Epidural Volume Extension During a Combined Spinal-Epidural Technique for Labor Analgesia.

Combined spinal-epidurals (CSE) involve the injection of pain relief medication into the cerebral spinal fluid (CSF) and the insertion of an epidural catheter in the epidural space to continue to give pain relief medication. During a CSE, after injection of the medication in the CSF and before inserting the epidural catheter, if normal saline is injected into the epidural space, there may be an increase in pain relief and an increase in the level of numbness. This injection of saline in the epidural space to increase pain relief and numbness is termed epidural volume extension (EVE). The purpose of this study is to determine if there is a benefit for EVE to improve labor analgesia (pain relief) using CSE in pregnant laboring patients.