title: Assessment of fluid responsiveness in mechanically ventilated cardiac surgical patients.
abstract: OBJECTIVE
  Accurate assessment of preload responsiveness is an important goal of the clinician to avoid deleterious volume replacement associated with increased morbidity and mortality in mechanically ventilated patients. This study was designed to evaluate the accuracy of simultaneously assessed stroke volume variation and pulse pressure variation using an improved algorithm for pulse contour analysis (PiCCO plus, V 5.2.2), compared to the respiratory changes in transoesophageal echo-derived aortic blood velocity (deltaVpeak), intrathoracic blood volume index, central venous pressure and pulmonary capillary wedge pressure to predict the response of stroke volume index to volume replacement in normoventilated cardiac surgical patients.
  
  
  METHODS
  We studied 20 patients undergoing elective coronary artery bypass grafting. After induction of anaesthesia, haemodynamic measurements were performed before and after volume replacement by infusion of 6% hydroxyethyl starch 200/0.5 (7 mL kg(-1) ) with a rate of 1 mL kg(-1) min(-1).
  
  
  RESULTS
  Baseline stroke volume variation correlated significantly with changes in stroke volume index (deltaSVI) (r2 = 0.66; P < 0.05) as did baseline pulse pressure variation (r2 = 0.65; P < 0.05), whereas baseline values of deltaVpeak, intrathoracic blood volume index, central venous pressure and pulmonary artery wedge pressure showed no correlation to deltaSVI. Pulse contour analysis underestimated the volume-induced increase in cardiac index measured by transpulmonary thermodilution (P < 0.05).
  
  
  CONCLUSIONS
  The results of our study suggest that stroke volume variation and its surrogate pulse pressure variation derived from pulse contour analysis using an improved algorithm can serve as indicators of fluid responsiveness in normoventilated cardiac surgical patients. Whenever changes in systemic vascular resistance are expected, the PiCCO plus system should be recalibrated.
authors.affiliation: University Hospital of Regensburg, Department of Anaesthesiology, Regensburg, Germany. christoph.wiesenack@klinik.uni-regensburg.de
authors.forename: C
authors.initials: C
authors.lastname: Wiesenack
authors.forename: C
authors.initials: C
authors.lastname: Fiegl
authors.forename: A
authors.initials: A
authors.lastname: Keyser
authors.forename: C
authors.initials: C
authors.lastname: Prasser
authors.forename: C
authors.initials: C
authors.lastname: Keyl
mesh_terms: D000368:Aged; D000465:Algorithms; D001011:Aorta / Q000502:physiology; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D002496:Central Venous Pressure / Q000502:physiology; D001026:Coronary Artery Bypass; D017548:Echocardiography, Transesophageal; D005260:Female; D006801:Humans; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage / Q000627:therapeutic use; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D010952:Plasma Substitutes / Q000008:administration & dosage / Q000627:therapeutic use*; D011669:Pulmonary Wedge Pressure / Q000502:physiology; D012119:Respiration; D012121:Respiration, Artificial; D013318:Stroke Volume / Q000502:physiology*; D013815:Thermodilution
chemical_list: D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes