I don't alter my technique. My partners and I started doing combined spinal-epidurals (CSE) for labor analgesia several years ago and have never looked back. Arrow makes what I think is the best CSE kit. To the epidural space with the Tuohy, pop intrthecally with the 26 gauge spinal needle, inject ropivicaine 2mg and sufentanil 5 mcg, pull out the spinal needle, thread the catheter, and you're done! Just hook up the infusion. We use ropivicaine .2% with sufentanil .5 mcg/ml and run it at 12 ml/hr for just about every lady. Our redose rate is very, very low, unlike the bupivicaine/fentanyl stuff we used before.
Many advantages in my humble opinion. One does not have to dose the catheter which saves time, and is safer since there is virtually no chance of a high block. The intrathecal dose given isn't enough to give a high block, or at least I've never seen one in the 3 or 4 years I've been doing it. Redose rate is VERY low, yet another advantage for the busy practitioner. I've had one post-dural puncture headache in the last eight months and our delivery unit does between 175-200 deliveries a month.
Not to mention the superior safety profile of ropivicaine. One disadvantage is the women itch for about thirty minutes after the procedure from the sufentanil, but usually resolves on it's own. The delivery nurses love it and so do the patients. The CRNAs love it too because at my facility we have an OB CRNA who does the redosing. Drastically reduces their workload.