title: Trendelenburg position, head elevation and a midline position optimize right internal jugular vein diameter.
abstract: OBJECTIVE
  The right internal jugular (RIJ) is commonly used to provide central venous access, and success of cannulation shows a positive correlation with the vein's diameter. The purpose of this study is to establish the patient position resulting in the largest RIJ diameter.
  
  
  METHODS
  2D ultrasound was used to measure RIJ diameter, in varying body positions, in 21 healthy volunteers.
  
  
  RESULTS
  In the neutral position (table flat, head on the table in midline) the RIJ diameter was (mean +/- standard deviation) 9.2 +/- 2.18 mm. A small pillow under the head increased RIJ diameter (10.6 +/- 2.16 mm, P < 0.001). Trendelenburg tilt of 15 degrees increased RIJ diameter (12.1 +/- 2.34 mm, P < 0.001). In the Trendelenburg position (15 degrees of tilt), a small pillow under the head further increased RIJ diameter (13.3 +/- 2.26, mm P < 0.001), palpating for the carotid artery decreased RIJ diameter (8.2 +/- 1.98 mm, P < 0.001), and rotation of the head 45 degrees to the left did not reduce RIJ diameter significantly (11.7 +/- 2.52 mm, P = 0.12).
  
  
  CONCLUSIONS
  The patient position to achieve maximal RIJ diameter cannulation is: 15 degrees of Trendelenburg tilt; a small pillow or head ring under the head; the head in or close to midline; and after palpation of the carotid artery, it should be released prior to vein cannulation.
authors.affiliation: Department of Anesthesia, University of British Columbia, Vancouver, British Columbia, Canada. garethandantonia@ntlword.com
authors.forename: Gareth
authors.initials: G
authors.lastname: Parry
mesh_terms: D006257:Head / Q000502:physiology*; D018475:Head-Down Tilt / Q000502:physiology*; D006801:Humans; D007601:Jugular Veins / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011187:Posture / Q000502:physiology*; D012016:Reference Values; D014463:Ultrasonography; D014654:Vascular Patency / Q000502:physiology*