|Year : 2022 | Volume
| Issue : 1 | Page : 3-8
Safe urethral catheterisation in males: Pearls and pitfalls
S Lal Darsan, Biju S Pillai, H Krishnamoorthy
Department ofUrology, Lourdes Hospital Post Graduate Institute of Medical Science & Research, Kochi, Kerala, India
|Date of Submission||19-Oct-2021|
|Date of Decision||18-May-2022|
|Date of Acceptance||27-May-2022|
|Date of Web Publication||14-Jul-2022|
Dr. S Lal Darsan
Department of Urology, Post Graduate Research Institute, Lourdes Hospital, Kochi - 682 012, Kerala
Source of Support: None, Conflict of Interest: None
Urethral catheterisation is a bedside clinical skill which is usually acquired by clinicians during their internship or initial medical career. However, many clinicians lack confidence for male catheterisation afterward. This review article revisits the steps of safe urethral catheterisation with a review on male urethral applied anatomy, catheter design, common difficult catheterisation scenarios with pearls and pitfalls to tackle them and steps to remove a stuck urethral catheter from a urologist's perspective.
Keywords: Applied anatomy, catheterisation, male urethra, prostatomegaly, stuck Foley catheter, urethral stricture
|How to cite this article:|
Darsan S L, Pillai BS, Krishnamoorthy H. Safe urethral catheterisation in males: Pearls and pitfalls. Kerala Surg J 2022;28:3-8
| Introduction|| |
Urethral catheterisation in a male person is an essential procedure in everyday clinical practice. This procedure is learnt as a bedside clinical skill during clinical postings and internship. Hence, a clinician's understanding of catheterisation varies depending on his/her exposure and experience. This article highlights the various aspects of safe urethral catheterisation from a urologist's perspective.
| Anatomy of the Male Urethra|| |
An understanding of the male urethral anatomy is essential for successful catheterisation. The male urethra extends from the internal urethral orifice at bladder neck to external urethral orifice (urethral meatus) at the tip of glans penis. Adult male urethra is about 18–20 cm long. It is broadly divided into anterior urethra and posterior urethra. Anterior urethra comprises of meatus, submeatal part called fossa navicularis, penile urethra and bulbar urethra. Posterior urethra comprises of membranous urethra, prostatic urethra and the pre-prostatic part or the bladder neck (the internal urethral orifice). Urethral meatus or the external urethral orifice is the narrowest part of male urethra, located slightly ventral at the tip of glans penis like a vertical slit of length 6–12 mm in the resting position and the lumen opens up when the glans is gently compressed vertically. The size of the adult male meatus is 18–28 Fr averaging 24 Fr. The submeatal part or the navicular fossa is the part of the urethra located inside the glans penis proximal to external meatus and is about 1.5 cm in length. Penile urethra extends from meatus up to the base of the penis and is covered by corpus spongiosum. Urethra is palpable at the ventral aspect of penile shaft. The length of penile urethra varies depending on the penile length of an adult male. The bulbar or perineal urethra extends from the base of penis (where suspensory ligament of penis attaches to Buck's fascia) and external urethral sphincter (at the level of pelvic diaphragm) and is palpable through the scrotal skin between the two testes. Bulbar urethra is invested by corpus spongiosum and the Bulbospongiosus muscle along its ventral aspect. The membranous urethra or the external urethral sphincter is the least dilatable segment of urethra and the second narrowest part of urethra after urethral meatus. Membranous urethra poses a natural constriction due to its muscular nature and tonic state of contraction. The sphincter relaxes during voiding. The prostatic urethra traverses the prostate gland and is about 2–3 cm long. The prostatic urethra is the most distensible part of urethra due to elastic fibres in the prostatic stroma. The bladder neck or the pre-prostatic urethra is the proximal most part of the urethra and contains the internal urethral sphincter muscle, which is in a state of tonic contraction during bladder filling and relaxes during micturition. The anatomical area between the two ureteric orifices and the bladder neck is called the trigone of the bladder, whereas the bladder outlet is a physiological unit comprising of the two ureteric orifices, trigone and the internal urethral sphincter at the bladder neck acting in synchrony during micturition [Figure 1].
| Clinical Relevance and Applied Anatomy of Male Urethra|| |
Understanding most common urethral pathologies that causes difficult catheterisation scenarios helps not only in successful catheterisation, but more importantly helps in detecting unsuccessful catheter passage and hence aborting catheterisation without causing iatrogenic urethral injuries. There are two curvatures in the anterior urethra of a male, one at the penobulbar junction and the other at the bulbar urethra. These curvatures make the urethra 'S' shaped when penis is flaccid or is pendulous. The curve at the penobulbar junction is straightened when the penis is held upright in a supine subject or held upwards towards the abdomen in a standing subject (making an S-shaped curve into a J-shaped curve) [Figure 2].
