Dexmedetomidine used to provide hypotensive anesthesia during middle ear surgery

This study was carried out to assess the hypotensive effect of low dose dexmedetomidine (DEX) infusion during middle ear surgery. 42 ASA grades I and II patients of either sex aged 18-45 years undergoing elective middle ear surgery were randomly divided into two groups of 21 each. Group I received placebo bolus and infusion of saline at a rate similar to DEX in Group II. Group II received 10-15 min prior to induction of anesthesia 1 µg/kg IV bolus DEX diluted in 10 ml of normal saline over 10 min. Immediately thereafter an infusion of 0.4 µg/kg/hr of DEX commenced. Standard anesthetic technique was used. Halothane was titrated to achieve a mean arterial pressure 30% below the control value (value taken just after premedication). We observed that a statistically significant reduction in the percentage of halothane required to reduce MAP 30% below control value occurred in patients receiving DEX infusion (1.3 ± 0.4%) in comparison to those receiving placebo (3.1 ± 0.3%). Patients receiving DEX infusion had a better surgical field. The mean awakening time was significantly reduced in patients of Group II (9.1 ± 2.7 min) when compared to patients of Group I (12.8 ± 2.2 min).We conclude that DEX can be safely used to provide hypotensive anesthesia during middle ear surgery.