What is the ideal dialysis prescription using a vascular (Vascular Access Device) catheter as access?

Ideal Dialysis Prescription Using a Vascular Catheter

When using a central venous catheter (CVC) for hemodialysis access, the prescription should target a blood flow rate of 300-350 mL/min with treatment times adjusted to achieve adequate dialysis adequacy (Kt/V ≥1.2), while recognizing that catheters should be used for the shortest duration possible as a bridge to permanent access. 1

Blood Flow Rate Targets

• Target blood flow rates of 300-350 mL/min are achievable with properly functioning tunneled cuffed catheters, though this is lower than the 400-600 mL/min typically achieved with arteriovenous fistulae 1, 2
• Catheters capable of rapid blood flow (≥350 mL/min at prepump pressures not more negative than -250 mmHg) are preferred 1
• Actual delivered blood flow averages 250-300 mL/min in clinical practice, requiring compensation through longer treatment times 3, 4

Treatment Time Adjustments

• Extend dialysis session duration beyond the standard 4 hours to compensate for lower blood flow rates and achieve adequate solute clearance 1
• Monitor delivered Kt/V to ensure adequacy targets are met (typically Kt/V ≥1.2-1.4) despite lower flow rates 3
• The lower overall blood flow rates with CVCs necessitate longer dialysis times compared to arteriovenous access 1

Catheter-Specific Considerations

Catheter Selection and Positioning

• Right internal jugular vein is the preferred insertion site as it provides the most direct route to the right atrium and optimal flow characteristics 1
• Long-term tunneled cuffed catheters should have tips positioned at the cavoatrial junction or right atrium, confirmed by fluoroscopy for optimal flow 1
• Catheter length matters: femoral catheters should be 24-31 cm to reach the inferior vena cava and minimize recirculation 1

Monitoring Parameters

• Prepump arterial pressure should not exceed -250 mmHg to avoid catheter collapse and hemolysis 1
• Monitor recirculation rates, which average 6-7% with properly functioning catheters but can be higher with malpositioned devices 3
• Venous pressures typically run 180-195 mmHg during treatment 3, 4

Critical Pitfalls to Avoid

• Never use subclavian vein catheters in patients who may need future arteriovenous access, as they cause central venous stenosis in a high percentage of cases and preclude ipsilateral arm access 1
• Avoid peripherally inserted central catheters (PICCs) entirely in CKD patients, as they cause upper-extremity venous thrombosis in 11-85% of cases and destroy potential access sites 1
• Do not accept inadequate blood flow rates without extending treatment time—this compromises dialysis adequacy and patient outcomes 1

Temporary Nature of Catheter Use

• CVCs should be viewed as temporary access only, used for the shortest duration necessary while a permanent access matures 1
• Establish a plan within 30 days of catheter placement to either discontinue or transition to permanent access 1
• Long-term catheter use is associated with significantly higher infection rates, thrombosis risk, and overall costs compared to arteriovenous access 1, 5

Infection Prevention

• Strict aseptic technique during catheter manipulation is essential, as infection is responsible for removal of 30-60% of hemodialysis catheters 5
• Hospitalization rates and mortality are higher among patients dialyzing via catheters compared to those with arteriovenous fistulae 1
• Use appropriate catheter lock solutions between treatments to maintain patency and reduce infection risk 1, 3

Prescription Optimization Strategy

The algorithmic approach should be:

1. Verify catheter tip position (cavoatrial junction/right atrium) 1
2. Target blood flow rate of 300-350 mL/min 1, 3
3. If blood flow <300 mL/min, extend treatment time proportionally to maintain Kt/V ≥1.2 3
4. Monitor prepump pressure (keep >-250 mmHg) and recirculation (<10%) 1, 3
5. Simultaneously work toward permanent access creation to minimize catheter duration 1

The evidence consistently demonstrates that while catheters can deliver adequate dialysis, they represent a compromise compared to arteriovenous access and should drive urgent planning for permanent access placement 1.