BACKGROUND: This study evaluated the position and relationship between the right internal jugular vein (IJV) and the surrounding external landmarks using ultrasonography.

METHODS: Fifty-four patients undergoing central vein access for cardiac surgery were enrolled in this study. The IJV, carotid artery (CA) and sternocleidomastoid muscle (SCM) at the cricoid cartilage level in 15° trendelenburg position with 30° head rotation were examined using a two dimensional ultrasound transducer of a TEE machine. Images of the vessels and the demographic data of the patients were recorded and analysed.

RESULTS: At the level of the cricoid cartilage, the position of the right IJV was medial to middle of the clavicular head of the SCM muscle in 26 cases (48.2%), lateral in 11 cases (20.4%) and just above the middle of clavicular head of the SCM muscle in 17 cases (31.5%). In 43 patients (79.6%), the IJV overlapped the CA anterolaterlly < 5 mm, and these cases were regarded as normal. Ten patients (18.5%) had a medially positioned IJV overlapping the CA more than 5 mm and the IJV was positioned lateral to CA in 1 (2%) patient. The mean ratio of the overlapped diameter and the diameter of the CA was 33.6% and the overlapping ratios were greater than 50% in 10 patients (31.4%). The mean skin-to-vein distance at the angle of 30° was 1.82 cm.

CONCLUSIONS: In 18.5% of patients positioned in the 15° Trendelenburg position, with their head turned to the left 30°, the IJV overlapped the CA medially more than 5 mm, which increased the risk of a carotid puncture using the blind technique.