Examination of laryngeal function of healthy dogs by using sedation protocols with dexmedetomidine

Abstract Objective To determine the ability to evaluate laryngeal function under sedation with dexmedetomidine alone or in combination with opioids. Study design Randomized, crossover, blinded study. Animals Eight adult research hounds weighing 8 to 22.5 kg. Methods Dogs were sedated with propofol, dexmedetomidine, dexmedetomidine and butorphanol, or dexmedetomidine and hydromorphone. Digital images were collected with video laryngoscopy before and after doxapram administration. Maximal inspiratory normalized glottal gap (GGA n ) and laryngeal motion were compared between and within protocols before and after doxapram by using a difference of least squares mean. Results Normal laryngeal function was confirmed in all dogs with all protocols except propofol, which resulted in two false positive results. No difference between protocols was detected for predoxapram GGA n . Postdoxapram GGA n was greater than predoxapram GGA n for all four sedation protocols ( P ≤ .0030). Compared with propofol, postdoxapram GGA n was greater for all three dexmedetomidine protocols ( P ≤ .0420). Conclusion Dexmedetomidine alone or in combination with opioids was an effective sedation protocol for laryngeal examination, producing sufficient immobilization to prevent jaw motion and without affecting arytenoid abduction. Clinical significance Dexmedetomidine sedation does not inhibit normal laryngeal motion. Laryngeal examination with propofol alone can produce false positive results.