title: Pulse pressure variation predicts fluid responsiveness following coronary artery bypass surgery.
abstract: OBJECTIVE
  To determine whether the degree of pulse pressure variation (PPV) and systolic pressure variation (SPV) predict an increase in cardiac output (CO) in response to volume challenge in postoperative patients who have undergone coronary artery bypass grafting (CABG), and to determine whether PPV is superior to SPV in this setting.
  
  
  METHODS
  This was a prospective clinical study conducted in the cardiovascular ICU of a university hospital.
  
  
  METHODS
  Twenty-one patients were studied immediately after arrival in the ICU following CABG.
  
  
  METHODS
  A fluid bolus was administered to all patients.
  
  
  METHODS
  Hemodynamic measurements, including central venous pressure (CVP), pulmonary artery occlusion pressure (PAOP), CO (thermodilution), percentage of SPV (%SPV), and percentage of PPV (%PPV), were performed shortly after patient arrival in the ICU. Patients were given a rapid 500-mL fluid challenge, after which hemodynamic measurements were repeated. Patients whose CO increased by >/= 12% were considered to be fluid responders. The ability of different parameters to distinguish between responders and nonresponders was compared.
  
  
  RESULTS
  In response to the volume challenge, 6 patients were responders and 15 were nonresponders. Baseline CVP and PAOP were no different between these two groups. In contrast, the %SPV and the %PPV were significantly higher in responders than in nonresponders. Receiver operating characteristic curve analysis suggested that the %PPV was the best predictor of fluid responsiveness. The ideal %PPV threshold for distinguishing responders from nonresponders was found to be 11. A PPV value of >/= 11% predicted an increase in CO with 100% sensitivity and 93% specificity.
  
  
  CONCLUSIONS
  PPV and SPV can be used to predict whether or not volume expansion will increase CO in postoperative CABG patients. PPV was superior to SPV at predicting fluid responsiveness. Both of these measures were far superior to CVP and PAOP.
authors.affiliation: Intensive Care Unit, Brandon Regional Health Center, 150 McTavish Ave East, Brandon, MB, R7A 2B3 Canada. atkramer@mts.net
authors.forename: Andreas
authors.initials: A
authors.lastname: Kramer
authors.forename: David
authors.initials: D
authors.lastname: Zygun
authors.forename: Harvey
authors.initials: H
authors.lastname: Hawes
authors.forename: Paul
authors.initials: P
authors.lastname: Easton
authors.forename: Andre
authors.initials: A
authors.lastname: Ferland
mesh_terms: D001794:Blood Pressure; D001810:Blood Volume; D001026:Coronary Artery Bypass; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010952:Plasma Substitutes / Q000008:administration & dosage*; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011446:Prospective Studies
chemical_list: D010952:Plasma Substitutes