PIVC Sizing: Catheter-to-Vein Ratio and Failure Risk

Study Overview
This single-centre prospective cohort study examined how the catheter-to-vein ratio (CVR) relates to peripheral IV catheter (PIVC) failure. The authors highlight that a large share of PIVCs fail before treatment completion and that many failures stem from placing relatively large catheters into small-diameter peripheral veins—especially in the hand and wrist. Ultrasound assessment and careful vein/size matching were central themes in the study’s rationale.

Key Findings

• Vein size matters: Common peripheral veins—particularly in the hand/wrist—are narrow (often ~1.8-2.3 mm), so oversizing the catheter relative to the vein increases mechanical stress and the risk of complications and failure. 
• Failure is common: A substantial proportion of PIVCs fail prior to completing therapy, underscoring the need to optimize selection and placement (including matching gauge to vessel size). 
• Contextual factors influence risk: Prior vessel damage, anatomical variation, and patient factors (e.g., sex differences in hand-vein diameter) affect safe sizing decisions. 

Implications

• Aim for a lower CVR: Choose the smallest gauge that meets clinical needs and a vein large enough to accommodate it.
• Favour larger, straighter vessels: When possible, select forearm veins over hand/wrist sites to reduce mechanical irritation.
• Use ultrasound when in doubt: Imaging can verify vein diameter and help avoid high CVR placements.
• Embed checks in workflow: Add prompts (e.g., “measure/estimate vein size ? choose gauge”) to insertion guides, audits, and training.
• Escalate early: If a suitable CVR cannot be achieved for the intended therapy, consider alternative devices (e.g., midline/PICC).

Read More:https://www.bjanaesthesia.org/article/S0007-0912(25)00465-9/abstract 

Authors: Nicole Marsh; Emily N. Larsen; Catherine O’Brien; Emily R. Young;  Hannah Peach;  Amanda Corley; Amanda J. Ullman; Samantha Keogh; Claire M. Rickard; Andrew Bulmer; Robert S. Ware