[1] Univ Pittsburgh Med Ctr, Anesthesiol, Williamsport, PA USA
[2] MVM Hlth, Pain Med, East Stroudsburg, PA USA
[3] Ohio State Univ Wexner Med Ctr, Dept Anesthesiol, Columbus, OH USA
[4] Baylor Coll Med, Phys Med & Rehabil, Houston, TX USA
[5] VA Palo Alto Hlth Care Syst, Anesthesiol & Perioperat Care Serv, Palo Alto, CA USA
[6] Stanford Univ Sch Med, Dept Anesthesiol Perioperat & Pain Med, Stanford, CA USA
[7] Univ Wisconsin Madison, Dept Anesthesia, Divs Pain Med, Sch Med & Publ Hlth, Madison, WI USA
[8] Univ Pittsburgh Med Ctr, Anesthesiol, Williamsport, PA 17701 USA