title: Measurement of central venous pressure from a peripheral intravenous catheter in the lower extremity.
abstract: OBJECTIVE
  The measurement of central venous pressure (CVP) is used to assess intravascular status. Although this is usually accomplished by placement of a central venous catheter (CVC), there are circumstances when placement of a CVC may be technically difficult or impossible. The current study investigates the feasibility of measuring CVP from a peripheral intravenous catheter.
  
  
  METHODS
  CVP was simultaneously measured from a CVC and from a peripheral intravenous site. The continuity of the peripheral intravenous catheter with the central venous system was evaluated by noting the change in the pressure measured from the peripheral catheter during a sustained inspiratory effort and during occlusion of the extremity (arm or leg) above the catheter.
  
  
  RESULTS
  The cohort for the study included 37 adult patients. In 8 of the 37 patients (22%), there was no increase in the peripheral venous pressure (PVP) in response to a Valsalva maneuver or occlusion of the extremity above the intravenous site. For the upper extremity intravenous sites without a PVP increase, the PVP-CVP difference was 11.2 +/- 6.2 mm Hg versus 2.7 +/- 2.2 mm Hg in the patients in whom the PVP increased with these maneuvers (P < 0.0001). For the lower extremity intravenous sites without a PVP increase, the PVP-CVP difference was 7.6 +/- 4.0 mm Hg versus 2.6 +/- 1.9 mm Hg in the patients in whom the PVP increased (P < 0.0001). No variation in the accuracy of the technique was noted, depending on the size of the intravenous cannula, its location (upper versus lower extremity), CVP value, or patient positioning (supine, prone, lateral).
  
  
  CONCLUSIONS
  Provided that the PVP increases to a sustained inspiratory breath and occlusion above the intravenous site, there is a clinically useful correlation between the PVP and the CVP.
authors.affiliation: University of Missouri School of Medicine and the Department of Anesthesiology, University of Missouri, Columbia, MO, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Cox
authors.forename: Joel O
authors.initials: JO
authors.lastname: Johnson
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Tobias
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002405:Catheterization, Central Venous / Q000379:methods*; D002496:Central Venous Pressure / Q000502:physiology*; D005260:Female; D006801:Humans; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D016684:Prone Position; D016683:Supine Position; D014636:Valsalva Maneuver / Q000502:physiology