 Following completion of preprocedure sedation assessments, patients will be randomly assigned to 1 of the 2 i.v. treatment groups at a 4:1 AQUAVAN. Injection: midazolam HCl allocation ratio. To ensure that a distribution of ages is obtained, enrollment will be stratified into 2 equal-size groups by age 65 to 72 years of age and 72 years of age. Randomization will be stratified by site within each age group. All patients will receive fentanyl citrate injection as an analgesic pretreatment. Supplemental doses of fentanyl citrate injection may be administered if the patient reports pain or if inadequate analgesia is present as demonstrated by increased heart rate andor blood pressure in the presence of adequate sedation. 