What is the preferred solution for catheter maintenance, heparinized (Heparin) flush or plain saline?

Saline is Preferred Over Heparinized Solution for Catheter Maintenance

Normal saline should be used instead of heparinized solution for routine maintenance of central venous catheters. 1

Evidence-Based Rationale

The most recent and highest quality evidence from multiple clinical guidelines consistently supports using normal saline for catheter maintenance:

• ESPEN 2021 guidelines explicitly state: "We suggest flushing catheters with saline to prevent central venous catheter occlusion" (Grade of evidence: low) 1
• ESPEN 2009 guidelines indicate: "Most central venous access devices for PN can be safely flushed and locked with saline solution when not in use" (Grade B) 1
• ESMO 2015 guidelines recommend: "Flushing with 0.9% normal saline is recommended" (Level III, C) 1

Clinical Application

For Routine Catheter Maintenance:

• Use 0.9% sodium chloride (normal saline) for flushing catheters that are in frequent use 1
• The minimum flush volume should be twice the catheter volume 1
• Adequate flushing with saline when the infusion is completed prevents catheter occlusion 1

Special Considerations:

• For catheters accessed intermittently (not daily use), heparinized saline (5-10 U/mL) may be considered for flushing 1-2 times weekly 1
• For implanted ports or open-ended catheter lumens scheduled to remain closed for more than 8 hours, heparinized solutions may be used as a lock (after proper flushing with saline) when recommended by the manufacturer 1

Management of Catheter Occlusion

If occlusion occurs, follow this stepwise approach:

1. First attempt: Forceful irrigation with saline 1
2. If unsuccessful and thrombotic occlusion is suspected: Consider fibrinolytic drugs (urokinase, alteplase) 1
3. For non-thrombotic occlusions: Treat according to primary etiology:
   • Lipid occlusion: 70% ethanol or sodium hydroxide
   • Mineral precipitates: 0.1 N hydrochloric acid
   • Drug precipitates: Treatment based on pH 1

Important Caveats

• Heparin may facilitate precipitation of lipids, so saline flushing is mandatory during parenteral nutrition with lipids before any flushing with heparin 1
• The most recent systematic review (2024) found no statistically significant difference between heparin and normal saline in reducing catheter occlusion 2
• Heparin use carries potential risks including thrombocytopenia and bone disease that may outweigh benefits 1
• Close-ended valve catheters should be flushed and locked with saline only, following manufacturers' instructions 1

Conclusion

The weight of evidence from multiple guidelines and recent research supports using normal saline for routine catheter maintenance. This approach is effective, simpler, less expensive, and avoids the potential complications associated with heparin use.