Effects of calcium supplementation to resuscitation fluids in endurance horses: A randomized, blinded, clinical trial.
Authors: Fielding C Langdon, Deane Emma L, Major Dustin S, Mayer Jennifer R, Love Juliette C, Peralez Michael S, Magdesian K Gary
Journal: Journal of veterinary internal medicine
Summary
# Calcium Supplementation in Endurance Horse Resuscitation: Clinical Trial Summary Whilst calcium gluconate is routinely added to IV fluids for metabolically compromised endurance horses, robust clinical evidence supporting this practice remains sparse. Researchers enrolled 16 horses eliminated from the Tevis Cup 100-mile ride for metabolic problems, randomising them to receive either 0.4 mg/kg/min calcium gluconate diluted in 10 L isotonic crystalloid or crystalloid alone over one hour, with blinded fluid administration and repeated measurements of heart rate (every 15 minutes), gastrointestinal sounds, and serum electrolytes before and after treatment. Calcium administration did produce lower heart rates at the 45-minute mark (P = 0.002) and increased plasma phosphorus concentration (P = 0.03), but counterintuitively, gastrointestinal sounds were significantly less likely to improve in the calcium group compared with controls (P = 0.005)—a finding that warrants caution given GI dysfunction's importance in endurance metabolic disease. For practitioners managing metabolically exhausted endurance horses, this trial suggests that whilst calcium may provide modest cardiovascular benefits through heart rate reduction, the impaired recovery of GI motility raises questions about whether routine calcium supplementation truly serves the horse's overall recovery trajectory and merits reconsideration of current resuscitation protocols.
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Practical Takeaways
- •While calcium supplementation to IV fluids reduces heart rate in metabolic-compromised endurance horses, it may delay recovery of gastrointestinal function—consider this trade-off when treating exhausted horses
- •If using calcium supplementation in resuscitation protocols, monitor gastrointestinal recovery separately as cardiac improvement does not necessarily indicate overall recovery
- •The impaired GI improvement with calcium supplementation warrants reconsideration of routine calcium addition to resuscitation fluids in endurance horses with metabolic complications
Key Findings
- •Calcium gluconate administration (0.4 mg/kg/min) was associated with significantly lower heart rates at 45 minutes post-infusion compared to control (P = 0.002)
- •Gastrointestinal sounds were significantly less likely to improve in the calcium-supplemented group versus control group (P = 0.005)
- •Calcium administration resulted in increased plasma phosphorus concentration (P = 0.03)