

[0044] The eyelets may consist only of eyelets pairs having a longitudinal displacement and a 90-degree rotational displacement from the adjacent eyelet pair(s).

[0045] The tubular portion may define a longitudinal axis.

[0046] The cross-sectional area of the eyelets may vary along the longitudinal axis. The eyelet pair with the largest cross-sectional area may be arranged adjacent to the tip. The eyelet pair with the smallest cross-sectional area may be arranged adjacent to the tip.

[0047] The cross-sectional area of the two eyelets in an eyelet pair may be the same.

[0048] According to a fifth aspect of the disclosure there is provided a method of manufacturing a urinary catheter comprising: a tip, a tubular portion and a drainage end, the tubular portion comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises at least four eyelets, wherein the eyelets are arranged in pairs, wherein the eyelets in a pair are arranged on opposing sides of the tubular member and wherein a second pair of eyelets are longitudinally displaced and rotationally displaced from a first pair of eyelets by 90 degrees.

[0049] The method of the fifth aspect may optionally include any features of the second aspect, including optional features thereof. The optional features of the second aspect may be selected in isolation from essential features of the second aspect.

[0050] According to a sixth aspect of the disclosure there is provided a method a draining a bladder, the method comprising providing a urinary catheter comprising: a tip, a tubular portion and a drainage end, the tubular portion comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises at least four eyelets, wherein the eyelets are arranged in pairs, wherein the eyelets in a pair are arranged on opposing sides of the tubular member and wherein a second pair of eyelets are longitudinally displaced and rotationally displaced from a first pair of eyelets by 90 degrees, inserting the urinary catheter tip first into a user’s urethra and draining the fluid in the bladder.

[0051] The method of the sixth aspect may optionally include any features of the third aspect, including optional features thereof. The optional features of the third aspect may be selected in isolation from essential features of the third aspect.

[0052] Detailed Description of the Invention

[0053] In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

[0054] Figure 1 shows a schematic view of a test apparatus for comparative testing of catheter draining characteristics;

[0055] Figure 2 shows a perspective view of a catheter tube according to the present disclosure;

[0056] Figure 3 shows a longitudinal cross-sectional view of the catheter tube of Figure 2;

[0057] Figure 4 shows a transverse cross-sectional view of the catheter tube of Figure 2; Figure 5 shows a perspective view of a further catheter tube according to the present disclosure;

[0058] Figure 6 shows a longitudinal cross-sectional view of the catheter tube of Figure 5;

[0059] Figure 7 shows a transverse cross-sectional view of the catheter tube of Figure 5;

[0060] Figure 8 shows a perspective view of a further catheter tube according to the present disclosure;

[0061] Figure 9 shows a longitudinal cross-sectional view of the catheter tube of Figure 8;

[0062] Figures 10a and b show transverse cross-sectional views of the catheter tube of Figure 8;

[0063] Figure 11 shows a perspective view of a further catheter tube according to the present disclosure;

[0064] Figure 12 shows a longitudinal cross-sectional view of the catheter tube of Figure 11; and

[0065] Figures 13a and b show transverse cross-sectional views of the catheter tube of Figure 11.

[0066] First Embodiment

[0067] With reference to Figures 2 to 4 a first embodiment of a catheter tube 51 according to the present invention is described. In this embodiment that catheter tube 51 is a 14 Charrire (CH14) gauge catheter tube. The catheter tube 51 defines a longitudinal axis A-A and comprises a tubular portion 52 having a wall 53 defining an inner lumen 59. In this embodiment there is provided at an insertion end 54 of the catheter tube 51 a tip 55 having a hemispherical shape (referred to by those in the art as a “Nelaton tip”), the tip 55 defines a proximal end of the catheter tube 51. In other embodiments alternative tip geometries may be used, for example a Coude or Tiemann tip. At a distal end 56 of the catheter tube 51 there is provided a drain 57. In some embodiments the catheter tube 51 may be functionalised, for example it may comprise or be coated in a hydrophilic material.

[0068] Arranged on the tubular portion are a plurality of eyelets 58 which extend through the wall 53 of the tubular portion 52, providing a fluid connection between the inner lumen 59 and an exterior of the catheter tube 51. The eyelets 58 are provided in pairs 58A,B,C,D,E with each eyelet in a pair being arranged on diametrically opposing sides of the catheter tube 51. Each eyelet pair 58 is displaced along the longitudinal axis A- A from the adjacent pairs. Each pair is also circumferentially displaced from the adjacent pairs by 90 degrees.

