Received from the Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri. Part I of this review article appeared in the previous issue (Anesth Analg 1990;70:303--415). Accepted for publication October 10, 1989. Address correspondence to Dr. White, Department of Anesthesiology, Box 8054, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110. The authors thank their chairman, William D. Owens, MD, for his enthusiastic support of this project. They also thank Sidney Gold- ring, MD, for his constant inspiration as both a clinician and scientist. In addition, they gratefully acknowledge the assistance of Diane Disbrow and Gerri Neumann in the preparation of this manuscript.