Fractional sodium excretion and its relation to in-hospital morbidity and mortality in patients admitted with decompensated heart failure

In general, failure to decrease the extracellular fluid volume despite liberal use of diuretics is often termed diuretic resistance. We aimed to correlate between urinary fractional sodium excretion as a marker of diuretic resistance in patients admitted with congestive heart failure and its impact on length of hospital stay together with in-hospital morbidity and mortality. 46 decompensated heart failure patients were enrolled in this study. We decided that the urine sample from which we can calculate the FENa level will be a 24-hour sample in an attempt to decrease the variability of FENa levels. FENa=100×Na(urinary)×creatinine(plasma)/Na(plasma)×creatinine(urinary) Intravenous furosemide was started on admission either as a continuous infusion or shots. It was followed-up during the hospital stay for inhospital mortality and morbidity. FENa results came out with a median value of 1.5% with minimum and maximum FENa results equal to 0.05% and 5.2%, respectively. The only three variables that contributed significantly to the prediction of hospital stay were Hb, LVEF, and FENa; with the latter variable showing the most significant relation. FENa can be used upon patient’s admission to guide therapy of heart failure in an attempt to reduce the hospital stay.