HK1153690A - Indwelling urinary catheter with self-retaining mechanism - Google Patents

Description

Indwelling catheter with self-retaining mechanism

RELATED APPLICATIONS

This application claims priority from U.S. patent application serial No. 12/490,669, filed 24/6/2009, the subject matter of which is incorporated herein by reference.

Technical Field

The present invention relates to a surgical instrument, and more particularly to a catheter which is indwelling within a patient's bladder for urination, irrigation or drug delivery.

More particularly, the present invention relates to an indwelling urinary catheter having self-retaining characteristics which is safe and reliable in operation, easy to handle, and does not retain urine.

Background

Indwelling catheters are urinary catheters designed to be inserted into the bladder of a patient for retention in the bladder during a certain surgical procedure or for longer periods of time. Under short or long term surgical or medical conditions, it is desirable to continually empty the bladder to flush the bladder, or to deliver drugs. For example, it is desirable to empty the bladder to measure the amount of urine output per hour, an important parameter in calculating the patient's response to a particular drug (e.g., a diuretic). Hourly urine output is also an important indicator in the study of the number of pulses, fluctuations in blood pressure, and cardiac monitoring. For comatose patients, voiding of urine is also very important as part of the overall assessment of the patient's medical condition.

It is known that complete emptying of urine is beneficial for accelerated recovery of spinal cord injuries. In addition, indwelling catheters indicate that the patient is suffering from a complex neurological condition or that they may be heavily sedated and unable to empty their bladder.

In prostate surgery, postoperative bleeding is common and, if left unchecked, can lead to the formation of blood clots in the bladder. Indwelling catheters are mandatory to ensure that there is no clotting in the bladder and to avoid painful conditions or shock due to unconsciousness of the bladder's blood clots.

After a particular prostate or bladder procedure, the bladder should be flushed continuously with fluid to prevent blood from clotting within the bladder. Continuous bladder irrigation can be achieved by using a three-way catheter having an inlet and an outlet tube for fluid infusion. If continuous delivery of the drug to the bladder is required, the catheter will be indwelling and retained in the bladder for the entire period of treatment.

In long-term medical and surgical conditions, the bladder may need to be emptied for weeks, months, or in some cases for life. Examples of such conditions include weak patients who are unable to urinate, and when the patient's medical condition does not permit surgery.

A common indwelling catheter, such as the Foley catheter type, has a balloon attached to one end. After the Foley catheter is inserted into the urethra and reaches the bladder, the balloon is filled with sterile water so that the filled balloon prevents the catheter from escaping from the bladder. Specifically, as shown in fig. 1A and 1B, the Foley catheter 10 has a tubular body 12 with a tip 14 at a proximal end 16. There are several holes or openings 18 (typically 3 x 5mm in size) near the tip 14 to empty urine or blood or deliver medication after the catheter has been inserted into the bladder.

In a catheterization procedure, as shown in fig. 1A, a catheter in an occluded state is inserted through the urethra into the bladder, and urine and/or blood from the bladder is infiltrated through the apertures 18 into the passageway in the tubular body 12 for discharge from the primary discharge port 20. To provide retention of the catheter in the bladder, sterile fluid is delivered into the bladder 22 by a syringe connected to the injection port 24. The injection port 24 is connected to the balloon 22 by a separate channel 26 extending along the tubular body 12 of the catheter 10. The main outlet 20 is typically connected to a large urine bag (not shown). A valve 28 is provided at the injection port 24 to facilitate the injection of sterile water when the catheter is indwelling.

In the expanded indwelling position of balloon 22, as shown in FIG. 1B, the catheter remains within the bladder until it is removed. To remove the catheter from the bladder, sterile fluid is expelled from the balloon 22 through the valve 28 by means of a syringe engaged with the injection port 24. Once the balloon is deflated and the catheter is converted to a "balloon deflated" state, the catheter may be removed.

Foley catheters have a number of drawbacks: 1. the bladder near the top end may weigh 5-50 grams when filled with water, depending on how many cubic centimeters of water are poured into the bladder. A bladder with such a large weight "rests" on the most sensitive part of the bladder (e.g. the trigone), causing discomfort, irritation and pain. The catheter balloon also hinders the complete discharge of urine, so that urine always remains in the bladder. This can lead to irritation and ultimately to infection of the bladder. 2. Accidental expansion of the balloon within the urethra (before reaching the bladder) is a highly undesirable condition as it can lead to urethral damage and even to partial urethral tears. Partial or complete urethral tears may result in narrowing of the urethra, known as "urethral stricture," which may require complicated surgical procedures to correct the stricture. In some cases, the balloon may not be able to empty when the catheter is removed. In this situation, the patient must undergo a complex operation in order to puncture the bladder within the bladder. 3. Accidental catheter pull-out may occur when the balloon is expanded within the bladder. This is very painful and may result in damage to the bladder neck and/or urethra. 4. In order to place the catheter within the bladder, it is necessary to expand the balloon using a sterile syringe and sterile fluid. Conversely, if it is desired to remove the catheter from the bladder, a sterile syringe is used to withdraw fluid from the balloon to deflate the balloon. The use of sterile syringes and the transfer of fluids complicates the operation.

