Equine fluid therapy

Two main administration routes should be considered: oral and IV.

-  Oral  fluids are contraindicated if ileus, intestinal obstruction or severe mucosal inflammation is present or if the horse is unable to stand or require rapid, large volume resuscitation. In these cases, only IV fluid therapy should be considered.

-  The two routes can be used alone or in combination.

Oral fluids

- The main advantages of oral fluids are easier  and the fact GI mucosa acts as a natural selective barrier – making iatrogenic imbalances less likely. Absorption from the GI tract is increased in hypovolaemia, so oral fluids have a haemodynamic effect in about 30 minutes, which is quick enough in many cases.

- The indications for oral fluids include restoration of electrolyte balance and hydration status:

- to prevent dehydration occurring in horses with ongoing losses that are not drinking.

- to increase hydration of the GI contents – for example, if a large intestinal impaction is present.

- to stimulate intestinal motility via the gastrocolic reflex.

- Oral  fluids can be administered via a nasogastric or naso-oesophageal tube, and as a bolus or continuously by gravity. Most commonly, a bolus is administered via a nasogastric tube. Up to 10L every 30 minutes (40ml/kg/hr) can be given and maintenance rates are 2.5ml/kg/hr. Ideally, the fluid should be isotonic. This can be achieved by adding 4.9g NaCl and 4.9g  (KCl) to each litre of water. Including glucose has no apparent beneficial effect on the rate of absorption in the horse.

Complications that should be monitored for include aspiration, nasogastric tube complications, abdominal discomfort, GI rupture and electrolyte imbalances.

IV fluid therapy

IV fluid therapy via  the jugular vein is the only site suitable for high volume resuscitation.

 However, it must be remembered thrombophlebitis at this site can cause significant morbidity. If the horse is severely dehydrated, fluids can be administered via both jugular veins simultaneously using a large gauge catheter combined with a wide bore delivery system, allowing a maximum administration rate of 35 L/hr.