Adam Nelson and Suzanne Biers1,2,3 / Michal Sut4
Urethral catheterisation of the urinary bladder is a core skill not just for the urologist, but for all medical practitioners. The principal indications and relative contraindications for urethral catheterisation are shown in Box 7.1. Note also the situations where advice should be sought from a urology consultant before attempting catheterisation.
Box 7.1 Indications for urethral catheterisation.
•Urinary retention (acute and chronic).
•Monitoring of urine output.
•Post-operative decompression of the bladder (e.g. following bladder repair).
•Bladder washout/irrigation for visible haematuria.
Consider referral to urology
•Recent/post-operative radical prostatectomy.
•Pelvic trauma with haematuria/blood at meatus (a single attempt by an experienced doctor is acceptable).
•Known urethral stricture disease.
•Artificial urinary sphincter in situ.
Types of catheter
For the purposes of this chapter, all catheters described will be variations of the Foley catheter, which has an inflatable balloon at the tip to keep the catheter in place. A typical catheter is also known as a ‘2-way catheter’ as it has two lumens. One lumen drains urine from the bladder and a much smaller second channel is used to fill or empty the balloon. Three-way catheters have an additional channel that may be used for irrigation. Catheters are typically made from either coated latex or silicone (Figure 7.1). Latex catheters tend to be for short-term use (less than 4 weeks), whereas silicone catheters may be left in place for up to 12 weeks. Silicone catheters are stiffer, which may make them easier to insert in certain patients (e.g. where there is resistance from an enlarged prostate) and as a result are often used if attempts at insertion of a latex catheter have failed. In patients with a latex allergy, silicone catheters can be used safely.
Catheters are sized according to their external diameter. The diameter is reported in ‘French’ (Fr), which equates to 1/3 of a millimetre. Therefore, an 18 Fr catheter has a diameter of 6mm. The unit ‘Charrière’ (Ch) is used interchangeably with ‘French’, after the scale’s inventor. A colour coding system is used that permits easy identification of catheter size (Figure 7.2). As a general rule, the smallest calibre catheter that is fit for purpose should be used to minimise the risk of urethral trauma. Male length catheters are 40–45cm in length. Shorter female catheters are rarely available because of the risks associated with selecting too short a catheter for male catheterisation.
Figure 7.2 2-way Foley catheters demonstrating the colours associated with common sizes. White=12 Fr, green=14 Fr, orange=16 Fr, red=18 Fr.
Specialist catheters
A number of catheters are made with specific features to make them useful in particular contexts (Figure 7.3):
Figure 7.3 Examples of specialist catheters. (a) Council tip catheter; (b) Tiemann tip catheter; (c) coudé tip 3-way catheter; (d) components of a 3-way catheter.
•Tiemann tip: a curved, narrow-tipped catheter usually made from silicone. A useful catheter for men with enlarged prostates where the curved tip helps pass the U-bend of the bulbar urethra, or women with a difficult to find urethral meatus high on the anterior vaginal wall.
•Straight/Couvelaire tip 3-way: a large-bore catheter with an additional lumen to allow instillation of fluid into the bladder and a wide opening to allow passage of debris or blood clots. These are 18–24 Fr calibre and used for bladder irrigation or washout in the event of visible haematuria with clot retention. Larger-calibre catheters will accept a larger volume of fluid in the balloon and the capacity is documented on the catheter or packaging.
•Coudé tip: a wide-bore, curved-tip catheter (coudé is French for elbow). Typically found on large (18–24 Fr) 3-way catheters as described above. Used for bladder irrigation/washout following transurethral prostatectomy as the curved tip enables smooth passage across the ‘U-bend’ of the bulbar urethra and resected prostate bed.
•Council tip: a straight, silicone catheter with an open, end-on hole in the tip. This catheter can be passed over a guidewire, and is therefore typically used in flexible cystoscopy-guided urethral catheterisation. Subsequently, it is possible to exchange catheters over a guidewire, without the need for further cystoscopy.
Technique of urethral catheterisation
As with any medical procedure, training in catheterisation should only be undertaken under the supervision of a competent person. The description below should, however, serve as initial preparation for those learning the procedure, or as an aide-mémoire for those who have been previously trained:
•Establish a clear indication for urethral catheterisation, and identify situations where urology input should be sought.
•Explain to the patient the nature of the procedure, the possible complications (see later section) and seek consent from the patient.
•Consider antibiotic prophylaxis, particularly if there have been multiple attempts at catheterisation, a history of recurrent urinary tract infection (UTI) or recent instrumentation of the urinary tract.
•Ensure all necessary equipment is within easy reach (Box 7.2).
•Wash hands and maintain a sterile technique throughout.
Box 7.2 Basic equipment.
•Sterile dressing pack.
•Sterile saline to clean glans/vulva.
•Sterile gloves.
•Local anaesthetic lubricant jelly.
•Catheter (selected according to indication).
•Syringe with sterile water (not saline) for catheter balloon (usually 10ml syringe).
•Catheter bag.