Catheters known as "Comficath" have been developed which are coated with antibiotics or silicon. In some catheters, as a source of stimulationHas been solved and a new generation of rubber silicone tubing has been developed. Despite all these innovations, problems still exist and there is still a need in the medical field for a catheter that overcomes the above-mentioned drawbacks of Foley catheters, namely the presence of residual urine, infection, discomfort, failure to function properly and possible accidental injury to the urethra and/or bladder neck.

It would therefore be desirable to provide a catheter with an improved retention mechanism that does not present the problems associated with balloon expansion/contraction, which has long been desired in the field of indwelling catheters, in order to address the above-mentioned problems.

Disclosure of Invention

It is an object of the present invention to provide an indwelling catheter with a retention mechanism whose condition can be easily controlled by the person performing the catheterization procedure and which is safe for the patient.

It is another object of the present invention to provide an indwelling catheter which can be used to empty the bladder, to flush the bladder with fluids or medications, in both short and long term surgical and medical conditions with minimal discomfort and irritation, and it is an additional object of the present invention to not leave urine in the bladder.

It is another object of the present invention to provide an indwelling catheter with an improved retention mechanism whose proximal end can be easily actuated by the person performing the procedure without the need for a sterile syringe or sterile fluid, and which is sufficiently stiff to be introduced into the interior of the bladder without the need for a stylet or catheter introducer.

The catheter of the present invention includes a tubular member defining a longitudinal passageway extending between its proximal and distal ends. A retention mechanism is located at the proximal end of the tubular member for insertion into the urethra of the patient. The trigger mechanism is positioned at the distal end of the tubular element. An actuating link extends in the longitudinal channel of the tubular element of the catheter and is operatively coupled to the retention mechanism and the trigger mechanism to actuate the retention mechanism to assume an "open" state to retain the catheter in the bladder or a "closed" state for insertion and removal of the catheter.

The actuating link is formed of stainless steel wire, nylon wire, polyester wire or plastic wire or the like and reciprocates within the longitudinal channel of the tubular element of the catheter under the control of the trigger mechanism. The retention mechanism transitions to an "open" state when the actuation link wire is retracted toward the distal end, and transitions to a "closed" state when the actuation link wire is moved toward the proximal end.

In addition to the distal port at the distal end of the tubular element to which the trigger mechanism is operatively attached, the catheter also includes an exhaust port coupled to the tubular element and in fluid communication with the longitudinal channel to exhaust fluid from the patient's urethra or to deliver medication or irrigation fluid into the bladder. In a three-way catheter design, additional ports are added to the wall of the catheter for continuous infusion of drugs or irrigation fluids.

In the urinary catheter of the invention, many variations of the retention mechanism are foreseen. For example, the retaining mechanism may comprise a pair of slits extending from the tip of the catheter along the wall of the tubular element, which may be converted into "wings" extending radially from the wall of the tubular element and spanning a distance at the proximal end of the tubular element corresponding to the length of the slits formed in the wall of the tubular element.

After insertion into the bladder in the "closed" state, the catheter is converted to the "open" state and the wings hold the catheter within the bladder against the bladder wall. The flexible material (silicone rubber or Latex) of the tubular element makes the wings of the retention mechanism formed thereby "user friendly", contact of the wings with the bladder wall will cause minimal irritation to the bladder wall. In addition, the openings formed between the wings are very large to allow fluid from the bladder to be completely expelled and to effectively deliver medication or irrigation fluid to the bladder when desired.

In an alternative embodiment, the retaining mechanism may comprise one or more pairs of blades coupled to the proximal end of the tubular element. In the "closed" state of the retaining mechanism, the blades are positioned in contact with each other along their entire length and in alignment with the tubular element. In the "open" state of the retention mechanism, the blades are moved a predetermined angle relative to each other so that the blade ends form a contact point with the bladder wall to securely hold the catheter in place.

The retention mechanism with the blades is modified to have a Λ -shape memory capable of "remembering" the shape. In the "open" state of the retention mechanism, the Λ -shaped memory is converted to a "deployed" state by actuating the coupling wire, wherein the legs of the Λ -shaped memory push the blades of the retention mechanism apart to form a predetermined angle between the blades.

To transition the retention mechanism to the "closed" position, the Λ -shaped memory is released from the "open" position by actuating the linkage, thereby closing the vanes. The retention mechanism remains in the "closed" state because the Λ -shape memory has the memory of a "closed" shape.

The trigger mechanism of the catheter of the present invention may have various embodiments, each of which is suitable for use with each of the aforementioned retention mechanisms. In one embodiment, the trigger mechanism comprises a bellows element having a flexible corrugated wall. The front end of the actuating link is connected to the retention mechanism and the rear end of the actuating link is connected to the end of the bellows element that is furthest from the proximal end of the catheter. The bellows element may be switched between its fully compressed and expanded states to actuate the "closed" and "open" states of the retaining mechanism, respectively.

