True patient‐controlled sedation

A modified patient-controlled analgesia pump provided doses of propofol 3 mg or midazolam 0.1 mg in 0.3 ml, over 5.4 s, with no lockout, during transvaginal oocyte retrieval. Alfentanil 0.2 mg was administered at three points during the procedure, and on request. Patients were randomly assigned to receive either propofol (25 patients) or midazolam (22 patients). The mean age, weight, duration of procedure and dose of alfentanil were similar in both groups. Onset of sedation with propofol or midazolam took 70.6 (SD 22.4) and 106.3 (50.7) s respectively. Mean doses over the first 5 min were midazolam 2.7 (1.2) mg, and propofol 54 (18) mg. Thereafter requirements decreased: midazolam 0.065 (0.065) mg.min-1, propofol 2.1 (1.3) mg.min-1. All patients successfully completed the procedure; none required additional sedation. P-deletion, reaction time, and critical flicker fusion tests revealed similar depression in both groups immediately postoperatively. After 30 min the p-deletion and critical flicker fusion scores were still impaired in the midazolam, but not in the propofol, group.