Use Normal Saline (0.9% NaCl) for Catheter Flushing During IJ Catheter Insertion
Normal saline is the appropriate alternative to heparin for flushing central venous catheters, including during IJ catheter insertion, as multiple high-quality guidelines confirm that saline is equally effective as heparin for maintaining catheter patency in frequently accessed catheters.
Primary Recommendation: Normal Saline
The ESPEN 2009 guidelines explicitly state that "most central venous access devices for PN can be safely flushed and locked with saline solution when not in use" (Grade B) 1. This recommendation is reinforced by the 2018 ESPGHAN/ESPEN pediatric guidelines, which note that "routine use of heparin flush for the prevention of thrombotic occlusion in CVC being used on a daily basis cannot be recommended over use of saline flush due to lack of proven benefit" 2.
Key Evidence Supporting Saline Use:
- Meta-analyses have consistently shown that intermittent flushing with heparin provides no additional benefit over normal saline alone for maintaining catheter patency 1
- A 2017 meta-analysis of 7,875 subjects demonstrated that normal saline is equally, if not more effective, than heparinized saline in keeping CVCs patent 3
- A randomized trial in ICU patients (326 CVCs, 709 lumens) found no significant difference in nonpatency rates between heparin (3.8%) and saline (6.3%) groups 4
When Saline is Sufficient
Sterile 0.9% sodium chloride should be used to flush and lock catheter lumens that are in frequent use (Grade A) 1. This applies to:
- Catheters accessed continuously or with short intervals (<8 hours between uses)
- Hospital-based parenteral nutrition with continuous infusion
- Any catheter being actively used during the insertion procedure and immediate post-insertion period
- Close-ended valve catheters (which should receive saline only per manufacturer instructions) 1
Important Caveats About Heparin
When Heparin May Be Considered:
According to ESPEN guidelines, heparinized solutions should be used as a lock (after proper flushing with saline) when recommended by the manufacturer, in the case of implanted ports or open-ended catheter lumens scheduled to remain closed for more than 8 hours (Grade C) 1.
For intermittently accessed CVCs: flushing with 5-10 U/mL heparinized saline 1-2 weekly helped maintain patency 2.
Critical Safety Warning:
The FDA explicitly warns: "Do not use Heparin Sodium Injection as a 'catheter lock flush' product" 5. Fatal hemorrhages have occurred in pediatric patients due to medication errors confusing concentrated heparin vials with catheter lock flush vials 5.
Heparin Risks to Consider:
- Bleeding and hemorrhage
- Heparin-induced thrombocytopenia (HIT)
- Allergic reactions
- Osteoporosis with prolonged use
- Increased risk of intraventricular hemorrhage in premature newborns 2
- Destabilization of lipid emulsions when used with parenteral nutrition 2
Practical Flushing Protocol
For IJ catheter insertion and immediate post-insertion:
- Use sterile 0.9% sodium chloride for all flushing during and immediately after insertion
- Flush volume: Use at least 10 mL of saline per lumen
- Technique: Use a 10 mL or larger syringe to avoid excessive pressure that could damage the catheter 1
- Frequency: For catheters in active use, flush before and after each use, or every 8 hours if not continuously infusing 1
Additional Considerations
Proper flushing technique with saline is more important than the use of heparin itself 1. The key is adequate volume and appropriate timing of flushes.
For catheters that will be accessed intermittently after insertion (not during the insertion procedure itself), follow manufacturer recommendations, but recognize that saline-only protocols are increasingly supported by evidence and avoid the risks associated with heparin use 6, 3, 4.
If lipid-containing solutions will be administered, always interpose a saline flush between heparin (if used) and lipid infusions to prevent precipitation 1.