The bellows element may be a memory having shape memory for either the expanded state or the compressed state, or both, or neither. Depending on the choice of shape memory of the bellows element, a latch may be used to hold the bellows element in the compressed state, for example if the bellows element has memory of an expanded state corresponding to the "open" state of the holding mechanism. When the catheter in the "closed" state is inserted into the bladder, the latch is released by the medical personnel performing the procedure, thereby releasing the bellows member to the expanded state, in which it remains due to shape memory.

When it is desired to remove the catheter from the bladder, the bellows member is compressed and closed by the latch. A pair of resiliently biased projections (buttons) may be mounted on one of the ends of the bellows member in engagement with the latch such that when it is desired to release the latch to convert the bellows member to the expanded condition, both buttons are depressed to release the latch.

If the bellows member has memory for the compressed shape, it can be manually expanded and "locked" in the expanded state by a locking mechanism (e.g., a latch).

Alternatively, it is contemplated that the trigger mechanism has a pair of threaded engagement members. The rear end of the actuating link is connected to one of the threaded elements so that the transition of the retaining mechanism between the "open" and "closed" states can be controlled by the degree of threaded engagement between the first and second threaded elements of the trigger mechanism.

Further, the trigger mechanism may comprise a squeezable unit attached to and in surrounding relation to the distal end of the tubular element. By squeezing and pushing the squeezable unit along the tubular element of the catheter, the movement of the squeezable unit along the tubular element can be controlled. The "open" and "closed" states of the catheter of the present invention are controlled by moving the squeezable element attached to the rear end of the actuating link.

The triggering mechanism, in particular the latching control of the bellows element, can be designed as a thumb-slide based actuator or as a lever action based mechanism.

As another example of a trigger mechanism, a syringe-based actuator is also envisioned, which includes a hollow cylindrical portion attached to the distal end of the tubular element and a plunger portion controllably slidable within the hollow cylindrical portion. The rear end of the actuating link in this embodiment is connected to the plunger portion. The transition of the retaining mechanism between the "open" and "closed" states may be controlled by repositioning the plunger portion within the hollow cylinder portion of the syringe-based actuator. The syringe-based actuator may include a locking mechanism for locking the retaining mechanism in an "open" state. The syringe-based actuator may further comprise a sealing means to prevent fluid from escaping from the distal end of the tubular element.

These and other features and advantages of the present invention will become more apparent from the following more detailed description, read in conjunction with the accompanying patent drawings.

Drawings

FIGS. 1A-1B are schematic illustrations of a Foley catheter of the prior art;

FIGS. 2A-2B are schematic illustrations of the two-winged self-retaining mechanism of the catheter of the present invention in the "closed" and "open" states, respectively;

FIGS. 3A-3B are schematic views of the catheter of the present invention with a three-winged self-retaining mechanism in the "closed" and "open" states, respectively;

FIGS. 4A-4C are schematic views of an alternative embodiment of a catheter of the present invention with dual blades, with the retention mechanism in the "closed" state (FIG. 4A), the "open" state (FIG. 4C), and the intermediate state (FIG. 4B), respectively;

5A-5D are schematic illustrations of variations of the catheter of the present invention with a four-bladed retention mechanism;

FIGS. 6A-6B show enlarged views of the trigger mechanism of the catheter presented in FIGS. 4A-4C;

7A-7B illustrate a trigger mechanism in the form of a bellows element in a compressed state (FIG. 7A) and an expanded state (FIG. 7B);

8A-8B illustrate a catheter of the present invention with the bellows element trigger mechanism in a "closed" state (FIG. 8A) and an "open" state (FIG. 8B);

FIGS. 9A-9B illustrate a catheter of the present invention with a trigger mechanism in the form of a bellows member with a latch;

FIGS. 10A-10B illustrate an alternative embodiment of a catheter of the present invention with a threaded trigger mechanism in the "closed" state (FIG. 10A) and the "open" state (FIG. 10B);

FIG. 11 shows an enlarged view of the thread triggering mechanism of the catheter of FIGS. 10A-10B;

FIGS. 12A-12B illustrate another embodiment of the catheter of the present invention with a squeezable slide unit to control the "open" and "closed" states of the retaining mechanism, respectively;

FIG. 13 shows a squeezable slide unit of the catheter shown in FIGS. 12A-12B;

FIGS. 14A and 14B illustrate a variation of the catheter of the present invention with a thumb slide based actuator in the "closed" and "open" states, respectively;

FIGS. 15A and 15B illustrate a catheter of the present invention with lever-action based actuators in the "closed" and "open" states, respectively;

FIGS. 16A-16B illustrate a lever action based actuator of the catheter shown in FIGS. 15A-15B of the present invention; and

fig. 17A and 17B illustrate an alternative embodiment of the catheter of the present invention with a syringe-based actuator with a locking mechanism in the "closed" and "open" states, respectively.

