WO2010090671A2

WO2010090671A2 - Urinary catheter

Info

Publication number: WO2010090671A2
Application number: PCT/US2009/066597
Authority: WO
Inventors: David Hannon; Martin P. Creaven; Daniel O'brien; Michael Murray; Brendan Heneghan
Original assignee: Hollister Incorporated
Priority date: 2009-01-20
Filing date: 2009-12-03
Publication date: 2010-08-12
Also published as: WO2010090671A3

Abstract

The present disclosure is directed to a Foley catheter comprising a catheter tube (12) having a proximal drainage end (14) and a distal insertion end (16) and having a urine drainage lumen (18) extending along a longitudinal axis (2). The catheter tube has a urine drainage opening (22) at the proximal drainage end thereof and a urine receiving opening (24) at the distal insertion end thereof. The urine drainage and receiving openings define the opposite ends of the urine drainage lumen to thereby accommodate the flow of urine through the catheter tube from one end to the other. Further, at least the urine receiving opening at the distal insertion end of the catheter tube is disposed about the longitudinal axis of the urine drainage lumen thereby eliminating the presence of a conventional catheter tip. With this arrangement, the Foley catheter also includes an inflatable and deflatable external balloon (26) associated with the distal insertion end of the catheter tube for retaining the distal insertion end within the bladder.

Description

URINARY CATHETER

Field of the Disclosure

[0001] The present disclosure relates generally to the field of urinary catheters and, more particularly, to urinary catheters that are designed to be indwelling for extended periods.

Background of the Disclosure

[0002] For many years, it has been a common practice to utilize a catheter for the drainage of urine from the bladder of infirm or disabled individuals who are unable to empty their bladder in a normal fashion. There are generally two types of urinary catheters used for this purpose, i.e., intermittent catheters that are usually marketed for single use by those individuals who suffer from incontinence and/or an inability to experience normal bladder function and catheters that are designed to be indwelling in the bladder for an extended period of time which are commonly known as Foley catheters. As for intermittent catheters, they may be a good solution for quadriplegics or others who lose normal bladder function due to injury, disease or disability in order to drain urine from the bladder on a regular basis.

[0003] However, for more infirm individuals such as those who are hospitalized or are permanently confined to a facility providing medical assistance, it is more common to utilize Foley catheters for bladder drainage. These catheters are typically employed by medical personnel and are opened, removed from their package, prepared for use and inserted into the urethra of a patient in a sterile field in a medical facility. Foley catheters include a balloon which is associated with the insertion end of the catheter and which may be inflated for retaining the catheter in the bladder for an extended period following insertion.

[0004] Because Foley catheters are typically indwelling for an extended period, the eyes near the insertion end can become blocked over time. It is important for the eyes to remain open in order to ensure the patient experiences proper drainage of urine from the bladder at all times during catheterization. Otherwise, in the opinion of some experts in the field the blockage of the eyes in Foley catheters can lead to urinary tract infections (UTIs). [0005J Specifically, it is believed that bacteria start to colonize over time around the eyes in Foley catheters due to the roughness of the eyes and the flow patterns for urine draining from the bladder through the eyes. Once bacteria begin to colonize, a biofilm is formed which leads to encrustation around the eyes and possible blockage. Users of Foley catheters are known to have a very high risk of incurring a UTI, and it is believed that biofilm which leads to encrustation around the eyes of a Foley catheter is one of the major causes of UTIs.

[0006] In other words, the absence of a smooth flow path of urine from the bladder into the catheter promotes the colonization of bacteria and the formation of a biofilm which leads to the encrustation. The nature of the eyes in a conventional Foley catheter are such that the roughness and disturbed flow patterns naturally result therefrom. However, because Foley catheters are so essential to health care for infirm individuals in medical facilities, the very high risk of incurring a UTI is tolerated since there is no realistic available alternative.

[0007] Nevertheless, it is recognized that the UTI risk is a significant drawback to using Foley catheters, and it is becoming even more significant as the already high cost of health care continues to rise. It has recently been announced in the U.S. that government health care programs such as Medicare and Medicaid will no longer reimburse hospitals for the cost of treating UTIs where the patient incurred the UTI during hospitalization. Because of the very high risk of incurring a UTI during hospitalization, there is a significant need to deal with the problems presented by conventional Foley catheters such as encrustation leading to UTIs.

