Comparison of internal jugular vein dilation between Valsalva maneuver and proximal internal jugular vein compression

The Valsalva maneuver is recognized as an effective method to dilate the internal jugular vein (IJV). However, this maneuver cannot be performed in many cases, such as children and unconscious patients. The aim of this study was to evaluate the effectiveness of proximal IJV compression, which can easily be performed, regardless of patient cooperation.

Healthy adult volunteers were recruited from tertiary hospital employees. Basic anatomic and physiologic data were collected. The subjects lay down as if they were undergoing IJV catheter insertion, in the supine position with their necks turned 30 degrees to the left. The main outcome was the cross-sectional area (CSA) of the distal IJV as measured by ultrasound in four stages. The first stage was sham without any maneuver. The second was Valsalva maneuver, the third was digital IJV compression, and the fourth was digital compression accompanied by simultaneous Valsalva maneuver.

A total of 41 volunteers were enrolled. Twenty-six (63.41%) were male with an average age of 28.15±2.85 years. Mean height was 170.74±8.66 cm and mean neck circumference was 35.28±3.87 cm. The mean CSA-IJV was 1.06±0.36 cm² without any maneuver. It increased to 1.34±0.45 cm² with Valsalva maneuver (P<0.001), to 1.26±0.41 cm² with digital compression (P<0.001), and to 1.41±0.47 cm² with the two maneuvers combined (P=0.01).

Digital proximal IJV compression effectively dilates the distal IJV. When performed simultaneously with the Valsalva maneuver, the effect was enhanced.