title: The dynamics of changing internal jugular veins diameter based on increasing head elevation angle.
abstract: BACKGROUND
  Venous outflow from the cranial cavity occurs mainly through the internal jugular vein (IJV). The increase in venous outflow through IJV is possible by head elevation. IJV collapse may indicate the reduction of blood volume in the vein and show the head elevation effectiveness.
  
  
  OBJECTIVE
  The aim of this study is to examine the impact of head elevation on IJV size.
  
  
  METHODS
  IJV ultrasound scanning in 31 healthy volunteers was carried after gradual head elevation at 15°, 30°, and 45°. Maximum and minimum IJV diameters were recorded. Mean ± standard deviation, median, range, and collapsibility index were calculated.
  
  
  RESULTS
  Thirty-one volunteers were involved (19 males), their average age was 37.0 ± 11.5 years. Increasing the head elevation angle by 15°, 30° and 45° resulted in a decrease in IJV diameter in the right and left sides in all patients. The occurrence of the vein walls collapse corresponds to the collapsibility index equal to 100%. The results showed that 100% collapsibility index was recorded in 6 patients (19%) at 15° head elevation, in 12 patients (39%) at 30°, in 11 patients (35%) at 45°. In two volunteers (6%), 100% collapsibility index was not recorded even at maximum 45° head elevation.
  
  
  CONCLUSIONS
  Ultrasound IJV scanning during gradual head elevation together with the collapsibility index calculation could be useful guidance for the venous outflow assessment. In order to prove and extend the study findings, more research is needed.
authors.affiliation: Department of General and Clinical Pharmacology, Izhevsk State Medical Academy, Izhevsk, Russia.
authors.forename: Aleksandr L
authors.initials: AL
authors.lastname: Urakov
authors.affiliation: Department of General and Clinical Pharmacology, Izhevsk State Medical Academy, Izhevsk, Russia.
authors.forename: Anton A
authors.initials: AA
authors.lastname: Kasatkin
authors.affiliation: Department of Anesthesiology and Intensive Care, Clinical Hospital, Izhevsk, Russia.
authors.forename: Anna R
authors.initials: AR
authors.lastname: Nigmatullina
keywords: Internal jugular vein; intracranial pressure; ultrasound scanning