Foley catheter

Last revised by Joshua Yap on 24 Sep 2022

The Foley catheter is a urinary catheter with a balloon at its distal tip, which is inflated post-insertion to ensure that the catheter remains in the bladder. Originally inflation of the balloon required the instillation of fluid or air via a separate port, next to the external end of the catheter, but modern catheters have a built-in reservoir that can be used to inflate the balloon.


Insertion of a Foley catheter is a common procedure, but still carries risks of complications, either during insertion or after 4, including:

  • traumatic insertion
    • pain
    • stricture
    • hemorrhage
    • creation of a false passage
    • bladder perforation
  • malposition
    • urethral placement
    • ureteric placement (rare)
      • increased risk in the neurogenic bladder, long-term catheterization, intra-operative placement, undistended bladder or non-routine catheterization (e.g. during guide-wire assisted insertion (Blitz technique) or micro-tip catheter insertion during cystometry) 5 
    • false passage placement
    • vaginal placement
  • urinary tract infection
  • catheter fragment retention

It should be noted that small locules of gas in an anti-dependent position are commonly observed (mostly on CT) in the bladder of recently catheterized patients, and alone are not a sign of complication 6

History and etymology

The American urologist Frederic E B Foley (1891-1966) 3 first provided details of his now eponymous "hemostatic bag catheter" in an article in 1929, although in a later paper stated he had developed it in 1927 1,2. It was originally introduced as a way of controlling perioperative and postoperative hemorrhage during and after a cystoscopic prostatectomy. He continued to refine it and in an article in 1937 described his improved "self-retaining bag catheter" 2.

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