1. Department of Anesthesiology and Perioperative Medicine, University of Alabama Birmingham, Birmingham, Alabama,
2. Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee
3. Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas, Texas
4. Rocky Mountain Regional Veterans Affairs Center, Denver, Colorado, Department of Anesthesiology, University of Colorado School of Medicine, Aurora, Colorado, Medical Corps, United States Army, Washington, DC
5. Department of Anesthesiology, Orthopedics and Rehabilitation, and Surgery, Larner College of Medicine, University of Vermont, Burlington, Vermont