Effects of concentrated electrolytes administered via a paste on fluid, electrolyte, and acid base balance in horses

Objectives - To test effectiveness of an electrolyte paste in correcting fluid, electrolyte and acid base alterations in response to furosemide administration. Animals - 6 Standardbreds. Procedures - Horses received electrolyte paste or water only (control). The paste was given orally 3 hours after furosemide administration (1 mg/kg of body weight, IM). Water was given ad libitum soon after the paste and 3 hours after furosemide administration to treated and control groups, respectively. Paste Na⁺, K⁺, and Cl^- composition was approximately 2,220, 620, and 2,840 mmol, respectively. The PCV and plasma concentrations of total protein ([TP]), [Na⁺], [K⁺], [Cl^- ]), and bicarbonate ([HCO₃^-]) were determined, and urinary fluid and electrolyte excretion, fecal water, and body weight changes were measured. Results - At the end of a 6-hour period, the paste-treated group had higher water consumption, which resulted in lower plasma [TP]; net electrolyte losses also were substantially less. With paste administration, [Na⁺] was approximately 2 mmol/L above a prefurosemide value of 137.3 mmol/L; control horses had values similar to the prefurosemide value. Plasma [Cl^-] remained at the prefurosemide value, but values in control horses decreased by 7 mmol/L with water consumption. Plasma [K⁺] remained approximately 0.8 mmol/L below prefurosemide values in both groups. Venous [HCO₃^-] returned to prefurosemide values after paste administration, but alkalosis persisted in control horses after consumption of water only. Body weight loss was less after paste administration. Conclusions - Administration of electrolyte paste is advantageous over water alone in restoring fluid, electrolyte, and acid base balance after fluid and electrolyte loss attributable to furosemide administration.