Effects of calcium supplementation to resuscitation fluids in endurance horses:

It remains unclear whether the addition of calcium to resuscitation fluids is on balance a good thing. It does suggest caution should be exercised for those horses with GI signs due to overexertion.
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Effects of calcium supplementation to resuscitation fluids in endurance horses: A randomized, blinded, clinical trial
J Vet Intern Med. 2023 May 2. doi: 10.1111/jvim.16715.
Authors
C Langdon Fielding 1 , Emma L Deane 1 , Dustin S Major 1 , Jennifer R Mayer 1 , Juliette C Love 1 , Michael S Peralez 2 , K Gary Magdesian 3
Affiliations

1 Loomis Basin Equine Medical Center, Penryn, California, USA.
2 Foothill Equine, Arcadia, California, USA.
3 The Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, California, USA.

PMID: 37129859
DOI: 10.1111/jvim.16715

Abstract

Background: The addition of calcium to resuscitation fluids is a common practice in horses, but studies evaluating the effects of calcium supplementation are limited. In healthy horses, decreases in heart rate and changes in serum electrolyte concentrations have been reported.

Hypothesis: Calcium gluconate administration at a rate of 0.4 mg/kg/min to eliminated endurance horses with metabolic problems will affect heart rate, gastrointestinal sounds, and serum electrolyte concentrations.

Animals: Endurance horses eliminated from the Tevis Cup 100-mile (160 km) endurance ride for metabolic problems and requiring IV fluid therapy were eligible.

Methods: Sixteen horses were randomly assigned to receive 0.4 mg/kg/min of calcium (23% calcium gluconate solution) over 1 hour diluted in 10 L of a non-calcium containing isotonic crystalloid (CAL group) or 10 L of a non-calcium containing isotonic crystalloid (CON group). Staff members administering the fluids were blinded to treatment group. Blood samples were collected and physical examinations performed before and after treatment. Heart rates were recorded every 15 min during fluid administration. Data were compared using 2-way analysis of variance (ANOVA) with repeated measures for continuous variables and Fisher’s exact test for categorical variables.

Results: Calcium was associated with lower heart rates 45 min after starting the infusion (P = .002). Gastrointestinal sounds were less likely to improve in the calcium group compared with the control group (P = .005). An increase in plasma phosphorus concentration (P = .03) was associated with calcium administration.

Conclusions: Intravenous calcium supplementation to endurance horses eliminated from competition after development of metabolic problems may decrease heart rate but impairs improvement in gastrointestinal sounds.

Keywords: dehydration; electrolytes; endurance; intravenous.

© 2023 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.