title: Is venous congestion associated with reduced cerebral oxygenation and worse neurological outcome after cardiac arrest?
abstract: BACKGROUND
  Post-cardiac arrest (CA) patients are at risk of secondary ischemic damage in the case of suboptimal brain oxygenation during an ICU stay. We hypothesized that elevated central venous pressures (CVP) would impair cerebral perfusion and oxygenation (venous cerebral congestion). The aim of the present study was to investigate the relationship between CVP, cerebral tissue oxygen saturation (SctO2) as assessed with near-infrared spectroscopy (NIRS) and outcome in post-CA patients.
  
  
  METHODS
  This was an observational study in 48 post-CA patients with continuous CVP and SctO2 monitoring during therapeutic hypothermia.
  
  
  RESULTS
  The relationship between CVP and mean SctO2 was best described by an S-shaped, third-degree polynomial regression curve (SctO2 = -0.002 × CVP(3) + 0.08 × CVP(2) - 1.07 × CVP + 69.78 %, R (2) 0.89, n = 1,949,108 data points) with high CVP (>20 mmHg) being associated with cerebral desaturation. Multivariate linear regression revealed CVP to be a more important determinant of SctO2 than mean arterial pressure (MAP) without important interaction between both (SctO2 = 0.01 × MAP - 0.20 × CVP + 0.001 × MAP × CVP + 65.55 %). CVP and cardiac output were independent determinants of SctO2 with some interaction between both (SctO2 = 1.86 × CO - 0.09 × CVP - 0.05 × CO × CVP + 60.04 %). Logistic regression revealed that a higher percentage of time with CVP above 5 mmHg was associated with lower chance of survival with a good neurological outcome (cerebral performance category (CPC) 1-2) at 180 days (OR 0.96, 95 % CI 0.92-1.00, p = 0.04). In a multivariate model, the negative association between CVP and outcome persisted after correction for hemodynamic variables, including ejection fraction and MAP.
  
  
  CONCLUSIONS
  Elevated CVP results in lower brain saturation and is associated with worse outcome in post-CA patients. This pilot study provides support that venous cerebral congestion as indicated by high CVP may be detrimental for post-CA patients.
authors.affiliation: Department of Cardiology, Ziekenhuis Oost-Limburg, Schiepse Bos, 3600, Genk, Belgium. Koen.ameloot@zol.be.
authors.forename: Koen
authors.initials: K
authors.lastname: Ameloot
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Cornelia
authors.initials: C
authors.lastname: Genbrugge
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Meex
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Ward
authors.initials: W
authors.lastname: Eertmans
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Frank
authors.initials: F
authors.lastname: Jans
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Ziekenhuis Oost-Limburg, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Cathy
authors.initials: C
authors.lastname: De Deyne
authors.affiliation: Department of Cardiology, Ziekenhuis Oost-Limburg, Schiepse Bos, 3600, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Joseph
authors.initials: J
authors.lastname: Dens
authors.affiliation: Department of Cardiology, Ziekenhuis Oost-Limburg, Schiepse Bos, 3600, Genk, Belgium.|Faculty of Medicine and Life Sciences, University Hasselt, Diepenbeek, Belgium.
authors.forename: Wilfried
authors.initials: W
authors.lastname: Mullens
authors.affiliation: Department of Cardiology, Ziekenhuis Oost-Limburg, Schiepse Bos, 3600, Genk, Belgium.
authors.forename: Bert
authors.initials: B
authors.lastname: Ferdinande
authors.affiliation: Department of Cardiology, Ziekenhuis Oost-Limburg, Schiepse Bos, 3600, Genk, Belgium.
authors.forename: Matthias
authors.initials: M
authors.lastname: Dupont
mesh_terms: D000368:Aged; D002496:Central Venous Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006323:Heart Arrest / Q000401:mortality* / Q000628:therapy; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D007036:Hypothermia, Induced / Q000706:statistics & numerical data; D002534:Hypoxia, Brain / Q000401:mortality / Q000517:prevention & control; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D009026:Mortality; D016896:Treatment Outcome
keywords: Central venous pressure; Cerebral perfusion; Outcome; Post-cardiac arrest