1. *Assistant Professor of Anesthesiology, †Associate Professor of Anesthesiology and Physiology, ‡Anesthesiology Resident, #Associate Professor of Anesthesiology, Department of Anesthesiology, College of Medicine, Mayo Clinic, Rochester, Minnesota. §Assistant Professor of Biostatistics, Department of Health Sciences Research, College of Medicine, Mayo Clinic. ‖Professor of Orthopedic Surgery, Depar