Objective: To compare the cross-sectional area (CSA) of the right internal jugular vein (RIJV) with the left internal jugular vein (LIJV) using two-dimensional ultrasound and to measure the response to the Valsalva maneuver in both the supine and Trendelenburg positions.
Design: Prospective and randomized.
Setting: University-affiliated hospital.
Participants: Fifty healthy adult volunteers.
Interventions: The CSA of both the RIJV and LIJV was measured with a 5-MHz, two-dimensional surface transducer before and during a 10-second Valsalva maneuver with the subjects in the supine position, and then with the subjects in a 10 degree Trendelenburg tilt.
Measurements and main results: After the baseline measurements were performed, the subjects were divided into two groups based on the CSA of the RIJV and LIJV. Group 1 had an LIJV CSA equal to or greater than that of the RIJV (n = 10) and group 2 had an LIJV CSA less than that of the RIJV (n = 40). Of the latter 40 patients, 17 (34%) had an LIJV CSA less than 50% of that of the RIJV. In both groups, the CSA of both veins increased significantly with the Valsalva maneuver, Trendelenburg tilt, and both maneuvers combined.
Conclusion: The findings suggest that in one third of adults (34%), the LIJV is significantly smaller compared with the RIJV and, combined with operator inexperience, may influence the success rate and risk for complications. Thus, the use of ultrasound and maneuvers that increase CSA is suggested during LIJV cannulation.