The entire anterior urethra is surrounded by corpus spongiosum. The navicular fossa is roomier than the urethral meatus, hence a stone that is passed down from the bladder can get impacted inside the navicular fossa without able to pass through the meatus causing acute retention. The normal para urethral gland secretions keep the urethra moist. In long standing indwelling catheterisation, the para urethral gland ducts can get obstructed and lead to micro-abscesses inside these glands, leading to urethritis which is manifested as purulent peri catheter secretion or pain along the penile urethra. Local tenderness on palpation of penile urethra occurs in urethritis, periurethral abscess and urethral diverticulum. Expressed secretion from urethra for microbiological analysis can be obtained by gently milking the penile urethra distally. Holding the penis straight upwards in a supine patient straightens the collapsed penile urethra which is required for the examination of urethra by palpation as well as for easy installation of lubricant and passage of catheter. Bulbar urethra is roomy and can accommodate a coiled Foley catheter due to a proximal obstruction, giving a false impression of the catheter having reached the bladder. This occurs in prostatomegaly or proximal bulbar stricture. A Foley balloon inflated within bulbar urethra leads to iatrogenic rupture of the bulbar urethra, leading to bleeding from the corpus spongiosal venous sinuses, manifested as urethral bleeding and absence of urine drainage through the catheter. This part of urethra is also vulnerable to injury from falling astride, called 'straddle injury'. External compression at the perineum can temporarily stop bulbar urethral bleeding. Any part of the anterior urethra from meatus to bulbar urethra can undergo strictures of varying degree and lengths in response to luminal or external injuries or inflammatory conditions as mentioned above. This can manifest as meatal stenosis, submeatal stenosis, penile or bulbar urethral strictures producing non-distensible narrowing, voiding difficulty and acute urinary retention and difficult catheterisation. The external urethral sphincter undergoes spasm during catheterisation in apprehensive adults and children, which is felt as a resistance to catheter passage simultaneously with a sharp pain perceived by the person. This occurs when about 12 cm to 15 cm length of catheter has been passed inside. Spasm and pain can be alleviated by reassuring the patient, giving time for anaesthetic jelly to act inside urethra, and asking the patient to inhale, which relaxes the sphincter which aids in passage of the catheter. In patients with benign prostatic hyperplasia (BPH), the ingrowth of the prostatic transitional zone adenoma causes a 'distensible narrowing' and a spectrum of voiding and storage lower urinary tract symptoms (LUTS). The luminal surface of the prostatic urethra is extremely vascular and hence spontaneous hematuria can occur in BPH. Patients taking antiplatelet/anticoagulant medications will have more severe and prolonged haematuria. The ingrowth of adenoma into the bladder causes most severe form of voiding LUTS with significant post-voidal residual urine, secondary stone formation in bladder and recurrent urinary infection risks. Irritation or inflammation of the bladder outlet (distal ureteric calculus, distal end of a ureteral stent, bladder calculus, inflated balloon of a Foley catheter, prostatic urethral calculus, etc.) can cause reflex spasm of urinary bladder and referred pain at the tip of penis. Bladder spasm can also cause peri catheter 'leak' of urine in patient with indwelling catheter. Alpha-1 adrenergic blocker medications such as Tamsulosin, Alfuzosin, Silodosin and Naftopidil relaxes the bladder outlet and hence relieve obstructive LUTS but cause varying degree of retrograde ejaculation. M-3 muscarinic receptor blockers such as Solifenacin, Darifenacin, Tolterodine and Beta-2 adrenergic agonists such as Mirabegron cause detrusor relaxation and relief of intermittent pain from bladder spasm.
