title: Renal Doppler Resistive Index as a Marker of Oxygen Supply and Demand Mismatch in Postoperative Cardiac Surgery Patients.
abstract: OBJECTIVE
  Renal Doppler resistive index (RDRI) is a noninvasive index considered to reflect renal vascular perfusion. The aim of this study was to identify the independent hemodynamic determinants of RDRI in mechanically ventilated patients after cardiac surgery.
  
  
  METHODS
  RDRI was determined in 61 patients by color and pulse Doppler ultrasonography of the interlobar renal arteries. Intermittent thermodilution cardiac output measurements were obtained and blood samples taken from the tip of pulmonary artery catheter to measure hemodynamics and mixed venous oxygen saturation (SvO2).
  
  
  RESULTS
  By univariate analysis, RDRI was significantly correlated with SvO2, oxygen extraction ratio, left ventricular stroke work index, and cardiac index, but not heart rate, central venous pressure, mean artery pressure, pulmonary capillary wedge pressure, systemic vascular resistance index, oxygen delivery index, oxygen consumption index, arterial lactate concentration, and age. However, by multivariate analysis RDRI was significantly correlated with SvO2 only.
  
  
  CONCLUSIONS
  The present data suggests that, in mechanically ventilated patients after cardiac surgery, RDRI increases proportionally to the decrease in SvO2, thus reflecting an early vascular response to tissue hypoxia.
authors.affiliation: Anaesthesia and Intensive Care Unit, E. O. Ospedali Galliera, 16128 Genoa, Italy ; Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Corradi
authors.affiliation: Department of Internal Medicine and Medical Specialties, University of Genoa, 16132 Genoa, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Brusasco
authors.affiliation: Radiology Department, E. O. Ospedali Galliera, 16128 Genoa, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Paparo
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Tullio
authors.initials: T
authors.lastname: Manca
authors.affiliation: Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, 16132 Genoa, Italy.
authors.forename: Gregorio
authors.initials: G
authors.lastname: Santori
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Benassi
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Molardi
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Alan
authors.initials: A
authors.lastname: Gallingani
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ramelli
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Tiziano
authors.initials: T
authors.lastname: Gherli
authors.affiliation: Department of Surgery, University Hospital of Parma, 43100 Parma, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Vezzani
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D006348:Cardiac Surgical Procedures; D005260:Female; D006801:Humans; D007668:Kidney / Q000098:blood supply / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D010100:Oxygen / Q000097:blood*; D018615:Ultrasonography, Doppler, Color
chemical_list: D015415:Biomarkers; D010100:Oxygen