The Effect of Head Position on the Cross-Sectional Area of the Subclavian Vein.

In 41 healthy volunteers, we investigated the cross-sectional area (CSA) of the subclavian vein (SCV) in the following head positions: neutral and 30° head rotation toward the contralateral or ipsilateral sides. Significant differences were observed in the CSA of the SCV at 3 different head positions: contralateral 30° versus neutral, -0.05 cm (95% confidence interval, -0.08 to -0.03); contralateral 30° versus ipsilateral 30°, -0.15 cm (-0.19 to -0.12); neutral versus ipsilateral 30°, -0.10 cm (-0.13 to -0.07); all Pcorrected< .001). For SCV catheterization, 30° head rotation to the ipsilateral side provided significant improvements in the CSA compared with the other head positions.