The role of lung ultrasonography in the assessment of overhydration in maintenance hemodialysis patients

Abstract

Purpose Existed methods like biochemical markers improve the accuracy of fluid evaluation for the maintenance hemodialysis patients, but none of them has become the gold standard. This study aimed to evaluate the potential of lung ultrasonography as a useful tool for monitoring the volume status of the patients. Methods A total of 88 patients undergoing maintenance hemodialytic were enrolled in this prospective observational study. Patients were divided into three groups: overhydration (OH), normohydration, and hypohydration according to bioimpedance spectroscopy. Lung ultrasonography parameters, echocardiography parameters, and clinical characteristics of three groups were analyzed. After an average follow-up of 433 days, all-cause mortality among groups was compared. Results The total number of lung comets was statistically reduced in patients after dialysis (Z= −6.891, p < 0.001). This reduction was related to ΔOH (OH – ΔW (the weight gain from dry weight)) and echocardiographic parameters, which proved the relationship among the comet-tail, hydration status of body and cardiac performance. The Kappa consistency test showed that lung ultrasonography and bioelectrical spectroscopy had moderate consistency. ROC analysis showed that the best cut-point of lung comet is 13. The pre-/post-dialysis lung comet-tail, cardiac function and total body impedance with all-cause mortality was investigated. Kaplan–Meier’s analysis revealed that the all-cause mortality was higher in lung congestion patients. Conclusions This study proposes a potentially reliable lung ultrasonography method for estimating fluids overload, which also has implication value of all-cause mortality.