You are caring for a patient undergoing thoracotomy. You decide to use dexmedetomidine intraoperatively as an adjunct for postoperative analgesia. Which is the most likely hemodynamic disturbance after a loading dose of 1 µg/kg?

Dexmedetomidine is a selective α2-receptor agonist with sympatholytic, sedative and analgesic effects. Stimulation of α2 receptors in the central nervous system results in sedation and analgesia (Figure 1). Interaction with presynaptic α2 adrenoreceptors inhibits the release of norepinephrine, which can lead to hypotension and bradycardia, the most common hemodynamic side effects. Rapid administration of a large dose of dexmedetomidine may result in hypertension because in high concentrations, dexmedetomidine will interact with α receptors in the vasculature, resulting in vasoconstriction. Ventricular fibrillation, tachycardia and heart block are rarely associated with the administration of dexmedetomidine.

Anesthesiology Continuing Education (ACE) is a...

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