Effects of clinical maneuvers on sonographically determined internal jugular vein size during venous cannulation.

We sought to define variations in internal jugular vein (IJV) anatomy and the effect of recommended cannulation maneuvers on a population of ICU patients. Maneuvers that decreased IJV lumen cross-sectional area were carotid artery palpation (1.48 to 0.82 cm2, p less than .05) and advancement of the needle (1.57 to 0.75 cm2, p less than .001). The head-down (modified Trendelenburg) position increased IJV lumen cross-sectional area (1.18 to 1.62 cm2, p less than .05). There was wide variability in IJV anatomic features, although most patients had patent veins.