Is a double-lumen catheter or an Arteriovenous (AV) shunt better for Continuous Renal Replacement Therapy (CRRT) line placement?

CRRT Vascular Access: Double-Lumen Catheter vs AV Shunt

Double-lumen venous catheters are the standard and preferred vascular access for CRRT, not arteriovenous shunts. AV shunts (arteriovenous fistulas or grafts) are designed for chronic intermittent hemodialysis and are inappropriate for continuous renal replacement therapy in the acute setting. 1, 2

Why Double-Lumen Catheters Are Standard for CRRT

Consensus Guideline Position

• The First International Consensus Conference on CRRT established that the majority of centers use single dual-lumen venous catheters for CRRT access, representing the current standard of care. 1
• Dual-lumen temporary hemodialysis catheters are explicitly identified as "the catheters of choice" for performing CRRT efficiently and without interruption. 2

Technical Requirements for CRRT

• CRRT requires continuous vascular access 24 hours per day for days to weeks, which is fundamentally incompatible with AV fistula/graft design. 2, 3
• Double-lumen catheters provide simultaneous arterial outflow and venous return through a single venous puncture site, enabling the continuous blood flow circuit essential for CRRT. 2
• AV shunts would require separate arterial and venous cannulation, creating unnecessary vascular trauma and immobilization in critically ill patients. 3

Optimal Catheter Selection and Placement Strategy

Catheter Type Based on Expected Duration

• Short-term use (up to 2-3 weeks): Semi-rigid double-lumen polyurethane catheters are appropriate for acute CRRT needs. 3
• Prolonged use (over 3 weeks): Soft silicone double-lumen or twin-catheters with subcutaneous tunneling are highly desirable to reduce infection risk and improve durability. 3
• Tunneled cuffed catheters demonstrate superior actuarial survival rates: 82% at 1 year, 56% at 2 years, and 42% at 3 years. 4

Site Selection Algorithm

First choice - Femoral vein when any of these risk factors are present: 3

• Respiratory failure
• Pulmonary edema
• Coagulopathy or active bleeding
• Need for immediate access without delay

Second choice - Right internal jugular vein for: 1, 2

• Mid-term use (beyond initial stabilization)
• Facilitating patient mobilization
• Reducing infection risk compared to femoral sites
• This is the preferred site once the patient is stabilized

Avoid - Subclavian vein because: 1, 3

• High risk of venous stenosis and thrombosis
• Compromises future permanent vascular access options if the patient progresses to chronic kidney disease requiring long-term dialysis
• This preservation of the vascular network is critical for patients who may need AV fistulas later

Mandatory Insertion Technique

• Ultrasound guidance is required for all catheter insertions to reduce mechanical complications and improve success rates. 2, 3
• Insertion must be performed by trained personnel using strict aseptic conditions. 2
• Verify catheter tip position in the superior vena cava (for jugular/subclavian) or inferior vena cava (for femoral) before use. 2

Infection and Thrombosis Prevention

Infection Rates and Prevention

• Catheter-related bloodstream infection rates with proper technique: 2.86 per 1000 catheter-days. 4
• Exit site infection rates: 5.2 per 1000 catheter-days. 4
• Femoral versus jugular/subclavian sites show no significant difference in infection rates when proper care protocols are followed (9.7 vs 8.8 CRCOL events per 1000 catheter-days, P=0.8). 5

Evidence-Based Prevention Strategies

• Implement strict hand hygiene and aseptic technique for all catheter manipulations. 2
• Use gauze dressings rather than occlusive transparent dressings. 2
• Consider antibiotic or antiseptic-coated catheters in high-risk patients, though concern for resistant organisms limits widespread use. 2
• Anticoagulation therapy reduces catheter malfunction rates; consider in all patients without contraindications. 4
• Micropatterned polymer-coated catheters demonstrate significantly prolonged survival (131±38 vs 113±21 hours, P=0.004) with lower thrombosis rates (2.3 vs 4.2 episodes per 1000 catheter-days, P=0.021). 6

Common Pitfalls to Avoid

Critical Errors in Access Management

• Never use subclavian veins in patients who may progress to chronic kidney disease, as this destroys future permanent access options. 1, 3
• Never attempt AV shunt creation for acute CRRT needs—this is a fundamental misunderstanding of CRRT requirements versus chronic intermittent hemodialysis. 1, 2
• Do not delay catheter insertion for "ideal" site selection in hemodynamically unstable patients; femoral access can be placed rapidly and safely. 3

Patient-Specific Risk Factors

• Older patients (>65 years) have 2.1-fold higher colonization risk. 5
• Patients weighing >90 kg have 2.2-fold higher colonization risk, particularly with femoral sites. 5
• These high-risk patients warrant enhanced surveillance and consideration of antimicrobial-coated catheters. 5

Catheter Exchange Considerations

• Guidewire exchange versus new venipuncture shows no significant difference in infection rates for extended CRRT use. 5
• Serial femoral catheterizations with either approach maintain low infection rates when proper technique is used. 5
• Thrombosis requiring urokinase treatment occurs in approximately 6% of dialysis sessions; maintain low threshold for intervention. 4