[0069] In this embodiment the eyelets 58 covers approximately 35% of the length of the tubular portion 52 from the tip 55. In alternative embodiments, there may be more, or fewer pairs of eyelets 58 increasing or decreasing the proportion of the tubular portion upon which eyelets are provided.

[0070] The eyelets 58 have an elongate stadium shaped outline (that is, a rectangle with semicircles on a pair of opposing edges). They have a length (measured longitudinally along the tubular portion 52) of 2.5 mm and a width (measured circumferentially around the tubular portion 52) of 1 mm, giving them a cross-sectional area (that is an area bounded by an edge of the eyelet 58 and perpendicular to the direction of flow as denoted by line B-B) of approximately 2.3 mm2.

[0071] Although the tubular portion is punctuated by a plurality of eyelets 58 the rigidity of the tubular portion 52 remains relatively constant along its length. This is because of the arrangement of the eyelets with a longitudinal and rotational displacement. Figure 4 shows a transverse cross-section of the catheter tube at C-C. As can be seen, at any given longitudinal position along the tubular portion the proportion of wall 53 which is absent on account of being an eyelet is minimised. In this embodiment at least 85% (as calculated as a proportion of the amount of the outer circumference of the wall 53 without eyelets (A) relative to the total circumference of the wall) of the wall 53 remains at any given longitudinal position.

[0072] When used by a user, the catheter tube 51 is inserted tip 55 first into the user’s urethra until the eyelets 58 are within the bladder (which the user will note from the flow of urine starting). Advantageously, as the eyelets 58 have a larger cross-sectional area than prior art examples with arrays of small eyelets they are less likely to be blocked by sediment and mucus as the eyelets 58 provide a sufficient degree of flow to draw these into the inner lumen 59 to be drained. Additionally, the eyelets 58 are smaller than those typically found on catheters with only two eyelets, this means more can be provided without adversely effecting the rigidity of the tubular portion 52 which could make insertion more difficult if the catheter had a tendency to flex too much. The relatively large number of eyelets 58 also reduces the effect of blockage of individual eyelets 58.

[0073] Second Embodiment

[0074] With reference to Figures 5 to 7 a second embodiment of a catheter tube 101 according to the present disclosure is described. In this embodiment that catheter tube 101 is a 14 Charrire (CH14) gauge catheter tube. The catheter tube 101 defines a longitudinal axis D-D and comprises a tubular portion 102 having a wall 103 defining an inner lumen 109. In this embodiment there is provided at an insertion end 104 of the catheter tube 101 a tip 105 having a hemispherical shape (referred to by those in the art as a “Nelaton tip”), the tip 105 defines a proximal end of the catheter tube 101. In other embodiments alternative tip geometries may be used, for example a Coude or Tiemann tip. At a distal end 106 of the catheter tube 101 there is provided a drain 107. In some embodiments the catheter tube 101 may be functionalised, for example it may comprise or be coated in a hydrophilic material.

[0075] Arranged on the tubular portion are a plurality of eyelets 108 which extend through the wall 103 of the tubular portion 102, providing a fluid connection between the inner lumen 109 and an exterior of the catheter tube 101. The eyelets 108 are provided in pairs 108A,B,C,D,E with each eyelet in a pair being arranged on diametrically opposing sides of the catheter tube 101. Each eyelet pair 108 is displaced along the longitudinal axis D-D from the adjacent pairs. Each pair 108 is also circumferentially displaced from the adjacent pairs by 90 degrees.

[0076] In this embodiment the eyelets 108 covers approximately 35% of the length of the tubular portion 102 from the tip 105. In alternative embodiments, there may be more, or fewer pairs of eyelets 108 increasing or decreasing the proportion of the tubular portion upon which eyelets are provided.

