After consent patients will be randomized to one of the two groups: Control Group or the Experimental Group. Patients will be blinded to the group assignment.
In each subject prior to labor epidural placement, intravenous access will be obtained and if indicated fluid bolus will be given. There after heart and lung monitors will be placed. Procedure will be placed in sitting position. Standard epidural kit will be used.
In the Control Group the patient will be seated. Low back area will be prepped and draped in a sterile fashion. Lumbar interspaces will be identified clinically and epidural catheter will be inserted in the interspace deemed most appropriate. Epidural space will be accessed using loss of resistance to air technique. Once identified, a 20g open tip catheter will be placed can into the space.
In the Experimental Group, subjects back will be scanned with an Ultrasound probe. The interspace L5/S1, the lowest interspace in the spine will be identified and marked with the marker on the skin. Thereafter epidural catheter will be place using the exactly the same technique as used in the control group.
Once in place, catheter will be aspirated to rule out any intravascular placement. Thereafter a test dose composed of 45 mg lidocaine and 15 microgram epinephrine will be injected via the catheter to rule out any misplacement of catheter either in the intrathecal space or blood vessels. Once proper placement confirmed, catheter will be dose with 10 ml 0.25% bupivacaine in 5 ml boluses.
The extent of block before the surgery will be evaluated at 30 minutes post injection. Dermatomal level will be assessed on each side using ice. S1 and S2 dermatomal blockage will be specifically assessed on each side by testing lateral margin of each foot (S1 dermatome) and medial side of the popliteal fossa ( S2 dermatome).
Thereafter catheter will be connected to epidural solution containing 0.1% bupivacaine and 2 mic of Fentanyl per ml. Starting dose will be 10 ml per hr with bolus dose 5 ml q 30 minutes self administered by patient if needed.
If pain relief is inadequate top-up doses will be given consisting of 5 ml 0.25% bupivacaine times two 20 minutes part if needed. If no relief, dermatomal level will be reassessed. If ones sided or unequal, catheter will be pulled back I-2 cm and re-dosed with bupivacaine 0.25% 5 ml times two if needed over twenty minutes. If still no relief and inadequate level, catheter will be replaced.
Epidural catheter will be left in place till delivery. Patients will be clinically monitored as part of routine anesthetic management. Once they deliver catheter is removed by nurses in the labor and delivery unit and patients are sent to floor for recovery. Last evaluation will take place on post delivery day number one to evaluate patient satisfaction and address any concern patients may have.
Primary End points:
Primary purpose is to assess the ability of L5/S1 catheter to numb S1 or S2 dermatomes in comparison to routine placement of epidural catheter Secondary outcome to be assessed VAS, catheter manipulation or replacement between the two groups.
