title: Predicting cardiac output responses to passive leg raising by a PEEP-induced increase in central venous pressure, in cardiac surgery patients.
abstract: BACKGROUND
  Changes in central venous pressure (CVP) rather than absolute values may be used to guide fluid therapy in critically ill patients undergoing mechanical ventilation. We conducted a study comparing the changes in the CVP produced by an increase in PEEP and stroke volume variation (SVV) as indicators of fluid responsiveness. Fluid responsiveness was assessed by the changes in cardiac output (CO) produced by passive leg raising (PLR).
  
  
  METHODS
  In 20 fully mechanically ventilated patients after cardiac surgery, PEEP was increased +10 cm H2O for 5 min followed by PLR. CVP, SVV, and thermodilution CO were measured before, during, and directly after the PEEP challenge and 30° PLR. The CO increase >7% upon PLR was used to define responders.
  
  
  RESULTS
  Twenty patients were included; of whom, 10 responded to PLR. The increase in CO by PLR directly related (r=0.77, P<0.001) to the increase in CVP by PEEP. PLR responsiveness was predicted by the PEEP-induced increase in CVP [area under receiver-operating characteristic (AUROC) curve 0.99, P<0.001] and by baseline SVV (AUROC 0.90, P=0.003). The AUROC's for dCVP and SVV did not differ significantly (P=0.299).
  
  
  CONCLUSIONS
  Our data in mechanically ventilated, cardiac surgery patients suggest that the newly defined parameter, PEEP-induced CVP changes, like SVV, appears to be a good parameter to predict fluid responsiveness.
authors.affiliation: Department of Anaesthesiology, Leiden University Medical Centre, Albinusdreef 2, P.O. Box 9600, 2300 RC Leiden, The Netherlands. b.f.geerts@lumc.nl
authors.forename: B F
authors.initials: BF
authors.lastname: Geerts
authors.forename: L P H J
authors.initials: LP
authors.lastname: Aarts
authors.forename: A B
authors.initials: AB
authors.lastname: Groeneveld
authors.forename: J R C
authors.initials: JR
authors.lastname: Jansen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology*; D006348:Cardiac Surgical Procedures; D002496:Central Venous Pressure / Q000502:physiology*; D003422:Critical Care / Q000379:methods; D005260:Female; D005440:Fluid Therapy / Q000379:methods; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011175:Positive-Pressure Respiration; D011182:Postoperative Care / Q000379:methods; D011187:Posture / Q000502:physiology