Study objective: To evaluate the effect of midazolam on the global perioperative experience, including patient satisfaction, postoperative nausea and vomiting, postoperative pain, and perioperative anxiety and amnesia.
Design: Prospective, randomized, placebo-controlled study.
Setting: Ambulatory surgical center affiliated with a tertiary-care hospital.
Patients: 88 ASA physical status I, II, and III patients scheduled for outpatient surgery.
Interventions: Patients were randomized into two groups to receive either 0.04 mg/kg of midazolam or placebo intravenously (IV) 20 minutes preoperatively.
Measurements: Perioperative measurements included blood pressure, heart rate, and oxygen saturation and the patient's level of anxiety; type of anesthetic administered; the anesthesiologist's guess at the treatment arm; perioperative dosages of fentanyl, morphine, and ondansetron; recovery room length of stay; frequency of nausea and vomiting, and level of postoperative pain in the 24 hours after surgery; the patient's overall satisfaction with the anesthetic, and whether the patient would recommend the premedication to a friend.
Main results: Patient demographics, type of surgery/anesthesia, vital signs, case duration, recovery duration, and postoperative pain were all similar between the midazolam and placebo groups. As expected, IV midazolam was an effective anxiolytic. There was no evidence of retrograde amnesia. Fewer patients in the midazolam group suffered from postoperative nausea than did those in the placebo group (25%vs. 50%;p = 0.03), despite receiving similar perioperative antiemetic and opioid administration. Similarly, fewer patients in the midazolam group experienced postoperative vomiting than placebo group patients (8%vs. 21%), although this difference did not reach statistical significance. Only 42% of patients in the placebo group would recommend their premedication to a friend, compared with 85% of patients in the midazolam group (p < 0.001).
Conclusions: In addition to the known anxiolytic effects of midazolam, midazolam premedication is an effective way to reduce the frequency of postoperative nausea, and perhaps vomiting, and increase patient satisfaction.