Lung ultrasound for fluid assessment in patients receiving dialysis-a systematic review

Accurate methods of assessing fluid status in patients with  kidney failure in need of dialysis are pivotal to preventing volume overload. Unidentified volume overload can lead to cardiac complications such as left ventricular hypertrophy, hypertension, and, ultimately, heart failure. Currently, there is no gold standard for determining the hydration status of this patient group. This systematic review aims to synthesise studies that have assessed the diagnostic accuracy of lung ultrasound in evaluating fluid status and the use of lung ultrasound to improve long-term endpoints in chronic dialysis patients.

The protocol was registered in the PROSPERO registry (CRD 42022334147), and was conducted in accordance with PRISMA guidelines. The search was conducted in the PubMed, Embase, Medline and Web of Science databases to identify studies related to lung ultrasound and dialysis.

The search yielded 2543 studies, and after screening, five diagnostic accuracy studies and seven randomised controlled trials (RCTs) were included in the final analysis. The diagnostic accuracy studies reported sensitivity between 33 and 94.5% and specificity from 39 to 80%, highlighting considerable heterogeneity among the studies. The RCTs indicated that using ultrasound in volume management was not associated with improving long-term endpoints such as all-cause mortality and cardiovascular events. The quality assessment of the included studies showed an overall risk of bias in both types of studies (RCT and diagnostic accuracy studies).

Lung ultrasound is an accurate, low-cost, and easily implementable method that could complement but not replace the standard of care. The available literature concerning the use of lung ultrasound in volume assessment of patients with kidney failure was characterised by heterogeneity and risk of bias. Future rigorous, high-quality research must involve randomised controlled trials to consolidate the efficiency and efficacy of lung ultrasound for kidney failure patients.