RESUMEN
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.