[1] Vanderbilt Univ, Sch Nursing, Nashville, TN 37240 USA
[2] Univ So Calif, Los Angeles Cty Med Ctr, Dept Anesthesiol, Los Angeles, CA 90033 USA
[3] Massachusetts Assoc Nurse Anesthestists, Boston, MA USA
[4] Wagner Coll, Sch Nursing, Staten Isl, NY 10301 USA
[5] Vanderbilt Addict Ctr, Dept Psychiat, Nashville, TN USA