Developed by the Task Force on Pain Management, Chronic Pain Section: Peter R. Wilson, M.B.B.S., Ph.D. (Chair), Rochester, Minnesota; Robert A. Caplan, M.D., Seattle, Washington; Richard T. Connis, Ph.D., Woodinville, Washington; Hugh C. Gilbert, M.D., Chicago, Illinois; Eric J. Grigsby, M.D., Napa, California; J. David Haddox, D.D.S., M.D., Atlanta, Georgia; Alan M. Harvey, M.D., M.B.A., Springfield, Massachusetts; Wilhelmina C. Korevaar, M.D., Bala Cynwyd, Pennsylvania; Timothy R. Lubenow, M.D., Chicago, Illinois; and Dana L. Simon, M.D., West Des Moines, Iowa.Submitted for publication December 13, 1996. Accepted for publication January 8, 1997. Supported by the American Society of Anesthesiologists, under the direction of James F. Arens, M.D., Chairman of the Ad-Hoc Committee on Practice Parameters. Approved by the House of Delegates, October 23, 1996. A list of the articles used to develop these Guidelines is available by writing to the American Society of Anesthesiologists.Address reprint requests to the American Society of Anesthesiologists, 520 North Northwest Highway, Park Ridge, Illinois 60068–2573.