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  • Urinary retention
  • Monitor fluid output (e.g. post-op, renal failure, trauma, sepsis, general illness) – in pretty much all seriously ill patients! – also pre-op to measure urine output during op.
  • Investigation – to determine residual volume
  • Manage incontinence – e.g. due to disability, e.g. spina bifida
  • To instil prescribed medicine (e.g. for treatment of bladder cancer)


  • UTI – There is a 5-10% risk of UTI each day the catheter is in!
  • Patient refusal
  • Known urethral strictures
  • Enlarged prostate (seek expert advice)
  • Trauma! – be careful e.g. in RTA or straddle injury – if there are any perineal signs of injury then don’t do it!
  • History of urethral stricture – e.g. a false passage (common in males)
  • Blood on the meatus (tip of penis)
  • Scrotal haematoma
  • Pyelonephritis (if the catheter is left in for long enough)
  • Patient has an erection!


  • Pain
  • Infection
  • Local trauma
  • Strictures (if catheter is left in long term)
  • Retention upon removal of catheter
  • Bladder spasm
  • Bleeding /trauma – although a small amount of blood within the first 24hours is normal.


They have a diameter, which is measured in ‘French’. 12 French is quite small, whereas 48 French is massive! 1 French = 1/3 mm – so they vary in diameter from 3mm-16mm. 12F is that standard diameter – but male and female catheters are different! Female are shorter, and male are longer.
You can have 1,2 or 3 channels in a catheter. Two channels are the most common type. One channel allows fluid out, and the other allows a balloon to be filled.
  • Single channel catheters (10ch) are often used in neurological disease just to allow fluid out.
  • Three channels might be used when you need to put something into the bladder, these can be up to 20ch.
They can be inserted either short term (~4weeks), or long term (>12 weeks). The length of insertion can affect which type of tubing is used – latex is generally used for short-term – ask for allergies. Silicone is used for long term.
Urinary Catheter with inflated balloon
Urinary Catheter with inflated balloon


