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Bladder catheters: urethral, suprapubic and CAUTI
An indwelling catheter is inserted only with an indication and removed as early as possible — the most important way to prevent catheter-associated urinary tract infection (CAUTI); when urethral injury is suspected or the catheter is needed long term, a suprapubic catheter is better.
Why it matters in the exam
Indications for an indwelling catheter: retention or obstruction, accurate output monitoring in a critically ill patient, certain operations, healing of a sacral or perineal wound in a patient with leakage, and comfort care at the end of life. Incontinence alone is not an indication. An absolute contraindication to a urethral catheter is suspected urethral injury — blood at the meatus, a pelvic fracture or a perineal haematoma. In a man with a large prostate a curved-tip catheter (Coudé) is used; with a stricture — insertion under flexible cystoscopic guidance. A balloon must not be inflated when there is no urine flow, because the balloon may be in the urethra. Catheter size on the French scale (Fr) equals three times the diameter in millimetres.
CAUTI prevention: sterile insertion, a closed system, the bag below bladder level, a daily review of whether the catheter is still needed, no routine irrigation and no prophylactic antibiotics. Routine cultures are not done and asymptomatic bacteriuria in a catheterised patient is not treated. When there is symptomatic CAUTI: a catheter older than two weeks is replaced before the culture is taken and treatment is started; treatment lasts 7 days when the response is prompt and 10 to 14 days when it is delayed.
A suprapubic catheter is inserted through the abdominal wall into a full bladder that is palpable or seen on ultrasound. Relative contraindications: suspected bladder cancer not yet evaluated, previous lower abdominal surgery (bowel may be in the way — insert under ultrasound guidance), bleeding disorder, a small contracted bladder and pelvic radiotherapy. Long term it is better than a urethral catheter in a man, because it prevents erosion of the urethra and meatus, and allows sexual activity. In neurogenic patients intermittent self-catheterisation is better than any indwelling catheter.
Key points
- Catheter only with an indication, early removal.
- Urethral injury — no urethral catheter.
- Do not treat asymptomatic bacteriuria.
- CAUTI — replace an old catheter before culture.
- Long term in a man — suprapubic.
Summary table
| Topic | Rule | Note |
|---|---|---|
| Indication | Retention, monitoring in critical illness, surgery, wound, end of life | Not for incontinence alone |
| Contraindication to urethral | Suspected urethral injury | Urethrography and suprapubic |
| CAUTI prevention | Early removal, closed system, low bag | No prophylactic antibiotics |
| Symptomatic CAUTI | Replace a catheter older than two weeks and culture | 7 days or 10 to 14 days |
| Suprapubic | Full bladder, ultrasound guidance | Better long term in a man |
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Sources
- CDC/HICPAC Guideline for Prevention of Catheter-Associated Urinary Tract Infections, 2009, updated 2019 — Appropriate use, insertion and maintenance
- IDSA Guidelines: Diagnosis, Prevention, and Treatment of Catheter-Associated Urinary Tract Infection in Adults, 2009 — Definitions and treatment
- BAUS Suprapubic Catheter Insertion Practice Guidelines, 2016 — Indications, contraindications and technique
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-06. The text may contain errors; when in doubt, check the source.