Use of plasma ionized calcium levels and Ca2+ substitution response patterns as prognostic parameters for ileus and survival in colic horses.

The research article explores the effect of hypocalcaemia (low levels of calcium in the blood) on the survival and occurrence of ileus in horses with colic. The study demonstrates the significance of measuring ionized calcium levels and the potential beneficial impact of calcium supplementation in improving the medical outcomes.

Objectives and Methodology

• The aim of the study was threefold: to examine parameters associated with hypocalcaemia in colic horses, to understand the impact of hypocalcaemia on the outcomes, and to investigate the possible benefits of calcium substitution (Ca2+ substitution).
• The method approach can be summarized as a randomized controlled trial carried out in an intensive care unit.
• The study sample comprised 144 horses with acute abdominal pain (colic) over a period of 1.5 years. These horses were routinely evaluated based on clinical criteria and whole blood ionized calcium levels.
• Horses suffering from hypocalcaemia were randomly assigned to receive calcium supplementation whereby 400 mEq Ca2+ was diluted in 10L of Ringer’s lactate solution and administered every 24 hours until minimum reference range limits were attained or until the horse’s demise.

Results and Findings

• At the time of admission, 88% of all colic patients were found to have blood ionized calcium levels below the standard range.
• Multivariable analysis disclosed several factors predisposing colic horses to low ionized calcium levels, including the presence of reflux, signs of endotoxaemia, elevation in the Packed Cell Volume (PCV), pH alkalinization, and the combined effect of PCV/pH.
• Horses with “very low” calcium levels had nearly twelve times higher odds of developing ileus during hospitalization compared to normocalcaemic horses.
• The odds of fatal outcomes were around ten and eight times higher for horses in the “very low” and “low” calcium ranges respectively.
• Calcium substitution increased the chances of survival, given that calcium levels could be normalized. Additionally, the lack of an increase in calcium levels, despite repeated substitutions, was considered a bad sign.

Conclusions

• Hypocalcaemia in colic horses is a critical factor concerning survival rates and the likelihood of developing ileus. Thus, routine measurement of ionized calcium levels is emphasized.
• The research also suggests that correcting hypocalcaemia (through calcium supplementation) could potentially enhance clinical outcomes for colic horses.