  • Use a chaperone. Fully explain what you are going to do, and get proper consent.
  • Say that you would like to pass a ‘rubber’ tube up the patient’s ‘water pipe’ and explain why you want to do it in their individual case. Say they may feel the need to pass urine (this is normal). Deep breathing can help the passing of the catheter if they feel particularly uncomfortable.
  • Explain the complications. ask the patient to tell you if it gets very painful – then you will stop.
  • Catheterisation is an ANTT procedure – aseptic non-touch technique – you need to demonstrate you understand this!
Never Force a catheter!
  • **Extremely important*** –  ALWAYS REPLACE THE FORESKIN IN MALES! – if not you may cause a paraphimosis. *** This can be very painful and may require surgical correction. Also check there is no phimosis in the first place.
  • Also, when you expose the patient you may want to clean the region is it is particularly dirty / soiled.
  1. Wash hands, put on apron, clean trolley with 70% alcohol wipe. Clean the surfaces of the trolley as well as the legs. (In OSCE probably just explain you would do this otherwise it would take too long). Get:
    1. Catheter pack
    2. Catheter
    3. Urine bag
    4. Instiller gel
    5. Water
    6. sterile gloves
    7. syringes x2 – these will probably come pre-packed – one for instiller gel, one for sterile water to fill catheter balloon with
    8. pot of aqua gel (the same stuff used for rectal examination)
    9.  when gathering your bits and pieces, put them ALL on the bottom tray. When you open them out, you can put them on the top tray.
  2. wash your hands again, put on some normal gloves
  3. Open the catheter pack being careful which bits you touch. Don’t lean over it (to prevent bits of fluff or whatever falling into it. This means you have to open one half, walk around it, then open the other half.
    1. If you need to move bits of the catheter pack, then you may be able to touch them if there is a bag for rubbish in the pack. If there is you can put your hand in the bag of rubbish, and this allows you to touch the various bits and pieces and move them around.
  4. Open the catheter bag, and the instiller gel. If things are pre-packed, you can open them out onto the blue sheet of the catheter pack. For other things with a non-sterile surface (e.g. the packet of water) then you just put these onto the tray, but not on the blue sheet.
  5. Clean the outside of the packet of water with an alcohol wipe, then pour water into the tray
  6. Wash your hands again!
  7. Put on the sterile gloves – don’t put the packet down on the sterile surface! You can use any old surface lying around. You can touch the ‘cuff’ of the gloves but not any other part with your bare hands. Once you have got one glove on, you can touch the outer surface of the other glove with your gloved hand.
  8. Ask the patient to lie on their back and expose themselves. Females need to bend their knees and spread the legs, males don’t.
  9. Put the kidney dish under the genitalia where you will later use it to catch urine
  10. For men, loop a bit of cloth round the penis to hold it up. The hand holding the penis is the NON-STERILE HAND. Using firm rather than gentle pressure help avoid an erection.Do not touch anything that is not sterile with the other hand. Roll back the foreskin and clean the four quadrants of the penis with the sterile water you poured out earlier, using the cleaning ball things. Use only one sweep with each bud, and sweep away from the tip.
    1. For women, use three buds, and wipe from front to back, three time, middle and two sides. Hold the labia apart with the thumb and forefinger of the non-dominant hand
  11. For men, make a ‘sterile field’ by tearing a hole in the sheet from the catheter pack. Put this over the penis. For women, just put the sterile sheet down between the woman’s legs.
  12. Put 1ml of gel on the end of the penis, and slowly inject another 10ml of gel up the urethra. This takes 3-4 minutes to act.
    1. For women, just inject 5ml of gel into the urethra
  13. Open the catheter – whatever you do: do not touch the catheter! Only take 1-2cm of the catheter out of the packet at once.
    1. Dip the end of the catheter into the aqua-gel as lubricant
    2. Start to insert the catheter gently. Never force it. At some point, urine will being to flow out of the catheter into the catheter packet. At the point put the kidney dish beneath the catheter packet.
    3. Having trouble? If the catheter does not seem to be passing very easily up the man’s urethra, the prostate may be to blame. In which case, you can ask the patient to cough, or you can try altering the position of the penis; try lifting it up, so that it ‘points’ more vertically.
  14. Fill the balloon up with sterile water – do not use saline stupid! About 10ml of fluid should be enough. Ask the patient if they feel any pain – if they do you probably aren’t in the bladder yet! Once you have filled it up, you can pull it back out, so it now rests in the neck of the bladder.
  15. Attach the catheter bag below the level of the bed, and retract the foreskin! Also remove your sterile field. Attach the catheter tube/bag tube to the abdomen or the thigh. Make sure there is no tension in the tube.
  • If you get stuck, stop and call for expert advice!
  • Always explain what you are doing, get good consent etc.
  • Normal urine output is 30ml/hour.

Finishing off

  • Measure the volume of urine collected (residual volume)
  • Do a urine dipstick
  • Note the colour and smell of the urine
  • Document in the notes:
    • ANTT used
    • Chaperone present
    • Date / sticker from catheter pack
    • Foreskin replaced
    • How much fluid used to inflate balloon
    • Lubricant was used


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Dr Tom Leach

Dr Tom Leach MBChB DCH EMCert(ACEM) FRACGP currently works as a GP and an Emergency Department CMO in Australia. He is also a Clinical Associate Lecturer at the Australian National University, and is studying for a Masters of Sports Medicine at the University of Queensland. After graduating from his medical degree at the University of Manchester in 2011, Tom completed his Foundation Training at Bolton Royal Hospital, before moving to Australia in 2013. He started almostadoctor whilst a third year medical student in 2009. Read full bio

This Post Has One Comment

  1. Ell

    Good day! If it’s okay with you, may I ask about its results and implications? or what does the results means.

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