Catheters - everything you need to know

Type of catheters and sizing

In clinical practice the following are the most commonly encountered types of catheters:

1. Latex catheters - short term catheters (up to 28 days)

2. Silicone catheters - the standard long term catheter (up to 12 weeks)

3. Tiemann tip catheters - a slightly curved tip allows bypassing a bulky prostate. This catheter should always be introduced with the tip pointing at 12 o clock and this position maintained throughout the procedure. There is a limited role for this type of catheter in females unless the urethra is stenosed.

4. Standard 3 way catheter - used in haematuria for continuous bladder irrigation and bladder washouts

5. Coude 3 way catheter - similar to the Tiemann tip catheter, the coude 3 way has a soft curved tip allowing the operator to bypass the prostate. Used in haematuria for continuous bladder irrigation and bladder washouts

6. Council tip catheter - an open ended catheter for specialist use. Allows the catheter to be inserted over a guidewire - useful in difficult catheter scenarios

As the number associated with a catheter size described in French (Fr) increases, so does the internal diameter (in contrast to intravenous cannulas)

Choosing the right size

Non haematuria setting:
A 14Fr catheter in men

A 12Fr catheter in women

In the haematuria setting:
A 20 Fr catheter at the very least is advised. The wider internal diameter allows washouts and clot evacuation / drainage

Top tip - some hospitals may use male (longer) and female (shorter) catheters. Check the product information. If in doubt, you're better off using a male (longer) catheter in all cases. Using a female catheter in a male will risk urethral trauma and cause bleeding once the balloon is inflated as it would sit distal to the bladder neck.

Indications of catheterisation:

Acute urinary retention - short term

Long term in high pressure chronic retention

Long term in neurological conditions or when incontinence may cause skin breakdown

Other indications such as monitoring fluid balances, post op, etc

Understanding anatomy goes a long way

The male urethra is ‘S’ shaped and is roughly 18 - 22 cm in length

The female urethra is straight and is much shorter at about 3 - 4 cm in length

The ‘S’ shaped nature of the male urethra is the major difference and not appreciating this will lead to multiple attempts of failed catheterisation, discomfort and trauma (to both the patient and operator)

Male catheterisation:

1. Gain consent, Position the patient supine

2. Don sterile gloves

3. Prep the penis using chlorhexidine prep - soak the cotton balls in the solution and using the forceps provided in a catheter pack thoroughly clean the glans, retracting the prepuce and cleaning the coronal sulcus. Be generous with the use of solution and cotton balls as it will prevent or minimise infections

4. Place the drape over the site with the cutout for the penis, give the drape a shake to get the penis over it onto a sterile field

5. With the left or nondominant hand, grasp the penis between the thumb and index finger and stretch it upwards towards the ceiling (perpendicular to the bed)

6. Use the prefilled lubricant syringe to instill lubricant which ideally would contain an anaesthetic such as lignocaine. Squeeze out a drop or two of jelly onto the urethral meatus before inserting the tip of the syringe for extra comfort. Warn the patient that it will sting for couple of minutes

7. Push down on the plunger slowly and empty the syringe

8. After 2 minutes, insert the catheter. Gently introduce it down the urethra with the penis stretched as far as possible towards the ceiling; guiding the catheter on its way down until a slight amount of resistance is felt. This is the membranous urethra

9. At the point of resistance, apply gentle pressure as you advance the catheter and drop the penis down to bring it almost parallel to the bed. This should help introduce it further

10. Advance the catheter upto the hilt (the junction of the 2 or 3 ports)

11. Ensure that urine is draining out of the catheter. This is a good time to get a catheter sample of urine if needed. If nothing comes out - gently aspirate with a bladder syringe or the syringe used to insert the lubricating jelly. This step clears out the jelly blocking the catheter

12. Inflate the balloon only if urine comes out. A standard catheter will require 10ml of distilled water to inflate the balloon whereas 3 way catheters usually indicate the volume on the drainage port and 20-30ml is a standard volume.

13. Connect the urine bag

14. Always replace the foreskin to avoid a paraphimosis

Female catheterisation:

Catheterising females is much more straightforward. Prepare the labia and vagina well with normal saline or chlorhexidine solution. With good lighting locate the urethra and instil about 5ml of lubricant/anaesthetic jelly. Insert the catheter gently until urine begins to drain. The length of insertion is about 8 cm or less.

Positioning a female patient is important - ask the patient to bend their knees and bring their ankles towards the buttock as close as possible before dropping the knees off onto either side. Reminding the patient that the position is similar to a “smear position” could be a useful aid.

Common issues faced and workarounds:

1. Cannot get beyond the prostate - At the point of resistance drop the penis down to bring it almost parallel to the bed. This should help introduce it further.

2. Still cannot get beyond the prostate - Use a Tiemann tip catheter

3. Bleeding after catheterisation - this is likely urethral and will settle over the next hour or two. Counsel the patient and reassure them that it will subside.