[0008] In particular, there is a need for an improved Foley catheter that reduces the risk of incurring a UTI because it: i) reduces the possibility of a biofilm forming and then causing encrustation, ii) provides a smooth flow path for urine from the bladder into the catheter, and iii) results in more complete drainage with less residual urine in the bladder.

Summary of the Disclosure

[0009] Accordingly, the present disclosure is directed to a Foley catheter comprising a catheter tube having a proximal drainage end and a distal insertion end and having a urine drainage lumen extending along a longitudinal axis. The catheter tube has a urine drainage opening at the proximal drainage end thereof and a urine receiving opening at the distal insertion end thereof. The urine drainage and receiving openings serve to define the opposite ends of the urine drainage lumen to thereby accommodate the flow of urine completely through the catheter tube from one end to the other. Further, at least the urine receiving opening at the distal insertion end of the catheter tube is disposed about the longitudinal axis of the urine drainage lumen. With this arrangement, the Foley catheter also includes an inflatable and deflatable external balloon associated with the distal insertion end of the catheter tube for retaining the distal insertion end in position within the bladder.

[0010] In one exemplary embodiment, the urine drainage lumen of the catheter tube has a substantially uniform diameter entirely from the proximal drainage end to the distal insertion end thereof. The urine receiving opening at the distal insertion end of the catheter tube also has a diameter substantially the same as the diameter of the urine drainage lumen. Thus, the urine receiving opening and the urine drainage lumen define one continuous urine flow path of uniform diameter from one end completely to the other end of the Foley catheter.

[0011] In this exemplary embodiment, the Foley catheter may also include an inflatable and deflatable internal balloon associated with the distal insertion end of the catheter tube for inflation during insertion. The inflatable and deflatable internal balloon is advantageously associated with an internal wall of the catheter tube defining the urine drainage lumen so as to be located generally adjacent to the urine receiving opening. The internal balloon preferably is inflatable to occlude, and at least partially extend distally of, the urine receiving opening to thereby temporarily define a rounded distal insertion end during insertion of the catheter tube.

[0012] In another exemplary embodiment, the Foley catheter may alternatively include an internal guide catheter having a proximal drainage end, a distal insertion end, and a urine drainage lumen extending along a longitudinal axis. The internal guide catheter preferably has an outer diameter accommodating sliding insertion of the internal guide catheter through the urine drainage lumen. It is preferably formed so as to be longer than the catheter tube for the purpose of extending the distal insertion end to a point located distally of the distal insertion end of the catheter tube. With this arrangement, the internal guide catheter advantageously has a urine drainage opening at the proximal drainage end and a urine receiving opening at the distal insertion end for the passage of urine therethrough.

[0013] With the foregoing arrangement, it is advantageous for the internal guide catheter to be formed such that the urine receiving opening at the distal insertion end thereof is located just distally of the distal insertion end of the catheter tube when the internal guide catheter has been fully inserted through the urine drainage lumen of the catheter tube. [0014] In another exemplary embodiment, the distal insertion end of the catheter tube normally curves inwardly but expands outwardly upon inflation of the inflatable and deflatable external balloon. The urine receiving opening in this embodiment then is advantageously formed to have a first, smaller diameter before inflation of the balloon and to have a second, larger diameter after inflation of the balloon. More specifically, the smaller diameter of the urine receiving opening is preferably as small as possible and at least smaller than the diameter of the urine drainage lumen and the larger diameter of the urine receiving opening is preferably larger than the diameter of the urine drainage lumen.

[0015] In this exemplary embodiment, the second, larger diameter of the urine receiving opening after inflation of the balloon is preferably at least as large as the diameter of the urine drainage lumen of the catheter tube.

