Assessment of Volume Status in Chronic Hemodialysis: Comparison of Lung Ultrasound to Clinical Practice and Bioimpedance

Abstract

Objective: To compare LUS with other volume assessment methods, and to verify the prognostic value of LUS in Thai chronic HD patients.
 Materials and Methods: We conducted a prospective cohort study in 36 chronic HD patients. Volume status before the HD session was evaluated by physical examinations, bioimpedance analysis (BIA), and ultrasound lung comets (ULCs). Mortality and morbidities were recorded during a 1-year follow-up period.
 Results: The degree of lung fluid accumulation was assessed by summation of the number of ULCs, and was classified into 3 groups: mild-to-moderate (ULC<15–29), severe (ULC=30–59), and very severe (ULC>60) in 11.1%, 77.8%, and 11.1% of the patients, respectively. Either clinical edema or lung crackle had low sensitivity (20-32%) to detect extravascular lung water excess in patient with mild-to-moderate ULC and severe ULC. Overhydration assessed by BIA was found in 75% and 64.3% of patients with mild-to-moderate and severe ULC, respecively. In patients with very severe ULC, the admission rate due to volume overload was significantly higher, there was also a trend of increased mortality, as well as intradialytic complications.
 Conclusion: Clinical assessment and BIA have limited value in determining extravascular fluid excess in the lung. Lung ultrasound is a useful tool to detect subclinical pulmonary congestion. The long-term outcome by using LUS-guided fluid management needs larger population studies.