After instilling a CathFlo (heparin) lock, how soon can the catheter line be accessed for blood draw, medication administration, or infusion?

Catheter Access After CathFlo (Alteplase) Instillation

After instilling CathFlo (alteplase, not heparin) for catheter occlusion, you must wait a minimum of 30 minutes dwell time before attempting to access the line, then aspirate the drug/clot mixture and discard it before using the catheter for blood draws or infusions. 1

Critical Timing Protocol

Minimum Dwell Time Requirements:

• Wait at least 30 minutes after instilling the thrombolytic agent before attempting to withdraw it 1
• For hemodialysis catheters specifically, alteplase infusion of 1-4 mg/lumen over 1-4 hours permits restoration of adequate flow (>200 mL/min) 1
• The dwell technique requires the lytic at the catheter tip to remain biochemically active, and the agent must have sufficient time to diffuse to the fibrin or thrombus 1

Step-by-Step Access Algorithm

After the dwell period:

1. Aspirate 4-5 mL of blood/drug mixture and discard - this removes the CathFlo and any dissolved clot material 1
2. Flush the catheter with normal saline using at least twice the catheter volume 2, 3
3. Verify patency by attempting gentle aspiration of blood 1
4. Only then proceed with blood draws, medication administration, or infusions 1

Important Distinction: CathFlo vs. Heparin Lock

You asked about "CathFlo (heparin)" but these are different agents:

• CathFlo is alteplase (tPA), a thrombolytic used to restore patency in occluded catheters 1
• Heparin lock is a maintenance solution used to prevent occlusion when catheters are not in use 1

If you meant heparin lock solution:

• Heparin lock can remain in the catheter for up to 8 hours or longer depending on catheter type 1
• Before using the line, simply aspirate and discard the heparin lock volume (typically 3-5 mL), then flush with saline 1
• No specific waiting period is required for heparin locks - you can access immediately after aspirating the lock solution 1

Common Pitfalls to Avoid

Never rush the thrombolytic dwell time:

• Attempting to use the catheter before 30 minutes may result in incomplete clot dissolution and persistent occlusion 1
• Infusion techniques (continuous administration over 1-4 hours) may be more effective than simple dwell when initial attempts fail 1

Always discard the aspirate:

• The first aspirate contains thrombolytic agent and clot debris that should never be infused into the patient 1
• Failure to adequately clear the catheter before use risks systemic exposure to concentrated thrombolytic 1

Post-clearance maintenance:

• After successful restoration of patency, flush with normal saline rather than immediately re-locking with heparin 1
• If heparin lock is used after lipid-containing infusions, always interpose a saline flush between the lipid and heparin to prevent precipitation 1