[0077] The eyelets 108 have an elongate stadium shaped outline (that is, a rectangle with semicircles on a pair of opposing edges). The eyelet has a width (measured circumferentially around the tubular portion 102) of 1 mm. The length (measured longitudinally along the tubular portion 102) of the eyelets is gradated along the length of the tubular portion. The eyelet pair 108A adjacent to the tip 105 have a length of 2 mm, giving them a cross-sectional area (that is an area bounded by an edge of the eyelet 108A and perpendicular to the direction of flow) of approximately 1.8 mm2. The adjacent, second, eyelet pair 108B have a length of 2.5 mm and thus a cross-sectional area of approximately 2.3 mm2. The length of each successive eyelet pair increases by 0.5 mm as compared to the previous pair with the distal, fifth, pair 108E having a length of 4 mm, and thus a cross-sectional area of approximately 3.8 mm2. The longitudinal separation between the adjacent pairs (as measured from an end of one eyelet to the adjacent end of the adjacent eyelet) remains constant at 2 mm.

[0078] Although the tubular portion is punctuated by a plurality of eyelets 108 the rigidity of the tubular portion 102 remains relatively constant along its length. This is because of the arrangement of the eyelets with a longitudinal and rotational displacement. Figure 7 shows a transverse cross-section of the catheter tube at E-E. As can be seen, at any given longitudinal position along the tubular portion the proportion of wall 103 which is absent on account of being an eyelet is minimised. In this embodiment at least 85% (as calculated as a proportion of the amount of the outer circumference of the wall 103 without eyelets (B) relative to the total circumference of the wall) of the wall 103 remains at any given longitudinal position.

[0079] When used by a user, the catheter tube 101 is inserted tip 105 first into the user’s urethra until the eyelets 108 are within the bladder (which the user will note from the flow of urine starting). Advantageously, as the eyelets 108 have a larger cross-sectional area than prior art examples with arrays of small eyelets they are less likely to be blocked by sediment and mucus as the eyelets 108 provide a sufficient degree of flow to draw these into the inner lumen 109 to be drained. Additionally, the eyelets 108 are smaller than those typically found on catheters with only two eyelets, this means more can be provided without adversely effecting the rigidity of the tubular portion 102 which could make insertion more difficult if the catheter had a tendency to flex too much. The relatively large number of eyelets 108 also reduces the effect of blockage of individual eyelets 108. As compared to the first embodiment, the provision of graded eyelet cross- sectional areas is advantageous as the smaller eyelets 108A proximate to the tip 105 induce a faster flow rate through said eyelets which testing has shown improved removal of mucus. Furthermore, the larger eyelets 108E are further from the tip 105 and thus, in use, are most likely to be at the bottom of the bladder at the urethra opening, where sediment is known to accumulate, these larger eyelets are more effective at removing sediment with a reduced risk of becoming clogged. Accordingly, the dimensions of the eyelets have been optimised to remove either mucus or sediment.

[0080] Third Embodiment

[0081] With reference to Figures 8 to 10 a third embodiment of a catheter tube 201 according to the present disclosure is described. In this embodiment that catheter tube 201 is a 14 Charrire (CH 14) gauge catheter tube. The catheter tube 201 defines a longitudinal axis F-F and comprises a tubular portion 202 having a wall 203 defining an inner lumen 209. In this embodiment there is provided at an insertion end 204 of the catheter tube 201 a tip 205 having a hemispherical shape (referred to by those in the art as a “Nelaton tip”), the tip 205 defines a proximal end of the catheter tube 201. In other embodiments alternative tip geometries may be used, for example a Coude or Tiemann tip. At a distal end of the catheter tube 201 there is provided a drain. In some embodiments the catheter tube 201 may be functionalised, for example it may comprise or be coated in a hydrophilic material.

[0082] Arranged on the tubular portion are a plurality of eyelets 208 which extend through the wall 203 of the tubular portion 202, providing a fluid connection between the inner lumen 209 and an exterior of the catheter tube 201. The eyelets 208 are provided in 6 rows 210 A,B,C,D,E,F with each row extending longitudinally along the tubular portion 202 and comprising 15 eyelets. The six rows 210 are equally spaced around the circumference of the tubular portion 202.

[0083] In this embodiment the eyelets rows 210 extend to cover approximately 45% of the length of the tubular portion 202 from the tip 205. In alternative embodiments, the rows may extend of more or less of tubular portion upon which eyelets are provided. The eyelets 208 have a circular outline. The diameter of the eyelets 208 is gradated along the length of the tubular portion 202. The eyelets 208 adjacent to the tip 205 have a diameter of 0.4 mm, giving them a cross-sectional area (that is an area bounded by an edge of the eyelet 208 A and perpendicular to the direction of flow) of approximately 0.13 mm2. The adjacent, second, eyelets 208 of each row have a diameter of approximately 0.43 mm and thus a cross-sectional area of approximately 0.15 mm2. The diameter of each successive eyelet pair increases by 0.03 mm as compared to the previous pair with the distal, fifteenth, eyelets of each row 210 having a diameter of 0.8 mm, and thus a cross-sectional area of approximately 0.5 mm2. The longitudinal separation between the adjacent eyelets in a row (as measured from the centres of each eyelet) remains constant at 2.5 mm.

