Colic is the most common emergency in equine medicine. Paralytic or adynamic ileus, a functional motor paralysis of the digestive tract, is commonly seen following abdominal surgeries (post-operative ileus) or caused by primary inflammatory conditions (proximal enteritis and septic ileus); both inducing an overall shift towards an abnormal level of sympathetic tone that reduces motility. Post-operative ileus (POI), the most feared complication secondary to exploratory celiotomy, has two major components: a neurogenic phase, propagated by an inflammatory phase. The current therapies for POI and other forms of paralytic ileus, include anti-inflammatories and prokinetics and unfortunately are still largely ineffective.

Intestinal motility is regulated by the enteric nervous system, including the interstitial cells of Cajal that initiate the inner pacemaker activity within the intestinal wall, and the parasympathetic and sympathetic systems that further influence the intrinsic motility. The sympathetic autonomic system neurons connect within specialized ganglia (celiac and mesenteric ganglia) before projecting to the digestive tract, and receiving also sensory fibers, establishes a reflex circuit regulating intestinal motility. The whole branching network of fibers projecting from, and reaching the ganglia, constitutes the celiac plexus.

Celiac plexus block or neurolysis is used in human medicine for management of chronic unrelenting abdominal pain. Our hypothesis is that a celiac plexus block would restore intestinal motility disrupted in paralytic ileus, by blocking the sympathetic tone and the transmission of visceral pain. Furthermore, we hypothesize that the celiac plexus block will improve comfort level in POI, proximal enteritis and other type of intestinal pathologies.

This study aims to investigate the effect of a transient anesthetic block of the celiac plexus in the horse. We investigated the safety of this anesthetic block in healthy horses, and with this study, we aim to verify its effects in horses with paralytic ileus and acute visceral pain.