The position of patients for safe central venous catheterization via the internal jugular vein: prospective observational study of critically ill patients

Patients and methods Eight positions were tested in each patient. The positions were classified by maneuver and ultrasound images of each position were stored. Two factors were determined at each position: “safety width” (the part of the internal jugular vein that did not overlap with the carotid artery) and “overlap width” (the part of the internal jugular vein that did overlap with the carotid artery).