Treatments to promote colonic hydration: enteral fluid therapy versus intravenous fluid therapy and magnesium sulphate.
Authors: Lopes M A F, Walker B L, White N A, Ward D L
Journal: Equine veterinary journal
Summary
# Editorial Summary: Enteral versus Intravenous Fluid Therapy for Colonic Impaction Large colon impactions remain a frequent colic presentation in equine practice, traditionally managed with intravenous fluid therapy paired with magnesium sulphate; however, enteral rehydration offers a more economical alternative whose efficacy had not been directly compared. Lopes and colleagues conducted a crossover study using four horses with right dorsal colon fistulae, administering either 60 litres of enteral fluids via nasogastric tube or identical volumes intravenously alongside 1 g/kg magnesium sulphate, with treatments separated by one week. Both protocols successfully increased faecal and ingesta hydration, reduced packed cell volume and plasma protein, and induced appropriate polyuria with dilute urine; enteral therapy proved superior at promoting ingesta hydration and caused greater abdominal distention and more pronounced bodyweight gain, whilst intravenous therapy produced hypocalcaemia and more marked plasma protein changes. For practitioners, these findings suggest enteral fluid therapy delivers superior colonic hydration with fewer systemic derangements, potentially making it a preferable first-line treatment for uncomplicated impactions—though the mild abdominal discomfort observed in two horses and increased distention warrant careful patient selection and monitoring.
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Practical Takeaways
- •Enteral fluid therapy may be considered as a cost-effective alternative to IV fluids for treating colonic impaction, as it more effectively hydrates ingesta with fewer systemic complications
- •IV fluids combined with MgSO4 produce notable electrolyte changes (hypocalcaemia, plasma protein reduction) that warrant monitoring, whereas enteral therapy's main concern is abdominal distention
- •Monitor for mild abdominal discomfort during enteral fluid therapy and consider systemic electrolyte impacts when choosing between treatment modalities
Key Findings
- •Enteral fluid therapy produced more pronounced changes in bodyweight and ingesta hydration compared to intravenous fluids plus magnesium sulphate
- •Both treatments produced pollakiuria, hypostenuria, increased bodyweight, increased faecal and ingesta hydration, and decreased PCV, plasma protein and plasma magnesium
- •Intravenous fluids plus MgSO4 produced hypocalcaemia and more pronounced changes in plasma protein, whereas enteral fluids produced more abdominal distention
- •Enteral fluid therapy is more effective in promoting ingesta hydration and produces less pronounced systemic effects than intravenous fluid therapy plus magnesium sulphate