1. Recommendations for Catheter-to-Vein Ratio
Catheter Size*
Minimum Vein Diameter (without tourniquet)
Catheter-to-vein ratio < 45% 1,2
2 x’s the
catheter size 3
3 x’s the
catheter size 4,5
3 FR / 20 g
2.1 mm
2 mm
3 mm
4 FR / 18 g
2.7 mm
2.6 mm
4 mm
5 FR / 16 g
3.5 mm
3.3 mm
5 mm
6 FR / 14 g**
4.2 mm
6 mm
1 Infusion Nurses Society (2016) Infusion Therapy Standards of Practice. Jour of Infusion Nurs. 39(1S):S112.
2Sharp, R., et al. (2015) The catheter to vein ratio and rates of symptomatic thromboembolism in patients with a PICC: a prospective cohort study. International Jour of Nurs Studies
3 Meyers, B.M. (2011) Managing Peripherally Inserted Central Catheter Thrombosis Risk: A Guide for Clinical Best Practice. JAVA. 16(3):
4 Pittiruti, M. (2015) What the world needs now is an insertion bundle to prevent catheter-related thrombosis. Presented at the 29th AVA Scientific Meeting, Dallas, TX.
5Nolan, M.E., et al. (2016) Complication rates among peripherally inserted central venous catheters and centrally inserted central catheters in the medical intensive care unit. Jour of Critical Care.
*Use smallest size catheter and fewest number of lumens to accommodate therapy.
**The use of 6 FR PICCs have shown to significantly increase the risk of venous thrombosis.