How can I safely place a central venous catheter in an adult receiving therapeutic unfractionated heparin infusion?

Central Line Insertion in a Patient on Heparin

You can safely place a central venous catheter in a patient receiving therapeutic unfractionated heparin infusion without stopping the heparin, using ultrasound guidance and selecting the internal jugular vein as the preferred site. 1

Optimal Insertion Technique to Minimize Bleeding Risk

Site Selection Priority

• Choose the right internal jugular vein as the first-line access site due to its direct route to the right atrium, lower mechanical complication rates, and compressibility if bleeding occurs 1
• Avoid the subclavian vein approach in anticoagulated patients, as this site is non-compressible and carries higher risk of uncontrolled bleeding if arterial puncture occurs 1
• The femoral vein is an acceptable alternative if the internal jugular veins are unavailable, though it has higher infection rates 1

Ultrasound-Guided Technique

• Use real-time ultrasound guidance throughout the entire procedure to minimize vein wall trauma and reduce the risk of arterial puncture 1
• Perform static ultrasound imaging before prepping and draping to confirm vessel patency and identify anatomical variations 2
• Ultrasound guidance reduces mechanical complications and subsequent thrombotic events compared to landmark-based techniques 1

Catheter Selection and Positioning

Device Characteristics

• Select the smallest caliber catheter compatible with your infusion needs to minimize vein trauma 1
• Choose silicone or second/third generation polyurethane catheters, as these materials are less thrombogenic than polyethylene or PVC 1
• Minimize the number of lumens to only what is clinically necessary 1

Tip Positioning

• Position the catheter tip at the superior vena cava-right atrium junction (cavoatrial junction) to minimize thrombotic complications 1, 2
• Confirm tip position with chest X-ray post-insertion, as poorly positioned tips increase risk of thrombosis, erosion, and pericardial tamponade 1
• For right internal jugular access, use a 15 cm catheter; for left internal jugular or right subclavian, use 20 cm; for left subclavian or femoral, use 24 cm 1

Heparin Management During Procedure

Continuation vs. Interruption

• Continue the heparin infusion during central line placement unless there are specific contraindications or extremely high bleeding risk 3, 4
• The evidence shows that therapeutic anticoagulation does not preclude safe central venous catheter placement when proper technique is used 4
• Monitor the activated partial thromboplastin time (APTT) before the procedure; if APTT is greater than 1.5 times control, heparin is therapeutic 3

Post-Insertion Anticoagulation

• Resume or continue heparin immediately after successful catheter placement if hemostasis is achieved at the insertion site 3, 4
• A study of cancer patients with central catheters treated with therapeutic anticoagulation (dalteparin 200 IU/kg/day) showed no line failures and no recurrent thromboembolism 4

Catheter Maintenance in Anticoagulated Patients

Flushing Protocol

• Use sterile 0.9% sodium chloride (normal saline) as the standard flush solution rather than heparin 1, 5
• Multiple meta-analyses confirm that heparin flushes provide no additional benefit over saline for maintaining catheter patency 1, 5
• Flush with a volume at least twice the catheter volume using 10 mL or larger syringes 5

When Heparin Flush May Be Considered

• Heparinized solutions (50-500 units/mL) should only be used if specifically recommended by the manufacturer or for open-ended catheter lumens closed for more than 8 hours 1, 5
• Never use heparin flushes immediately before or after lipid-containing parenteral nutrition, as heparin facilitates lipid precipitation; always interpose a saline flush 1, 5

Critical Pitfalls to Avoid

Technical Errors

• Never rely on blood color or absence of pulsatile flow alone to confirm venous access, as these are unreliable indicators of arterial puncture 2
• Avoid left-sided internal jugular approaches when possible, as they are associated with higher rates of stenosis and thrombosis 2
• Do not attempt "blind" infraclavicular subclavian puncture, as this can lead to pinch-off syndrome with catheter compression between the clavicle and first rib 1

Anticoagulation-Related Concerns

• Routine thromboprophylaxis with heparin or warfarin is not recommended for all patients with central venous catheters, as the risks (thrombocytopenia, bleeding, bone disease) outweigh benefits in most cases 1, 5
• Prophylactic low molecular weight heparin (100 IU/kg daily) is only reasonable for high-risk patients with malignancy, chronic inflammatory disease, or personal/family history of idiopathic venous thrombosis 1

Monitoring for Complications

• Assess for signs of catheter malposition including pain on injection, difficulty aspirating blood, or abnormal pressure waveforms 1
• If catheter-related thrombosis develops, treat with anticoagulation and maintain the catheter in place unless it is infected, occluded, or causing persistent symptoms despite anticoagulation 1, 4