1. Neurocritical Care Service, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
2. Department of Anesthesiology and Pain Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
3. Department of Neurological Surgery, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
4. Harborview Injury Prevention and Research Center, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
5. Department of Neurology, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
6. Department of Nursing, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
7. Department of Emergency Medicine, Harborview Medical Center, University of Washington, Seattle, WA 98195, USA
8. Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA