1 Sections of Orthopedic and Regional Anesthesiology, Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce Street, Dulles 7th, Philadelphia, PA 19104, USA. Electronic address: Nabil.Elkassabany@uphs.upenn.edu.
2 Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University School of Medicine, Anesthesiology and Perioperative Care Service, VA Palo Alto Health Care System, 3801 Miranda Avenue (112A), Palo Alto, CA 94304, USA. Electronic address: emariano@stanford.edu.