CRRT Vascular Access Requirements
A dedicated dialysis catheter (hemodialysis catheter) is required for CRRT and a standard central venous catheter is inadequate. CRRT requires specialized dual-lumen hemodialysis catheters with specific design features that standard CVCs lack, including larger bore size (12-16 French), adequate length for proper tip positioning, and internal lumen configuration to minimize recirculation 1, 2.
Why Standard CVCs Cannot Be Used
Standard central lines lack the necessary specifications for effective CRRT delivery:
Insufficient lumen diameter: CRRT requires blood flow rates of 200-400 mL/min, which standard CVCs (typically 5-7 French) cannot accommodate. Hemodialysis catheters must be 12-16 French to ensure adequate blood flow 1.
Inadequate catheter length and tip design: Dialysis catheters have staggered dual-lumen tips specifically designed to prevent recirculation of dialyzed blood, which standard CVCs lack 1.
Flow characteristics: The distal tip shape of hemodialysis catheters is engineered to deliver sufficient blood flow with low aspiration pressure while limiting recirculation rates, features absent in standard CVCs 1.
Required Catheter Specifications for CRRT
Use dual-lumen temporary hemodialysis catheters as the catheter of choice for CRRT 2:
Size: 12-16 French external diameter to ensure adequate blood flow 1.
Type: Non-tunneled (temporary) hemodialysis catheters for short-term use (<3 weeks), or tunneled cuffed catheters if CRRT is expected to be prolonged (>3 weeks) 3, 2.
Material: Silicone or polyurethane for biocompatibility and reduced thrombogenic risk 1.
Optimal Insertion Site Selection
The right internal jugular vein is the preferred insertion site for CRRT catheters 3, 2, 4:
Avoid subclavian veins in patients with advanced chronic kidney disease or those at risk for future hemodialysis to prevent subclavian vein stenosis 3.
Femoral vein access should be reserved for bed-bound patients and catheters should not remain in place longer than 5 days. Femoral catheters require at least 19 cm length to minimize recirculation 3, 4.
Left internal jugular vein is associated with increased risk of catheter dysfunction and re-catheterization compared to right internal jugular vein 4.
Insertion Technique Requirements
All hemodialysis catheters must be inserted under ultrasound guidance by trained personnel using maximal sterile barrier precautions 3, 2:
Use cap, mask, sterile gown, sterile gloves, and sterile full body drape 3.
Prepare skin with 0.5% chlorhexidine with alcohol (or tincture of iodine/70% alcohol if chlorhexidine contraindicated) 3.
Confirm internal jugular catheter placement with chest radiograph 3.
Ultrasound guidance significantly decreases mechanical complications 3, 2.
Catheter Management During CRRT
Reserve the dialysis catheter exclusively for CRRT to prevent unnecessary manipulation and infection risk 3:
Do not use the catheter for medication administration, blood draws, or other purposes 3.
Replace catheters when clinically indicated rather than on a routine schedule, as this approach is as safe as routine replacement every 5 days with comparable infectious and mechanical complications 5.
Mean catheter duration can safely extend to 7.3 days when replaced based on clinical indication versus routine 5-day replacement 5.
Common Pitfalls to Avoid
Using standard triple-lumen CVCs: These lack adequate flow capacity and will result in inadequate CRRT delivery and frequent circuit clotting 1, 2.
Subclavian vein placement in CKD patients: This increases risk of vessel stenosis with multiple insertions and compromises future arteriovenous fistula creation 3.
Inadequate catheter length in femoral position: Femoral catheters must be ≥19 cm to minimize recirculation 3.
Less prolonged prothrombin time is associated with earlier catheter dysfunction and should prompt closer monitoring 4.