Background
Assessment of volume status is crucial in patients with chronic renal failure who are maintained on regular hemodialysis.
Aim of the work
The aim of the study was to evaluate the effectiveness of lung ultrasound in detecting changes in volume status in chronic hemodialysis patients and compare it with the gold standard bioimpedance technique.
Patients and methods
Forty chronic renal failure patients on regular hemodialysis (three times per week) since at least 6 months were subjected to full history taking and physical examination, full anthropometric measurements, routine laboratory studies, and conventional transthoracic echocardiography. Lung comet score was assessed in both lungs using lung ultrasound, and total body water (TBW) and TBW% were assessed using bioelectrical impedance. The last two investigations were carried out both before and after a midweek dialysis session.
Results
Most of the patients were male (57.5%) and hypertensive (75%). The mean age was 49.40±16.06 years. The mean lung comet score before and after dialysis was 20.1±15.8 and 14.6±11.8, respectively (<0.001) and the mean TBW was 37.2±9.1 and 35.8±8.5 l, respectively (=0.002). Before dialysis, the lung comet score showed significant correlation with TBW% (=0.01), left ventricular end-diastolic (=0.02) and end-systolic (<0.001) dimensions and significant negative correlation with left ventricular ejection fraction (=0.003). After dialysis, the lung comet score showed only significant negative correlation with left ventricular ejection fraction (<0.001). There was no significant correlation between change in lung comet score (before and after dialysis) and change in TBW% (=0.93).
Conclusion
Bioimpedance and ultrasound lung comet score may provide different but complementary information. Whereas bioimpedance may be more specific to hydration state, lung ultrasound may indicate cardiac condition coexisting with overhydration. It also gives an idea about the hydration state and the effect of dialysis.