Urethral catheterisation, and the difficult one

Operative visualisation

UrOops3D · UroRef · © Nity G

Operative steps

1. Before the catheter: indication, safety, consent Every catheter has a reason written down: retention, output monitoring, a wound to keep dry, a bladder to rest. Then the question that stops a urethral catheter: is the urethra safe? Blood at the meatus, a pelvic fracture, a high-riding prostate or recent urethral surgery means stop and ask; the same for a known stricture or an artificial sphincter that has not been deactivated. The patient is told what will happen and that it will be uncomfortable but not painful. On the trolley: sterile gloves, cleaning solution, a drape, a 10 ml syringe of sterile water, 11 ml of 2 per cent lidocaine gel, the catheter, a bag and a specimen pot.
2. The catheter: size and tip A 14 or 16 French two-way Foley for a man, 12 or 14 for a woman; a three-way 22 French only for haematuria that needs irrigation. Silicone for anyone likely to keep it more than a few weeks. The coudé tip has a fixed upward bend that rides over a large median lobe and a high bladder neck; it is the second catheter to try in an older man, not the fifth. The balloon takes 10 ml of sterile water, never saline, which crystallises. A smaller catheter is not a gentler catheter: it buckles at the first resistance and makes a false passage.
3. Prepare: gel and position Clean the glans with the foreskin retracted, drape, and put the whole syringe of gel into the urethra, not onto the catheter. Squeeze the glans gently for two minutes to hold it there; the anaesthetic needs the time and the lubrication needs to be ahead of the tip. The penis is held up at ninety degrees to the body with the non-dominant hand, gently stretched. This straightens the penoscrotal angle and takes the first curve out of the urethra before the catheter reaches it.
   where it bites: a foreskin left retracted at the end of the procedure becomes a paraphimosis by the morning.
4. The penile urethra The catheter goes in by hand, held near the tip, a few centimetres at a time, and never with forceps. The navicular fossa just inside the meatus is the widest part; beyond it the penile urethra runs straight while the penis is held up. Resistance here in a young man is a meatal stenosis or a stricture, and it is met with gel and a smaller step down the ladder to a wire under vision, not with force.
5. The bulbar curve At the penoscrotal angle the tip enters the bulbar urethra, the widest and most dependent part, and meets the first curve. The hand holding the penis brings it down toward the feet as the catheter passes the curve, so that the tip follows the lumen round rather than driving into the roof of the bulb. A catheter that stops here has met the curve, not a stricture: lower the penis and advance again. This is where a forced catheter leaves the urethra and enters the spongiosum, and the bleeding that follows is the sign of it.
   where it bites: the bulbar curve is where a false passage is made; the fix is the angle of the penis, not more push.
6. The external sphincter Two centimetres beyond the bulb the tip meets a definite resistance: the external urethral sphincter, a ring of striated muscle that closes reflexly on the foreign body. This is the moment most catheters are pushed too hard. The move is steady gentle pressure held on the catheter while the patient is asked to take slow deep breaths, or to try to pass urine; both relax the sphincter and the catheter goes through, often with a small give. Once it has passed, the veru sits on the floor just beyond and the prostatic urethra begins.
   where it bites: pushing through a closed sphincter injures it; the sphincter opens for a patient who is breathing, not for a house officer who is pushing.
7. The prostatic urethra The prostatic urethra curves upward and forward over the median lobe to the bladder neck: the second curve, and in a big gland the longest and tightest part of the whole passage. A standard catheter tends to dig into the median lobe or the floor of the neck; a coudé tip with its bend kept at twelve o'clock rides over the lobe. The bladder neck is a final ring of resistance in a long prostatic urethra, and beyond it the catheter runs free.
8. In the bladder: urine before balloon The catheter is advanced to the hub before anything else is done, so that the tip and the balloon are well inside the bladder and not sitting in the prostatic urethra. Then wait for urine. If nothing comes, press suprapubically, wait a minute, flush 20 ml of saline down the catheter and aspirate. Urine back means the bladder; nothing back means either an empty bladder or a tip that is not in it, and a bladder scan settles which. Only when the catheter has proved its position does the balloon go up: 10 ml of water, slowly, stopping at any pain.
   where it bites: a balloon inflated in the prostatic urethra splits it; urine first, balloon second, every time.
9. Seat, secure and write Draw the catheter back until the balloon sits on the bladder neck and the catheter stops. Replace the foreskin over the glans. Connect the bag and hang it below the level of the bladder so it drains; secure the catheter to the thigh so the balloon is not dragged against the neck. The note records the indication, the size and type, the balloon volume, the residual volume drained, the colour of the urine, whether it was easy or difficult and why, and the plan: the date of the trial without catheter or the reason it stays.
10. The difficult catheter: the ladder Two gentle failed attempts is the limit for one pair of hands. The ladder, in order: more gel and more time at the sphincter with the patient breathing; a coudé tip; a size up, 18 French, because a stiffer catheter follows the lumen where a floppy one buckles. Then urology. The registrar passes a flexible cystoscope, sees the true lumen, places a guidewire into the bladder and railroads a catheter over it; or, if the urethra will not pass at all and the bladder is palpable, puts in a suprapubic catheter under ultrasound. Nobody should have the urethra instrumented five times in one night.

Complications and immediate saves

Trigger each of these live in the Animation tab, then read the save: the first move, the escalation trigger, and the line that goes in the op note.

FRCS viva questions

The examiner stems this scene prepares you for. Try to answer out loud first, then reveal, and learn the discriminator, the detail that turns a pass into a strong pass.

Evidence and guidance