[0084] Although the tubular portion is punctuated by a plurality of eyelets 208 the rigidity of the tubular portion 202 remains relatively constant along its length. This is because the eyelets 208 have a relatively small diameter and relatively few are provided at a single longitudinal point. Figure 10a shows a transverse cross-section of the tubular portion at G-G corresponding to the widest part of the largest eyelets 208. As can be seen approximately 66% (as calculated as a proportion of the amount of the outer circumference of the wall 203 without eyelets (C) relative to the total circumference of the wall) of the wall 203 remains even at the point with the minimum proportion of remaining wall 203. Figure 10b shows a transverse cross-section of the tubular portion at H-H corresponding to the widest part of the smallest eyelets. As can be seen, approximately 84% (as calculated as a proportion of the amount of the outer circumference of the wall 203 without eyelets (D) relative to the total circumference of the wall) of the wall 203.

[0085] When used by a user, the catheter tube 201 is inserted tip 205 first into the user’s urethra until the eyelets 208 are within the bladder (which the user will note from the flow of urine starting). Advantageously, the provision of lots of smaller eyelets reduces the effect of a blockage on the drainage of the bladder. Furthermore, the gradient can allow the eyelets to be tailored to better clear mucus or sediment.

[0086] Fourth Embodiment With reference to Figures 11 to 13 a fourth embodiment of a catheter tube 301 according to the present disclosure is described. In this embodiment that catheter tube 301 is a 14 Charrire (CH14) gauge catheter tube. The catheter tube 301 defines a longitudinal axis I-I and comprises a tubular portion 302 having a wall 303 defining an inner lumen 309. In this embodiment there is provided at an insertion end 304 of the catheter tube 301 a tip 305 having a hemispherical shape (referred to by those in the art as a “Nelaton tip”), the tip 305 defines a proximal end of the catheter tube 301. In other embodiments alternative tip geometries may be used, for example a Coude or Tiemann tip. At a distal end of the catheter tube 301 there is provided a drain. In some embodiments the catheter tube 301 may be functionalised, for example it may comprise or be coated in a hydrophilic material.

[0087] Arranged on the tubular portion are a plurality of eyelets 308 which extend through the wall 303 of the tubular portion 302, providing a fluid connection between the inner lumen 309 and an exterior of the catheter tube 301. The eyelets 308 are provided in six rows 310 A,B,C,D,E,F with each row extending longitudinally along the tubular portion 302 and comprising 15 eyelets. The six rows 310 are equally spaced around the circumference of the tubular portion 302.

[0088] In this embodiment the eyelets rows 310 extend to cover approximately 45% of the length of the tubular portion 302 from the tip 305. In alternative embodiments, the rows may extend of more or less of tubular portion upon which eyelets are provided.

[0089] The eyelets 308 have a circular outline. The diameter of the eyelets 308 is gradated along the length of the tubular portion 302. The eyelets 308 adjacent to the tip 305 have a diameter of 0.8 mm, giving them a cross-sectional area (that is an area bounded by an edge of the eyelet 208 A and perpendicular to the direction of flow) of approximately 0.5 mm2. The adjacent, second, eyelets 308 of each row have a diameter of approximately 0.77 mm and thus a cross-sectional area of approximately 0.47 mm2. The diameter of each successive eyelet pair deceases by 0.03 mm as compared to the previous pair with the distal, fifteenth, eyelets of each row 310 having a diameter of 0.4 mm, and thus a cross-sectional area of approximately 0.13 mm2. The longitudinal separation between the adjacent eyelets in a row (as measured from the centres of each eyelet) remains constant at 2.5 mm. Although the tubular portion is punctuated by a plurality of eyelets 308 the rigidity of the tubular portion 302 remains relatively constant along its length. This is because the eyelets 308 have a relatively small diameter and relatively few are provided at a single longitudinal point. Figure 13a shows a transverse cross-section of the tubular portion at J-J corresponding to the widest part of the smallest eyelets 308. As can be seen approximately 84% (as calculated as a proportion of the amount of the outer circumference of the wall 303 without eyelets (E) relative to the total circumference of the wall) of the wall 303 remains even at the point with the minimum proportion of remaining wall 303. Figure 13b shows a transverse cross-section of the tubular portion at K-K corresponding to the widest part of the largest eyelets. As can be seen, approximately 66% (as calculated as a proportion of the amount of the outer circumference of the wall 303 without eyelets (F) relative to the total circumference of the wall) of the wall 303.

