1. Department of Anesthesiology, Walter Reed National Military Medical Center , Bethesda, MD 20814, USA
2. Department of Anesthesiology, Uniformed Services University , Bethesda, MD 20814, USA
3. Department of Anesthesia Services, Alexander T. Augusta Military Medical Center , Fort Belvoir, VA 22060, USA
4. School of Medicine, Uniformed Services University , Bethesda, MD 20814, USA
5. Department of Orthopedic Surgery, Walter Reed National Military Medical Center , Bethesda, MD 20814, USA
6. Orthopaedic Service, Department of Surgery, Memorial Sloan Kettering Cancer Center , New York, NY 10065, USA
7. Department of Research Programs, Walter Reed National Military Medical Center , Bethesda, MD 20814, USA