Fractional excretion of electrolytes in volume‐responsive and intrinsic acute kidney injury in dogs: Diagnostic and prognostic implications

• DOI: 10.1111/jvim.15146
• Publication Date: 2018-05-17T09:51:55Z
• Authors: Roberta Troìa; Marta Gruarin; Chiara Grisetti; Federica Serafini; Luca Magna; Erika Monari; Massimo Giunti; Francesco Dondi
• Keywords: AKI grade; Natriuresis; Tubular damage; Urine chemistry; Urine output; Veterinary (all); Sodium; Acute Kidney Injury; Kidney Function Tests; Prognosis; Severity of Illness Index; 3. Good health; Electrolytes; 03 medical and health sciences; Dogs; 0302 clinical medicine; Case-Control Studies; Animals; SMALL ANIMAL; Dog Diseases; Prospective Studies

BackgroundThe value of fractional excretion (FE) of electrolytes to characterize and prognosticate acute kidney injury (AKI) is poorly documented in dogs.ObjectivesTo evaluate the diagnostic and prognostic roles of FE of electrolytes in dogs with AKI.AnimalsDogs (n = 135) with AKI treated with standard care (February 2014‐December 2016).MethodsProspective study. Clinical and laboratory variables including FE of electrolytes, were measured upon admission. Dogs were graded according to the AKI‐IRIS guidelines and grouped according to AKI features (volume‐responsive, VR‐AKI; intrinsic, I‐AKI) and outcome (survivors/non‐survivors). Group comparison and regression analyses with hazard ratios (HR) evaluation for I‐AKI and mortality were performed.P < .05 was considered significant.ResultsFifty‐two of 135 (39%) dogs had VR‐AKI, 69/135 (51%) I‐AKI and 14/135 (10%) were unclassified. I‐AKI dogs had significantly higher FE of electrolytes, for example, FE of sodium (FENa, %) 2.39 (range 0.04‐75.81) than VR‐AKI ones 0.24 (range 0.01‐2.21;P < .001). Overall, case fatality was 41% (55/135). Increased FE of electrolytes were detected in nonsurvivors, for example, FENa 1.60 (range 0.03‐75.81) compared with survivors 0.60 (range 0.01‐50.45;P = .004). Several risk factors for death were identified, including AKI‐IRIS grade (HR = 1.39,P = .002), FE of electrolytes, for example, FENa (HR = 1.03,P < .001), and urinary output (HR = 5.06,P < .001).Conclusions and Clinical ImportanceFractional excretion of electrolytes performed well in the early differentiation between VR‐AKI and I‐AKI, were related to outcome, and could be useful tools to manage AKI dogs in clinical practice.