[0090] When used by a user, the catheter tube 301 is inserted tip 305 first into the user’s urethra until the eyelets 308 are within the bladder (which the user will note from the flow of urine starting). Advantageously, the provision of lots of smaller eyelets reduces the effect of a blockage on the drainage of the bladder. As compared to the fourth embodiment the reversal of the gradient, such that the eyelets 308 with the largest diameter a proximate to the tip 305 improves the flow rate proximate to the tip resulting in improved mucus clearing.

[0091] Comparative Test Methodology

[0092] With reference to Figure 1, a test apparatus 1 for running a test method to determining flow rates through a catheter and the results thereof is described. The test apparatus 1 is set up as outlined in ISO 20696:2018 “Sterile Urethral Catheters For Single Use” Annex E and comprises a l m hydrostatic head 2 connected to a bladder chamber 3. At the bottom of the bladder chamber 3 there is provided an approximately 2 cm thick layer of gelatin 4 to simulate the soft tissue of the bladder. A suitable sized rod (not shown) for example a 12 or 14 Charriere gauge is inserted through the gelatin 4 to create a simulated urethra with a urethral opening 5 to the bladder chamber 3.

[0093] In the presence of a number of conditions, in addition to urine in the bladder there can be an increased amount of mucus and sediment. Bladder sediment can be a result of infection, inflammation or contamination of the bladder, it comprises an increased concentration of cells (red blood cells, white blood cells), urinary casts and mineral debris. In order to simulate this mucus and sediment, egg whites and glass microbeads 6 are included in the test solution (hashed region).

[0094] In testing the test apparatus 1 is filled with 1.5 kg (approximately 1.5 L) of test solution, the test solution comprises:

[0095] 95% w / w synthetic urine comprising 142 mmol sodium chloride and 2.5 mmol calcium chloride;

[0096] 0.005% w / w nonionic surfactant;

[0097] 5% w / w egg white to simulate mucus; and

[0098] 10 cm3250-425 pm glass microbeads (not to scale) 6 to simulate sediment.

[0099] The microbeads 6 settle to the bottom of the test apparatus and rest on top of the gelatin 4, whereas the egg whites more freely mix with the synthetic urine.

[0100] To test a catheter 7, it is inserted tip 8 first into the simulated urethra 5 until all eyelets 9 and / or small eyelets are within the bladder chamber 3, with the lowest most eyelet or small eyelet being aligned with the urethral opening 5 a. Through qualitative observations the following parameters are assessed:

[0101] Initial Flow rate - the volume of synthetic urine passing through the catheter 7 in a given time period at the beginning of the test.

[0102] Clearance of simulated mucus - an observation as to whether the simulated mucus is drawn into and through the catheter 7 and where this is the case, how much volume around the catheter 7 has a reduced) concentration (or is completely cleared) of simulated mucus.

[0103] Clearance of simulated sediment - an observation as to whether the simulated sediment is drawn into and through the catheter 7 and where this is the case, the distance from the catheter 7 which is clear of simulated sediment. The test was considered completed when the bladder chamber was drained, or the catheter was blocked and the flow stopped.

[0104] Comparative Testing Results

[0105] Below are provided qualitative test results of the four embodiments described above, along with two commercially available catheters; GentleCath Glide as sold by ConvaTec Inc., and Luja™ as sold by Coloplast A / S. Each of the catheters was subjected to the testing regime set out above, with the flow rate, mucus clearance and sediment clearance qualitatively assessed.

[0106] The one or more embodiments are described above by way of example only.

[0107] Many variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

CLAIMS1. An intermittent urinary catheter comprising, a tip, a tubular portion and a drainage end, the tubular portion defining a longitudinal axis and comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises a plurality of eyelets arranged along the longitudinal axis, and wherein the cross-sectional area of the eyelets varies in a gradient along the longitudinal axis.

