Irrigating a Foley catheter means flushing sterile saline through the catheter and into the bladder to clear blockages, usually caused by blood clots, mucus, or sediment. The procedure restores urine flow and keeps the catheter working properly. It can be done manually with a syringe or continuously through a special three-way catheter, depending on the situation.
Why a Foley Catheter Needs Irrigation
Catheter irrigation isn’t routine maintenance. The CDC recommends against irrigating unless an obstruction is anticipated or already present, such as bleeding after prostate or bladder surgery. Unnecessary irrigation increases the risk of urinary tract infection because it can introduce bacteria into a closed system.
The most common reasons for irrigation include clearing blood clots after urological surgery, flushing out mucus or debris that blocks urine drainage, and restoring flow in a catheter that has stopped draining. Patients receiving palliative care whose catheters frequently block with clots or debris may also need periodic irrigation.
Manual vs. Continuous Irrigation
There are two main approaches, and they serve different purposes.
Manual (open) irrigation uses a catheter-tipped syringe to push saline into the catheter, then withdraw it along with any clots or debris. This is the method most people search for when they want to know how to irrigate a Foley. It’s a targeted intervention to fix a blockage that has already happened. Because it requires disconnecting the drainage system, it carries a higher infection risk than the closed method.
Continuous (closed) irrigation runs saline steadily through a three-way catheter, one channel for the balloon, one for saline flowing in, and one for fluid draining out. The drainage system stays sealed throughout, which significantly reduces infection risk. This is standard after prostate or bladder surgery, where ongoing bleeding is expected. It typically runs for three to five days post-surgery.
Supplies You Will Need
For manual irrigation, gather the following before you start:
- A 60 mL catheter-tipped piston syringe
- Sterile normal saline (0.9% sodium chloride), usually a 500 mL or 1 liter bottle
- Alcohol pads or antiseptic wipes (at least three)
- Sterile gauze pads
- A clean towel or absorbent pad
- A container to catch drainage
- Gloves
- A connection cover for the drainage tubing
Do not use antimicrobial solutions for irrigation unless specifically instructed to do so. The CDC has found no benefit to routine antimicrobial flushes, and normal saline is the standard irrigating fluid.
How To Perform Manual Irrigation
Wash your hands thoroughly with soap and water for at least 15 seconds, scrubbing all surfaces. Put on clean gloves. Place the clean towel under the catheter connection point to protect the surrounding area.
Draw up the prescribed amount of normal saline into your 60 mL syringe. For adults, this is commonly 30 to 60 mL per flush, though your provider may specify a different volume. For children, the amount may be as small as 10 mL or whatever the care team has directed.
Clean the junction where the catheter connects to the drainage tubing with an alcohol pad, wiping firmly for several seconds. Then disconnect the catheter from the drainage bag tubing. Place a connection cover on the exposed end of the drainage tubing to keep it sterile, and set it aside on the sterile gauze.
Insert the tip of the syringe into the catheter opening. Gently push the saline in, using slow, steady pressure. Do not force the fluid. If you meet strong resistance, stop and reposition the catheter slightly before trying again. Forcing saline against a stubborn blockage can injure the bladder lining.
Once the saline is instilled, release the syringe plunger (or gently pull back) and allow the fluid to drain back into your collection container by gravity. The returning fluid may contain clots, sediment, or discolored urine. Repeat the process until the fluid returns relatively clear, or as many times as your healthcare provider has instructed.
When finished, wipe the catheter tip and the drainage tubing end with fresh alcohol pads. Reconnect the catheter to the drainage bag. Make sure the connection is secure and the tubing is not kinked. Remove your gloves and wash your hands again.
Keeping the System Sterile
Every time you disconnect the catheter from its drainage bag, you’re opening a closed system and creating an opportunity for bacteria to enter. This is why the CDC emphasizes maintaining a closed drainage system whenever possible and using standard precautions, including gloves, during any catheter manipulation.
If the sterile connection is compromised, contaminated, or leaking at any point during irrigation, both the catheter and the drainage system should be replaced using sterile equipment. Never touch the inside of the catheter tip or the syringe tip with bare hands or unclean surfaces. Keep all sterile supplies on a clean, dry surface while you work.
What To Watch for After Irrigation
After irrigation, pay attention to the color, clarity, and volume of urine draining into the bag. Urine that starts dark red or opaque and gradually lightens to pink or clear is a normal progression after clot evacuation. If the fluid stays heavily blood-tinged or stops flowing again shortly after irrigation, the catheter may be re-obstructing.
A sudden drop in outflow (more than a 70% decrease in a short window) can signal that a new clot has formed or that the catheter has kinked. A mismatch between the amount of saline you instilled and the amount draining back can indicate a blockage, a leak in the system, or that the drainage bag is positioned incorrectly. The bag should always hang below the level of the bladder to allow gravity drainage.
Bladder Spasms and Other Risks
Bladder spasms are the most common side effect of irrigation, particularly with continuous irrigation after surgery. Studies report spasm rates between 11% and 29% in patients receiving continuous irrigation after prostate procedures. Spasms feel like sudden, intense cramping in the lower abdomen, sometimes with an urgent need to urinate around the catheter. They can cause urine to leak around the catheter and, in post-surgical patients, may trigger additional bleeding.
Other risks include introducing infection (especially with the open method), minor trauma to the bladder lining from forceful flushing, and in rare cases with prolonged continuous irrigation, fluid and electrolyte imbalances from absorption of irrigating solution. If spasms are severe or persistent, medication can help, and the irrigation rate may need adjustment.
Troubleshooting: When Fluid Won’t Drain Back
If you instill saline and nothing returns, don’t panic. Several things can cause this. The catheter tip may be pressed against the bladder wall: try repositioning the patient or gently rotating the catheter. An “airlock,” where trapped air in the catheter prevents fluid from flowing, is another common culprit. Flushing with another syringe of saline or applying gentle suction with the syringe can break the air column.
Check the tubing for kinks or loops that sit above the bladder level, as these can trap fluid. If the catheter material itself seems to be causing repeated blockages through encrustation or buildup, replacing the catheter entirely is often more effective than repeated irrigation attempts. When fluid consistently won’t return despite these steps, the catheter likely needs to be changed rather than flushed again.