[Use of high-dose dexmedetomidine infusion for anesthesia and sedation in a patient for microlaryngeal surgery maintained with spontaneous breathing].

We experienced the anesthetic management using high-dose dexmedetomidine for microlaryngeal surgery maintaining spontaneous breathing. The anesthesia was maintained with dexmedetomidine infusion (initial dose 6 microg x kg(-1) x hr(-1) over 10 min followed by continuous infusion of 0.5 microg x kg(-1) x hr(-1)), intermittent small doses of fentanyl and topical application of lidocaine on the tongue, pharynx and larynx. The infusion of dexmedetomidine was increased over 30 min to 3 microg x kg(-1) x hr(-1) to reach the adequate sedation level and maintained at this rate for a further 15 min during the operation. During the whole perioperative period, there was no respiratory depression as measured by arterial blood gas analysis that recorded normal PaCO2 in the patient breathing supplemental oxygen. Hypotension (systemic arterial blood pressure less than 100 mmHg) occurred twice during dexmedetomidine administration, but was normolized by ephedrine administration. The preservation of respiratory drive offers the possibility that this anesthetic technique may be another method for providing anesthesia for the patient with a difficult airway. Moreover, there is one consensus on the importance of the basic principle that adequate topical or intravenous anesthesia is also essential during high-dose dexmedetomidine infusion.