Acid base imbalances in ill neonatal foals and their association with survival.
Authors: Viu J, Armengou L, Ríos J, Cesarini C, Jose-Cunilleras E
Journal: Equine veterinary journal
Summary
# Acid-Base Imbalances in Ill Neonatal Foals: What the Blood Gas Tells Us Ill neonatal foals frequently present with acid-base disturbances that may differ fundamentally from those seen in healthy foals, yet the prognostic significance of these imbalances had not been systematically characterised in the equine literature. Researchers compared acid-base parameters—measured using quantitative strong ion difference methodology—from 65 sick foals (32 septic, 33 non-septic) against a control group of 33 healthy neonates, examining electrolytes, lactate, albumin, and calculated buffer components on admission. Sixty-three per cent of ill foals presented with respiratory alkalosis whilst 58.5% exhibited strong ion difference acidosis, with particularly striking differences in strong ion difference (31–32 mmol/l in sick foals versus 40.3 mmol/l in healthy controls), potassium (3.5–3.6 mEq/l versus 4.2 mEq/l) and L-lactate concentrations (5.0–5.1 mmol/l versus 2.5 mmol/l). Most importantly, non-surviving foals showed significantly elevated venous pCO₂ and lactate levels at admission—both readily available parameters that clinicians can act upon immediately rather than waiting for complex quantitative analysis. For equine practitioners, these findings suggest that elevated lactate concentration and venous carbon dioxide tension warrant heightened clinical concern regarding prognosis in sick neonates, and systematic blood gas assessment on admission provides objective prognostic information to guide intensive care decisions and owner communication.
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Practical Takeaways
- •Monitor venous blood gas and lactate levels in critically ill neonatal foals as prognostic indicators; elevated pCO2 and lactate predict poor survival outcome
- •Expect mixed acid-base disorders (respiratory alkalosis with strong ion acidosis) in sick foals rather than simple pH abnormalities; quantitative analysis of strong ion difference provides better diagnostic clarity than pH alone
- •Early recognition of hypokalemia and strong ion acidosis in ill foals may facilitate targeted therapeutic intervention to improve survival rates
Key Findings
- •63% of ill foals presented with respiratory alkalosis and 58.5% had strong ion difference acidosis, with 21 foals showing both alterations simultaneously
- •Ill foals had significantly lower strong ion difference (31.6-32.0 mmol/l) and potassium levels compared to healthy controls (40.3 mmol/l and 4.2 mEq/l respectively)
- •Elevated venous pCO2 (51 mmHg) and L-lactate concentration (6.4 mmol/l) were significantly associated with mortality in ill neonatal foals
- •L-lactate was elevated in both septic and nonseptic ill foals compared to healthy controls (5.0-5.1 vs 2.5 mmol/l)