PROPOFOL AND ALFENTANIL FOR SEDATION DURING PLACEMENT OF RETROBULBAR BLOCK FOR CATARACT-SURGERY

Study Objective: To determine if the addition of alfentanil to propofo l alone to provide adequate conditions for placement of a retrobulbar block prior to cataract surgery. Design: Randomized, double-blinded st udy. Setting: Outpatients at a university hospital. Patients: 40 adult s ASA physical status I, II, and III outpatients scheduled for electiv e cataract surgery. Interventions: Patients were randomly assigned to receive one of four drug combinations prior to the placement of a retr obulbar block: Group 1, propofol alone; Group 2, alfentanil 5 mu g/kg plus propofol; Group 3, alfentanil 10 mu g/kg plus propofol; Group 4, alfentanil 15 mu g/kg plus propofol. All patients were preoxygenated b y face mask for two minutes prior to drug administration. The quality of conditions for block placement were determined by: (1) assessing th e amount of movement by the patients while the block needle was in pla ce, (2) cooperativeness of the patients during the operation, (3) hemo dynamic side effects, (4) incidence and severity of respiratory depres sion, (5) incidence of nausea and vomiting, (6) recall of placement of the block, and (7) time to discharge from the hospital. Measurements and Main Results: The addition of alfentanil to propofol for sedation prior to placement of the retrobulbar block resulted in a dose-depende nt reduction in movement by the patients. However, the highest dose of alfentanil (15 mu g/kg) resulted in the greatest frequency (40% of th e patients in this group) of respiratory depression (SpO(2) < 90%). Al l patients were cooperative during the operation and responsive to ver bal command within 5 minutes of placement of the block. In addition, a ll of the patients denied being nauseated, having vomited, or recallin g block placement in the recovery room or the next day. Conclusions: T he combination of alfentanil and propofol may be used to sedate patien ts in order to limit movement and provide a cooperative, alert patient with stable hemodynamics and limited respiratory depression during pl acement of retrobulbar block prior to ophthalmic surgery. However, exc essive dosage of these drugs may result in hazardous respiratory depre ssion in this patient population. (C) 1996 by Elsevier Science Inc.