Efficacy of Two Bolus Doses of Remifentanil on the Incidence of Coughing During Emergence of Anesthesia

This study is designed to compare the effects of two bolus doses of intravenous remifentanil given prior to the emergence of anesthesia: * on the incidence of perioperative coughing * on the time needed for the emergence of a desflurane-based anesthesia * on the incidence of sore throat after extubation. The investigators hypothesis is that the use of a higher remifentanil bolus dose (0.5 mcg/kg) given prior to emergence of a desflurane-based anesthesia will reduce the incidence of perioperative coughing when compared to a lower dose of remifentanil (0.25 mcg/kg).