The Influence of Arm Positioning on Ultrasonic Visualization of the Subclavian Vein: An Anatomical Ultrasound Study in Healthy Volunteers.

We hypothesized that placing the arm in 90° abduction, through 90° flexion and 90° external rotation, could improve ultrasound visualization of the subclavian vein. In 49 healthy volunteers, a single operator performed a view of the subclavian vein in neutral position and abduction position. A second blinded operator measured the cross-sectional area of the subclavian vein. Abduction position increased the cross-sectional area of the subclavian vein from 124 ± 46 (mean ± SD) to 162 ± 58 mm (P = 0.001). An increase of the cross-sectional area of ≥50% was observed in 41% volunteers (95% confidence interval, 27%-56%, n = 20); this technique offers an alternative approach (maybe safer) for ultrasound-guided catheterization of the subclavian vein.