Comparison between propofol and alfaxalone anesthesia for the evaluation of laryngeal function in healthy dogs utilizing computerized software

Abstract

Laryngeal paralysis is a well-documented cause of upper respiratory tract obstruction in canines. Diagnosis of laryngeal paralysis is usually made by visual evaluation of laryngeal motion whilst patients are under a light-plane of anesthesia. However, in human studies of laryngeal function evaluation, it has been shown that subjective scoring can lead to significant interobserver variance, which may cause false diagnosis. In this study, we propose to introduce a more objective method of assessing laryngeal function using GlotAnTools and Tracker software to directly measure laryngeal motion in anaesthetized patients. Additionally, two anesthetic agents, alfaxalone and propofol, were compared in this study to assess their relative effect on laryngeal motion and thus their suitability for use in this diagnostic process. This study was a two-stage, cross-over, 1:1 randomization, with two active treatment arms. Ten beagles (10–18 months, five males and five females) were exposed to both anesthetic agents and laryngeal motion was recorded using videoendoscopy. GlotAnTools and Tracker software were applied to the recorded images to measure glottal gap area (A) and length (L). A normalized measure of laryngeal function–computed as A/L–was created, representing the "elongatedness" of the rima glottidis. The glottal gap area was significantly reduced in dogs receiving alfaxalone. This study objectively establishes that alfaxalone impacted laryngeal motion significantly more than propofol and confirms the capability of these computational methods to detect differences in laryngeal motion.

Case report: Laryngospasm following ethanol ablation of a parathyroid nodule in a dog with primary hyperparathyroidism

“…The dog in this case report was administered butorphanol, followed by alfaxalone to facilitate the sedated oral exam. Previous studies have indicated that alfaxalone can falsely reduce arytenoid opening and movement after its administration ( 19 , 20 ), while other studies have found alfaxalone to be an acceptable alternative to propofol for laryngoscopy ( 17 , 18 ). In this specific case, the dose of alfaxalone used (total dose of 0.5 mg/kg IV) was lower compared to the doses described to negatively affect arytenoid motion ( 19 , 20 ) and enabled preservation of pharyngal and laryngeal function.…”

“…Previous studies have indicated that alfaxalone can falsely reduce arytenoid opening and movement after its administration ( 19 , 20 ), while other studies have found alfaxalone to be an acceptable alternative to propofol for laryngoscopy ( 17 , 18 ). In this specific case, the dose of alfaxalone used (total dose of 0.5 mg/kg IV) was lower compared to the doses described to negatively affect arytenoid motion ( 19 , 20 ) and enabled preservation of pharyngal and laryngeal function. The addition of doxapram, a centrally acting respiratory stimulant, could have been utilized however to further optimize laryngeal function in this case ( 19 , 21 ).…”