Effect of three anesthetic induction protocols on laryngeal motion during laryngoscopy in normal cats.

OBJECTIVES

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.

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

METHODS

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/height(2) ) was calculated. Subjective scores for arytenoid movement were obtained. Kruskal-Wallis test was performed on change of NGGA and rima glottidis area.

RESULTS

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.

CONCLUSIONS

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