Detailed Description

Referring to fig. 2A-5C, 8A-10B, 12A-12B, 14A-15B and 17A-17B, a catheter 30 of the present invention includes a tubular member 32, a retention mechanism 34 at a proximal end 36 of the tubular member 32, and a trigger mechanism 38 at a distal end 40 of the tubular member 32. A passageway 42 is defined by a wall 44 of the tubular member 32 and extends between the proximal end 36 and the distal end 40 of the tubular member 32.

The actuating link 46 is in the form of a wire made of plastic, dacron, stainless steel or nylon, with its forward end 48 connected to the retaining mechanism 34 and its distal end 50 connected to the trigger mechanism 38 to switch the retaining mechanism between its "open" and "closed" under the control of the trigger mechanism 38 manipulated by the physician or nurse or other medical personnel performing the procedure.

The catheter is inserted into the urethra in the "closed" state and remains in place for a period of time depending on the particular procedure. When the catheter is in the bladder, it may be used to empty urine or blood, deliver medication to the bladder, and/or flush the bladder. To maintain it in the bladder, the retention mechanism 34 is switched to an "open" state, which can be accomplished in different catheter embodiments in different ways as disclosed below. Once the procedure is complete, the catheter is removed if it does not need to be held for a longer period of time. To this end, the retention mechanism 34 is transitioned from its "open" state to its "closed" state so that the catheter may be easily removed from the bladder by a medical professional.

In the embodiment of the catheter 30 of the present invention shown in FIGS. 2A-3B, 8A-10B, 12A-12B, 14A-15B and 17A-17B, the retention mechanism 34 is designed with a plurality of slits 52, such as 2, 3 or 4 slits, extending at the proximal end 36 of the tubular member 32 in contact with the tip 54. Each slit 52 is cut at a predetermined position and has a predetermined length. In the "closed" state of the retaining means 34, the slit is closed and the retaining means occupies the smallest dimension possible for the design, without any part extending outside the tubular element. This reduces discomfort when the catheter is inserted into or removed from the urethra of a patient.

When the catheter is observed to be delivered into the bladder by the presence of urine or blood at the exhaust port 56 as best shown in figures 10A-10B, 12A-12B, 15A-15B and 17A-17B, the retention mechanism 34 is converted to an "open" state if the catheter needs to be indwelling or retained in the bladder.

In the "open" state, the slit 52 of the retaining mechanism 34 is open such that the wings 58 are formed to extend radially from the tubular member 32. The wings 58 have a span corresponding to the length of the slit 52. The wings 58 are separated by large openings 60, wherein the openings 60 are of sufficient size to allow efficient drainage of fluid (urine, blood) from the bladder to the drain 56 of the catheter without residual urine in the bladder.

When a drug or irrigation fluid is delivered into the bladder through the plurality of openings 60, the drug and irrigation fluid can be brought into full contact with the bladder wall in different directions, thereby increasing the efficacy of the performed procedure. The tip 54 has a smooth surface and therefore does not cause discomfort to the patient when in contact with the bladder wall. The wings 58 form a smooth curve between the tip 54 and the tubular member 32 at the lower end of the slit 52 and they are sufficiently flexible to avoid damage to the bladder wall when in contact therewith in the indwelling position of the catheter. As an additional advantage of the present design, even if the wings open abruptly when the retention mechanism is in the urethra rather than the bladder, the impact of the wings 58 on the urethral wall is very slight and does not cause damage to the urethral wall. It is very rare that the wings of the catheter in question inadvertently open inside the urethral wall.

To transition the retention mechanism 34 from the "closed" position, in which the slit 52 is closed, to the "open" position, in which the wings 58 extend radially from the tubular element, the actuating link 46, whose forward end 48 is connected to the tip 54, is retracted by the trigger mechanism 38 toward the distal end 40 of the catheter, as will be further described in the following paragraphs. This action brings the tip 54 of the catheter closer to the lower end of the slit 52, forming wings 58 separated by openings 60. Next, the rear end 50 of the actuating linkage wire 46 is secured in place by the trigger mechanism 38 to maintain the retention mechanism 34 in the "on" state when it is desired to retain the catheter in the bladder.

While embodiments of 2, 3 and 4 wings are presented in fig. 2A-3B and 14A-14B, it should be clear that any number of wings is possible depending on the needs and particulars of the catheterization procedure.

Referring to fig. 4A-4C and 5A-5C, which illustrate another embodiment of the catheter 30, the retaining mechanism 34 is formed with a plurality of blades 62, each of which is attached to each other along the entire length of the blade in the "closed" state of the retaining mechanism 34. When the retention mechanism 34 is converted to the "open" state (in the indwelling position of the catheter), the blades 62 open at the lower end 64 by the rotational movement of the activation of the Λ -shaped memory 66 so as to be in the "open" state with the blades 62 at a predetermined angle to each other.

