Prospective randomized controlled blinded clinical trial evaluating biomarkers of acute kidney injury following 6% hydroxyethyl starch 130/0.4 or Hartmann's solution in dogs.

Objective: To evaluate the effect of 6% hydroxyethyl starch (HES) 130/0.4, compared with a Hartmann's solution control (CRYST), on urine biomarkers of acute kidney injury (AKI) in dogs prescribed a fluid bolus.

Design: Randomized, controlled, blinded clinical trial January 2018 to February 2019.

Setting: University teaching hospital.

Animals: Forty client-owned dogs.

Interventions: Dogs prescribed a fluid bolus were randomized to receive at least 10 mL/kg of HES or CRYST with clinicians and investigators blinded to fluid type. Study fluid was used for further boluses as required in the following 24 hours, to a limit of 40 mL/kg total, after which fluid administration was open-label.

Measurements And Main Results: Urine was collected prior to and 6, 12, and 24 hours after the first study fluid bolus. Urine concentrations of AKI biomarkers: neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, kidney injury molecule-1 (KIM), clusterin, and osteopontin were measured using a magnetic bead multiplexed assay. Osmolality-indexed biomarker concentrations were compared between groups over time with linear mixed-effects models, with P < 0.05 considered significant. The mean volume of study fluid administered was not significantly different between groups (HES: 23.1 mL/kg, CRYST: 25.9 mL/kg; P = 0.47, t-test). There were no significant differences between groups in change over time of osmolality-indexed urine concentrations of NGAL (P = 0.91), cystatin C (P = 0.95), KIM (P = 0.77), clusterin (P = 0.63), or osteopontin (P = 0.91). The maximum Veterinary Acute Kidney Injury (VAKI) score up to 7 days during hospitalization (P = 1.0) and in-hospital mortality (P = 0.49) were not significantly different between groups, as compared by Fisher's exact test.

Conclusions: There were no differences in change over time of urine AKI biomarkers in dogs treated with 10 - 40 mL/kg HES or CRYST over 24 hours. Larger clinical trials with patient-centered outcomes are required to investigate the safety of HES in dogs.