[1] Duke Univ, Dept Anesthesiol, Durham, NC 27708 USA
[2] Univ Washington, Harborview Injury Prevent & Res Ctr, Seattle, WA 98195 USA
[3] Univ Washington, Dept Epidemiol, Seattle, WA 98195 USA
[4] Univ Washington, Dept Med, Div Cardiol, Seattle, WA 98195 USA
[5] Univ Washington, Dept Anesthesiol & Pain Med, Seattle, WA 98195 USA