1. 1Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon.
2. 2Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon.
3. 3Biostatistics and Design Program, Oregon Health & Science University, Portland, Oregon.
4. 4Departments of Medicine and Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon.
5. 5Department of Anesthesiology, University of Washington, Seattle, Washington.
6. 6Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, Oregon.
7. 7Department of Anesthesiology, University of Michigan Medicine, Ann Arbor, Michigan.
8. Anesthesiology, University of Virginia, Charlottesville, Virginia.
9. Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina.
10. Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan.
11. Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee.
12. Anesthesiology, Yale School of Medicine, New Haven, Connecticut.
13. Anesthesiology & Pain Medicine, University of Washington, Seattle, Washington.
14. Department of Anesthesia and Perioperative Care, University of California-San Francisco, San Francisco, California.
15. Anesthesiology, Perioperative and Pain Medicine, University of Utah, Salt Lake City, Utah.