| Urethral Catheters|| |
Single lumen catheters are used for temporary or intermittent urinary drainage. They are effective to drain bladder since whole internal lumen is utilized for drainage, example: Nelaton catheter ('Nelcath'), Infant feeding tube (IFT). A 14 fr single lumen polyvinyl chloride (PVC) catheter can be used to aspirate blood clots from bladder to relieve 'clot-retention' in an emergency setting. They do not have a retention mechanism, hence cannot be used for continuous bladder drainage. Dr. Frederic Foley in 1929 developed a rubber catheter with an inflatable balloon as a retention mechanism. Modern day Foley catheters are made up of latex, silicone, hydrophilic polymer coated latex or PVC. These two-lumen catheters are the most commonly used catheters for continuous bladder drainage. Parts of a two-lumen foley catheter are drainage port, balloon port with one way valve, stem of catheter with two lumens, inflatable balloon, catheter tip with 'eye' or inlet. The bigger lumen is for urine drainage and the narrow lumen is the balloon channel. The drainage lumen is considerably smaller than the outer diameter of the catheter. Hence, pus flakes or blood clots can easily clog the drainage and result in catheter block, urinary retention, pain and peri catheter urine leakage. Three-lumen catheters or 'haematuria catheters' have an additional lumen for irrigation. They are used for bladder irrigation and aspiration of clots in hematuria and post-transurethral surgery of prostate. They are made of latex or more preferably, of silicone or PCV, both of which are compression resistant and hence the drainage lumen does not collapse when negative pressure is applied using a syringe for aspiration of clots. Tip of the catheter can be straight tip or Coude tip. Councilman type catheters have a hole at the tip for passage of guidewire. Two studies show lower incidence of urethritis and urethral symptoms with silicone catheters compared to latex catheters., Silicone foleys and PVC tubes (Nelcath, IFT) have the advantage of being stiffer than latex which enables them to negotiate narrowed urethra due to strictures or prostatomegaly. Very rarely some persons have allergy to latex or latex products (rubber tree sap, latex glove, Foley catheter etc). Silicone or PVC catheters can be used in such situations.
| Size, Dimensions and Fr Conversion|| |
French (Fr) size of a tube is its outer circumference in millimetre or its diameter in millimetre × π, or approximately diameter in mm ×3. A normal adult male urethral meatus varies from 6 to 8 mm in diameter, hence allows 18–24 Fr size catheters. The length of Foley catheter also varies with the size of the tube. Smaller Foley catheters are designed for children with shorter urethra. An adult male urethra length requires Foley catheters of 14 Fr or above. The colour coding according to Fr size is universal for all tubes (Foley catheter, silicone catheter, Nelaton catheter, IFT, Nasogastric tube, suction catheter, etc.) however, the lengths differ according to the purpose of the tubes [Figure 3].
|Figure 3: (a) 24 Fr 2-way silicone catheter, (b) 18 Fr 3-way latex catheter, (c) 12 Fr Nelaton catheter, (d) 8 Fr Infant Feeding Tube. Colour coding according to Fr size is given as inset|
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| Steps of Safe Urethral Catheterisation|| |
A sterile catheterisation pack contains a stainless-steel tray with a bowl for antiseptic solution, cotton balls and sponge holder for skin preparation, gauze, hole-towel, and a kidney tray for collecting urine spillage from catheter. Sterile gloves, sterile lubricant jelly, 10 or 20 cc syringe, povidone iodine or chlorhexidine solution for skin preparation, sterile water for balloon inflation, and sterile foley catheter of appropriate size should be readily available. An assistant must be there to help during catheterisation. Catheterisation in difficult settings additionally requires a hydrophilic coated guidewire of size 0.035” or 0.025”, Teflon urethral dilators, IFTs. Consent is taken for catheterisation and steps are explained briefly.
A male patient in placed in the supine position for catheterisation where as a female patient is placed in supine 'frog leg' position.
In males, foreskin is retracted and skin preparation is given from umbilicus to mid-thigh level. A hole-towel is then spread to expose the penis.
Instillation of lubricant
Male urethra is sensitive to pain and hence 2% lignocaine jelly is used as lubricant for catheterisation. The penis, after retracting the prepuce, is grasped below the glans on the lateral sides with two fingers (hence not occluding the ventrally located urethral lumen) and held vertically. This hold opens up the collapsed urethral lumen and straightens the peno bulbar curve for easy lubricant and catheter passage. After briefing the next step to the patient, about 10–15 ml of anaesthetic jelly is instilled slowly into the meatus. The lubricant should not be suddenly pushed into the urethra, especially in an awake patient. The sudden distension of urethral lumen results in severe pain and the clinician loses patient's confidence for further procedure. Explaining the steps and gentle instillation of lubricant has to be done. The lubricant is directed towards bulbar urethra by gently milking the penile urethra proximally while compressing the glans. It takes about 5 min for onset of anaesthetic action.
