title: Computer-Aided Quantitative Ultrasonography for Detection of Pulmonary Edema in Mechanically Ventilated Cardiac Surgery Patients.
abstract: BACKGROUND
  Lung ultrasonography (LUS) has been used for noninvasive detection of pulmonary edema. Semiquantitative LUS visual scores (visual LUS [V-LUS]) based on B lines are moderately correlated with pulmonary capillary wedge pressure (PCWP) and extravascular lung water (EVLW). A new computer-aided quantitative LUS (Q-LUS) analysis has been recently proposed. This study investigated whether Q-LUS better correlates with PCWP and EVLW than V-LUS and to what extent positive end-expiratory pressure (PEEP) affects the assessment of pulmonary edema by Q-LUS or V-LUS.
  
  
  METHODS
  Forty-eight mechanically ventilated patients with PEEP of 5 or 10 cm H2O and monitored by PCWP (n = 28) or EVLW (n = 20) were studied.
  
  
  RESULTS
  PCWP was significantly and strongly correlated with Q-LUS gray (Gy) unit value (r(2) = 0.70) but weakly correlated with V-LUS B-line score (r(2) = 0.20). EVLW was significantly and more strongly correlated with Q-LUS Gy unit mean value (r(2) = 0.68) than with V-LUS B-line score (r(2) = 0.34). Q-LUS showed a better diagnostic accuracy than V-LUS for the detection of PCWP >18 mm Hg or EVLW ≥ 10 mL/kg. With 5-cm H2O PEEP, the correlations with PCWP or EVLW were stronger for Q-LUS than V-LUS. With 10-cm H2O PEEP, the correlations with PCWP or EVLW were still significant for Q-LUS but insignificant for V-LUS. Interobserver reproducibility was better for Q-LUS than V-LUS.
  
  
  CONCLUSIONS
  Both V-LUS and Q-LUS are acceptable indicators of pulmonary edema in mechanically ventilated patients. However, at high PEEP only Q-LUS provides data that are significantly correlated with PCWP and EVLW. Computer-aided Q-LUS has the advantages of being not only independent of operator perception but also of PEEP.
authors.affiliation: Anaesthesia and Intensive Care Unit, E.O. Ospedali Galliera, University of Genoa, Genoa, Italy. Electronic address: francescorradi@gmail.com.
authors.forename: Francesco
authors.initials: F
authors.lastname: Corradi
authors.affiliation: Anaesthesia and Intensive Care Unit, E.O. Ospedali Galliera, University of Genoa, Genoa, Italy; Department of Internal Medicine and Medical Specialties, University of Genoa, Genoa, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Brusasco
authors.affiliation: Department of Surgery, University Hospital of Parma, Parma, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Vezzani
authors.affiliation: Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.
authors.forename: Gregorio
authors.initials: G
authors.lastname: Santori
authors.affiliation: Department of Surgery, University Hospital of Parma, Parma, Italy.
authors.forename: Tullio
authors.initials: T
authors.lastname: Manca
authors.affiliation: Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Ball
authors.affiliation: Department of Surgery, University Hospital of Parma, Parma, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Nicolini
authors.affiliation: Department of Surgery, University Hospital of Parma, Parma, Italy.
authors.forename: Tiziano
authors.initials: T
authors.lastname: Gherli
authors.affiliation: Department of Internal Medicine and Medical Specialties, University of Genoa, Genoa, Italy.
authors.forename: Vito
authors.initials: V
authors.lastname: Brusasco
mesh_terms: D000368:Aged; D006348:Cardiac Surgical Procedures; D015633:Extravascular Lung Water / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008168:Lung / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D011175:Positive-Pressure Respiration; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D011654:Pulmonary Edema / Q000000981:diagnostic imaging*; D011669:Pulmonary Wedge Pressure; D015203:Reproducibility of Results; D012121:Respiration, Artificial; D014463:Ultrasonography
keywords: cardiology monitoring; chest imaging; chest ultrasonography; congestive heart failure