Is a heparin lock necessary for a Peripherally Inserted Central Catheter (PICC) line?

Heparin Lock for PICC Lines: Evidence-Based Recommendations

Normal saline (0.9% sodium chloride) should be used instead of heparin for routine locking of PICC lines in adults, as there is no clear evidence that heparin provides additional benefit for maintaining catheter patency. 1, 2

Evidence on Flushing Solutions for PICC Lines

• Current guidelines strongly recommend using 0.9% sodium chloride (normal saline) for flushing and locking PICC lines that are in frequent use, as it is equally effective as heparin in preventing occlusion 1, 2
• The ESPEN 2023 practical guideline specifically states that "sodium chloride 0.9% instead of heparin should be used to lock long-term CVAD" with a grade B recommendation and strong consensus (95.5%) 1
• Multiple systematic reviews and randomized controlled trials have demonstrated that normal saline flushing is not inferior to heparin flushing regarding catheter occlusion, reflux dysfunction, and flow dysfunction 1
• Heparin may actually increase the risk of catheter-related bloodstream infections (CRBSIs) by promoting intraluminal biofilm formation 1

When Heparin May Be Considered

• For PICC lines that are accessed intermittently (not daily), flushing with 5-10 U/mL heparinized saline 1-2 times weekly may be considered to help maintain patency 1, 2
• The 2018 ESPEN guideline states: "For CVC that are being accessed intermittently, flushing with 5-10 U/mL heparinized saline 1-2 weekly helped maintain patency" 1
• However, even for intermittently accessed catheters, the evidence for heparin's benefit is limited, with only conditional recommendations based on extrapolated evidence from adult studies 1

Special Considerations and Risks

• In newborns, routine use of heparin has shown effectiveness in prevention of PICC occlusion, but potential risks have not been well-defined, so its routine use cannot be recommended 1
• Heparin should not be used immediately before or after administration of lipid-containing parenteral nutrition admixtures, as it may facilitate lipid precipitation 2
• Potential adverse effects of heparin include heparin-induced thrombocytopenia, although this is rare with low concentrations 3
• The 3P-O study found that PICCs flushed with normal saline and then "locked" with heparin were less likely to become occluded (OR = 0.54; 95% CI = 0.33-0.88), but this is just one study and contradicts other evidence 4

Alternative Locking Solutions

• Taurolidine is effective in preventing catheter-related bloodstream infections and should be considered during long-term catheter use 1
• Multiple RCTs have shown that taurolidine significantly reduces CRBSI rates compared to heparin or saline 1
• For treating catheter occlusions, recombinant tissue plasminogen activator or urokinase should be used rather than routine heparin prophylaxis 1

Best Practices for PICC Maintenance

• Proper flushing technique with normal saline is more important than the addition of heparin for preventing occlusion 5
• If a PICC is used for home parenteral nutrition, a sutureless device should be used to reduce the risk of infection 1
• For securing medium to long-term PICCs (>1 month), a subcutaneously anchored stabilization device can help prevent migration and save time during dressing changes 1

In conclusion, current evidence and guidelines support the use of normal saline rather than heparin for routine locking of PICC lines in adults. Heparin should be reserved for specific situations such as intermittently accessed catheters, and even then, the evidence for its benefit is limited.