Continuous fluid infusion per rectum compared with intravenous and nasogastric fluid administration in horses

Rectal fluid administration may offer a simple, safe and inexpensive alternative to intravenous or nasogastric fluid therapy in equine clinical cases.To evaluate the tolerance and effects of rectally administered fluid and compare the measurements of haemodilution and intravascular volume with those during nasogastric and intravenous fluid administration.Randomised controlled experimental trial.Six clinically normal Standardbred geldings were used in a 4-way crossover study: each received three different fluid treatments (intravenous, nasogastric and rectal) at 5\ua0mL/kg/h for 6\ua0h and underwent a control (no treatment) with water and feed withheld. Bodyweight was measured at baseline and 6\ua0h. Packed cell volume (PCV), total solids (TS), albumin, electrolytes, lactate, urine specific gravity, vital parameters, gastrointestinal borborygmi and central venous pressure were measured every 2\ua0h.Rectal fluid administration with plain water was well tolerated and caused clinical chemistry changes consistent with haemodilution, indicating absorption. Mean (95% confidence interval) PCV decreased from 40% [40-42] at 0\ua0h to 35% [34-36] at 6\ua0h during rectal fluid treatment (