If you choose to have an epidural or need one for medical reasons you may be able to discuss the types of medications you would prefer as well as play a role in deciding how you would like your epidural to be administered.
You are unlikely to meet the anaesthetist during the pregnancy and in some cases the woman will have limited ability to express her wishes, especially if she is in strong labour (usually when the epidural is requested!)
It may be that the partner or support person will need to play a role in expressing the woman's wishes or that you write your preferences on a
birth plan. Be aware that birth plans are meant to be flexible, and act as a guide for you and your caregiver(s). There have been cases where a woman's birth plan has stated "No Epidural" only to be revoked by her once in labour (or visa versa).