Ultrasound Characterization of the Distal Thigh Great Saphenous Vein Dimensions in Children and Adults: Implications...

Peripheral intravenous (PIV) cannulation is the most common in-hospital procedure. In patients with difficult access, standard upper-extremity veins may be unsuitable, and alternative access sites need to be sought. The great saphenous vein (GSV) at the level of the distal medial thigh has been proposed as a potential alternative site for rescue access. Yet, the feasibility and reliability of targeting this site remain underexplored.

To assess the feasibility of ultrasound visualization and measurement of the GSV in the distal medial thigh as a reliable target for rescue PIV access.

This prospective, cross-sectional study enrolled 166 pediatric and adult emergency department participants at a tertiary academic medical center. The GSV was evaluated bilaterally using high-frequency linear ultrasound. Depth and diameter measurements were recorded at proximal, medial, and distal sites. Detection rates and vessel characteristics were compared across age, sex, comorbidity status, and history of difficult IV access.

The GSV was visualized in ≥95% of participants across all thigh regions. Median depth was greatest proximally (11.7 mm) and shortest distally (9.9 mm), while median diameter was largest proximally (3.0 mm) and smallest distally (2.8 mm). Visualization was consistent across age groups, sex, and history of difficult IV access.

The distal medial thigh GSV can be reliably visualized using ultrasound across pediatric and adult populations, including those with prior difficult intravenous access. Its consistent visualization and favorable anatomical characteristics support its potential as a rescue site for ultrasound-guided peripheral venous access in the emergency department.