Same-day echocardiography in dogs sedated with intravenous dexmedetomidine followed by reversal with intramuscular atipamezole.

Abstract

OBJECTIVE: To estimate the time until reliable echocardiography in healthy dogs by evaluating differences in measured echocardiographic variables in dogs before sedation, during sedation with dexmedetomidine, and after reversal with atipamezole. METHODS: 13 dogs were prospectively enrolled. Two-dimensional echocardiographic measurements on left atrial and ventricular dimensions and ventricular systolic function were obtained at each time point. Dogs underwent IV sedation with 10 µg/kg of dexmedetomidine and 0.2 mg/kg of butorphanol, and dexmedetomidine was reversed with atipamezole IM. Echocardiography was performed before sedation, during sedation, and 30 to 60 minutes, 2 hours, and 6 hours after reversal. Data were analyzed with a Bayesian multivariate hierarchical model. RESULTS: There were effects of sedation on the mean values of all echocardiographic variables. These effects varied among dogs, with most dogs expected to remain within normal reference ranges during and after sedation for all variables except ejection fraction and fractional shortening. The effects of sedation on ejection fraction and fractional shortening were widespread and persistent, such that 88% and 79% of dogs, respectively, were expected to measure outside the normal ranges during sedation. After reversal with atipamezole, this proportion declined, with approximately 9% of dogs estimated outside the normal reference ranges after 6 hours. CONCLUSIONS: Effects of dexmedetomidine on echocardiographic measurements were detected 6 hours after reversal with atipamezole. Accurate cardiac assessment in dogs sedated with this drug is not likely to be possible on the same day as sedation. CLINICAL RELEVANCE: Dogs sedated with this protocol and that have echocardiography performed within 6 hours following reversal should have results interpreted with caution.