title: Accuracy of ultrasound B-lines score and E/Ea ratio to estimate extravascular lung water and its variations in patients with acute respiratory distress syndrome.
abstract: Extravascular lung water (EVLW) could increase by permeability pulmonary oedema, cardiogenic oedema, or both. Transthoracic echocardiography examination of a patient allows quantifying B-lines, originating from water-thickened interlobular septa, and the E/Ea ratio, related to pulmonary capillary wedge pressure. The aim of our study was to assess the correlation and the trending ability between EVLW measured by transpulmonary thermodilution and the B-lines score or the E/Ea ratio in patients with ARDS. Twenty-six intensive care unit patients were prospectively included. B-lines score was obtained from four ultrasound zones (anterior and lateral chest on left and right hemithorax). E/Ea was measured from the apical four-chamber view. EVLW was compared with the B-lines score and the E/Ea ratio. A linear mixed effect model was used to take account the repeated measurements. A p value<0.05 was considered significant. A total of 73 measurements were collected. The correlation coefficient between EVLW and B-lines score was 0.66 (EVLW=0.71 B-lines+7.64, R2=0.44, p=0.001), versus 0.31 for E/Ea (p=0.06). The correlation between EVLW changes and B-lines variations was significant (R2=0.26, p<0.01), with a concordance rate of 74%. A B-lines score≥6 had a sensitivity of 82% and a specificity of 77% to predict EVLW>10 ml/kg, with an AUC equal to 0.86 (0.76-0.93). The gray zone approach identified a range of B-lines between four and seven for which EVLW>10 ml/kg could not be predicted reliably. The correlation between ultrasound B-lines and EVLW was significant, but the B-lines score was not able to track EVLW changes reliably.
authors.affiliation: Service de Réanimation Polyvalente, Centre Hospitalier de Narbonne, Bd Dr Lacroix, 11100, Narbonne, France, b_bataille2@yahoo.fr.
authors.forename: Benoît
authors.initials: B
authors.lastname: Bataille
authors.forename: Guillaume
authors.initials: G
authors.lastname: Rao
authors.forename: Pierre
authors.initials: P
authors.lastname: Cocquet
authors.forename: Michel
authors.initials: M
authors.lastname: Mora
authors.forename: Bruno
authors.initials: B
authors.lastname: Masson
authors.forename: Jean
authors.initials: J
authors.lastname: Ginot
authors.forename: Stein
authors.initials: S
authors.lastname: Silva
authors.forename: Pierre-Etienne
authors.initials: PE
authors.lastname: Moussot
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D003422:Critical Care; D015150:Echocardiography, Doppler / Q000379:methods; D015633:Extravascular Lung Water / Q000737:chemistry*; D005260:Female; D006321:Heart / Q000502:physiology; D006439:Hemodynamics; D006801:Humans; D007362:Intensive Care Units; D016014:Linear Models; D008168:Lung / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D015588:Observer Variation; D010539:Permeability; D011446:Prospective Studies; D011654:Pulmonary Edema / Q000000981:diagnostic imaging; D011669:Pulmonary Wedge Pressure; D012128:Respiratory Distress Syndrome / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D013815:Thermodilution; D014463:Ultrasonography / Q000379:methods*