title: Cross-sectional area and intravascular pressure of the right internal jugular vein during anesthesia: effects of Trendelenburg position, positive intrathoracic pressure, and hepatic compression.
abstract: OBJECTIVE
  To determine changes in the cross-sectional area of the right internal jugular vein (RIJV) in response to positive intrathoracic pressure and hepatic compression in mechanically ventilated patients during general anesthesia.
  
  
  METHODS
  Prospective, nonrandomized study.
  
  
  METHODS
  A university medical center.
  
  
  METHODS
  15 ASA physical status II and III adult patients undergoing RIJV cannulation after anesthetic induction and endotracheal intubation.
  
  
  METHODS
  Patients were studied first supine and then at a 10 degrees and 20 degrees Trendelenburg tilt. The cross-sectional area of the RIJV was determined by two-dimensional ultrasound before and during 1) an end-inspiratory hold of 20 cm H2O; 2) hepatic compression for 10 seconds; and 3) both maneuvers applied simultaneously. Subsequently, the RIJV was cannulated and the intravascular pressure was measured during the same sequence of maneuvers.
  
  
  RESULTS
  In supine patients, the cross-sectional area of the RIJV significantly increased during the end-inspiratory hold, during hepatic compression, and with both maneuvers performed simultaneously (p < 0.05). With a 10 degrees Trendelenburg tilt, only both maneuvers applied simultaneously increased the cross-sectional area of the RIJV significantly, and with the 20 degrees Trendelenburg tilt, no further increase was seen. Intravascular pressure of the RIJV consistently increased with each maneuver in all positions.
  
  
  CONCLUSIONS
  Hepatic compression and positive inspiratory hold effectively dilate the RIJV in supine patients and can be used when the Trendelenburg position is not advisable or possible. Performing these maneuvers with patients in the Trendelenburg position may facilitate cannulation, possibly by making the vein less collapsible due to increased intravascular pressure.
authors.affiliation: Department of Anesthesiology, University of Florida College of Medicine, Gainesville 32610-0254, USA.
authors.forename: E B
authors.initials: EB
authors.lastname: Lobato
authors.forename: O G
authors.initials: OG
authors.lastname: Florete
authors.forename: G B
authors.initials: GB
authors.lastname: Paige
authors.forename: T E
authors.initials: TE
authors.lastname: Morey
mesh_terms: D000328:Adult; D000769:Anesthesia, Inhalation; D001794:Blood Pressure / Q000502:physiology; D002404:Catheterization; D006801:Humans; D007601:Jugular Veins / Q000033:anatomy & histology / Q000502:physiology*; D008099:Liver / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011446:Prospective Studies; D013909:Thorax / Q000502:physiology*