1. Chief, Anesthesia Service, USVA Hospital, Ann Arbor, Michigan 48105, and Assistant Professor, University of Michigan Medical Center, Ann Arbor, Michigan 48104
2. Professor and Chairman, Department of Biostatistics, School of Public Health. University of Michigan, Ann Arbor, Michigan 48104
3. Resident, Department of Anesthesiology, University of Michigan Medical Center, Ann Arbor, Michigan 48104
4. Research Technologist, USVA Hospital, Ann Arbor, Michigan 48105