Assessment of head and neck position for optimal ultrasonographic visualisation of the internal jugular vein and its relation to the common carotid artery: A prospective observational study.

Background And Aims: There is a wide variation in the anatomical relationship of the Internal Jugular Vein (IJV) to the Common Carotid Artery (CCA). This makes landmark based techniques of IJV cannulation and head rotation questionable and may lead to accidental arterial puncture. We conducted this study to determine the anatomical relation of the IJV to the CCA using (USG) in patients undergoing IJV cannulation for central venous access, and to analyse the effect of head rotation on this relationship.

Material And Methods: A prospective observational study was conducted on 100 patients requiring central venous access, in the operation theatre or the intensive care unit. Anatomical relationship of the IJV to CCA at the level of the cricoid cartilage was analysed by noting the segment position (1-12) around the CCA using a high frequency linear USG probe on patients in neutral head position, on both sides and also with the head rotated to the contra lateral side by 15° and 45°.

Results: Antero-lateral segments 1 and 2 were the most common positions (50% on the right and 73% on the left side). Change in segment causing increase in overlap of IJV and CCA with 15° head rotation was seen in 44% subjects on the right and 39% on the left. Statistically, a higher number of subjects showed overlap with 45° rotation (99% on right and 97% on left, < 0.05).

Conclusion: There is a wide variation in anatomical location of the IJV in relation to the CCA as seen by USG. Excessive head rotation causes overlap of IJV over CCA which may cause inadvertent arterial puncture, even under USG guidance. Thus, it is preferable to cannulate the IJV in neutral or near neutral head and neck position.