If you have a pt that has chronic renal failure and you as a picc nurse have only one arm to utilize. If you have a picc line in place that the physician is wanting replaced due to lack of blood return. Cath-flo has already been used on the line and the line is still not drawing blood. Would you consider and over the wire exchange? Should you try a different site or vessel or what would be the most appropriate choice? the current picc has been in place for 2 weeks.