Passing the catheter and retaining it
Introduce a 14 Fr or 16 Fr catheter into the lubricated urethra. A resistance may be encountered at the external urethral sphincter at around 15 cm from meatus, which is overcome as patient takes relaxed breaths. Foley stem is inserted fully inside the urethra. Urine starts draining when the catheter tip reaches the bladder. Foley bulb should only be inflated after confirming urinary drainage. In case of empty bladder or when lubricant jelly has clogged the catheter lumen, urine drainage does not happen immediately. When catheter is fully passed and urine does not drain, instil 10 ml of saline and re-aspirate the fluid to confirm position inside the bladder. A coiled catheter does not allow saline instillation or aspiration since the lumen is kinked. After position is confirmed inside the bladder by urine drainage, instil balloon with 10–15 ml of sterile water. Caution must be taken to avoid slipping of catheter before balloon inflation which causes the catheter tip to slip back in the urethra, which still leads to urethral rupture if balloon is inflated.
Securing the catheter and the urine bag
Accidental pull on the catheter cause trigone irritation, bladder spams, pain and hematuria from injury to prostatic urethra. The urine collection bag is fixed to the thigh so that the weight of urine bag or accidental traction on bag is not transferred to the catheter [Figure 4]. Patients with dementia, delirium or psychosis often try to remove any indwelling tubes, hence special attention or restraining of the arms after taking informed consent from a relative is equally important as securing the catheter and urine bag in such patients.
|Figure 4: (a) a common way of fixing a tube to skin. The tube has least area of contact with the adhesive and easily falls off. (b) The 'mesentery' method – An appropriate way of fixing a tube to skin. Adhesive is applied all around the tube and holds more securely to the skin|
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| Difficult Male Urethral Catheterisation-Scenarios|| |
Phimosis secondary to recurrent balanoposthitis is encountered in old age with diabetes, chronic illnesses, neglect of personal hygiene, etc. In case of partly-retractile prepuce (incomplete phimosis), use the thumb and index finger to retract the prepuce until meatus is seen. Sometimes sliding the prepuce ventrally enables exposure of meatus than trying to retract the prepuce all around. Once the meatus is seen, catheterisation is done without trying to further retract. Non-retractile prepuce (complete phimosis)-dilatation with an artery forceps to be done [Figure 5] under penile block in awake patients or without any anaesthesia in drowsy or comatose patient in critical care units. Dorsal slit under penile block is done as a bedside emergency procedure to reveal the meatus in severe phimosis.
|Figure 5: Dilating a phimotic prepuce to visualise the meatus for catheterisation|
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If the prepuce is tight but accommodates a syringe hub, retract as much as possible and then instil sterile anaesthetic jelly inside the prepuce using a syringe. The jelly with its high refractive index act as a convex lens which will magnify the underlying meatus (with good overhead lighting). If the meatus is seen, catheterisation is done promptly without trying to further retract the prepuce.
Meatal stenosis and urethral stricture
Stricture can occur at any location and in any length [Figure 6]. A tube made of PVC or Silicone ideal to negotiate the stricture-example: IFT (6, 8, 10 Fr), Nelaton catheter or silicone catheter (12, 14, 16 Fr). If the meatus is pinpoint or the stricture is too narrow for even the smallest of these tubes, try to pass a hydrophilic coated guidewire and pass serial Teflon urethral dilators starting from 6 Fr followed by 8, 10, 12 and 14 Fr as possible, and catheterise with the biggest passable size catheter by railroading over the same guidewire. Pan urethral stricture involving meatus, submeatus and entire anterior urethra is rarely seen, associated with Balanitis Xerotica Obliterans or with history of multiple endourological procedures. Sometimes, a 6 or 8 Fr IFT is the only tube that can be passed to relieve retention. Suprapubic catheterisation would be required in most severe cases.
|Figure 6: Urethral stricture and clinical signs. Note the use of a guidewire to railroad serial Teflon dilators followed by a catheter into the bladder|
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Benign hyperplastic prostate with its elastic property poses a dynamic obstruction to urine flow as well as catheter passage. Resistance to catheterisation due to prostatomegaly is felt at about 15 cm from the meatus. Adequate amount of jelly hydro distends the prostatic lumen and allows the passage of catheter. A rigid catheter can transfer the force applied to its tip, hence an 18 Fr latex catheter or 16 Fr silicone or a PVC catheter can negotiate an occlusive prostate easier than the more flexible 16 or 14 Fr latex catheter [Figure 7].
|Figure 7: Prostatomegaly and secondary changes in the bladder. Note that smaller, flimsier catheters fail to negotiate prostatic urethra|
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In a strictured urethra (static narrowing), resistance is felt against lubricant instillation and it backflows immediately. In BPH (dynamic narrowing), lubricant will pass through and distend the prostatic lumen. Thus, anticipate stricture and difficult catheterisation if there is resistance to lubricant instillation.