4. No urine coming out once inserted - If there isn't any urine coming through, using the empty lubricant syringe, place it into the outflow port with a good seal and pull on the plunger. This usually works to displace the jelly blocking the catheter and urine should follow thereafter.

5. Blocked catheter - before removing a catheter just because it’s blocked, try flushing it first. Debris may very well block the catheter and a good washout will solve the problem and minimise chances of infection by reinserting a catheter. You can also try deflating the balloon, pushing the catheter in, flushing it and reinflating it.

6. Catheter bypassing - Can be caused by a blocked catheter or bladder spasms. Check the volume of water in the balloon. Make sure that it is the recommended volume. Deflate the balloon, push the catheter in further, flush the catheter and inflate it.

7. Catheter bypassing with lower abdominal pain (bladder spasms) - Try Solifenacin or Mirabegron. Please read up on the side effects of both these drugs on BNF such as dry mouth and the risks of orthostatic hypotension and falls and counsel the patient. Contraindications include glaucoma and myasthenia gravis.

8. Phimosis - a non retractile foreskin can make visualisation of the urethra impossible. Insert 1-2 tubes of instillagel to “balloon” the foreskin. Remember that the urethral meatus lies ventrally (at the bottom) of the penis. Use a normal silicone catheter in these cases as they are slightly stiffer. Insertion into the urethral meatus in this case is bline and is done by gently probing with the catheter using your fingers externally to guide it inferiorly. You will immediately know that you are in the urethra when you feel a give and the catheter passes in with ease. Artery clips can be used to stretch out the foreskin and buy some space. This is generally tolerated very well and does not need an anaesthetic however ensure that the rip of the instrument is just below the skin and not accidentally within the urethra.

9. Elderly females - Difficulty arises primary due to poor positioning or because of atrophic changes of the urethral meatus and vagina. Good lighting and an assistant will generally suffice. Techniques such as finger occlusion of the vagina to guide the catheter above it into the urethral meatus may be needed and verbal consent must be obtained.

Unable to catheterise:

1. Phimosis - If the above steps fail, If this is not achievable, a flexible cystoscope may be needed to locate the meatus and pass a wire. If unable to do access, a dorsal slit may be required.

2. Buried penis - penoscrotal oedema or a large body habitus may bury the penis. Positioning the patient in a head down position (Trendelenberg) in the presence ensuring the patient does not slip off the bed with an assistant to shift the overhanging fatty apron towards the patient's head and a second assistant to press down on the pubic region and exteriorise the penis may help.

3. A catheter introducer may be used if experienced in the technique. This is a slender, metallic disposable bougie inserted into the catheter ex-vivo to help stiffen it and bypass the prostate.

4. If the resistance is distal (closer to the meatus) - think strictures / false passages. In these cases, a flexible cystoscope, a hydrophilic tipped guidewire, urethral dilators and an open ended catheter insertion will become necessary. This must not be performed if you lack the experience to proceed.

5. Last resort - Suprapubic catheterisation ideally under ultrasound guidance to avoid the risk of inadvertent bowel injury.

Sometimes less is more. Avoid overambitious trials of catheterisation which only risks trauma and causes pain and apprehension - all of which make the procedure harder for a registrar or consultant. If you feel that the procedure is more complex than anticipated... ask for help early.

Unable to deflate:
What goes in must come out but this does not always go to plan.

1. Balloon port failure - in long term catheters, the balloon port valve may fail. Sometimes, the little release button within the port does not get pushed down by a syringe alone. First, try inflating the balloon with an additional 5ml of water followed by aspirating the contents of the balloon. Avoid overinflating to burst the balloon as fragments of the balloon may remain within the bladder forming a nidus for stones and infection.

2. If unsuccessful, the back (hard end) of a standard wound swab can be used to push down on the button which releases the water held within the balloon

3. If this fails, the balloon port can be cut just below the valve to release water

4. If step 3 is unsuccessful, the stiffer back end of a wire can be passed along the port to dislodge any crystal deposits along the path of the channel

5. If this is unsuccessful, a 22G spinal anaesthetic needle can be passed over the guidewire and into the balloon itself to drain the water.

6. If all of the above fails, needle puncture of the balloon may be needed under ultrasound guidance by the urologist or interventional radiologist. A transabdominal or transrectal approach can both be used.

7. In women, traction on the catheter balloon may bring it into view through the urethral meatus. A needle can then be used to puncture the balloon.

Reference:
https://www.aafp.org/pubs/afp/issues/2000/0915/p1397.html#:~:text=The%20primary%20reason%20for%20the,kinking%20of%20the%20inflation%20channel.

Giovannopoulou, E., & Chondros, K. (2017). A technique for non-deflating balloon catheter removal in female patients. The Pan African medical journal, 26, 222. https://doi.org/10.11604/pamj.2017.26.222.12291

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