Effects of an Iso‐Osmotic Chloride‐Free Solution With High Strong Ion Difference vs. Ringer's Lactate on Non‐Lactate Metabolic Acidosis in Dogs

ABSTRACT Background Metabolic acidosis is a common acid–base disorder in critically ill dogs, with fluid therapy being a key but debated treatment. Sodium bicarbonate's risks have spurred interest in safer alternatives such as sodium lactate. Objectives To compare the efficacy of a chloride‐free, high strong ion difference solution (H‐SID) to Ringer's lactate (RL) for treating metabolic acidosis, hypothesizing the superiority of the H‐SID solution. Animals Forty‐six dogs with metabolic acidosis from two veterinary hospitals. Methods Prospective randomized multicenter study. Dogs were randomly assigned to receive either RL or H‐SID at infusion rates of 4 or 10 mL/kg/h for 4 h, based on their volume status. H‐SID was compounded with sodium (145 mmol/L), lactate (145 mmol/L), potassium (10 mmol/L), and aspartate (10 mmol/L) in sterile water for injection. Results The H‐SID group showed a significant increase in BE‐ecf (mmol/L) at infusion rates of 4 mL/kg/h (p < 0.001) and 10 mL/kg/h (p < 0.001) when compared to the RL group. At the lower infusion rate, the median increase was 4.1 mmol/L (95% CI: 3.37, 6.71), whereas the RL group exhibited a variation of −0.1 (95% CI: −0.75, 2.2). At the higher infusion rate, the median increase was 11 mmol/L (95% CI: 8.16, 12.52) compared to the RL group variation of 1.3 (95% CI: 0.01, 2.96). Conclusions and Clinical Importance Our results indicate a significant alkalizing effect of the H‐SID solution in dogs with non‐lactic metabolic acidosis, demonstrating a superior effect compared to the RL solution without notable adverse effects.