Propofol-fentanyl versus midazolam-fentanyl: a comparative study of local sedation techniques for cataract surgery

Administering intravenous sedation in conjunction with intraoperative monitoring to cataract surgery patients is a widely accepted technique. Numerous articles report local sedation techniques for cataract surgery that are, in essence, abbreviated general anesthetic techniques for insertion of the retrobulbar block (RBB). Because of variations in levels of consciousness, a number of complications have been encountered with this specific patient population, ie, movement upon insertion of the RBB, intraoperative patient movement, confusion, hypotension, respiratory depression, and respiratory arrest. In an attempt to meet the specific needs of this patient population, a study comparing propofol-fentanyl with midazolam-fentanyl was initiated. Seventy-five (ASA 1 to 3) patients were randomly assigned to two groups: propofol-fentanyl (P/F) or midazolam-fentanyl (M/F). The mean age of patients in the P/F group was 71.1 +/- 13 SD, and the mean age in the M/F group was 74.4 +/- 8.8 SD. All patients entered the operating room unpremedicated. Before the RBB, patients in both groups were given a single intravenous dose of 50 micrograms fentanyl. Propofol (mean dose, 24.7 mg) or midazolam (mean dose, 1.58 mg) was then titrated to slurred speech or nystagmus. Patients' responses to the RBB were evaluated and recorded by an objective observer. The amnestic properties of both agents were evaluated by patient questioning at 10 minutes and 24 hours. Levels of discomfort were evaluated on a scale of 1 to 5, with 1 being extremely uncomfortable and 5 being noticeable without pain. Respiratory depressant effects of both techniques was assessed via continuous pulse oximetry. Results were analyzed using the chi 2 test, rank t test, and SD.(ABSTRACT TRUNCATED AT 250 WORDS)