The viscous jelly entering the catheter lumen will delay urine drainage. To clear the lumen off jelly, push 5–10 ml of sterile saline into the drainage port after the foley is fully inserted inside the urethra.
A foley catheter coiled inside the bulbar urethra will not allow instillation of saline since the tube and its lumen are kinked. One should not inflate the balloon if there is resistance to saline instillation into drainage port. It is a red flag sign for coiled catheter inside urethra. Remove and re-catheterise until urine drains or abandon catheterisation without inflating balloon in such situations.
Foley balloon inside the urethra will offer more resistance to filling than when inside the bladder. Non-drainage of urine combined with forceful balloon inflation against a resistance invariably end up in the complete tear of the urethra.
| Bleeding, Abandoned Catheterisation, and Use of Guidewire|| |
A traumatic catheterisation presents with urethral bleeding and acute retention. A straightforward catheterisation is often not possible because of hematoma at the site of urethral injury. The catheter may not pass across the hematoma or coil just distal to the site of injury. A guidewire may pass across the hematoma into the true lumen and reach bladder. If guidewire could be successfully passed in a few attempts, a catheter can be railroaded over it and passed to bladder. Use of a No. 0.035” or 0.025” hydrophilic coated guidewire for the purpose. Insert the floppy end inside the urethra (The other end is rigid-should not be passed as it can pierce the mucosa and make a false track submucosally). If guidewire coils and returns in all attempts, catheterisation is better abandoned. If guidewire passes easily inside the bladder (sometimes followed by trickling of urine along the guidewire) a foley can be passed over the guidewire by Railroading technique as follows: The tip of the foley is slit open with a no. 11 blade (do not cut away the foley catheter tip-the blunt tip enables the smooth passage) and rigid end of guidewire is brought out through the drainage port. The catheter is then passed along the guidewire taking care not to pull the guidewire out. Once the catheter has reached the bladder, balloon is inflated and the guidewire is pulled out. Pulling the guidewire without inflating the balloon may sometimes pull the catheter out due to friction. Inflated balloon will prevent this. Urethral bleeding or hematuria after successful catheterisation in urethral trauma does not require removal of the catheter. The catheter is kept in position and urethral bleed or hematuria is often managed conservatively with perineal compression, hydration, replacement of blood products etc.
The Four rules of thumb for safe urethral catheterisation are: (1) Drainage of urine confirmed, (2.) No resistance to saline instillation, (3) Re-aspiration of instilled saline is possible, (4) No resistance to foley balloon inflation.
| Removal of Catheters Including Stuck Catheters|| |
A foley catheter is removed by applying a syringe hub firmly to the balloon port, which opens the one-way valve and drains the inflated balloon. Using a needle to puncture and aspirate the balloon port will also deflate the balloon, but will make the valve functionless due to air leak. The Reasons for stuck catheters are saline crystallisation inside the balloon channel if normal saline is used instead of sterile water, poor quality latex foley catheter in which the narrow balloon channel occluded with time or by clamping the foley catheter using instruments like the artery forceps applied on the stem of foley (crushing the balloon channel). There are several methods to remove stuck catheter. Safest method is suprapubic puncture under ultrasound guidance. A low frequency transabdominal probe is placed suprapubically to visualise bladder and the foley balloon. A long needle (e.g.: spinal needle) is used to puncture the balloon under guidance under aseptic precautions [Figure 8]. A quick way to deflate the balloon is by injecting Ether into the balloon channel which will recannalise the balloon channel and burst open the balloon but with the expense of mild bladder mucosal irritation due to ether exposure. Recannalising the balloon channel and bursting the balloon by puncture by passing the rigid end of the guidewire through the channel is another method. In females, Foley balloon (especially an over inflated balloon) can be palpated and punctured pervaginally.
| Conclusion|| |
Safe urethral catheterisation is a basic clinical skill to be achieved by clinicians for the care of their patients. An understanding of the male urethral anatomy and solution for difficult catheterisation scenarios will help clinicians to tackle emergency situations with confidence.
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Conflicts of interest
There are no conflicts of interest.
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Nacey JN, Tulloch AG, Ferguson AF. Catheter-induced urethritis: A comparison between latex and silicone catheters in a prospective clinical trial. Br J Urol 1985;57:325-8.
Gülmez I, Ekmekçioğlu O, Karacagil M. Management of undeflatable Foley catheter balloons in women. Int Urogynecol J Pelvic Floor Dysfunct 1997;8:81-4.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]