title: Estimation of central venous pressure by ultrasound.
abstract: BACKGROUND
  Increasing blood volume and cardiac output is one of the most commonly needed intervention in the primary care of traumatized and severely ill patients. Although cardiac filling pressures have severe limitations in assessing the preload, central venous pressure (CVP) is the invasive measure most frequently used in clinical practice for the assessment of volume status and cardiac preload. We combined ultrasound and tissue pressure measurement for non-invasive jugular and brachial venous pressure estimation.
  
  
  METHODS
  CVP was measured invasively and non-invasively using the new technique in 32 critically ill patients. In six volunteers, increasing PEEP was used for the assessment of changes in non-invasive CVP.
  
  
  RESULTS
  Non-invasive CVP increased linearly with increasing PEEP, independent of the investigator. Median (range) coefficient of variation (CV) for five consecutive measurements performed by three investigators in volunteers was 15% (6-31%), 14% (4-31%), and 21% (8-42%). Absolute differences between the average non-invasive CVP between investigators was 1.7 cm H2O (0.4-6.6 cm H2O), and the inter-examiner CVP was high (182%, 40-415%). In patients, invasive CVP was 10 mmHg (5-18 mmHg), and the corresponding non-invasive venous pressures were 8 mmHg (3-14 mmHg, basilic vein, p<0.01) and 6 mmHg (3-13 mmHg, jugular vein, p<0.01). The coefficients of variation were 4% (<1%-64%, invasive CVP), 22% (5%-51%, non-invasive basilic vein pressure), and 17% (7%-34%, non-invasive jugular vein pressure).
  
  
  CONCLUSIONS
  Ultrasound-based, non-invasive measurement of venous pressure provides a relatively easy method rapid estimation of changes in CVP, although absolute values may differ substantially from invasive CVP and between different investigators.
authors.affiliation: Department of Internal Medicine, Regional Hospital, 3110 Münsingen, Switzerland.
authors.forename: Ulrich A
authors.initials: UA
authors.lastname: Baumann
authors.forename: Claudia
authors.initials: C
authors.lastname: Marquis
authors.forename: Christoforos
authors.initials: C
authors.lastname: Stoupis
authors.forename: Thorsten Andreas
authors.initials: TA
authors.lastname: Willenberg
authors.forename: Jukka
authors.initials: J
authors.lastname: Takala
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Jakob
mesh_terms: D000328:Adult; D000368:Aged; D002496:Central Venous Pressure / Q000502:physiology*; D005260:Female; D006801:Humans; D007601:Jugular Veins / Q000000981:diagnostic imaging* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional / Q000379:methods* / Q000706:statistics & numerical data