Chest ultrasound and hidden lung congestion in peritoneal dialysis patients

Chest ultrasound (US) is a non-invasive well-validated technique for estimating extravascular lung water (LW) in patients with heart diseases and in end-stage renal disease. We systematically applied this technique to the whole peritoneal dialysis (PD) population of five dialysis units. We studied the cross-sectional association between LW, echocardiographic parameters, clinical [pedal oedema, New York Heart Association (NYHA) class] and bioelectrical impedance analysis (BIA) markers of volume status in 88 PD patients. Moderate to severe lung congestion was evident in 41 (46) patients. Ejection fraction was the echocardiographic parameter with the strongest independent association with LW (r 0.40 P 0.002). Oedema did not associate with LW on univariate and multivariate analysis. NYHA class was slightly associated with LW (r 0.21 P 0.05). Among patients with severe lung congestion, only 27 had pedal oedema and the majority (57) had no dyspnoea (NYHA Class I). Similarly, the prevalence of patients with BIA, evidence of volume excess was small (11) and not significantly different (P 0.79) from that observed in patients with mild or no congestion (9). In PD patients, LW by chest US reveals moderate to severe lung congestion in a significant proportion of asymptomatic patients. Intervention studies are necessary to prove the usefulness of chest US for optimizing the control of fluid excess in PD patients.