1. Anesthesia Service, Veterans Affairs Palo Alto Health Care System, Palo Alto and Department of Anesthesiology, Perioperative, and Pain Medicine; Stanford University; Stanford California
2. Anesthesia Service, Veterans Affairs Medical Center, San Francisco, and Department of Anesthesiology and Perioperative Care; University of California; San Francisco California
3. Cooperative Studies Program Coordinating Center, Veterans Affairs Palo Alto Health Care System; Palo Alto California
4. Health Economics Resource Center,Veterans Affairs Palo Alto Health Care System; Palo Alto California