Remifentanil versus remifentanil/midazolam for ambulatory surgery during monitored anesthesia care

Anesthesiology. 1997 Jul;87(1):51-7. doi: 10.1097/00000542-199707000-00007.


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 monitored anesthesia care setting.

Methods: One hundred fifty-nine patients scheduled for outpatient surgery participated in this multicenter, double-blind study. Patients were randomly assigned to one of two groups: remifentanil, 1 microgram/kg, given over 30 s followed by a continuous infusion of 0.1 (remifentanil), remifentanil, 0.5 microgram/kg, given over 30 s followed by a continuous infusion of 0.05 (remifentanil+midazolam). Five minutes after the start of the infusion, patients received a loading dose of saline placebo (remifentanil) or midazolam, 1 mg, (remifentanil+midazolam). If patients were not oversedated, a second dose of placebo or midazolam, 1 mg, was given. Remifentanil was titrated (in increments of 50% from the initial rate) to limit patient discomfort or pain intraoperatively, and the infusion was terminated at the completion of skin closure.

Results: At the time of the local anesthetic, most patients in the remifentanil and remifentanil+midazolam groups experienced no pain (66% and 60%, respectively) and no discomfort (66% and 65%, respectively). The final mean (+/-SD) remifentanil infusion rates were 0.12 +/- 0.05 (remifentanil) and 0.07 +/- 0.03 (remifentanil+midazolam). Fewer patients in the remifentanil+midazolam group experienced nauses compared with the remifentanil group (16% vs. 36%, respectively; P < 0.05). Four patients (5%) in the remifentanil group and two patients (2%) in the remifentanil+midazolam group experienced brief periods of oxygen desaturation (SpO2 < 90%) and hypoventilation (< 8 breaths/ min).

Conclusions: Remifentanil alone or combined with midazolam provided adequate analgesia and maintained adequate respiration at the doses reported. The low dose of remifentanil combined with 2 mg midazolam, compared with remifentanil alone, resulted in fewer side effects, slightly greater sedation, and less anxiety.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analgesics, Opioid / administration & dosage*
  • Anesthesia*
  • Anesthetics, Intravenous / administration & dosage*
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Midazolam / administration & dosage*
  • Middle Aged
  • Piperidines / administration & dosage*
  • Remifentanil


  • Analgesics, Opioid
  • Anesthetics, Intravenous
  • Piperidines
  • Remifentanil
  • Midazolam