I am helping to rewrite some of our hospital policies on dialysis catheters and need some advice from experienced dialysis staff, please. Question: has it become standard procedure to overfill catheters, or do most units fill exactly to the volume printed on the catheters? How much should the overfill be? Do most units use 5000 units/ml, and do most units draw up one ml of the 5000 units and for the rest of the volume draw up normal saline? Are there any studies out there comparing overfill to exact fill? Any help with these questions is very greatly appreciated. Thank you!