For example, as shown in FIG. 4B, the Λ -shaped memory 66 opens the leaves 62 to a neutral position, and as shown in FIG. 4C, the Λ -shaped memory 66 opens the leaves 62 further and to a fully open position that allows the catheter to remain in the bladder for a desired time.

The vanes 62 in the retaining mechanism 34 may have any number. For example, a design with two blades is shown in FIGS. 4A-4C and 6A-6B, while a design with four blades is presented in FIGS. 5A-5D. The four-lobe design may have a spherical tip element 63 connected to the front end 48 of the actuating linkage wire 46 and movable in the A-B direction under the control of the trigger element 38. When the catheter is in its "closed" state, as shown in fig. 5A-5B, the spherical tip element 63 is in its proximal most position and the leaves 62 are closed to each other along the length of the leaves. However, when the catheter is converted to the "open" state, the actuating linkage wire 46 is retracted in direction A by the trigger mechanism 38, thereby "pulling" the spherical tip element 63 toward the distal end 40, thereby opening the leaves 62, as shown in FIGS. 5C-5D. In the "open" condition, as best shown in fig. 5D, the discharge opening 65 is formed sufficiently to accommodate effective catheterization.

Fig. 6A-6B illustrate the diagonally open blade configuration of fig. 4A-4C in more detail. Each of the blades 62 includes a portion formed of a material (e.g., silicone rubber) having a tubular member of a predetermined length, with the lower end 64 of the blade being connected to the tubular member 32. The upper end 68 of each blade 62 has a rounded smooth surface to prevent pain to the urethral tissue upon contact. Beams 70 are embedded in each blade 62 along its length, and the Λ -shaped memory 66 is pivotally attached to each beam 70. The Λ -shaped memory 66 has a pair of legs 72, the legs 72 being joined to each other at points 74 and to the beam by ends 76.

The front end 48 of the actuating linkage wire 46 is connected to the upper end 74 of the Λ -shaped memory 66. By reciprocating the actuating linkage wire 46 along the channel 42 of the tubular element 32, the upper end point 74 of the Λ -shaped memory 66 moves relative to the point 64 at the root of the vane 62, thereby changing the angle between the legs 72 of the Λ -shaped memory 66. In this manner, the change in the relative arrangement between the legs 72 of the Λ -shaped memory 66 is translated into an angular displacement of the blades 62 relative to one another through the coupling, which includes the interconnection between the legs 72 and the beams 70 embedded in the blades 62.

As the actuating link wire 46 is retracted in the direction indicated by arrow a toward the distal end 40 of the catheter, the leaves 62 assume an angled relative arrangement at point 64 as the actuating link wire 46 continues to slide toward the distal end 40. Conversely, as the actuating link wire 46 moves in the direction indicated by arrow B toward the proximal end 36 of the catheter, the angle between the leaves 62 gradually decreases, thereby closing the leaves 62 against one another. The Λ -shaped memory 66 has a shape memory of a "closed" position. Once the wire 46 is released, the Λ -shaped memory 66 will "close," thereby "closing" the leaves 62 to each other and having slits between the leaves 62.

The Λ -shaped memory 66 has shape memory, particularly preferably of the angle between the legs 72 corresponding to the "closed" state of the retention mechanism 34. With this configuration, when the actuating link 46 pulls the upper end point 74 of the Λ -shaped memory 66 in the a direction to a position corresponding to the "open" state of the retention mechanism 34, the actuating link 46 must be fixed in a particular position during the indwelling state of the catheter.

When this is done, the catheter is returned to the "closed" position to allow the Λ -shaped memory 66 to return to its original "memorized" shape by releasing the trailing end 50 of the actuating coupling wire 46, thereby "closing" the blades 62 and removing the catheter from the patient's urethra.

Alternatively, the beam 70 may also form part of the Λ -shaped memory 66. In this way, the Λ -shaped memory 66 "memorizes" the overall shape and relative positions of all elements corresponding to the "closed" state of the catheter.

7A-17B, various types of triggering mechanisms 38 may be used with catheter 30, each of which may be adapted for use with the various retaining mechanisms 34 described above. Referring to fig. 7A-9B, the trigger mechanism 38 includes a bellows member 75 having a flexible corrugated wall 77, wherein an end 78 of the bellows member 75 is connected to the distal end 40 of the tubular member 32. The other end 80 of the bellows member 75 is located at an opposite edge, and the rear end 50 of the actuating link 46 is connected to the other end 80 by various mechanisms known in the art. For example, the rear end 50 may be glued or welded to an end 80 of the bellows element 75, or may be secured in place by means of a block 82 resting on the corrugated wall 77. However, other forms of connection between the rear end 50 of the actuating link 46 and the bellows member 75 are also contemplated as falling within the scope of the present invention.

Due to the nature of the wall 77, the bellows element 75 is able to change its length between a "compressed" state, shown in fig. 7A, and an "expanded" state, shown in fig. 7B. In the "expanded" state of the bellows element 75, the rear end 50 of the actuating link 46 moves toward the distal end 40 of the catheter 30. The forward end 48 of the actuating link 46 moves along the conduit, thereby shifting the retention mechanism 34 shown in fig. 2A to the "open" state, as previously described.

