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czajka carol
alteplase for CVC occlusion

When dosing alteplase in pediatrics patients < 30kg; the dosing recommendation is 110% of the priming volume of the line.

My question is how do people define the priming volume.  Is it the priming volume of the cut or uncut catheter.

This has become a concern with the increased use of a particular cuffed polyurethane catheter, used in infants and toddlers, whose uncut priming volume is 0.79mls.  This dose appears to be too large for patients < 30 kg (specifically those less the 15kg).

We are trying to standardize our practice for all catheters to prevent harm from overdosing use of alteplase.

It should be the internal

It should be the internal volume or priming volume of the specific catheter cut to the length for this patient. That is why the length MUST follow the patient from insertion to all venues of care. If you don't have this length and the specific internal volume of the original catheter from the manufacturer, then you will have to estimate the internal volume by using an empty syringe and slowly aspirating until you have blood reach the external catheter hub. Obviously if you have an occluded lumen, you can't use this method. So your practice needs to change to have all inserters document the specific length of catheter inserted, along with the lumen sizes and the brand so you can find this internal volume. Or your policy must include this withdrawal assessment before occlusion. There will always be overfill and that is a good thing so that tPA reaches the fibrin/thrombosis directly at the tip of the catheter. Even then there will be fibrin/thrombosis that remains present and will regrow to occlude the catheter again in a few weeks. This would mean a low dose infusion of tPA over 2-3 hours. Low dose instillation or infusion will not result in an over dose. 2 mg in 2 mL for adults is the smallest fraction of the 50 to 100 mg therapeutic doses used. Read the INS SOP on CVAD Occlusion, 

Lynn Hadaway, M.Ed., RN, NPD-BC, CRNI

Lynn Hadaway Associates, Inc.

PO Box 10

Milner, GA 30257


Office Phone 770-358-7861

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