Small Intestine Ultrasound Findings on Horses Following Exploratory Laparotomy, Can We Predict Postoperative Reflux?

SIMPLE SUMMARY: Postoperative reflux is a well-recognized complication after exploratory laparotomy, particularly in horses that present with small intestine pathology. Even though much has been written about the pathophysiology and management of this postsurgical complication, we could not find a study that describes the monitoring of small intestine appearance after laparotomy via transcutaneous abdominal ultrasound. Therefore, the aim of the study was to provide clinical evidence of ultrasound finds in 58 horses over three days post exploratory laparotomy. The results from these exams were compared to the abdominal ultrasounds of 20 horses undergoing general anesthesia for an elective procedure, which were used as a control group. Differences were found between horses with versus without small intestinal pathology. Horses operated on because of large colon pathology had similar ultrasound findings to the control group during the postoperative period. In contrast, horses that were presented with small intestinal pathology had more visible small intestine loops, increased loop diameter, and wall thickness, before and after surgery, particularly those cases that had undergone a resection and anastomosis. A quick abdominal ultrasound in horses, during the postoperative period after colic surgery, was a useful method to identify horses with abnormal small intestinal parameters, both pre- and post-surgery. Further investigation as to whether these parameters can be used to predict postoperative reflux (POR) in a larger population is warranted. ABSTRACT: Postoperative reflux (POR) is a well-recognized complication after colic surgery in horses, particularly when presenting small intestinal pathology. Even though much has been written about the pathophysiology and management of POR, additional clinical studies are needed to better understand and anticipate this complication. The aim of the study was to provide clinical evidence of ultrasound findings in the postoperative period (three days). The study is based on transcutaneous abdominal ultrasounds of the caudoventral abdomen during the postoperative period (three days), in 58 horses, presented for an exploratory laparotomy, and compared to 20 horses that underwent general anesthesia for an elective surgical procedure. Small intestine (SI) images and videos were analyzed for loop number, loop diameter, wall thickness, motility, and echogenic type of loop contents. Ultrasound findings of horses that had a large colon pathology were similar to those of the control group. Interestingly, horses that presented an SI pathology had significantly thicker SI walls, increased loop diameter, slower motility, and hypoechoic contents, particularly in horses that had undergone small intestinal resection and anastomosis. Although the number of horses that developed POR in our study was too small for statistical analysis, they all had the aforementioned ultrasonographic changes. Abdominal ultrasound, during the postoperative period (three days), was a useful method to identify horses with abnormal small intestinal parameters. Further investigation as to whether these parameters can be used to predict POR in a larger population is warranted.