Current Strategies for Prevention and Treatment of Equine Postoperative Ileus: A Multimodal Approach

Abstract

Equine paralytic (postoperative) ileus generally refers to an acute condition of impaired gastrointestinal motility. Paralytic ileus is most frequently seen following abdominal surgery on the small intestine in horses. Three main mechanisms are involved separately or simultaneously in its causation, namely neurogenicendocrinic, inflammatory-endotoxic and pharmacological mechanisms. Regardless of the cause, equine paralytic ileus can be fatal, if not properly diagnosed and treated. Over the past 22 years (1997-2019), we have diagnosed and treated more than 180 horses with postoperative ileus using differing methods. Based on our results and experience, and that of others, we have developed a multimodal strategy to reduce the incidence of postoperative ileus. This has resulted in effective treatment of ileus-diagnosed patients in 94% of cases, a significant improvement in survival rates over the last 20 years. In this review, we described pre-, intra-, and postoperative multiple supplementary preventative and treatment procedures that cure this condition. These methods are dependent on individual cases but include the control of endotoxemia and inflammation, as well as using the least traumatic surgical techniques, carrying out the pelvic flexure colotomy, improved anesthesia techniques, treating with continuous postoperative peritoneal lavage, the use of fluid, antibiotic and NSAIDs therapy, according to a scheme the use of different prokinetic agents (including metoclopramide, neostigmine methylsulfate and domperidone), nasogastric decompression, management to minimize the surgical and postoperative stress reaction and judicious timing of postoperative feeding of horses.An appreciation of the basic mechanisms that regulate gastrointestinal motility is a key component to understanding paralytic ileus. The musculature of the gastrointestinal tract in horses is made up of smooth muscle cells that are intimately associated, thus allowing them to conduct electrophysiological functions. There are three distinctive electrical potentials in the equine intestine: resting potential, slow-wave and spike potential that trigger contractions. Slow waves are rhythmic pacemaker currents initiated by the interstitial cells of Cajal (ICC). Normal gastrointestinal motility in horses results from very complex interactions among the enteric nervous system (ENS), autonomic and central nervous systems, ICC, gastrointestinal hormones, immune cells, glial cells and local factors that affect smooth-muscle activity [21,[23][24][25]. Extrinsically, the sympathetic nervous input through noradrenaline has an inhibitory effect on gastrointestinal motility, whereas parasympathetic input increases motility. The ENS is involved in all aspects of gastrointestinal function, not only motility, as well as by enteric processes such as immune responses, detecting nutrients, microvascular circulation, intestinal barrier function, and epithelial secretion of fluids and ions [10]. The neurons of the ENS are collected into two types of ganglia: myenteric (...

Retrospective Examination of Small Colon Pathology in 72 Horses

“…Based on our examination, the prognosis of surgical cure of enteroliths and other forms of small colon constipation in horses is good (compared to other small intestine pathologies) in case of rapid diagnosis and timely treatment of such horses (Kovač et al, 2015;Kovač et al, 2019). Based on our long-term examination, postoperative (paralytic) ileus in the small colon pathology practically does not occur in horses, compared to small intestine pathologies (Kovač et al, 2020). However, if intestinal necrosis has occurred due to the prolonged presence of enteroliths, small colon resection is required (in addition to removal of enteroliths).…”

“…All postoperative horses underwent standard postoperative therapy (infusion therapy, antibiotics, nonsteroidal anti-inflammatory drugs, and prokinetics) (Kovač et al, 2020). During postoperative hospitalization, 3 horses were euthanized or died due to septic peritonitis, endotoxemia, and adhesive ileus.…”

A survey of non‐steroidal anti‐inflammatory drug use in the post‐operative period following equine colic surgery

“…POI may result from intestinal ischaemia or physical trauma (distension and handling) during surgery leading to the activation of intestinal macrophages, which release cytokines and nitric oxide, further inhibiting intestinal motility (Doherty, 2009). It is also likely that, as NSAIDs reduce pain and inflammation, which is in turn associated with impaired GI motility due to sympathetic stimulation (Kovac et al, 2020), this mechanism is another explanation as to why NSAIDs have been found to help prevent POI. In a study investigating the prevention of POI, flunixin was a commonly prescribed drug (Lefebvre et al, 2016); however, there is no evidence that flunixin is superior to meloxicam when it comes to the POI prophylaxis in surgical colic patients (Naylor et al, 2013).…”

Updates on Veterinary Anatomy and Physiology

“…There are numerous equine pathologies that are directly or indirectly associated with stress factors. According to our clinical experience, due to stress exposure, the most commonly noticed diseases in horses are-gastric ulcers, proximal enteritis, acute colitis, and pleuropneumonia [177][178][179]. It is important to note that for the occurrence of these diseases along with stress, other pathogenomonic factors have also had a significant impact.…”

“…For example, for the occurrence of paralytic ileus or colitis, a high concentration of endotoxins in the blood also plays a very important role [177,178]. Noxious gases (e.g., NH, NO, and CO) in the transport environment may be partially responsible for transport-related equine pleuropneumonia [179]. It is known that equine transport causes strong psychological stress reactions as it often combines the effects of neophobia, claustrophobia, social separation, and balancing.…”