There is a clinical profile of potency for motor block for the pipecolylxylidines when administered spinally: low, intermediate, and high for ropivacaine, levobupivacaine, and bupivacaine, respectively.

Maintenance of epidural analgesia with PIEB compared with CEI resulted in a lower incidence of maternal motor block and instrumental vaginal delivery.

This study suggests a potency hierarchy of spinal bupivacaine > levobupivacaine > ropivacaine.

No abstract

This study determined the minimum analgesic doses of fentanyl and sufentanil for epidural anesthesia in the first stage of labor. The sufentanil/fentanyl potency ratio was 5.9. This ratio may be used to establish the equivalent doses for fentanyl and sufentanil for epidural analgesia in labor.