title: Effect of Trendelenburg position on right and left internal jugular vein cross-sectional area.
abstract: BACKGROUND
  Unlike the right internal jugular vein (RIJV), there is a paucity of data regarding the effect of the Trendelenburg position on the left internal jugular vein (LIJV). The purpose of this study is to investigate the cross-sectional area (CSA) of the LIJV and RIJV and their response to the Trendelenburg position using two-dimensional ultrasound in adult subjects.
  
  
  METHODS
  This study enrolled fifty-eight patients with American Society of Anesthesiologists physical status class I-II who were undergoing general anesthesia. CSAs of both the RIJV and LIJV were measured with a two-dimensional ultrasound in the supine position and then in a 10° Trendelenburg position.
  
  
  RESULTS
  In the supine position, the transverse diameter, anteroposterior diameter, and CSA of the RIJV were significantly larger than those of the LIJV (P < 0.001). Of 58 patients, the RIJV CSA was larger than the LIJV CSA in 43 patients (74.1%), and the LIJV CSA was larger than the RIJV CSA in 15 patients (25.9%). In the Trendelenburg position, CSAs of the RIJV and LIJV increased 39.4 and 25.5%, respectively, compared with the supine position. However, RIJV changed at a rate that was significantly greater than that of the LIJV (P < 0.05). Of 58 patients, the RIJV CSA was larger than the LIJV CSA in 48 patients (82.8%), and the LIJV CSA was larger than the RIJV CSA in 10 patients (17.2%).
  
  
  CONCLUSIONS
  In supine position, the RIJV CSA was larger than the LIJV CSA. The increased CSA in the Trendelenburg position was greater in the RIJV than the LIJV.
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Jeong Gil
authors.initials: JG
authors.lastname: Lee
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Hee Bin
authors.initials: HB
authors.lastname: Park
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Hye Young
authors.initials: HY
authors.lastname: Shin
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Ju Deok
authors.initials: JD
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Soo Bong
authors.initials: SB
authors.lastname: Yu
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Doo Sik
authors.initials: DS
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Sie Jeong
authors.initials: SJ
authors.lastname: Ryu
authors.affiliation: Department of Anesthesiology and Pain Medicine, Kosin University College of Medicine, Busan, Korea.
authors.forename: Gyeong Han
authors.initials: GH
authors.lastname: Kim
keywords: Central venous catheter; Cross-sectional area; Internal jugular vein; Trendelenburg position