Remifentanil group had lower duration of procedure (2.5 ± 1.6 versus 4.6 ± 1.8 minutes, p < 0.001), higher pain reduction (53.7 ± 13.3 versus 33.5 ± 19.6, p < 0.001), lower failure rate (1 (2.1%) versus 15 (31.3%), p < 0.001), higher satisfaction (p = 0.005).
Remifentanil 
Fentanyl/midazolam
Failure rate 