A comparison of the effect of propofol and alfaxalone on laryngeal motion in nonbrachycephalic and brachycephalic dogs

Daisy Norgate,Gert Ter Haar,Nicola Kulendra,Kata Orsolya Veres-Nyéki

doi:10.1016/j.vaa.2018.06.013

Daisy Norgate, Gert Ter Haar + Show 2 more

Open Access

https://doi.org/10.1016/j.vaa.2018.06.013

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Abstract

ObjectiveTo compare the effect of propofol and alfaxalone on laryngeal motion under a light plane of anaesthesia in nonbrachycephalic and brachycephalic dogs anaesthetized for nonemergency procedures. Study designProspective, randomized clinical trial. AnimalsA total of 48 client-owned dogs (24 nonbrachycephalic and 24 brachycephalic). MethodsA standardized premedication of methadone (0.2 mg kg−1) and acepromazine (0.01 mg kg−1) was administered intramuscularly. Dogs were randomly assigned to be induced with increments of propofol (1–4 mg kg−1) or alfaxalone (0.5–2 mg kg−1). Laryngeal assessment was performed under a light plane of anaesthesia by a surgeon (GTH) who was unaware of the induction protocol. Laryngeal movement was assessed as either being present when abduction of the laryngeal cartilages upon inspiration was identified, or absent when abduction was not recognized. Simultaneously, a 60-second video was recorded. The same surgeon (GTH) and an additional surgeon (NK) re-evaluated the videos 1 month later. Categorical comparisons were studied using Chi square and Fisher’s exact test where appropriate. Pairwise evaluation of agreement between scorers was undertaken with the kappa statistic (κ). ResultsThere were no significant differences (p > 0.05) identified between the presence or absence of laryngeal motion between dogs administered propofol or alfaxalone, as well as when analysing nonbrachycephalic and brachycephalic dogs separately. The majority of dogs (>75%) maintained some degree of laryngeal motion with both protocols. Agreement between assessors was excellent (κ = 0.822). ConclusionsAlfaxalone maintained laryngeal motion similarly to propofol in nonbrachycephalic and brachycephalic dogs. Clinical relevanceBoth agents would appear appropriate for allowing assessment of laryngeal motion in nonbrachycephalic and brachycephalic dogs. The assessment technique of subjective evaluation of laryngeal motion via peroral laryngoscopy under a light plane of anaesthesia produced consistent results amongst assessors, regardless of the induction agent used.

Highlights

Objective To compare the effect of propofol and alfaxalone on laryngeal motion
brachycephalic dogs anaesthetized for non-emergency procedures
90 Animals The study was approved by the Ethics

Summary

Methods

Methods and Materials90 Animals The study was approved by the Ethics and Welfare Committee of the Royal Veterinary College (URN 2016 1603) and informed owner consent was obtained. A total of 48 93 client-owned dogs were included (24 non-brachycephalic and 24 brachycephalic dogs) all of which were admitted to the Queen Mother Hospital requiring general anaesthesia for non-emergency procedures This sample size was chosen as it was deemed an achievable number of dogs to enrol onto the study within the time frame that it could be performed. One month after the last assessment, all the videos were reassessed for the presence or absence of laryngeal motion by the same surgeon (GTH) as well as another board certified small animal surgery specialist (NK). During reassessment of the videos, a third intermediate answer category (presence of minimal laryngeal motion) (Table 2) was added This third category was added to refine the grading system and potentially detect more subtle differences between induction agents as during the data collection process varying degrees of laryngeal movement were detected.

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