title: Bedside ultrasonographic measurement of the inferior vena cava fails to predict fluid responsiveness in the first 6 hours after cardiac surgery: a prospective case series observational study.
abstract: OBJECTIVE
  To assess validity of respiratory variation of inferior vena cava (IVC) diameter to predict fluid responsiveness and guide fluid therapy in mechanically ventilated patients during the first 6 hours after elective cardiac surgery.
  
  
  METHODS
  Prospective observational case series study.
  
  
  METHODS
  Single-center hospital.
  
  
  METHODS
  50 consecutive patients undergoing elective cardiac surgery.
  
  
  METHODS
  Transthoracic bedside echocardiography.
  
  
  RESULTS
  Parameters derived from ultrasonographic assessment of the IVC diameter (collapsibility index [CI], distensibility index [DI], and IVC/aorta index). In the whole study group, change in fluid balance correlated with change in IVC maximum diameter (p = 0.034, r = 0.176). IVC-CI and IVC-DI correlated with IVC/aorta index. A weak correlation between central venous pressure (CVP) and IVC-derived parameters (IVC-CI and IVC-DI) was noticed. Despite statistical significance (p<0.05), all observed correlations expressed low statistical power (r<0.21). There were no statistically significant differences between fluid responders and nonresponders in relation to clinical parameters, CVP, ultrasound IVC measurement, and IVC-derived indices.
  
  
  CONCLUSIONS
  Dynamic IVC-derived parameters (IVC-CI, IVC-DI, and IVC/aorta index) and CVP are not reliable predictors of fluid responsiveness in the first 6 hours after cardiac surgery. Complexity of physiologic factors modulating cardiac performance in this group may be responsible for the difficulty in finding a plausible monitoring tool for fluid guidance. Bedside ultrasonographic measurement of IVC is unable to predict fluid responsiveness in the first 6 hours after cardiac surgery.
authors.affiliation: Department of Interventional Cardiology, John Paul II Hospital, Krakow, Poland. Electronic address: dorotasobczyk@yahoo.com.
authors.forename: Dorota
authors.initials: D
authors.lastname: Sobczyk
authors.affiliation: Department of Interventional Cardiology, John Paul II Hospital, Krakow, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Nycz
authors.affiliation: the 2nd Department of Anaesthesiology and Intensive Care, Warsaw Medical University, Warsaw, Poland.
authors.forename: Pawel
authors.initials: P
authors.lastname: Andruszkiewicz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006348:Cardiac Surgical Procedures / Q000379:methods* / Q000639:trends; D004452:Echocardiography / Q000379:methods* / Q000639:trends; D005260:Female; D005440:Fluid Therapy / Q000379:methods* / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D000067716:Point-of-Care Testing / Q000639:trends; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013997:Time Factors; D014682:Vena Cava, Inferior / Q000000981:diagnostic imaging* / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000502:physiology
keywords: cardiac surgery; fluid responsiveness; inferior vena cava; ultrasound-guided fluid therapy