Effects of combined the trendelenburg and passive leg raising positions on the cross-sectional area of the right internal jugular vein

Objective: The primary aim of this study was to assess the effects of a combination of the passive leg raising (PLR) and Trendelenburg positions on the cross-sectional area (CSA) of the right internal jugular vein (RIJV) using ultrasound measurement in awake patients. Methods: This prospective observational cross-over study measured the CSA of RIJV in patients in supine (Supine-I), Trendelenburg, Trendelenburg with passive leg raising (T + PLR position), and repeated supine position (Supine-II). The CSA and vertical and horizontal diameters of the RIJVs were compared before and after each position. Results: A total of 120 adult patients were enrolled in the study. The mean CSA of the RIJV significantly increased from 91.2 ± 31.7 mm2 to 110.4 ± 38.2 mm2 in the Trendelenburg position compared to the supine position (P < 0.05). However, there were no statistically significant differences in CSA were observed between the Trendelenburg and Trendelenburg + PLR positions. Conclusion: Although the PLR + Trendelenburg position increased the jugular vein diameter relative to the supine position, its clinical usefulness is limited as this increase was still lower than that achieved with the Trendelenburg position alone.