[0016] Other advantages and features of the present disclosure will become apparent from a consideration of the following specification taken in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0017] Figure IA is a schematic drawing in cross-section showing a Foley catheter having the advantages and features of the present disclosure in a bladder;

[0018] Figure IB is a schematic drawing in cross-section showing a Foley catheter of conventional design in a bladder for comparison with the Foley catheter of Figure IA;

[0019] Figure 2A is a cross-sectional view of a first alternative embodiment of the Foley catheter of Figure IA arranged for insertion into the urethra of an individual;

[0020] Figure 2B is a cross-sectional view of the embodiment of Figure 2A arranged for use in an indwelling state following insertion into the urethra and inflation of the balloon;

[0021] Figure 3A is a cross-sectional view of a second alternative embodiment of the Foley catheter of Figure IA arranged for insertion into the urethra of an individual;

[0022] Figure 3B is a cross-sectional view of the embodiment of Figure 3A arranged for use in an indwelling state following insertion into the urethra and inflation of the balloon;

[0023] Figure 4A is a cross-sectional view of a third alternative embodiment of the Foley catheter of Figure IA arranged for insertion into the urethra of an individual; and

[0024] Figure 4B is a cross-sectional view of the embodiment of Figure 4A arranged for use in an indwelling state following insertion into the urethra and inflation of the balloon. Detailed Description of the Present Disclosure

[0025] Referring to Figure IA, the reference numeral 10 designates generally a Foley catheter in accordance with the present disclosure comprising a catheter tube 12 having a proximal drainage end 14 and a distal insertion end 16. The catheter tube 12 has a urine drainage lumen 18 extending along a longitudinal axis 20. The catheter tube 12 also has a urine drainage opening 22 associated with the proximal drainage end 14 and a urine receiving opening 24 at the distal insertion end 16. As will be appreciated, the urine drainage and receiving openings 22 and 24 define opposite ends of the urine drainage lumen 18 to accommodate flow of urine through the catheter tube 12 for draining urine from a bladder.

[0026] Still referring to Figure IA, an inflatable and deflatable external balloon 26 is associated with the distal insertion end 16 of the catheter tube 12 for the purpose of retaining the distal insertion end 16 in the bladder. It will be appreciated that the balloon 26 is inflatable and deflatable through a small lumen 28 associated with the catheter tube 12 and extending the length thereof. Since the inflation and deflation lumen 28 for the balloon 26 is conventional, and well known to those skilled in the art, its structure and operation will not be described in detail to focus upon the unique features of the present disclosure.

[0027] As will also be understood by making reference to Figure IA, the Foley catheter 10 is formed such that the urine receiving opening 24 at the distal insertion end 16 of the catheter tube 12 is disposed about the longitudinal axis 20 of the urine drainage lumen 18 of the catheter tube 12. It will also be seen that the urine drainage lumen 18 of the catheter tube 12 has a substantially uniform diameter from the proximal drainage end 14 to the distal insertion end 16. Further, the urine receiving opening 24 at the distal insertion end 16 has a diameter substantially the same as the urine drainage lumen 18. In addition, the Foley catheter 10 preferably has a funnel 29 integral with the proximal drainage end 14 of the catheter tube 12 to facilitate urine drainage therethrough. Referring now to Figure IB, a conventional Foley catheter 10' is illustrated in a bladder which also includes a catheter tube 12' having a proximal drainage end 14' and a distal insertion end 16', and the Foley catheter 10' also has a urine drainage lumen 18' extending along a longitudinal axis 20'. [0028] As with the Foley catheter 10, the Foley catheter 10' has a urine drainage opening 22' at the proximal drainage end 14' of the catheter tube 12'. However, unlike the Foley catheter 10, the Foley catheter 10' does not have a urine receiving opening such as 24 but, instead, has a pair of small, diametrically opposed eyes 30 located proximal to the distal insertion end 16'. In contrast, the entirety of the distal insertion end 16 of the Foley catheter 10 in Figure IA is open to accommodate the flow of urine from the bladder.

[0029J While the Foley catheters 10 and 10' both include inflatable and deflatable external balloons 26 and 26' generally associated with the distal insertion ends 16 and 16', the balloon 26' is located proximally of the distal insertion end 16' so as to be able to accommodate the eyes 30 in the side wall of the catheter tube 12' proximally of the distal insertion end 16'. However, unlike the Foley catheter 10', the balloon 26 of the Foley catheter 10 is located at the distal insertion end 16 of the catheter tube 12 adjacent the urine receiving opening 24 which is possible because of its large size which is preferably of the same diameter as, and leads directly into, the urine drainage lumen 18 of the catheter tube 12.

