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

Abstract

Summary Background Rectal fluid administration may offer a simple, safe and inexpensive alternative to intravenous or nasogastric fluid therapy in equine clinical cases. Objectives 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. Study design Randomised controlled experimental trial. Methods 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 mL/kg/h for 6 h and underwent a control (no treatment) with water and feed withheld. Bodyweight was measured at baseline and 6 h. 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 h. Results 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 h to 35% [34–36] at 6 h during rectal fluid treatment (P<0.001), similar to decreases in PCV occurring also with i.v. and nasogastric (NGT) treatment (P<0.001). The TS also decreased with i.v. and rectal fluid (P<0.001). There was a decrease in bodyweight in the control (P<0.001) but not with any of the fluid treatments. Main limitations A small sample size of healthy, euhydrated horses and a relatively short duration of fluid administration was used. Conclusions Rectal fluid administration requires clinical evaluation, but may offer an inexpensive, safe alternative or adjunct to i.v. fluid administration, particularly when administration via NGT is not possible or contraindicated. The Summary is available in Portuguese ‐ see Supporting Information

Current Concepts in Fluid Therapy in Horses

“…While little objective evaluation of the PR administration route exists in horses, some concern has been raised about the type of fluid administered. It has been suggested that hypotonic solutions, such as tap water, may be damaging to the rectal mucosa (29). However, a pilot study performed as part of an experimental study evaluating PR fluid administration found that horses tolerated tap water better than a more isotonic polyionic solution (29).…”

“…It has been suggested that hypotonic solutions, such as tap water, may be damaging to the rectal mucosa (29). However, a pilot study performed as part of an experimental study evaluating PR fluid administration found that horses tolerated tap water better than a more isotonic polyionic solution (29). While the reported method of administration via a small, soft indwelling catheter is apparently well-tolerated, and considered unlikely to cause significant trauma to the rectum, this cannot be said about other administration devices.…”

“…A separate part of this study evaluated how far orally fluid migrated in horses and found it rarely reached the level of the pelvic flexure (53). More recently, a letter to the Veterinary Record reports briefly on one practitioner's use of PR fluid administration and two studies have been performed in horses evaluating PR fluids -one small study in horses with naturally occurring mild dehydration and another experimental study comparing IV, IG, and PR fluids in healthy horses (15,29,54).…”

Highlights of recent clinically relevant papers

“…This randomised controlled crossover study by Adeel Khan and colleagues in Australia and the UK compared the use of rectally administered fluids with nasogastric and intravenous administration .…”

Clinical insights: Update on colic

“…The biosensor was able to remotely discriminate between horses that were fasted or fed, or administeredxylazine just as well as auscultation or ultrasonography techniques.This technology could allow for remote monitoring of medically managed or post-operative hospitalised patients. Another management technique was proposed by Khan et al9 who described a technique for administration of rectal fluids. This publication compared the efficacy of rectal fluids with that of nasogastric and intravenous fluid administration techniques finding that rectal fluid administration of water at a rate of 5 mL/kg/h was well tolerated and induced haematologic changes similar to intravenous and nasogastric fluids indicating absorption.…”