Various types of bellows elements 75 may be suitable for use with the catheter of the present invention, allowing the alternative mechanism to transition between its "compressed" and "expanded" states. For example, the bellows element 75 can be a memory plastic bellows that has memory for an "expanded" state or a "compressed" state, or both. Furthermore, the bellows element may also have no memory.

For example, in embodiments in which the bellows element 75 has memory for both a compressed ("closed") shape and an expanded ("open") state, the catheter is inserted into the bladder in its compressed state while leaving the retention mechanism 34 of the catheter in a "closed" state, as shown in fig. 8A. During the introduction of the catheter into the urethra, the "compressed" state of the bellows element is ensured by its shape memory. The button 84 is held while the catheter is being manipulated. Once the catheter is in place, the clinician still holds the button 84 in one hand and manually expands the bellows element 75 to the "expanded" state with the other hand to transition the retention mechanism 34 to the "open" state, as shown in FIG. 8B. Because the bellows member 75 has an "expanded" shape memory, the bellows member 75 will remain "open" once expanded.

To convert the bellows to the "closed" (compressed) state when the catheter needs to be removed from the urethra, the medical practitioner is required to press on the button 84 with one hand and then push the end 80 of the bellows element 75 toward the button 84 to convert the bellows element 75 to the "compressed" state, thereby closing the retaining element 34 and preparing the catheter for removal. Because the bellows member 75 has a "compressive" shape memory, the bellows member 75 will remain compressed once compressed.

To allow the bellows member 75 to be compressed when it has only "expanded" shape memory, a latch 86 is used to hold the bellows member 75 in its "compressed" state, as shown in FIG. 9A. When the catheter has been inserted into the urethra, it may be transitioned to the "open" state shown in fig. 9B to remain in the bladder. To do so, the healthcare worker presses the two resiliently biased buttons 84 towards each other, thereby releasing the latch 86 that restrains the bellows member 75 in the "compressed" state. When the latch 86 is released, the bellows member 75 transforms to its "expanded" state, and the bellows member 75 remains in this state until the end of the operation due to its "expanded" shape memory. At the end of the procedure, when it is desired to remove the catheter from the urethra, the bellows member 75 is manually compressed until the opening 85 in the latch 86 engages the button 84, as shown in fig. 9A, wherein the bellows member 75 is held compressed in this position to remove the catheter from the urethra.

Referring to fig. 10A-10B and 11, there is shown another alternate embodiment of the catheter 30 of the present invention in which the trigger mechanism 38 is formed with a pair of threaded engagement members 88 and 90. As shown in fig. 11, the rear end 50 of the actuating link 46 is joined to a block 90. Rotation of the block 88 relative to the block 90 produces a reciprocating motion of the block 90 with a corresponding movement of the rear end 50 of the actuation link wire 46. This motion is transferred to the motion of the front end 48 of the actuating link 46, causing the retaining mechanism 34 to transition between its "open" or "closed" states, respectively.

With further reference to fig. 12A-12B and 13, in another alternative embodiment, the trigger mechanism 38 includes a squeezable mass 92 that closely surrounds the tubular member 32. When squeezed, the squeezable mass 92 is released from contact with the tubular element 32 and is slidable along the tubular element 32 between a position corresponding to the "closed" state of the catheter shown in fig. 12A and a position corresponding to the "open" state shown in fig. 12B.

As shown in fig. 13, the squeezable element 92 has a ring 94 and a resilient cylinder 96 resiliently surrounding the tubular member 32. When the ring 94 is pushed towards the cylinder 96, the elastic connection between the cylinder 96 and the tubular element 32 is released, so that the entire structure can slide along the tubular element. The rear end 50 of the actuating link wire 46 attached to the crushable member also moves along the tubular member.

To actuate the trigger mechanism 38 shown in fig. 12A-12B and 13, the person performing the catheterization procedure inserts the catheter in the "closed" state shown in fig. 12A into the urethra and in particular into the bladder. A urine bag 98 is attached to the discharge port 56. The urine bag 98 is a bag of approximately 10 inches by 10 inches in size connected to a long tube (approximately 2 feet long). When urine or blood is seen in the urine bag 98 attached to the discharge port 56 of the catheter, the person squeezes the squeezable mass 92 and slides the squeezable mass 92 distally, as shown in fig. 12B, thereby retracting the actuating coupling wire 46 from the proximal end of the catheter and converting the retention mechanism 34 to an "open" state. When the "open" condition is achieved, the clinician "locks" the squeezable block 92 in place by releasing the ring 94 and positions the block 92 in a position corresponding to the "open" condition, as shown in FIG. 12B.

