Author: Rob Greig / Editor: Ben Hughes, Charlotte Davies / Codes: SLO1, SLO6, UP3, UP6 / Published: 29/10/2020
Here’s part two of our urological problems in men blog – focussing on catheterisation and problems associated with it.
Acute Urinary Retention (AUR)
Having recently had surgery this is a topic very close to my heart as I went into post-operative retention. It was quite an eye opener, especially since the clinician bladder scanned me at my umbilicus and said there was only 750ml in my bladder. I had 1.7l in my bladder! So, first lesson, if you are going to mess around with bladder scanners ensure you are trained and that you’re pointing the probe in the correct direction!
Personally, it’s PoCUS all the way because you can check also for hydronephrosis (a reason alone to admit an AUR case), however I digress. There’s a guide on how to use POCUS here.
The PSA will be raised in acute retention and has no bearing on the ED management. I’m not saying PSA per se has no role but is beyond the scope of this acute piece. There’s a great RCEM learning piece on Assessment and management of Acute Urinary retention so I won’t go over much from that. However, AUR is responsible for 30K admissions in the UK per annum.
There are 4 basic mechanisms:
- Often the lumen is blocked with sediment or lumen too small. Balloon not fully inflated, or the catheter end is too low down the leg causing a negative pressure.
- If bypassing caused by blocked catheter then on PoCUS a large bladder will be seen.
- If bypassing caused by partially inflated balloon, then the balloon volume will be less than 10ml and you won’t see on PoCUS a nice circular balloon image.
- If bypassing caused by catheter attached too low down the leg this will be alleviated by attaching higher up the leg or simply attach a flip-flow valve. Is the bag below the level of the patient’s bladder? (if the bag is more than 30cm away from the bladder, there is an increased negative pressure which may increase the risk of blockage or bypassing – the negative pressure sucks bladder epithelial tissue into the tip thus blocking the drainage lumen – RCN Catheter Care document, excellent read). So flushing a bypassing catheter is unlikely to help!
Blocked catheters
This is a fascinating YouTube video on blocked catheters. Sometimes you just can’t win, and patients get recurrent blocked catheters. I elect to replace if possible, rather than flush simply because the biofilm, encrusted debris, bladder pseudo-polyps or impaction on bladder wall may recur rapidly or just float around in the bladder and block the catheter later, so flush the catheter and bladder, allow to drain and then replace. (If recurrent blockages in LTC then worth a urology review for cystoscopy to rule out bladder stones.)
Cases where patients are having multiple early changes may benefit from a new style of catheter, not a Foley catheter (80 year old tech) but the Flume Catheter. See image above and click the link for a review of this new style of catheter where the tip doesn’t protrude from the balloon. There is also something called the EZ Catheter, but it looks like it’s in the development only stage.
The author points out that at this stage The Flume catheter doesn’t have a CE mark, but the manufacturer hopes to have that by 2021.
You may ask whether you should flush a blocked catheter. Flushing is normally harmless, and the catheter might be just blocked by a small bit of calcification. Certainly worth trying before replacing the catheter. If a flush fails, the catheter will need replacement, and if the catheter is regularly blocking outpatient urology referral will be useful.
Antibiotics and new catheters and catheter changes (!!!)
Well flip a coin quite frankly! The evidence fluctuates but is weak – most guidance is against. NICE guidelines suggest antibiotics if >2 attempts, frank haematuria post catheterisation and history of UTI post change.
Please follow local guidance and genuinely question how a bolus of 80mg Gentamicin is useful in any way, shape or form.
Further Reading
Urinary Retention Reference and Learning Session
Haematuria Learning Session
- Increased resistance to outflow e.g. tumour, haematoma, enlarged prostate, urethral stricture.
- Inappropriate detrusor muscle innervation courtesy of neurological pathology such as stroke, spinal cord injury/lesions and diabetic neuropathy.
- Bladder over distention post op, chronically and with alcohol use
- Drugs, and there are many, but commonly anticholinergics, anti-psychotics, tricyclics and opiates
3 responses
Thank you
Excellent article
Good practical points