[0030] With this understanding of the basic concept of the present disclosure relative to a conventional Foley catheter 10', several embodiments incorporating the basic concept have been illustrated and will be described below. In this connection, these different embodiments will be described in detail only to the extent they include advantages or features which are in addition to those already described above relative to the embodiment of Figure IA.

[0031] Referring to Figures 2A and 2B, the Foley catheter 100 includes an inflatable and deflatable internal balloon 132 associated with the distal insertion end 116 of the catheter tube 112 for inflation during insertion (see Figure 2A). The internal balloon 132 is associated with an internal wall 134 of the catheter tube 112, which defines the urine drainage lumen 118, generally adjacent to the urine receiving opening 124 as will be more fully appreciated by referring specifically to Figure 2B. By comparing Figures 2 A and 2B, it will be seen that the internal balloon 132 is inflatable to occlude and at least partially extend distally of the urine receiving opening 124 to serve as a tip during insertion of the catheter tube 112. [0032] More specifically, the internal balloon 132 can be inflated and deflated through a small lumen 135 extending from the internal balloon 132 along the internal wall 134 to a point at or near the proximal drainage end of the Foley catheter 100 where a suitable fitting may be provided for connection to a syringe for supplying inflating water/liquid to the balloon 132 in a manner generally the same as inflating a retention balloon on a conventional Foley catheter.

[0033] In addition, it will be appreciated that the Foley catheter 100 has an inflatable and deflatable external balloon 126 associated with the distal insertion end 116 of the catheter tube 112 for retaining the distal insertion end 116 in a bladder. It will be appreciated that the external balloon 26 is also inflatable and deflatable through a small lumen (not shown) associated with the catheter tube 112. Since the inflation and deflation lumen for the balloon 126 is conventional, and well known to those skilled in the art, it has not been shown in Figures 2A and 2B to focus upon the unique features of the present disclosure.

[0034] As with the embodiment illustrated and Figure IA, the inflatable and deflatable external balloon 126 can be inflated using a syringe after the Foley catheter 100 has been inserted and the inflatable and deflatable internal balloon 132 has been deflated using a syringe to thereby secure the Foley catheter 100 in place within the bladder.

[0035] Referring to Figures 3A and 3B, the Foley catheter 200 includes an internal guide catheter 236 having a proximal drainage end 238, a distal insertion end 240, and a urine drainage lumen 242 extending along a longitudinal axis 244. The internal guide catheter 236 is formed to have an outer diameter accommodating sliding insertion of the internal guide catheter through the urine drainage lumen 218 (Figure 3B) of the catheter tube 212 as will be appreciated by making reference specifically to Figure 3 A. The internal guide catheter 236 can be made of a harder material than the catheter tube 212 which can be made of a softer material than a conventional Foley catheter to thereby reduce trauma during the extended periods such catheters are often indwelling. In addition, the internal guide catheter 236 is formed so as to be longer than the catheter tube 212 for extending the distal insertion end 240 distally of the distal insertion end 216 of the catheter tube 212 as shown in Figure 3 A.

[0036] Still referring to Figure 3A, the internal guide catheter 236 has a urine drainage opening 246 at the proximal drainage end 238 and a urine receiving opening 248 at the distal insertion end 240 thereof. The urine receiving opening 248 may comprise one or more eyes generally of the type found in conventional Foley catheters and as shown in Figure IB and designated by the reference numeral 30, and the eyes will not be a problem in this instance because the internal guide catheter is only used to properly place the Foley catheter 200 following which it is withdrawn. By utilizing one or more eyes 248, it is possible to know when the Foley catheter 200 has reached the bladder and is properly located because urine will start to flow through the internal guide catheter 236 when this occurs.

