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Foley Catheter

The Foley catheter — named for Frederic Foley (1930s design) — is the universal indwelling urethral drainage catheter. The defining feature is the inflatable retention balloon near the tip, filled with 10 mL of sterile water after insertion to prevent dislodgement.

Design Variants​

2-Way Foley (Standard)​

  • Two internal lumens: drainage (large) and balloon inflation (small)
  • 14–24 Fr typical; 16 Fr is the standard adult size
  • 5 mL balloon standard; 30 mL variants for bladder-neck retention / postoperative hemostasis

3-Way Foley (Irrigation / CBI)​

  • Three lumens: drainage, balloon, and irrigation inflow
  • Allows continuous bladder irrigation (CBI) — used after TURP, after hematuria management, for clot evacuation
  • 20–26 Fr typical — large diameter for flow and debris handling

Material & Coating Variants​

  • Latex — classic, lowest cost; contraindicated in latex allergy
  • Silicone — latex-free; preferred for longer dwell (less tissue reaction, less encrustation)
  • Silicone-coated latex — balances cost and biocompatibility
  • Silver-coated / antimicrobial — marketed for CAUTI reduction; mixed evidence
  • Hydrophilic-coated — for single-use intermittent catheterization; see Intermittent Catheter

Indications​

  • Acute urinary retention
  • Bladder decompression before, during, and after surgery
  • Accurate urine output monitoring in ICU / intraoperative settings
  • CBI after TURP, radical cystectomy, open stone surgery
  • Post-reconstructive surgery (urethroplasty, VUA, bladder repair) — protective catheter drainage

Sizes & Selection​

Clinical contextTypical French size
Adult outpatient / inpatient indwelling14–16 Fr
Large patient, viscous urine, hematuria18–20 Fr
Post-TURP CBI22–24 Fr 3-way
Pediatric5–10 Fr (weight-based)
Intermittent self-catheterization10–14 Fr straight

Complications​

  • CAUTI — catheter-associated UTI; risk rises with dwell time
  • Urethral trauma — balloon inflation within the urethra, false passage, urethral stricture
  • Balloon failure — inability to deflate for removal; managed by overinflation / pin-burst / retrograde fluid push
  • Bladder neck injury — with prolonged dwell, particularly in males
  • Leak around the catheter — a sign of bladder spasm, catheter obstruction, or under-sized catheter in a large bladder neck
  • Encrustation — struvite and calcium phosphate crystallization; mandates exchange

Dwell Management​

  • Remove as early as possible — universal principle to reduce CAUTI
  • Exchange every 2–4 weeks for chronic indwelling (standard latex/silicone)
  • Silicone can dwell 8–12 weeks when necessary

See also: Council Tip Catheter, Coudé Catheter, Suprapubic Catheter.