2. An intermittent urinary catheter according to claim 1 wherein one, or more, or each eyelet with the largest cross-sectional area is arranged adjacent to the tip.

3. An intermittent urinary catheter according to claim 2 wherein the cross- sectional area of the other eyelets decrease away from the tip.

4. An intermittent urinary catheter according to claim 1 wherein one, or more, or each eyelet with the smallest cross-sectional area is arranged adjacent to the tip.

5. An intermittent urinary catheter according to claim 4 wherein the cross- sectional area of the other eyelets increase away from the tip.

6. An intermittent urinary catheter according to any preceding claim wherein the eyelets are arranged in rows extending along the longitudinal axis.

7. An intermittent urinary catheter according to claim 6 wherein there are 4 rows, and the eyelets in each row are longitudinally offset from the eyelets in the adjacent row.

8. An intermittent urinary catheter according to any preceding claim wherein the eyelets have a cross-sectional area of between 1 and 5 mm2.

9. An intermittent urinary catheter according to any preceding claim wherein the eyelets have a cross-sectional area of between 1.7 and 3.9 mm2.

10. An intermittent urinary catheter according to any of claims 1 to 7 wherein the eyelets have a cross-sectional area of between 0.05 and 1 mm2.

11. An intermittent urinary catheter according to any of claims 1 to 7 wherein the eyelets have a cross-sectional area of between 0.1 and 0.6 mm2.

12. An intermittent urinary catheter according to any preceding claim wherein the tubular portion is rigid.

13. An intermittent urinary catheter according to any preceding claim wherein when viewed on a cross-section perpendicular to the longitudinal axis the eyelets comprise no more than 30% of a circumference of the tubular portion.

14. An intermittent urinary catheter according to any preceding claim wherein the eyelets extend at least 20 mm along the tubular portion from the tip.

15. An intermittent urinary catheter according to any preceding claim wherein the eyelets extend at least 35 mm along the tubular portion from the tip.

16. An intermittent urinary catheter according to any preceding claim wherein the catheter tube comprises or is coated in a hydrophilic material.

17. A urinary catheter comprising: a tip, a tubular portion and a drainage end, the tubular portion comprising an inner lumen which defines a portion of a drainage flow path, wherein the tubular portion comprises at least four eyelets, wherein the eyelets are arranged in pairs, wherein the eyelets in a pair are arranged on opposing sides of the tubular member and wherein a second pair of eyelets are longitudinally displaced and circumferentially displaced from a first pair of eyelets by 90 degrees.

18. A urinary catheter according to claim 17 wherein there are at least 4 eyelet pairs.

19. A urinary catheter according to claim 17 or 18 wherein the eyelets consist only of eyelet pairs having a longitudinal displacement and a 90-degree circumferential displacement from the adjacent eyelet pair(s).

20. A urinary catheter according to claim 17 wherein the cross-sectional area of the eyelets vary along a longitudinal axis defined by the tubular portion and wherein the eyelet pair with the largest cross-sectional area is arranged adjacent to the tip.

21. A urinary catheter according to claim 20 wherein the eyelets decrease in cross- sectional area away from the tip.

22. A urinary catheter according to claim 17 wherein the cross-sectional area of the eyelets vary along a longitudinal axis defined by the tubular portion and wherein the eyelet pair with the smallest cross-sectional area is arranged adjacent to the tip.

23. A urinary catheter according to claim 22 wherein the eyelets increase in cross- sectional area away from the tip.

24. A urinary catheter according to any of claims 17 to 23 wherein the eyelets have a cross-sectional area of between 1 and 5 mm2.

25. A urinary catheter according to any of claims 17 to 24 wherein the eyelets have a cross-sectional area of between 1.7 and 3.9 mm2.

26. A urinary catheter according to any of claims 17 to 25 wherein the tubular portion is rigid.

27. A urinary catheter according to any of claims 17 to 26 wherein when viewed on a cross-section perpendicular to the longitudinal axis the eyelets comprise no more than 20% of a circumference of the tubular portion.

28. A urinary catheter according to any of claims 17 to 27 wherein the eyelets extend at least 20 mm along the tubular portion from the tip.

29. A urinary catheter according to any of claims 17 to 28 wherein the catheter tube comprises or is coated in a hydrophilic material.

30. A urinary catheter according to any of claims 17 to 29 wherein the catheter is an intermittent catheter.

Images