In a patient with a severely over‑distended bladder (>800 mL) where straight catheterisation has failed, how should I insert an indwelling Foley catheter and confirm placement, such as by flushing with 30 mL normal saline?

Foley Catheter Insertion and Confirmation After Failed Straight Catheterization in Severe Bladder Overdistention

When straight catheterization fails in a patient with severe bladder overdistention (>800 mL), insert an indwelling Foley catheter using standard sterile technique, advance it fully until urine flows freely, inflate the balloon only after confirming intravesical placement, and verify proper positioning by gently flushing with 30 mL of normal saline—which should flow easily without resistance and return freely. 1

Critical Pre-Insertion Considerations

Before attempting Foley placement in this high-risk scenario, you must:

• Rule out urethral injury or bladder rupture, especially if there is gross hematuria with pelvic fracture or penetrating trauma, as catheterization is contraindicated until retrograde cystography is performed 2
• Assess for urethral stricture or obstruction that may have caused the initial straight catheterization to fail 1
• Consider suprapubic catheterization or urology consultation if urethral catheterization is repeatedly unsuccessful, as forced attempts risk urethral trauma 2

Step-by-Step Insertion Protocol

Catheter Advancement

• Advance the Foley catheter fully to the hub (in males, this means advancing well past the external sphincter into the bladder) before inflating the balloon 3
• Wait for spontaneous urine flow before proceeding—this confirms the catheter tip has entered the bladder 1
• Watch for the "long catheter sign" (excessive catheter remaining outside the patient), which indicates the tip has not reached the bladder 3

Balloon Inflation

• Inflate the balloon only after urine flows freely and the catheter is fully advanced 3
• Never inflate the balloon in the urethra, as this causes severe complications including autonomic dysreflexia in spinal cord injury patients and urethral trauma in all patients 3
• Use the manufacturer-recommended balloon volume (typically 10 mL for standard adult Foley catheters) 4

Confirmation of Proper Placement

Flushing Technique

The 30 mL normal saline flush you propose is an appropriate and practical bedside confirmation method. 1 Here's how to perform it correctly:

• Gently inject 30 mL of sterile normal saline through the main catheter lumen using a catheter-tip syringe 1, 3
• Proper placement is confirmed when:
  • The saline flows easily without resistance 1
  • Fluid returns freely when you aspirate or allow gravity drainage 1
  • The patient does not experience sudden severe pain (which would suggest urethral balloon inflation) 3

Additional Confirmation Methods

• Observe for continuous urine drainage into the collection bag positioned below bladder level 1
• Palpate the suprapubic area—the bladder should decompress and become less distended 3
• If any doubt exists about balloon position, particularly if the patient develops sudden pain or autonomic symptoms, obtain imaging (plain radiograph or ultrasound) before proceeding 3

Management of the Overdistended Bladder

Decompression Strategy

In severely overdistended bladders (>800 mL), you face a critical decision about decompression rate, though current guidelines do not provide definitive evidence-based protocols for this specific scenario. Based on physiologic principles:

• Allow complete drainage initially rather than clamping intermittently, as older concerns about post-obstructive diuresis or hematuria from rapid decompression lack strong evidence 1
• Monitor for gross hematuria after decompression, which may indicate bladder mucosal injury from overdistention 2
• Measure initial drainage volume to document the degree of retention 5

Post-Insertion Monitoring

• Ensure the collection bag remains below bladder level to maintain gravity drainage 1
• Check catheter patency if drainage slows or stops—flush with 30 mL normal saline to clear potential clots or debris 1
• Reposition the patient if drainage is inadequate despite a patent catheter 1

Common Pitfalls and How to Avoid Them

Premature Balloon Inflation

The most dangerous error is inflating the balloon before the catheter is fully in the bladder. 3 This causes:

• Urethral trauma and stricture formation 3
• Severe pain and autonomic dysreflexia in neurogenic patients 3
• Inability to advance or remove the catheter 3

Prevention: Always advance the catheter to the hub and wait for urine flow before touching the balloon port. 3

Inadequate Advancement

Stopping advancement as soon as urine appears is a common mistake, especially in males where urine may flow when the catheter tip is still in the prostatic urethra. 3

Prevention: After urine flows, advance the catheter an additional 2-3 cm (to the hub in males) before inflating the balloon. 3

Missed Catheter Malposition

Assuming the catheter is correctly placed without confirmation leads to complications. 1, 3

Prevention: Always perform the saline flush test and observe for easy flow and return. 1 If resistance occurs or the patient reports pain, deflate the balloon immediately and reassess position. 3

When to Seek Urgent Consultation

Contact urology immediately if: 5

• Multiple catheterization attempts fail 1
• Gross hematuria develops after catheter insertion 5
• The patient develops signs of bladder perforation (abdominal pain, distention, peritoneal signs) 2
• You cannot advance the catheter despite adequate lubrication and gentle technique 1
• The balloon cannot be deflated for catheter removal 6

Closed Drainage System Maintenance

Once the catheter is properly positioned and confirmed: 2

• Maintain a closed sterile drainage system with ports for needle aspiration if urine sampling is needed 2
• Plan for early removal (ideally within 24-48 hours) and transition to intermittent catheterization if ongoing bladder drainage is required, as each additional day increases infection risk by approximately 5% 5, 7
• Never use prophylactic antibiotics at insertion or removal, as they do not reduce infection rates and promote resistance 5