As shown in fig. 14A-14B, which illustrate a four wing design and actuator 38 with thumb slide 100. In this variant, the catheter is transformed into the "closed" condition shown in fig. 14A by moving the adjustment block 102 along the slot 104 formed in the holder 106, wherein said holder 106 is attached at the distal end 40 of the tubular element 32 of the catheter, by which action the rear end 50 of the actuating link 46 operatively coupled to the adjustment block 102 is moved away from said distal end 40. To convert the retention mechanism 34 to the "open" state, four wings are radially extended from the tubular member, as shown in fig. 14B, in a one-handed operation, the adjustment block 102 is moved down the chute 104 closer to the distal end 40 of the catheter by the thumb of the healthcare worker.

As shown in fig. 15A-15B and 16A-16B, a lever action based actuator 108 is attached to the distal end 40 of the tubular member 32. The wire of the actuating link 46 can be pulled or pushed by manipulating the lever 110, as shown in fig. 16A-16B. An end 112 of the lever 110 is pivotally connected to a wire holder 114 that resiliently reciprocates in the direction indicated by arrows C-D. By manipulating the lever 110, the wire holder 114, to which the rear end 50 of the actuating link wire 46 is attached, moves between a position corresponding to the "closed" state shown in fig. 16A and a position corresponding to the "open" state shown in fig. 16B, thereby displacing the rear end 50 of the actuating link wire 46 accordingly and transitioning the retaining mechanism 34 between the "closed" and "open" states as needed.

In another alternative embodiment, as shown in fig. 17A-17B, the trigger mechanism 38 is a syringe-based actuator 116 with a locking mechanism 124. The syringe-based actuator 116 includes a hollow cylindrical portion 118 attached to the distal end 40 of the tubular member 32 and a plunger portion 120 reciprocating within the hollow cylindrical portion 118. The plunger portion 120 may be manipulated by the ring holder 122 or any other structure. In the "closed" state shown in fig. 17A, plunger portion 120 is in its forwardmost position within hollow cylinder portion 118. To transition the retention mechanism 34 to the "open" state when the catheter 30 is indwelling in the bladder, the healthcare worker pulls the plunger 120 in the cylindrical portion 118 by means of the ring holder 122 in the direction E so as to retract the rear end 50 of the actuating coupling wire 46 attached to said plunger 120 towards the distal end of the catheter, forming a wing 58 at the proximal end of the tubular element 32 so as to be retained in the bladder of the patient, as shown in fig. 17B.

In the "closed" state, relative movement between components of the syringe-based actuator 116 is locked by the locking unit 124, wherein the locking unit 124 may be of any design as long as it provides a locking action between the opposing components. For example, the locking unit 124 may be a resiliently biased tooth 126 on the barrel portion 118 that releasably engages a slotted beam 128 on the shaft of the plunger. Alternatively, the locking mechanism may be designed with a resiliently biased hook element that engages the opposing member.

A Tuohy-Borst valve 130 may be mounted at the connection between the distal end of the tubular element 32 and the syringe-based actuator 116 to seal the fluid flow. Alternatively, a sealing material may be used in the channel actuation coupling lumen to prevent urine from entering the syringe-based actuator. As an alternative to or in addition to the Tuohy-Borst valve, a ball seal may be used, wherein a ball is bonded to the trailing end 50 of the actuating coupling wire 46 that reciprocates within the channel 42 at the distal end 40 of the catheter to close the channel when the catheter is indwelling.

For greater safety, the basic state of the catheter of the present invention is the "closed" state. The catheter can only be transitioned to the "open" state if the retention mechanism 34 is intentionally triggered when the actuating link 46 is pulled toward the distal end 40 of the catheter. Even with this very low likelihood that the indwelling mechanism may be accidentally triggered when the tip of the catheter is in the urethra but not in the bladder cavity, the opening force of the retention mechanism is not sufficient to overcome the strength of the urethral wall to initiate the indwelling state. Thus, the new catheter is safe to use and avoids damage to the urethra.

Although the present invention has been described in connection with the specified forms and embodiments, it should be understood that various modifications other than those discussed above may be made without departing from the spirit or scope of the invention as defined by the appended claims. For example, functionally equivalent elements may be substituted for those specifically illustrated or described, certain parts may be used independently of the others, and in certain instances, certain positions of elements may be reversed or otherwise adjusted, all without departing from the spirit or scope of the invention as defined in the appended claims.

Claims (20)

1. A urinary catheter, comprising:

(a) a tubular member having a proximal end and a distal end, the tubular member defining a longitudinal passage extending between the proximal end and the distal end,

(b) a retention mechanism insertable into a urethra of a patient and positioned at said proximal end of said tubular element, said retention mechanism being controllable and selectively in an "open" position and a "closed" position,

(c) a trigger mechanism positioned at the distal end of the tubular element,

(d) an actuating linkage extending in the longitudinal channel of the tubular element and coupling the retaining mechanism and the trigger mechanism to one another, the actuating linkage being reciprocally movable in both directions in the longitudinal channel under control of the trigger mechanism to thereby actuate the retaining mechanism to be in one of the "open" and "closed" states.

