Background Dry weight assessment in hemodialysis (HD) remains a challenge. The aim of the study was to investigate the prevalence of subclinical pulmonary congestion using lung ultrasound (LUS) in maintenance HD patients with no clinical or bioimpedance signs of hyperhydration. The correlation between B-lines Score (BLS) and brain natriuretic peptide (BNP) was also evaluated. Methods Twenty-four HD patients underwent LUS and BNP dosage at the end of the mid-week HD session, monthly for 6 months . LUS was considered as positive when BLS was >15. Hospitalizations and cardiovascular events were also evaluated in relation to the BLS. Results LUS+ patients at baseline were 16 (67%), whereas 11 (46%) showed LUS + in at least 50% of the measurements (rLUS+ patients). Only the rLUS+ patients had a higher number of cardiovascular events [p=0.019, OR: 7.4 (CI 95%. 1.32-39.8)] and hospitalizations [p=0.034, OR 5.5 (CI 95% 1.22- 24.89)]. A BNP level of 165 pg/ml was identified as cut-off value for predicting pulmonary congestion, defined by BLS >15. Conclusion Prevalence of pulmonary congestion as assessed by LUS and persistent or recurrent BLS >15 were quite prevalent findings in euvolemic HD patients. In the patients defined as rLUS+, a higher rate of cardiovascular events and hospital admissions was registered. BNP serum levels > 165 pg/ml resulted predictive of pulmonary congestion at LUS. In the dialysis care, regular LUS examination should be reasonably included among the methods useful to detect subclinical lung congestion and to adjust patients’ dry weight.

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mediante il costante monitoraggio del flusso è una premessa essenziale per raggiungere l'adeguatezza dialitica e il mantenimento della FAV.Le Linee Guida 2006 della National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF KDOQI) indicano che una sorveglianza della fistola, sia essa nativa o protesica, può permettere in caso di stenosi un tempestivo intervento correttivo e migliorare così la pervietà del vaso e diminuire l'incidenza dell'ostruzione. Le stenosi emodinamicamente significative infatti riducono il flusso, aumentano le turbolenze nel lume e spingono le piastrine contro la parete del vaso, favorendone l'attivazione (3).Oltre alle tecniche dirette come l'Eco-Color-Doppler (ECD) ci sono anche tecniche indirette di misurazione del flusso della FAV che possono essere eseguite direttamente al letto del paziente durante il trattamento emodialitico.Le tecniche impiegate sono la termodiluizione, la diluizione a ultrasuoni, la dialysance ionica e l'otticodiluizione. Tutte queste si basano sulla formula introdotta da Krivitski, che prevede la stima del flusso dell'accesso vascolare Flow estimate of arteriovenous fistula by thermodilution in patients on chronic hemodialysis: monocentric experience Purpose: Vascular access surveillance in hemodialysis is today an important challenge for nephrologist. Low blood flow is a risk factor for development of thrombosis of native fistula or graft. The aim of the study is to evaluate the correspondence between flow measurements by thermodilution and Color Doppler, and to identify flow rate values using the Blood Temperature Monitor (BTM) method in the case of stenosis. Methods: We evaluated 29 patients on chronic hemodialysis. The evaluations of blood flow with BTM were performed during the first hour of the hemodialysis session. All patients underwent a Color Doppler of vascular access within 10 days from the BTM measurements. Results: The mean vascular access flow calculated with BTM resulted 1142 ± 700 mL/min and there was a correlation with Color Doppler data 1199 ± 644 mL/min (p = 0,0001 r = 0,829). The flow of patients with hemodynamically significant stenosis was 332 ± 92 mL/min with a minimum value of 270 mL/min and a maximum value of 440 mL/min. Conclusions: The correspondence between thermodilution and Color Doppler supports the implementation of intradialitic evaluation of the vascular access blood flow with the BTM method. Thermodilution allows to identify earlier patients with high risk of vascular access failure and the need for further diagnostic and therapeutic investigations.

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