Serum Electrolyte Changes in Foals Receiving Rhodococcus equi-Specific Hyperimmune Plasma.

Overview

• This study investigated how Rhodococcus equi-specific hyperimmune plasma (Re-HIP), given to newborn foals to prevent pneumonia, affects their blood electrolyte and protein levels.
• The research found that Re-HIP increases certain electrolytes and proteins in the blood of healthy foals, with potential risks for sick or dehydrated foals.

Background and Purpose

• Rhodococcus equi infection: A serious pneumonia-causing bacterial infection in neonatal foals that can be fatal if untreated.
• Use of Re-HIP: Re-HIP is plasma containing high levels of antibodies specific to Rhodococcus equi, administered to protect foals early in life.
• Composition of Re-HIP: Besides antibodies, frozen plasma products like Re-HIP contain electrolytes such as sodium (Na), chloride (Cl), and potassium (K), and proteins like albumin and globulin.
• Research gap: Since hyperimmune plasma has higher electrolyte concentrations compared to neonatal plasma, understanding how its administration impacts foals’ internal balance (homeostasis) is important, especially in critically ill foals.

Methods

• Subjects: Healthy neonatal foals were selected for evaluation.
• Intervention: Foals received Rhodococcus equi-specific hyperimmune plasma (Re-HIP).
• Measurements: Blood samples were taken to measure serum concentrations of key electrolytes – sodium (Na), chloride (Cl), potassium (K) – and proteins – albumin and globulin – before and after Re-HIP administration.

Results

• High sodium in Re-HIP: The plasma product itself had a higher sodium concentration compared to normal neonatal plasma.
• Increase in serum levels: After administering Re-HIP, neonatal foals showed increased serum concentrations of:
• Sodium (Na)
• Chloride (Cl)
• Albumin
• Globulin
• No significant change in potassium (K): Potassium levels were not significantly affected by Re-HIP administration.
• Clinical significance in healthy foals: The observed increases in electrolytes and proteins were considered minor and unlikely to cause problems in healthy foals.

Conclusions and Clinical Implications

• Minor effects in healthy foals: Electrolyte changes from Re-HIP appear to be clinically insignificant in healthy newborn foals.
• Potential risk in ill foals: Use of hypernatremic (high sodium) plasma in foals who are sick, septic, or dehydrated could worsen electrolyte imbalances and cause harm.
• Recommendation: Veterinarians should exercise caution and closely monitor electrolytes when administering frozen plasma products to critically ill or compromised foals.
• Overall implication: While hyperimmune plasma is valuable for disease prevention and treatment, its non-antibody components (such as electrolytes) can impact foal physiology and must be considered in clinical decisions.