[0037] As will be appreciated from Figures 3A and 3B, the internal guide catheter 236 has a profiled tip 236a at the distal insertion end 240, and it has eyes 248 located proximal to the profiled tip 236a. The internal guide catheter 236 protrudes from the distal insertion end 216 of the catheter tube 212 by a distance sufficient for the eyes 248 to be located distally of the distal insertion end 216 of the catheter tube 212 as shown in Figure 3 A. With this arrangement, the internal guide catheter 236 is prevented from extending too far by a stop 238a associated with the proximal drainage end 238 as also shown in Figure 3 A.

[0038] As mentioned above, urine will start to flow through the internal guide catheter 236 when the Foley catheter 200 has been fully inserted into the urethra with the distal insertion end 216 properly positioned within the bladder. Urine will flow through the eyes 248 at the distal insertion end 240 of the internal guide catheter 236 and through the urine drainage lumen 242 until it ultimately passes through the urine drainage opening 246 which is located at the proximal drainage end 238. When this occurs, the internal guide catheter 236 can be removed by sliding it from the Foley catheter 200, and urine can continue to flow through the urine drainage lumen 218 in the catheter tube 212 of the Foley catheter 200.

[0039] One other feature of the Foley catheter 200 is that the inflatable and deflatable balloon 226 adjacent the distal insertion end 216 of the catheter tube 212 is preferably inflated before the internal guide catheter 236 is removed, and the ballon 226 has its proximal end 226a sealed to the external wall 235 of the catheter tube 212 and has its distal end 226b sealed to the internal wall 234 of the catheter tube 212 to provide a smooth entrance into the lumen 218 thereby preventing the turbulent flow of urine.

[0040] Referring to Figures 4A and 4B, the Foley catheter 300 includes a distal insertion end 316 of the catheter tube 312 that normally curves inwardly (Figure 4A) but is capable of expanding outwardly (Figure 4B). The urine receiving opening 324 will be seen to have a first, smaller diameter before inflation of the external balloon 326 and, because the distal insertion end 316 expands outwardly Upon inflation of the balloon 326, the urine receiving opening 324 will have a second, larger diameter after balloon inflation to accommodate smooth flow of urine into the Foley catheter 300. As a result, the Foley catheter 300 can readily be inserted through the urethra into the bladder in the inwardly curved form and then the urine receiving opening 324 can be moved to the fully open position shown in Figure 4B.

[0041] As will be appreciated, the urine receiving opening 324 will move from the first, smaller diameter before inflation of the balloon 326 to the second, larger diameter following inflation of the balloon 326. The second, larger diameter of the urine receiving opening 324 can be at least as large as, or larger than, the diameter of the urine drainage lumen 318 and, in particular, the urine receiving opening 324 can be formed so the smaller diameter is as small as possible and at least smaller than the diameter of the urine drainage lumen 318. With the diameter of the urine receiving opening 324 after inflation of the balloon 326 being at least as large as and preferably larger than the diameter of the urine receiving lumen 318 of the catheter tube 312. the flow of urine into the urine drainage Iumen318 is facilitated.

[0042] As shown in Figures 4 A and 4B, the distal insertion end 316 of the catheter tube 312 can be formed to have a number of slits 350 defining flaps 352 which, e.g., may comprise 8 slits and corresponding flaps. The external balloon 326 is formed so that when it is inflated, it inflates to a pre-determined shape and is sufficient to overcome the unstressed, formed shape for the flaps 352 as shown in Figure 4A. Since the external balloon 326 is attached to the flaps 352, the flaps are opened outwardly as shown in Figure 4B as the external balloon 352 expands during inflation to its predetermined shape.

[0043] From the foregoing, it will be appreciated that the present disclosure relates to a new Foley catheter design which facilitates the smooth flow of urine through the distal insertion end of the catheter tube rather than through eyes as in a standard Foley catheter. Draining urine through the distal insertion end of the catheter tube leads to a significant reduction in the likelihood of encrustation as a result of biofilm formation which, in turn, leads to a significant reduction in the possibility of blockage of the catheter lumen. Furthermore, since the possibility of blockage of the catheter lumen is significantly reduced, and such blockage in the past is believed to have been one of the major causes of UTIs, the present disclosure will result in a reduced occurrence of UTIs. [0044] In a conventional Foley catheter, there is a tip at the distal insertion end which remains in the bladder from the time of insertion. This tip protrudes beyond the inflatable and deflatable anchoring balloon and over the extended period of time during which the catheter remains indwelling in the patient, the bladder wall and tip can come into contact leading to potential trauma and a UTI. With the embodiments of the present disclosure, there is no protruding tip therefore minimizing the risk of trauma and a UTI.

