Anesthesiology
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Comparative Study
Premedication with oral dexmedetomidine alters hemodynamic actions of intravenous anesthetic agents in chronically instrumented dogs.
Dexmedetomidine (the D-stereoisomer of medetomidine), a highly selective alpha 2-adrenoceptor agonist, has been demonstrated to produce analgesia and sedation and attenuate hemodynamic responses to emergence from inhalational anesthetics, which suggests a potential use for this drug as a premedicant for general anesthesia. The authors examined hemodynamic interactions between dexmedetomidine and three commonly used intravenous anesthetic agents with markedly different hemodynamic effects. Conscious, chronically instrumented dogs received intravenous induction doses of ketamine, propofol, or etomidate, followed by continuous infusions of each drug at four different doses for 15-min intervals on different days. ⋯ However, ketamine significantly reduced left ventricular dP/dt50 compared to control in dogs premedicated with dexmedetomidine. Except for a significant reduction in systemic vascular resistance, dexmedetomidine did not significantly affect the hemodynamic response to induction of anesthesia with propofol. Similarly, dexmedetomidine did little to alter the hemodynamic response to induction of anesthesia with etomidate.(ABSTRACT TRUNCATED AT 250 WORDS)