Introduction: Urine output (UO) is a key vital sign, particularly in critically ill patients, where it plays a central role in hemodynamic management. UO may help evaluate responses to interventions such as diuretics and fluids. For example, Furosemide Stress Test (FST), relying on UO response to diuretics, was proposed to assess the risk of progression to severe AKI stages. FST was established on manual and intermittent UO measurements. Here, we explore whether UO responses can be further utilized for predicting clinical outcomes of ICU patients, when measured continuously and accurately using FIZE kUO®. In particular, whether UO immediate responses to furosemide bolus are indicative of kidneys state, as reflected by 30-day mortality. Methods: This retrospective analysis is part of a larger study evaluating the clinical and operational impact of the FIZE kUO® device in the ICU. This device digitally tracks UO minute-by-minute at a sub-mL resolution, thus reflecting kidney function in real-time. Adult ICU patients at a single tertiary center who were catheterized and monitored with the device were included in this analysis. We measured UO responses to the first IV furosemide bolus using FIZE kUO®. Patient survival during 30 days following furosemide was analyzed using Cox regression. As predictors we used UO volume within 15 minutes following furosemide administration, age, and sex. Results: A total of 180 patients received IV furosemide. Median patient age was 68.3 years, 42.2% female. Overall, 48 (26.7%) patients died within 30 days of the furosemide dose. Patients with larger UO responses to furosemide had significantly better survival probability (hazard rate decreased by 52.7% for an increase of 100 mL in UO, p< 0.005) after controlling for age and sex. Conclusions: We show that UO response to diuretics, when measured continuously in high-resolution, can be used as a novel tool to assess patient survival with a simple 15-minutes test. This highlights the prognostic potential of minute-by-minute UO monitoring in guiding clinical decisions in the ICU.
Klein et al. (Sun,) studied this question.