1. Graduate Medical Education, University of Minnesota, Minneapolis, MN, USA;
2. Department of Anesthesiology, University of Minnesota, Minneapolis, MN, USA;
3. Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA;
4. Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, USA;
5. Minneapolis VA Health Care System, Minneapolis, MN, USA;
6. Department of Neurology, University of Minnesota, Minneapolis, MN, USA