In maintenance hemodialysis patients (MHD), extravascular lung water (EVLW) can increase due to heart failure or increase in extra-cellular water compartment (ECW). The direct evaluation of EVLW, by means of lung ultrasounds (LUS) should help in assessing the “ideal” body weight and to evaluate the mechanism of dyspnea in individual MHD patients.
Aim of this study is to compare LUS with total body and segmental lung electrical impedance analysis (BIA), with plasma concentrations of natriuretic peptides BNP and NT-Pro-BNP, with echocardiographic, and inferior vena cava measurements.
Thirty-three adults MHD patients (24 M and 9F), aged 44-86 years, dialysis vintage 0.1-18.6 years, treated by standard (25) or high-flux (8) HD, have been examined immediately before and after a dialytic session. LUS was performed by means of a by-dimensional grey scale ultrasound apparatus equipped with a convex probe.
Total body and segmental lung electrical impedance were analyzed by means of a single frequency (sf) and of a multiple frequency (mf) impedance analyzer.
The mean reduction in body weight during the dialysis session was 2.4 ± 1.4 kg. B-lines at LUS decreased significantly. Total body BIA demonstrated a significant reduction in: ECW and TBW. A significant correlation was found between the number of B-lines and the ECW. B-lines at LUS decreased significantly from 16 to 9 and from 16 to 8 (right and left emitorax respectively). The number of B-lines was significantly correlated with BNP and NT pro-BNP values. No correlation was found between B-lines and the diameters of the inferior vena cava, or with cardiac ejection fraction. At the end of the dialysis sessions lung BIA demonstrated a significant increase in resistance and impedance.
LUS can evaluateEVLW in MHD patients and its results are correlated with total body and segmental lung electrical impedance analysis, and with plasma natriuretic peptides.