In men:
•Ensure you have selected a male length catheter. A female length catheter will not reach the male bladder and will cause significant trauma if the balloon is inflated within the urethra.
•Retract the foreskin if present and clean the glans with sterile saline.
•With the patient supine, grasp the penis with a swab and raise it vertically.
•Gently insert local anaesthetic lubricant jelly into the urethral meatus. Spill some jelly on the glans around the meatus, as this will lubricate the catheter as it passes.
•With the penis pointing upwards, insert the catheter. When you feel the catheter is in the bulbar urethra, angle the penis to the patient’s feet. Insert the catheter ‘to the hilt,’ ensuring that it does not spring back when released. A catheter that springs back may have coiled in the bulbar or prostatic urethra.
•Wait for drainage of urine to confirm correct placement within the bladder. If not certain, try aspirating through the catheter lumen as lubricant jelly may inhibit the flow.
•Inflate the balloon slowly with sterile water. Most 2-way catheter balloons have a 10ml balloon. Watch the patient’s face while doing so; if he experiences any pain, deflate the balloon immediately.
•Replace the foreskin, if present.
•Attach the appropriate catheter bag.
In women:
•A male or female length catheter may be used in a female patient.
•With the patient supine, ask her to bend the knees, feet together and then place the knees apart. Gently spread the labia with one hand and with the other hand, clean the vulva and urethra with saline.
•Locate the external urethral meatus, bearing in mind that it may be located on the anterior vaginal wall, particularly in post-menopausal women.
•Insert a few millilitres of local anaesthetic lubricant jelly into the meatus.
•Insert the catheter until urine drains, or until more than 5cm of the catheter has passed.
•Inflate the balloon with sterile water. Watch the patient’s face while doing so; if she experiences any pain, deflate the balloon immediately.
•Attach the appropriate catheter bag.
Documentation
After urethral catheterisation, the following details should be recorded in the patient’s notes:
•The indication for the catheter.
•Consent and whether a chaperone was present.
•Whether antibiotic prophylaxis was given.
•The type of catheter used, and the number of attempts required for successful insertion.
•The volume of water in the balloon.
•The volume of urine drained from the bladder immediately following catheterisation (the residual volume). This is particularly important as it will often determine the subsequent management of patients presenting with urinary retention.
•Plan for subsequent catheter removal/renewal as appropriate.
Difficult female catheterisation
Occasionally it can be difficult to identify the female external urethral meatus. Where practical, place the patient’s bottom onto a pillow. This tilts the pelvis forward and can make it easier to identify the urethra. Should this fail, after careful explanation and verbal consent, insertion of a finger may occlude the lumen of the vagina and lead the catheter into the urethral meatus. It is also possible to sometimes feel the urethral meatus with the tip of the finger helping the direction of the catheter. Alternatively, place the patient in the left lateral position, lift the uppermost leg in the air, and place a Sims speculum into the posterior part of the vagina to help visualise the anterior vaginal wall and urethra.
Unable to site a catheter and no specialist help available
If the patient has a palpable bladder and you are unable to get help to place either a urethral catheter or suprapubic catheter, it is possible to aspirate the bladder suprapubically to make the patient with acute painful urinary retention comfortable until help is available. Take patient consent, and prepare the lower abdomen with iodine solution and drapes. Inject 5–10ml 1% lignocaine into the skin 2cm above the symphysis pubis in the midline, and also towards the bladder. Use a green needle and 50ml syringe. Direct the needle perpendicular to the skin and slightly downward, aspirate until you reach the bladder. A 3-way tap can be attached to the end of the needle. Urine can then be removed in small aliquots until the patient feels more comfortable.
Key Points
•Establish the indication for catheterisation and the absence of any contraindications where specialist urology input may be required.
•Select a catheter appropriate for the indication and the patient’s past medical history.
•Maintain aseptic technique throughout.
•In the event of failure, follow the difficult catheterisation algorithm (Figure 7.4).
•Always remember to replace the foreskin in a man.
•Clearly document the procedure.
•Suprapubic aspirations can be used as a temporising measure when a patient is in retention, catheter insertion has failed and no specialist help is immediately available.
Suprapubic catheterisation involves the insertion of a Foley catheter through the suprapubic region of the anterior abdominal wall, directly into the urinary bladder. In the elective setting, it may be used for patients who lack the manual dexterity or cognitive ability to perform clean intermittent self-catheterisation (CISC) or as an alternative in patients otherwise reliant on a long-term indwelling urethral catheter. Elective indications for a suprapubic catheter (SPC) include chronic urinary retention due to bladder outlet obstruction or bladder underactivity, or for voiding dysfunction seen in spinal cord injury and neuropathic bladder. Post-operatively, a SPC is often used after bladder repair or reconstruction to decompress the bladder and facilitate healing and is usually combined with a urethral catheter in that setting. The advantages of SPCs over a urethral catheter for long-term use is that it avoids trauma to the soft tissues of the urethra (Figure 7.5), which can result in a patulous urethra and incontinence in women, and spatulation or splitting of the glans and penile shaft in men.
