Have you noticed any problems with decels and fentanyl-only spinals in pregnant women? Last night my attending was discussing how nobody can figure out why solo fentanyl intrathecal causes decels in patients, yet it's less common (but still occurs) when fentanyl is given with bupivicaine. Epidural clonidine supposedly has a risk of 30% of patients developing fetal decels. That makes some sense if clonidine passes to the fetus. I haven't looked any of this up myself, but this particular attending is like a walking encyclopedia of medicine, so I suspect his assertions are well founded. This came up after I suggested doing a CSE on an uncomfortable woman ~5 cm dilated (multiparous) having scattered late decels. My attending wanted me to do a straight epidural so future decels wouldn't be blamed on our spinal injection (I would have done 2.5 mg bupi with 20 mcg fent). The literature suggests this has something to do with fetal head engagement vs disengagement- if it's not engaged, decels are more common. The mechanism of this phenomenon is something of a mystery.
In response to the walking epidural issue- all our patients are on bedrest once the epidural goes in. It makes sense that you would be wide open to a lawsuit if a patient fell with a so-called walking epidural.
If I remember correctly there was some data about prolonged decelerations after intrathecal (Fentanyl + Bupivacaine) in the context of CSE for labor, and there was also data about fetal decelerations after IV Fentanyl in Parturients, both these things make physiological sense ( Uterine hypo perfusion for the first and fetal fentanyl effect for the second).
There was also some data about uterine tetany after intrathecal Fentanyl given late in labor.
I don't recall any solid data about Fentanyl given alone intrathecally causing decelerations, but any effective analgesia, especially if fast acting like a spinal, could cause rapid engagement of the head, because of pelvic relaxation, and consequently cause variable decelerations.
Anyway I am in no way a "walking encyclopedia" like your attending, and this is why he is a big shot academic guy and I am a simple private practice anesthesiologist
Returning to the main subject, I don't like walking epidurals, and I haven't done one in years, but if for any mysterious reason you find yourself compelled to do one, I still think the safest way would be a CSE with a narcotic only spinal during the ambulatory period followed by bupivacaine epidural and bed rest.
