Increased occlusions with prefilled syringes

[DAVID LONGSETH]

Last summer our hospital had to switch from BD prefilled NS syringes to a  
Kendall product for flushing our PICC's. Since then,our occlusion rate has 
gone way up,based on TPA usage. In Aug 2005,for example we used 19 vials of 
TPA. Last month it was 30-some.
I am convinced that the new product is at fault. The cannula that comes in 
the new package is thicker and longer than the BD one and thus takes up more 
space in the cap when you flush,so when you pull it out you create more of a 
vaccuum/dead-space in the lumen (It's a split-septum style cap). It seems to 
me that this negative pressure within the lumens is sucking in just enough 
blood to clot off the lumen. The PICCs are 95% Groshongs,5% Bard PP's.
I asked that some samples of our product combination be sent to our Bard rep 
so the company can maybe check this out but haven't heard back.
Anyone with anything similar happen?
Regards
David