Loss of Resistance, w/wo Stimulation, For Epidural Placement

Loss of Resistance With Nerve Stimulation Versus Loss of Resistance Alone; Effect on Success of Thoracic Epidural Placement.

The purpose of this randomized, observer-blinded, investigative trial is to determine if the use of electrical stimulation, compared to the traditional loss of resistance technique alone, improves the success rate of epidural catheter placement at an academic teaching institution.

All subjects will receive a thoracic epidural catheter placement at the level appropriate for their surgery and will be randomized to either have the epidural placed with a loss of resistance technique alone or loss of resistance technique with confirmation by nerve stimulation. In the traditional loss of resistance technique group, the epidural catheter will be placed after achieving loss of resistance to air. In the electrical stimulation group, following the location of the epidural space with a loss of resistance technique (using air), nerve stimulation will be utilized to elicit a myotomal contraction of the abdominal or thoracic wall. Nerve stimulation will be started at a pulse width of 0.3 ms and a frequency of 1 Hz and a current of 0.2mA.

Inclusion Criteria:

• Adults undergoing intra-thoracic or intra-abdominal procedures that normally would receive thoracic epidurals for post-operative analgesia will be eligible.

Exclusion Criteria:

• Subjects with contraindications to regional anesthesia:
• history of allergy to amide local anesthetics
• presence of a progressive neurological deficit
• patients that are on anticoagulant medications that prohibit placement of an epidural
• Systemic infection
• Infection at the site of placement