How many times should I flush a catheter with a 10 (cubic centimeter) saline syringe?

Catheter Flushing Protocol with 10 cc Saline Syringe

You should flush a catheter twice with a 10 cc saline syringe - once before and once after medication administration or blood sampling. 1, 2

Standard Flushing Protocol

Frequency Based on Catheter Type

• Standard peripheral IV lines and frequently used central lines:

  • Saline flush only (5-10 mL) before and after each use 2
  • No heparin needed for catheters in frequent use 2

• Open-ended central venous catheters:

  • When not in use for >8 hours: Saline flush followed by heparin (10-100 units/mL, 3-5 mL) every 8-24 hours 2

• Implanted ports:

  • When not in use: Saline flush followed by heparin (100 units/mL, 5 mL) every 4 weeks 2

• Tunneled cuffed catheters and PICC lines:

  • Weekly flush recommended when not in active use 1

Proper Flushing Technique

1. Use normal saline (0.9% sodium chloride) for flushing
2. Flush with 5-10 mL of saline before medication administration 2
3. Administer medication or draw blood
4. Flush with 5-10 mL of saline after medication administration or blood sampling 2
5. For catheters requiring heparin, add heparin flush after the saline flush

Special Considerations

Parenteral Nutrition with Lipids

• Mandatory saline flush between lipid solutions and heparin is required 2
• This prevents precipitation that can occur between lipids and heparin

Catheter Occlusion Prevention

• The minimum flush volume should be twice the catheter volume 1
• Adequate flushing with saline when infusion is completed can prevent catheter occlusion 1

Flushing Frequency for Maintenance

• For peripheral IV lines, once daily flushing is sufficient to maintain patency 3
• This reduces unnecessary manipulation, costs, and patient discomfort

Evidence on Saline vs. Heparin

• Normal saline flushing is not inferior to heparin flushing regarding catheter occlusion 2
• Saline has a lower risk of biofilm formation in the catheter lumen 2
• The 2023 ESPEN guidelines recommend using sodium chloride 0.9% instead of heparin to lock long-term central venous access devices 2

Potential Complications to Avoid

• Never forcefully flush an occluded catheter 2
• Potential complications of heparin use include bleeding, thrombocytopenia, allergic reactions, and osteoporosis 2
• In premature newborns, heparin use may increase risk of intraventricular hemorrhage 2

Management of Occlusion

If occlusion occurs despite proper flushing:

1. First attempt: Forceful irrigation with saline 1
2. If unsuccessful: Consider thrombolytic agents for established occlusions 2
3. For non-thrombotic occlusions: Treatment depends on primary etiology (lipid occlusion, mineral precipitates, drug precipitates) 1

Remember that proper flushing technique is more important than the concentration of heparin used, and saline-only protocols are increasingly supported by evidence for many catheter types.