Ultrasonographic Assessment of Small Intestinal Motility Following Hyoscine Butylbromide Administration in Horses: A Pilot Study.

The research study investigates the effects of Hyoscine Butylbromide (HB) on the small intestine motility of horses and how it influences their heart rate. The results show that HB does not significantly reduce small intestine motility or induce the appearance of dilated turgid loops in the small intestine, a common sign of intestinal issues, and should not impact clinical decisions for horses without intestinal disease.

Study Design and Methodology

• The study focused on horses hospitalized for medical colic, a common condition in horses caused by gastrointestinal tract disturbance, without any significant abnormalities on their baseline abdominal ultrasound examination.
• Ultrasounds were conducted in three specific positions (right inguinal, left inguinal, and hepatoduodenal window) before and after the administration of HB at different time intervals (1, 5, 15, 30, 45, 60, 90, and 120 minutes) post-injection.
• Three blinded reviewers assessed the small intestine motility by using a subjective grading from 1 (normal motility) to 4 (no motility).

Findings

• The impact of hyoscine butylbromide on small intestinal motility was not significant. Based on the given P-values of 0.60 for the left inguinal area, 0.16 for the right inguinal area, and 0.09 for the duodenum, these values indicate a lack of statistical significance in motility variation after hyoscine butylbromide administration.
• None of the horses in the study developed dilated turgid loops of the small intestine, which are typically associated with severe intestinal conditions such as strangulation lesions.

Heart Rate Changes

• The average heart rate before hyoscine butylbromide injection was found to be 33 ± 3 and it peaked at 71.3 ± 9, approximately just one minute after the injection.
• However, it was noted that this increase in heart rate was significant only for up to 45 minutes (measuring 48 ± 9) post HB administration with a P-value of 0.04, suggesting a temporary heart rate increase instigated by the drug.

Implications

• The study shows that hyoscine butylbromide does not significantly impact small intestinal motility in horses which implies that it will not affect clinical decision-making when these animals are tested for underlying intestinal diseases using ultrasound.
• The absence of dilated turgid loops, after administering the drug, also indicated that it does not trigger symptoms of more severe intestinal issues in horses.