[0045] While an internal guide catheter having a tip is used in one embodiment, the internal guide catheter is removed following insertion of the Foley catheter. After the internal guide catheter has been removed, the Foley catheter has no tip during continued use thereof. Moreover, the internal guide catheter permits the use of a softer material for the Foley catheter to further reduce the risk of trauma while it remains indwelling.

[0046] While in the foregoing a detailed description of the embodiments of the present disclosure have been set forth for the purpose of illustrating the features and advantages of the present disclosure, it will be appreciated that the details of the present disclosure which are herein given may be varied by those skilled in the art without departing from the true spirit and scope of the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A Foley catheter, comprising: a catheter tube having a proximal drainage end and a distal insertion end and having a urine drainage lumen extending along a longitudinal axis; the catheter tube having a urine drainage opening at the proximal drainage end of the catheter tube and a urine receiving opening at the distal insertion end; the urine drainage and receiving openings defining opposite ends of the urine drainage lumen to accommodate the flow of urine through the catheter tube; at least the urine receiving opening at the distal insertion end of the catheter tube being disposed about the longitudinal axis of the urine drainage lumen; and an inflatable and deflatable external balloon associated with the distal insertion end of the catheter tube for retaining the distal insertion end in the bladder.

2. The Foley catheter of claim 1 wherein the urine drainage lumen of the catheter tube has a substantially uniform diameter from the proximal drainage end to the distal insertion end.

3. The Foley catheter of claim 2 wherein the urine receiving opening at the distal insertion end of the catheter tube has a diameter substantially the same as the urine drainage lumen.

4. The Foley catheter of claim 3 including an inflatable and deflatable internal balloon associated with the distal insertion end of the catheter tube for inflation during insertion.

5. The Foley catheter of claim 4 wherein the internal balloon is associated with an internal wall of the catheter tube defining the urine drainage lumen adjacent the urine receiving opening.

6. The Foley catheter of claim 5 wherein the internal balloon is inflatable to occlude and at least partially extend distally of the urine receiving opening during insertion of the catheter tube.

7. The Foley catheter of claim 3 including an internal guide catheter having a proximal drainage end, a distal insertion end, and a urine drainage lumen extending along a longitudinal axis.

8. The Foley catheter of claim 7 wherein the internal guide catheter has an outer diameter accommodating sliding insertion of the internal guide catheter through the urine drainage lumen.

9. The Foley catheter of claim 8 wherein the internal guide catheter is longer than the catheter tube for extending the distal insertion end distally of the distal insertion end of the catheter tube.

10. The Foley catheter of claim 9 wherein the internal guide catheter has a urine drainage opening at the proximal drainage end and a urine receiving opening at the distal insertion end thereof.

11. The Foley catheter of claim 2 wherein the distal insertion end of the catheter tube normally curves inwardly but expands outwardly upon inflation of the inflatable and deflatable external balloon.

12. The Foley catheter of claim 11 wherein the urine receiving opening has a first, smaller diameter before inflation of the balloon and has a second, larger diameter after inflation of the balloon.

13. The Foley catheter of claim 12 wherein the smaller diameter of the urine receiving opening is at least smaller than the diameter of the urine drainage lumen and the larger diameter of the urine receiving opening is larger than the diameter of the urine drainage lumen.

14. The Foley catheter of claim 12 wherein the larger diameter of the urine receiving opening after inflation of the balloon is at least as large as the diameter of the urine drainage lumen of the catheter tube.

