RESUMEN
BACKGROUND: It has been previously reported that subhypnotic doses of propofol could offer an advantage over midazolam for premedication. This study was designed to test the hypothesis that a 20 mg IV dose of propofol would be more effective than a standard 2 mg IV dose of midazolam for reducing acute anxiety prior to induction of anesthesia. METHODS: One hundred twenty outpatients scheduled to undergo orthopedic surgery were randomly assigned to one of three study groups: control (saline); propofol (20 mg); or midazolam (2 mg). Immediately before administering the study medication, each patient evaluated their level of acute anxiety and sedation on 11point verbal rating scales (VRSs) 0=none- 10=highest, and they were also shown a picture. Upon arrival in the OR ~5 min after administering the study medication, anxiety and sedation levels were reassessed and a second picture was shown. At discharge from the recovery area, anxiety and sedation levels and their ability to recall the two pictures were reassessed. RESULTS: Compared to the saline group, both propofol and midazolam produced significant increases in the patient's level of sedation upon entering the OR (+2.5±2.4 vs. +4.6±2.5 and +5.2±2.3, respectively [p<0.001]). Propofol was effective as midazolam compared to saline in reducing the patient's level of preinduction anxiety (from 3.2±2.2 to1.8±1.8 vs. 3.1±2.2 to 2.3±2.1 and 2.7±1.8 to 2.8±2.1, respectively). Propofol produced more pain on injection and midazolam significantly reduced recall of the second picture. CONCLUSIONS: When administered ~5 min prior to entering the OR, propofol, 20mg IV, was as effective as midazolam 2mg IV in reducing anxiety.