Background: The short onset and offset of remifentanil may allow for accurate dosing of sedative effect with few side-effects and rapid recovery. In this study remifentanil is compared with propofol for sedation during successful regional anaesthetic blocks.
Methods: After informed consent was given, 125 patients undergoing surgery under spinal or brachial plexus anaesthesia were randomized to receive, either propofol: bolus 500 microg/kg plus initial infusion 50 microgkg/min or remifentanil: bolus 0.5 microg/kg plus initial infusion 0.1 microgkg/min. Study drug infusion rate was titrated throughout the procedure according to level of sedation and side-effects. Pain, discomfort, sedation level and side-effects were recorded at regular intervals until discharge from the post operative care unit (PACU).
Results: Two patients in the remifentanil group versus ten in the propofol group were treated for discomfort or pain during surgery (P<0.02). Due to a significantly higher rate of respiratory depression (46% vs. 19% with propofol, P<0.01) the mean remifentanil infusion rate was decreased to 0.078 +/- 0.028 microgkg/min, whereas it was kept stable with propofol. Propofol patients had significantly higher (P<0.05) sedation levels and experienced more frequent amnesia of the procedure. Eleven propofol patients experienced pain at injection site, versus two remifentanil patients (P<0.02). Nausea and vomiting were more frequent in the remifentanil patients during infusion (27% vs. 2% in the propofol group, P<0.001) but similar postoperatively. Time to discharge from PACU was similar in the two groups.
Conclusion: Propofol results in less respiratory depression and nausea when sedation is needed during a case with a successful regional block. Remifentanil may be considered as an alternative if pain during the procedure is a major concern or if amnesia is contraindicated.