REMIFENTANIL VERSUS REMIFENTANIL MIDAZOLAM FOR AMBULATORY SURGERY DURING MONITORED ANESTHESIA CARE/

Background. This study was designed to define the appropriate dose of remifentanil hydrochloride alone or combined with midazolam to provide satisfactory comfort and maintain adequate respiration for a monitore d anesthesia care setting. Methods: One hundred fifty-nine patients sc heduled for outpatient surgery participated in this multicenter, doubl e-blind study. Patients were randomly assigned to one of two groups: r emifentanil, 1 mu g/kg, given over 30 s followed by a continuous infus ion of 0.1 mu g.kg(-1).min(-1) (remifentanil); remifentanil, 0.5 mu g/ kg, given over 30 s followed by a continuous infusion of 0.05 mu g.kg( -1).min(-1) (remifentanil + midazolam). Five minutes after the start o f the infusion, patients received a loading dose of saline placebo (re mifentanil) or midazolam, 1 mg, (remifentanil + midazolam). If patient s were not oversedated, a second dose of placebo or midazolam, 1 mg, w as given. Remifentanil was titrated (in increments of 50% from the ini tial rate) to limit patient discomfort or pain intraoperatively, and t he infusion was terminated at the completion of skin closure. Results: At the time of the local anesthetic, most patients in the remifentani l and remifentanil + midazolam groups experienced no pain (66% and 60% , respectively) and no discomfort (66% and 65%, respectively). The fin al mean (+/- SD) remifentanil infusion rates were 0.12 +/- 0.05 mu g.k g(-1).min(-1) (remifentanil) and 0.07 +/- 0.03 mu g.kg(-1).min(-1) (re mifentanil + midazolam). Fewer patients in the remifentanil + midazola m group experienced nausea compared with the remifentanil group (16% v s. 36%, respectively; P < 0.05). Four patients (5%) in the remifentani l group and two patients (2%) in the remifentanil + midazolam group ex perienced brief periods of oxygen desaturation (Sp(O2) < 90%) and hypo ventilation (< 8 breaths/ min). Conclusions: Remifentanil alone or com bined with midazolam provided adequate analgesia and maintained adequa te respiration at the doses reported. The low dose of remifentanil com bined with 2 mg midazolam, compared with remifentanil alone, resulted in fewer side effects, slightly greater sedation, and less anxiety.