Q: Which of the following cause frequent clotting (access failure) in Continuous Renal Replacement Therapy (CRRT)? 

A) high venous pressures 
B) length and inner diameter of the catheter 
C) CRRT via side holes of catheter 
D) curvy route (like subclavian access) 
E) high abdominal or thoracic pressure 
F) very negative thoracic pressures
G) All of the above 



 Answer: G

Objective of above question is to highlight various reasons which may cause issue with patency of catheter. Some of them are well know, and some of them are under appreciated.


References:

1. Unger JK, Haltern C, Portz B, Dohmen B, Gressner A, Rossaint R. Relation of haemofilter type to venous catheter resistance is crucial for filtration performance and haemocompatibility in CVVH – an in vitro study. Nephrol Dial Transplant. 2006;21:2191–2201. 

2. Jean G, Chazot C, Vanel T, Charra B, Terrat JC, Calemard E, Laurent G. Central venous catheters for haemodialysis: looking for optimal blood flow. Nephrol Dial Transplant. 1997;12:1689–1691. 

3. Mandolfo S, Borlandelli S, Ravani P, Imbasciati E. How to improve dialysis adequacy in patients with vascular access problems. J Vasc Access. 2006;7:53–59.