Comparison of Fentanyl, Remifentanil, Sufentanil and Alfentanil in 
Combination with Propofol for General Anesthesia: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND: Opioid analgesics are commonly used along with propofol during general anesthesia. Due to the dearth of data on the quality of anesthesia achieved with this combination, the present meta-analysis was carried out. METHODS: Electronic databases were searched for appropriate studies using a suitable search strategy. Randomized clinical trials comparing the combination of remifentanil/sufentanil/alfentanil with propofol with fentanyl and propofol, were included. The outcome measures were as follows: total propofol dose to achieve the desired general anesthesia; time of onset and duration of general anesthesia; depth of general anesthesia; and recovery time (time for eye-opening and time taken for extubation). Risk of bias was assessed and Forest plots were generated for eligible outcomes. The weighted mean difference [95% confidence intervals] was used as the effect estimate. RESULTS: Fourteen studies were included in the systematic review and 13 were included in the meta-analysis. Statistically significant differences were observed for remifentanil in comparison to fentanyl when combined with propofol: Propofol dose (in mg) -76.18 [-94.72, -57.64]; time of onset of anesthesia (min) -0.44 [-0.74, -0.15]; time taken for eye-opening (min) -3.95 [-4.8, -3.1]; and time for extubation (min) -3.53 [-4.37, -2.7]. No significant differences were observed for either sufentanil or alfentanil about the dose of propofol required and due to scanty data, pooling of the data could not be attempted for other outcome measures for either sufentanil or alfentanil. CONCLUSION: To conclude, we found that remifentanil has a statistically significant anesthetic profile than fentanyl when combined with propofol. Scanty evidence for both alfentanil and sufentanil precludes any such confirmation.