Propofol infusion for sedation during spinal anesthesia.

PURPOSE: The dose and time course of propofol infusion required to induce rapid sedation without oversedation during spinal anesthesia were investigated.

METHODS

Forty patients scheduled for spinal and epidural anesthesia were studied. After premedication with intramuscular midazolam 0.04 mg.kg(-1), an epidural catheter was inserted, followed by spinal anersthesia at L4-L5 with 0.5% hyperbaric tetracaine with epinephrine. The infusion of propofol was started with 10 mg.kg(-1).h(-1) and was decreased to 5 mg.kg(-1).h(-1) at spontaneous eye closure. According to the increase or decrease of the sedation level, the infusion does was decreased or increased to half or twice the initial dose, respectively, to keep the Observer's Assessment of Alertness Sedation (OAAS) score at 3 or 4.

RESULTS

Eye closure was observed at 1.0 +/- 0.4 min after the start of insusion. The maintenance insusion dose to keep the OAAS score at 3 or 4 was about 2.5 mg.kg(-1).h(-1).

CONCLUSION

Propofol infusion, starting with 10 mg.kg(-1).h(-1), decreasing to 5 mg.kg(-1).h(-1) after 1 minute, and then decreasing to 2.5 mg.kg(-1).h(-1) after another min induced rapid onset of sedation and kept the OAAS score at 3 or 4 during spinal anesthesia.