Randomized Controlled Trial of Combined Lidocaine - Chlorprocaine in Labor Epidural Analgesia.

we aim to examine whether selective nociceptive analgesia can be obtained in epidural analgesia for women in labor by using a combination of lidocaine (opens TPRV-1 and TPRA-1 channels) and chlorprocaine (polarized local anesthetic)

Study participants will receive lidocaine alone

study participants randomized to this study arm will receive a a 50:50 mixture of both drugs - where all drugs are administered in concentrations based on their ED50 doses, together with epidural opioids (fentanyl)