Pilot Study Identifying Predictive Factors of Diuretic Effectiveness in Emergency Department Patients with Fluid Overload

Abstract

Background

Effective diuretic therapy in emergency department (ED) patients with fluid overload is challenging.

Objectives

The objective of this study was to evaluate clinical and laboratory parameters for predicting an adequate response to initial diuretic therapy in ED patients with edema.

Methods

In this prospective, observational study, patients presenting to the ED of a tertiary hospital with edema of cardiac or renal cause were included. Intravenous furosemide was administered according to a prespecified protocol and urine output was recorded. Group comparison and univariable logistic regression analyses were performed to explore the predictive impact of various clinical and laboratory factors on diuretic success defined as urine volume ≥ 600 mL in the first 6 h vs. failure (< 600 mL in the first 6 h)—focusing on urinary sodium and conductivity as a simple and inexpensive test.

Results

A total of 101 patients were analyzed. The median 6-h urine output was 1100 mL (interquartile range 600, 1700). A higher systolic blood pressure, estimated glomerular filtration rate, urine sodium, and urine electrical conductivity were each associated with achieving at least 600 mL urine output in 6 h. In univariable analysis, a urine sodium threshold of > 72.5 mmol/L and a urine conductivity > 12.0 mS/cm showed a positive predictive value of 93% and 89%, for sufficient diuresis.

Conclusions

Urine sodium and urine electrical conductivity were associated with diuretic success in this pilot study. As these parameters can be determined prior to treatment initiation, their value as predictive markers should be evaluated in further studies.