title: The influence of PEEP and positioning on central venous pressure and venous hepatic hemodynamics in patients undergoing liver resection.
abstract: OBJECTIVE
  In order to assess the occurrence of blood congestion in the liver during liver resection, we aimed to evaluate the influence of a positive-end-expiratory-pressure (PEEP) and positioning of patients on central venous pressure (CVP) and venous hepatic blood flow parameters. We further analyzed correlations between CVP and venous hepatic blood flow parameters.
  
  
  METHODS
  In 20 patients scheduled for elective liver resection we measured CVP and quantified venous hepatic hemodynamics by ultrasound assessment of flow-velocity and diameter of the right hepatic vein and the portal vein after equilibration following these maneuvers: M1: 0° supine position, PEEP 0 cmH2O; M2: 0° supine position, PEEP 10 cmH2O; M3: 20° reverse-trendelenburg position; PEEP 10 cmH2O; M4: 20° reverse-trendelenburg position, PEEP 0cmH2O.
  
  
  RESULTS
  Changing from supine to reverse-trendelenburg position led to a significant decrease in CVP (M3 5.95 ± 2.06 vs. M1 7.35 ± 2.18 mmHg and M2 8.55 ± 1.79 mmHg). A PEEP of 10 cmH2O and reverse-trendelenburg position led to significant reduction of systolic (VsHV) and diastolic (VdHV) flow-velocities of the right hepatic vein (VsHVM3 19.96 ± 6.47 vs. M1 27.81 ± 11.03 cm s-1;VdHVM3 14.94 ± 6.22 vs. M1 20.15 ± 10.34 cm s-1and M2 20.19 ± 13.19 cm s-1) whereas no significant changes of flow-velocity occurred in the portal vein. No correlations between CVP and diameters or flow-velocities of the right hepatic and the portal vein were found.
  
  
  CONCLUSIONS
  Changes of central venous pressure due to changes of PEEP and positioning were not correlated with changes of venous hepatic blood flow parameters as measured after equilibration. Strategies aiming for low central venous pressure cannot be supported by these results. However, before ruling out low-CVP-strategies during liver resections these results should be confirmed by further studies.
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany.
authors.forename: Asi
authors.initials: A
authors.lastname: Ukere
authors.affiliation: Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Meisner
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany.
authors.forename: Gillis
authors.initials: G
authors.lastname: Greiwe
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Opitz
authors.affiliation: Department of Internal Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Benten
authors.affiliation: Department of Hepatobiliary Surgery and Visceral Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Nashan
authors.affiliation: Department of Hepatobiliary Surgery and Visceral Transplantation, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Fischer
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany.
authors.forename: Constantin J C
authors.initials: CJC
authors.lastname: Trepte
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany.
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Reuter
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany.
authors.forename: Sebastian A
authors.initials: SA
authors.lastname: Haas
authors.affiliation: Department of Anesthesiology, Center of Anesthesiology and Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 22087, Hamburg, Germany. c.behem@uke.de.
authors.forename: Christoph R
authors.initials: CR
authors.lastname: Behem
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001795:Blood Pressure Determination; D002496:Central Venous Pressure; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006503:Hepatic Veins / Q000503:physiopathology / Q000601:surgery; D006801:Humans; D008099:Liver / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011169:Portal Vein / Q000601:surgery; D011175:Positive-Pressure Respiration; D011446:Prospective Studies; D014463:Ultrasonography
keywords: CVP; Flow-velocities; Liver resection; Positioning; Venous hepatic blood flow parameters