The effect of romifidine on endoscopic grading of laryngeal function in horses

BACKGROUND: To our knowledge, the effect of sedation with romifidine on the grading of laryngeal function in horses has not been studied. Our objective was to examine the effects of romifidine on the grading of laryngeal function and the cross-sectional area of the rima glottis (CSARG). METHODS: Ten horses underwent three endoscopic examinations of the larynx: once while unsedated (group R1), once after being sedated with romifidine (0.04 mg/kg intravenously; group R2) and once again, while still sedated, after receiving a repeat dose of romifidine (0.08 mg/kg intravenously, total dose; group R3). The recorded examinations were randomised and examined by three blinded reviewers who graded laryngeal function. The CSARG was measured from still images obtained during peak inspiration. RESULTS: Sedation had no significant effect on the endoscopic laryngeal function grade assigned. There was no statistical difference in CSARG between Groups R1 and R2 (p = 0.164). Significant reduction in CSARG was noted between Groups R1 and R3 (p < 0.001) and Groups R2 and R3 (p = 0.045). LIMITATIONS: The low number of horses examined may have resulted in the analyses being insufficiently powered. As such, the findings should be interpreted cautiously. CONCLUSION: A dose of 0.04 mg/kg romifidine administered intravenously had no significant effect on horses' laryngeal function grade and CSARG.