Old Horses Aren’t at Higher Risk of Reflux Post-Colic Surgery
Various complications can develop following colic surgery, some more consequential than others. While veterinarians can treat incisional infections or low-grade fevers with antibiotics, persistent postoperative gastric reflux (POR, fluid accumulation in the stomach) is a more serious problem that’s more difficult to resolve. And, as a multi-institution research team recently found out, POR can prove more deadly to its victims.

“Postoperative reflux can indicate stasis (lack of movement) of the intestinal tract, mechanical obstruction at an anastomosis (where intestines have been joined together after a resection during colic surgery) or adhesion site, or even an intestinal repair breakdown,” said surgical resident Sophie Boorman, BVetMed, of Auburn University’s College of Veterinary Medicine.

She said predicting which horses have a higher risk of developing postoperative gastric reflux might:

  1. Help identify horses that will need more intense management following surgery, and
  2. Help owners prepare for this expensive, potentially fatal complication.

“The perception that older horses have more complications after colic surgery is widespread and extends to postoperative reflux,” said Boorman. “This is likely because older horses tend to develop strangulating lipomas—a benign fatty tumor that can entrap and strangulate the small intestine, causing bowel devitalization and necessitating surgery.”

Horses colicking because of small intestine strangulations are more likely to develop postoperative reflux. Therefore, the perception that older horses are more likely to reflux might relate to them being more likely to have a small intestine lesion, rather than any physiological or anatomical predisposition.

“Several studies have attempted to determine whether or not older horses suffer postoperative reflux more commonly than younger animals following colic surgery,” said Boorman. “To date, no clear answer has presented itself.”

Looking to finally put this question to rest, Boorman and colleagues from Penn Vet’s New Bolton Center reviewed medical records of horses that underwent surgery at the University of London’s Royal Veterinary College for correction of small intestine lesions from December 2009 to June 2015. They divided horses into two groups based on age: those ≥16 years (44) and mature horses 2-15 years of age (39).

After scouring those patients’ records, Boorman’s team found that horses most likely to develop postoperative reflux had a resection of the small intestine during surgery, longer surgery times, and gastric reflux upon arrival to the hospital.

“Age was not associated with either postoperative reflux or survival, but horses with postoperative reflux had decreased survival,” said Boorman.

“There are many reasons to decide against pursing surgery during a colic episode: finances, emotional stress, perceived prognosis of the horse, etc.,” she added. “Older horses with a small intestinal lesion that survive colic surgery are just as likely as younger horses to develop postoperative reflux or to survive to hospital discharge. Therefore, the age of the horse should not be considered a prognostic factor.”