Alternatives to Heparin Lock Solution

Heparin in low concentrations of 10 or 100 units per mL has long been the standard solution for locking a central venous catheter. Recently numerous issues with the use of heparin are being discussed especially the incidence of heparin induced thrombocytopenia (HIT). You can read a literature review of these issues at www.hadawayassociates.com and click on Clinical Articles to find the title of "Heparin Locking for Central Venous Catheters."

When a patient develops HIT, all heparin must be stopped including the use of heparin lock solution. These situations bring up the question of what should be used instead of heparin. Saline as a locking solution can be used for many situations when you are using a catheter with an integral valve or when you have added a needleless connector with instructions allowing for saline only flushes. There are situations where saline alone may not be sufficient and there is very little published data to report on catheter patency when saline alone is used. This would apply to large bore dialysis catheters or possibly to an implanted port when it has been de-accessed.

Recently I have found two studies reporting on the use of alteplase and lepirudin as possible alternatives to heparin locking solution. Haymond, et al. reported on the use of alteplase 1 mg per lumen to lock hemodialysis catheters. This was done to restore patency of the catheter and was left inside the lumen for either 60 minutes or until the next dialysis treatment which usually was a period of 48 to 72 hours.

Horne, et al., compared lepirudin 100 micrograms per mL to heparin 100 units per mL in a randomized double-blind clinical trial. They reported that lepirudin was not more effective than heparin, but attributed this to the very low dose of lepirudin.

There are published reports from other countries of using alternative catheter locking solutions including 4% sodium citrate, taurolodine/citrate combination, and various concentrations of ethanol. None of these products are commercially available in the US at this time. These studies focus on using these solutions to reduce catheter-related bloodstream infections, another worthy goal. But there are numerous questions about the routine locking of a catheter using these solutions in the same manner as we now use heparin lock solution.

Until these questions are answered and an alternative medication has passed the FDA processes, we are left with the alternatives of alteplase and lepirudin based on the 2 small studies discussed above. If you have experience with any of these as a catheter locking solution, please share what you have seen.