15. A Foley catheter, comprising: a catheter tube having a proximal drainage end and a distal insertion end and having a urine drainage lumen extending along a longitudinal axis, the catheter tube having a substantially uniform outer diameter from the proximal drainage end to the distal insertion end, the urine drainage lumen having a substantially uniform inner diameter from the proximal drainage end to the distal insertion end; the catheter tube having a urine drainage opening at the proximal drainage end of the catheter tube and a urine receiving opening at the distal insertion end, the drainage and receiving openings defining opposite ends of the urine drainage lumen for flow of urine through the catheter tube from the receiving opening to the drainage opening, the drainage and receiving openings at the proximal and distal ends of the catheter tube being coaxial with and the same diameter as the urine drainage lumen; and an inflatable and deflatable external balloon associated with the distal insertion end of the catheter tube for retaining the distal insertion end in the bladder, and an inflatable and deflatable internal balloon associated with the distal insertion end of the catheter tube for inflation during insertion and deflation during use.

16. The Foley catheter of claim 15 wherein the internal balloon is associated with an internal wall of the catheter tube defining the urine drainage lumen adjacent the urine receiving opening thereof.

17. The Foley catheter of claim 16 wherein the internal balloon is inflatable to occlude and at least partially extend distally of the urine receiving opening during insertion of the catheter tube.

18. A Foley catheter, comprising: a catheter tube having a proximal drainage end and a distal insertion end and having a urine drainage lumen extending along a longitudinal axis, the catheter tube having a substantially uniform outer diameter from the proximal drainage end to the distal insertion end, the urine drainage lumen having a substantially uniform inner diameter from the proximal drainage end to the distal insertion end; the catheter tube having a urine drainage opening at the proximal drainage end of the catheter tube and a urine receiving opening at the distal insertion end, the drainage and receiving openings defining opposite ends of the urine drainage lumen for flow of urine through the catheter tube from the receiving opening to the drainage opening, the drainage and receiving openings at the proximal and distal ends of the catheter tube being coaxial with and the same diameter as the urine drainage lumen; an inflatable and deflatable external balloon associated with the distal insertion end of the catheter tube for retaining the distal insertion end in the bladder; and an internal guide catheter having a proximal drainage end, a distal insertion end, and a urine drainage lumen extending along a longitudinal axis.

19. The Foley catheter of claim 18 wherein the internal guide catheter has an outer diameter accommodating sliding insertion of the internal guide catheter through the urine drainage lumen.

20. The Foley catheter of claim 19 wherein the internal guide catheter is longer than the catheter tube for extending the distal insertion end distally of the distal insertion end of the catheter tube.

21. The Foley catheter of claim 20 wherein the internal guide catheter has a urine drainage opening at the proximal drainage end and a urine receiving opening at the distal insertion end thereof.

22. A Foley catheter, comprising: a catheter tube having a proximal drainage end and a distal insertion end and having a urine drainage lumen extending along a longitudinal axis, the catheter tube having a substantially uniform outer diameter from the proximal drainage end to the distal insertion end, the urine drainage lumen having a substantially uniform inner diameter from the proximal drainage end to the distal insertion end; the catheter tube having a urine drainage opening at the proximal drainage end of the catheter tube and a urine receiving opening at the distal insertion end, the drainage and receiving openings defining opposite ends of the urine drainage lumen for flow of urine through the catheter tube from the receiving opening to the drainage opening, the drainage and receiving openings at the proximal and distal ends of the catheter tube being coaxial with and the same diameter as the urine drainage lumen; and an inflatable and deflatable external balloon associated with the distal insertion end of the catheter tube for retaining the distal insertion end in the bladder; the urine receiving opening having a first, smaller diameter before inflation of the balloon and having a second, larger diameter after inflation of the balloon.

23. The Foley catheter of claim 22 wherein the distal insertion end of the catheter tube normally curves inwardly but expands outwardly upon inflation of the inflatable and deflatable external balloon.

24. The Foley catheter of claim 23 wherein the smaller diameter of the urine receiving opening is at least smaller than the diameter of the urine drainage lumen and the larger diameter of the urine receiving opening is larger than the diameter of the urine drainage lumen.

25. The Foley catheter of claim 23 wherein the larger diameter of the urine receiving opening after inflation of the balloon is at least as large as the diameter of the urine drainage lumen of the catheter tube.