1. Department of Anesthesiology and Critical Care, University of Chicago Medical Center, Chicago, Illinois
2. Department of Anesthesia, Emory University, Atlanta, Georgia
3. Department of Anesthesiology, Northwestern University, Chicago, Illinois
4. Feinberg School of Medicine, Northwestern University, Chicago, Illinois
5. Department of Public Health Services, University of Chicago, Chicago, Illinois
6. Department of Obstetrics and Gynecology, The Ohio State University Wexner Medical Center, Columbus
7. Department of Anesthesia and Critical Care, University of Chicago Medical Center, Chicago, Illinois
8. Department Obstetrics & Gynecology, University of Chicago Medical Center, Chicago, Illinois
9. Department of Anesthesiology, Perioperative Medicine and Pain Management, University of Miami Miller School of Medicine, Miami, Florida