[Sedation and analgesia with propofol plus low-dose ketamine for retrobulbar block]

To determine if adding ketamine to propofol provides better sedation than propofol alone for patients receiving a retrobulbar block for eye surgery.

Randomized double-blind trial enrolling 50 patients receiving a retrobulbar nerve block for eye surgery. Patients were randomly assigned to 2 groups. In the propofol group sedation was induced with 0.45 mg x kg(-1) of propofol. In the ketamine plus propofol group sedation was induced with 0.45 mg x kg(-1) of propofol plus 0.25 mg x kg(-1) of ketamine. We recorded patient characteristics (age, weight, ASA class, height, sex), hemodynamic variables (blood pressure, heart rate), puncture conditions, sedation (score on the Observer's Assessment of Alertness/Sedation [OAA/S] scale), ventilation (end-tidal carbon dioxide pressure, apneas, need for reanimation maneuvers, pulse oximetry), time until onset of effect, duration of effect, and amnesia.

No significant differences were observed in time to onset, duration of effect, patient characteristics, hemodynamic or respiratory variables, or amnesia. Sedation assessed on the OAA/S-scale was lower in the propofol group and the puncture conditions were significantly better in the ketamine plus propofol group. The only adverse psychomimetic reaction was transient agitation, observed in 2 propofol group patients.

Low doses of ketamine associated with propofol improve puncture conditions for performing a retrobulbar block without increasing unwanted side effects.