Ultrasound Assessment of Right Internal Jugular Vein Diameter: Effects of the Trendelenburg Position, Passive Leg Raising, and the Valsalva Maneuver

Summary: Which position best enlarges the jugular vein? A comparative study found the Valsalva maneuver had the largest effect; leg raising may substitute for head-down tilt. #Anesthesia #VascularAccess

Nazemroaya B ; Honarmand A ; Aslani P
Source: Tehran University Medical Journal Published:2026

Abstract

Background: Central venous catheterization is a common procedure in anesthesia and critical care. Enlargement of the right internal jugular vein may facilitate safer venous access, especially when ultrasound-guided puncture is planned. This study compared the effects of the Trendelenburg position, passive leg raising, and the Valsalva maneuver on ultrasonographic right internal jugular vein diameter. Methods: This prospective, within-subject, data-analyst-blinded clinical trial included 90 adults aged 18-65 years with American Society of Anesthesiologists physical status I who were scheduled for elective surgery. Right internal jugular vein diameter was measured at the level of the cricoid cartilage using a 12-MHz linear ultrasound probe. Measurements were obtained at baseline and during three randomized conditions: Trendelenburg position at 10-15 degrees, passive leg raising with both legs elevated approximately 30 degrees, and the Valsalva maneuver at 20 cmH2O for 15 seconds. A washout interval was used between conditions. Data were analyzed using the Friedman test for repeated comparisons, Wilcoxon signed-rank tests with Bonferroni adjustment for pairwise analyses, and linear regression to assess the association between body mass index and venous response. Results: The participants had a mean age of 43.2±16.2 years, and 48 patients (53.3%) were male. Mean body mass index was 24.8±4.8 kg/m2. The mean right internal jugular vein diameter increased from 1.13±0.33 cm at baseline to 1.32±0.39 cm in the Trendelenburg position, 1.27±0.37 cm during passive leg raising, and 1.46±0.36 cm during the Valsalva maneuver. The overall difference among conditions was statistically significant (P<0.001). Pairwise comparisons showed that the Valsalva maneuver produced a significantly greater increase in diameter than both Trendelenburg and passive leg raising (both P<0.001), whereas Trendelenburg and passive leg raising did not differ significantly after correction. Body mass index was positively correlated with the response to the Valsalva maneuver (r=0.34, P=0.001). Conclusion: The Valsalva maneuver produced the greatest increase in right internal jugular vein diameter. Passive leg raising showed an effect comparable to Trendelenburg positioning and may be a practical alternative when Trendelenburg positioning is undesirable or contraindicated. © 2026 Nazemroaya et al. Published by Tehran University of Medical Sciences. This work is licensed under a Creative Commons Attribution-Non-Commercial 4.0 International license (https://creativecommons.org/licenses/by-nc/4.0/). Non-commercial uses of the work are permitted, provided the original work is properly cited.