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Effect of Three Anesthetic Induction Protocols on Laryngeal Motion during Laryngoscopy in Normal Cats


  • Pieter Nelissen DVM,

    Corresponding author
    • Dick White Referrals, Six Mile Bottom, United Kingdom
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  • Federico Corletto PhD, Diplomate ECVAA,

  • Francesco Aprea DVM,

  • Richard A. S. White BVetMed, PhD, Diplomate ACVS&ECVS

Corresponding Author

Pieter Nelissen, DVM, Dick White Referrals, Station Farm, London Road, Six Mile Bottom, CB8 OUH, UK




To objectively measure and subjectively score the effect of 3 anesthetic induction protocols on arytenoid cartilage motion in normal cats.

Study Design

Randomized prospective clinical study.


Cats (n = 35) without previous history of respiratory dysfunction.


Cats were randomly assigned to administration of alfaxalone, propofol, or midazolam and ketamine to induce anesthesia after premedication with methadone. Videolaryngoscopy was performed. Still images at maximum inspiration and expiration were used to measure the area and height of the rima glottidis. Change in rima glottidis area and of normalized glottal gap area (NGGA = area/height2) was calculated. Subjective scores for arytenoid movement were obtained. Kruskal–Wallis test was performed on change of NGGA and rima glottidis area.


No statistically significant difference was found between groups for age, sex, body weight, and body condition score. Percentage increase of rima glottidis area and change in NGGA were similar for all groups (P = .33 and P = .29). No significant differences were found for subjective scores between groups (P = .54). Arytenoid movement was not detected during videolaryngoscopy and subjective scoring in 3 cats anesthetized with propofol and in 3 cats anesthetized with midazolam and ketamine, despite presence of respiratory movements.


No difference in laryngeal motion was observed between the 3 protocols used to induce anesthesia in cats premedicated with methadone.