2. The urinary catheter according to claim 1, wherein said actuating link is retracted towards said distal end to switch said retention mechanism to said "open" state.

3. The urinary catheter according to claim 1, wherein the actuating coupling is selected from the group consisting of stainless steel wire, nylon wire, polyester wire, and plastic wire.

4. The urinary catheter according to claim 1, further comprising an outlet port coupled to said tubular member and in fluid communication with said longitudinal channel of said tubular member.

5. The urinary catheter according to claim 1, wherein said retention mechanism comprises a tip at said proximal end and at least one pair of slits extending from said tip along the wall of said tubular element at predetermined positions of the wall of said tubular element, one end of said actuation link being connected to said tip,

wherein in the "open" state of the retention mechanism, the tubular element forms at least one pair of resilient wings defined by the at least one pair of slits and spanning a distance radially from the apex, wherein the distance corresponds to the length of each slit of the at least one pair of slits.

6. The urinary catheter according to claim 1, wherein said retaining mechanism comprises at least one pair of blades coupled to said proximal end of said tubular member at predetermined positions,

in said "closed" condition of said retention mechanism, said at least one pair of blades are positioned in contact with each other and in alignment with said tubular element along substantially the entire length of the blades, and

in the "open" state of the retention mechanism, the at least one pair of vanes are angled with respect to each other.

7. The urinary catheter according to claim 6, wherein the retention mechanism further comprises a Λ -shaped memory having at least one pair of legs, first ends of the at least one pair of legs being connected to each other to form a connection point of the Λ -shaped memory, a second end of each of the at least one pair of legs being joined to a respective one of the at least one pair of blades, an angle defined between the legs of the Λ -shaped memory being controlled by the trigger mechanism so as to control the relative arrangement between the blades.

8. The urinary catheter according to claim 7, wherein the retention mechanism further comprises at least one pair of beams, each beam being attached to a respective one of the at least one pair of blades,

the second end of each leg of the Λ -shaped memory is pivotally connected to a respective one of the at least one pair of beams, and

one end of the actuating link is connected to the connection point of the Λ -shaped memory.

9. The urinary catheter according to claim 7, wherein the Λ -shaped memory has a memorized shape corresponding to the "closed" state of the retention mechanism.

10. The urinary catheter according to claim 1, wherein said trigger mechanism comprises a bellows element having a first end bonded to said distal end of said tubular element, a second end opposite said first end, and a flexible corrugated wall extending between said first and second ends of said bellows element,

the front end of the actuating link is connected to the retaining mechanism,

a rear end of the actuating link is connected to the second end of the bellows element, and

the bellows element is compressed to a compressed state to actuate the "closed" state of the retention mechanism, and the bellows element is expanded to an expanded shape to actuate the "open" state of the retention mechanism.

11. The urinary catheter according to claim 10, wherein said bellows member has a shape memory to memorize said expanded shape.

12. The urinary catheter according to claim 10, wherein said bellows member has a shape memory to memorize said compressed shape.

13. The urinary catheter according to claim 10, further comprising a latch member operatively coupled to said bellows member, said latch member being actuated to transition said bellows member between said compressed and expanded shapes.

14. The urinary catheter according to claim 13, further comprising a pair of protrusions operatively coupled between said latch member and said bellows member, said protrusions being actuated to control latching engagement between said latch and said bellows member.

15. A catheter according to claim 1, wherein said trigger mechanism comprises first and second threaded elements,

the front end of the actuating link is connected to the retaining mechanism,

the rear end of the actuating link is connected to a respective one of the first and second threaded elements of the trigger mechanism, and

the transition between the "open" and "closed" states of the retaining mechanism is controlled by the degree of threaded engagement between the first and second threaded elements.

16. The urinary catheter according to claim 1, wherein said trigger mechanism comprises a squeezable element attached in elastically embracing relation to said distal end of said tubular element and reciprocally engaged therewith,

the front end of the actuating link is connected to the retaining mechanism,

the rear end of the actuating link is connected to the squeezable element, an

The transition between the "open" and "closed" states of the retention mechanism is controlled by the repositioning of the squeezable member along the distal end of the tubular member.

17. The urinary catheter according to claim 1, wherein the trigger mechanism comprises a thumb-slide based actuator.

18. The urinary catheter according to claim 1, wherein the trigger mechanism comprises a lever action based actuator.

19. The urinary catheter according to claim 1, wherein said trigger mechanism comprises a syringe-based actuator comprising a hollow cylinder part attached to said distal end of said tubular element and a plunger part controllably slidable within said hollow cylinder part,

the front end of the actuating link is connected to the retaining mechanism,

the rear end of the actuating link is connected to the plunger portion, and

the transition between the "open" and "closed" states of the retaining mechanism is controlled by the repositioning of the plunger portion within the hollow cylindrical portion.

20. The urinary catheter according to claim 1, further comprising a sealing mechanism applied to said channel and preventing leakage of fluid from said distal end of said tubular element.