Filtering Epidural Medications

I am a nurse at RVMC and we currently use special tubing for all of our patients receiving epidural medication for pain control via a drip after surgery. The tubing fits our Plum XL pumps but it is not filtered. Do your institutions require epidural medications to be run through filtered tubing? Have you read any articles pertaining to the need to filter the medication?
Please respond if you have any information as we have had a sentinal event related to epidurals and are trying to revise our policy to meet best practice.
Thanks!

Karen Bales, RN BSN
Clinical Education
RVMC
Medford, OR 97504
1-800-944-7073 ext 11674