The effects of early-phase furosemide use on the progression of oliguric acute kidney injury across different central venous pressure: A retrospective analysis.

BACKGROUND: Furosemide is a commonly used loop diuretic in critical care. However, its effect on the progression of oliguric acute kidney injury across different central venous pressure (CVP) remains unknown. This study therefore aims to investigate the association between Furosemide6-12h (defined as the use of furosemide within 6 h after the diagnosis of AKI according to the urine output [UO] criteria set by the Kidney Disease: Improving Global Outcomes [KDIGO] guidelines) and the progression of AKI across different CVP6-12h (defined as CVP within 6 h after the diagnosis of AKI by the KDIGO UO criteria) levels.

METHODS: Patients involved in this study were identified from the Medical Information Mart for Intensive Care (MIMIC) IV database with the following criteria: (i) adults with UO < 0.5 ml/kg/h for the first 6 h upon admission to the intensive care unit (ICU) (meeting stage 1 AKI by UO), and (ii) CVP6-12h ranging from 0 to 30 mmHg. From thereon, the target primary outcome would be progression to stage 3 AKI by UO among these chosen patients. The secondary outcome was 28-day mortality since ICU admission. The risks of severe-stage AKI progression and 28-day mortality were respectively examined against Furosemide6-12h (vs without Furosemide6-12h) within the full cohort and across different subgroups of CVP6-12h, using multivariate adjusted logistic regression and inverse probability treatment weighting (IPTW). Sensitivity analyses were performed to assess the robustness of our findings.

RESULTS: 1180 patients were ultimately selected for this study, of which 643 (54.5%) progressed to stage 3 AKI from stage 1 based on the UO criteria by KDIGO. Multivariate analysis showed that Furosemide6-12h is significantly associated with this severe-stage progression within the full cohort (OR was 0.62 at 95% CI of 0.43-0.90, P = 0.011). After dividing the patients into CVP6-12h subgroups according to their CVP during the early phases, lower risk of AKI progression was only observed in Furosemide6-12h application at CVP6-12h of ≥12 mmHg (adjusted OR was 0.40 at 95% CI of 0.25-0.65, P < 0.001), as confirmed by the IPTW analysis (OR was 0.47 at 95% CI of 0.29-0.76, P = 0.002). The robustness of these findings was confirmed by sensitivity analyses. In addition, for patients with CVP6-12h ≥ 12 mmHg, Furosemide6-12h is also significantly associated with lower risk of 28-day mortality (adjusted OR was 0.47 at 95% CI of 0.25-0.92, P = 0.026) in the multivariate logistic regression analysis, and there was a similar trend in the IPTW analysis (adjusted OR was 0.55 at 95% CI of 0.28-1.10, P = 0.092).

CONCLUSIONS: Among the identified early-stage AKI patients in critical care, the use of furosemide was only associated with lower risk of oliguric AKI progression and 28-day mortality within the high CVP group. These findings suggest the potential of CVP as a guidance or reference point in the usage of furosemide among early-stage oliguric AKI patients in the ICU.