Procedure if unable to aspirate 4% citrate locks

Hello,

If catheter is clotted and nurse has to push in 4% citrate locks do you hold the heparin bolus or not?

Also, does can anyone provide me with a good reference as to the safety of pushing in 4% citrate locks? [The letter to the editor by Polaschegg only discusses that 1 mL of 5% citrate is safe. I also have a presentation by Andreas Pierratos from Humber River which has a slide stating 3.5 mL 4% citrate results in an ionized Ca = 1.02 but I have no idea where this table came from.]

We are fairly new to 4% citrate locks and the nurses want a definitive statement on the safety of pushing 4% citrate locks in if unable to aspirate as well as what to do with the heparin bolus in our procedure.

Thank you,
Lori Wazny, Pharm.D.
Clinical Pharmacist
Manitoba Renal Program