Anesthetic, Circulatory and Respiratory Effects of Medetomidine/Ketamine in Dogs

Abstract

The anesthetic, circulatory and respiratory effects of medetomidine 40μg/kg with ketamine 5 mg/kg (MK5) or 10 mg/kg (MK10) injected intramuscularly were compared with those of xylazine 2 mg/kg with ketamine 10 mg/kg (XK) . The anesthetic effect of MK5 was comparable to or more than that of XK, and MK10 was the most effective combination. In all the combinations, an immediate decrease in heart rate, respiratory rate and end tidal volume after drug administration was observed. A transient decrease in PaO₂, SaO₂, pHa, [HCO₂] p and B.E. and a transient increase in PaCO₂ were accompanied by repressed circulatory and respiratory function. All the anesthetic combinations accentuated respiratory arrhythmia of the three dogs in each group. One dog given XK developed transient, second-degree atrioventricular heart block. In all the combinations, mean blood pressure transiently increased immediately after drug administration and then decreaced. An increase in mean blood pressure of MK5 and MK10 was larger than that of XK. The repression of circulatory and respiratory function in MK5 and MK10 was longer than in XK, but the repression was not prominent.