Figure 7.5 An elderly man with a recently placed suprapubic catheter. This catheter and the defunctioning colostomy were placed to help in the management of a complex colovesical fistula and penile abscess.
The focus of this chapter, however, will be on the use of SPC insertion in the emergency setting (Box 7.3). Guidance published by the British Association of Urological Surgeons (BAUS)1 summarises many of the relevant issues relating to the use of SPCs (Box 7.4).
Box 7.3 Emergency SPC insertion.
Indications
•Acute, painful urinary retention where urethral catheterisation has failed.
•Urethral injury, e.g. pelvic trauma.
Contraindications
•Impalpable bladder.
•Known bladder cancer.
•Anticoagulated patient.
•Abdominal wall sepsis.
•Subcutaneous vascular graft in suprapubic region, e.g. femorofemoral crossover graft
•Previous abdominal/pelvic surgery (requires an open cystotomy approach).
Box 7.4 BAUS guidance on SPC insertion.1
•In the patient with a palpable bladder and no previous abdominal surgery, blind percutaneous SPC insertion is reasonable if urine can be easily aspirated with a needle at the planned insertion site.
•Blind insertion should not be performed in the patient with previous abdominal surgery and an impalpable bladder. Consider using ultrasound scanning (USS) or cystoscopy to assist the procedure.
•In patients with previous surgery or where distension of the bladder is not possible, an open technique of insertion should be used.
Techniques for insertion of a percutaneous SPC
There are two commonly used methods used for emergency percutaneous insertion of a SPC (Figure 7.6). Firstly, a trocar-based technique (e.g. BARD® suprapubic kit) and secondly, a Seldinger-based technique (e.g. Mediplus Ltd. S-Cath™ system suprapubic Catheterisation with Seldinger technique). As with any medical procedure, training in suprapubic catheterisation should only be undertaken under the supervision of a competent person. The description below should however serve as initial preparation for those learning the procedure, or an aide-mémoire for those who have been previously trained.
Figure 7.6 (a) Components of the Mediplus Ltd S-Cath™ system (images used with permission); (b) components of the Bard™ suprapubic catheter set.
Trocar-based technique
•Establish a clear indication for a SPC.
•Explain to the patient the nature of the procedure, the possible risks (Box 7.5) and seek consent from the patient.
•Give antibiotic prophylaxis (e.g. gentamicin 80mg IV/IM).
•Ensure all necessary equipment has been checked and is present within easy reach.
•Wash hands and maintain a sterile technique throughout.
•Identify the insertion site, 2cm above the symphysis pubis in the midline.
•Where available, obtain USS confirmation that no bowel is interposed between the anterior abdominal wall and the bladder at the proposed insertion site.
•Prepare the lower abdomen with antiseptic solution (e.g. betadine).
•Administer local anaesthesia along the planned track, until urine is aspirated from the bladder (10ml 1% lignocaine, remembering to aspirate first to ensure you are not injecting into a blood vessel).
•Make a small, stab skin incision at the insertion site with a blade. It is very important to cut down with the blade onto the rectus sheath to incise it. Cutting the rectus sheath feels like scraping the grit with the blade, which limits the depth of the incision.
•Insert the SPC introducer (trocar with a sheath) at an angle perpendicular to the bladder wall (a gentle twisting motion may be required). Apply gentle and controlled pressure in this direction. If the incision of the rectus sheath was done appropriately then a little resistance on entering the bladder is expected. There is often a slight give at this point, and you will see urine draining out of the sheath, which confirms your placement in the bladder.
•Quickly (before the bladder empties) remove the trocar, leaving the outer sheath in place and insert the Foley catheter down the channel of the sheath.
•Inflate the catheter balloon with 10ml water.
•Divide and remove the sheath (this then peels off).
•Attach an appropriate catheter drainage bag. In the emergency setting, you may be expecting large urinary residual or post-obstructive diuresis, so a urometer bag may be best to start with.
Seldinger-based technique
•Establish a clear indication for a SPC.
•Explain to the patient the nature of the procedure, the possible risks (Box 7.5) and seek consent from the patient.
•Give antibiotic prophylaxis (e.g. gentamicin 80mg IV/IM).
•Ensure all necessary equipment has been checked and is present within reach.
•Wash hands and maintain a sterile technique throughout.
•Identify the insertion site, 2cm above the symphysis pubis in the midline.
•Where available, obtain USS confirmation that no bowel is interposed between the anterior abdominal wall and the bladder at the proposed insertion site.
Box 7.5 Risks of SPC insertion.2
•Common (>10%): haematuria.
•Occasional (2–10%):
›UTI.
›Recurrent catheter blockages.
›Bladder discomfort.
›Persistent urethral leakage of urine.
›Development of stones/debris in the bladder, which may require surgical treatment.
•Rare (<2%):
›Heavy bleeding requiring bladder irrigation or evacuation of clot.
›Injury to bowel or other abdominal organs.
›Hospital-acquired infection (e.g. methicillin-resistant Staphylococcus aureus, Clostridium difficile).
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