The Optimal Angle of Head Rotation for Internal Jugular Cannulation as Determined by Ultrasound Evaluation

Objectives: The aim of this study was to determine the degree of head rotation that creates the maximal anatomic separation between the right internal jugular vein and the carotid artery.

Design: Single-center prospective, observational cohort study.

Setting: University medical center.

Participants: Fifty patients aged>21 years and undergoing cardiac surgery.

Interventions: An ultrasound machine equipped with a digital caliper was used to determine the relational anatomy of the internal jugular vein and the carotid artery, with patients in the Trendelenburg position at head angles of -15°, 0°,+15°,+30°,+45°,+60°,+75°, and+90°.

Measurements and main results: When examining the percentage of the internal jugular vein vertical diameter that is not overlapped by the carotid artery (vertically unencumbered), there was a difference between the head angle groups (p<0.01). Unencumbered vertical distance was different between+75° versus 0°, and+75° versus+15°. At+75°, 60.3%±5.3% of the internal jugular vein was unencumbered vertically, whereas at 0°, it was 37.2%±3.9%, and at+15° it was 40.3%±3.8%. Only 72% of the patients were able to position their head at+75°, and 54% of the subjects were able to position their head at+90°.

Conclusion: The authors found the internal jugular vein becomes more vertically separated from the carotid artery at more extreme angles of contralateral head rotation.