Comparison of two multimodal intramuscular anaesthetic protocols in uncooperative feline patients: effects on sedation and echocardiographic measurements.

Objectives: The aims of this study were to compare the sedative effect, feasibility of venous angiocatheter placement and influence on heart rate (HR), systemic blood pressure (SBP) and echocardiographic variables of two multimodal anaesthetic protocols in uncooperative cats; and to compare their influence on HR, SBP and echocardiographic variables 20 mins after sedation and after elective ovariectomy.

Methods: Eighteen stray female cats randomly received intramuscular (IM) ketamine (2 mg/kg) and methadone (0.3 mg/kg) plus dexmedetomidine (7 µg/kg; group D, n = 9) or alfaxalone (2 mg/kg; group A, n = 9). A sedation score (0-15 [from none to good sedation]) was assigned at 5 mins, 10 mins, 15 mins and 20 mins after IM injection. Venous angiocatheter placement and echocardiographic examination feasibility scores (both from 0 to 3 [from very difficult to very easy]) were recorded at 20 mins. Echocardiography, HR and blood pressure measurements (Doppler and oscillometric methods) were performed at 20 mins and at the end of surgery.

Results: Sedation and angiocatheter feasibility scores did not differ significantly between groups ( >0.05); the feasibility score of echocardiographic examination was higher in cats in group D ( = 0.01). HR was higher in group A at 20 mins and after surgery ( <0.05). The systolic arterial pressure obtained with the Doppler method was statistically significantly higher in cats in group D than in group A at 20 mins ( = 0.01), while postoperatively there were no differences between groups. Cats in group D showed significantly higher atrial diameters ( <0.05) and slower atrial flows ( = 0.04) compared with group A; ventricular thickness and atrial function did not differ between groups ( >0.05). Most echocardiographic variables were not different at 20 mins vs postoperatively.

Conclusions And Relevance: Both protocols allowed for effective sedation; however, cats in group D presented alterations in some echocardiographic measurements; the use of alfaxalone, combined with ketamine and methadone, is recommended to obtain a reliable echocardiographic evaluation in uncooperative cats.