[1] Univ Maryland, Sch Med, R Adams Cowley Shock Trauma Ctr, Div Trauma Anesthesiol,Dept Anesthesiol, 22 South Greene St, Baltimore, MD 21201 USA
[2] Univ Maryland, Sch Med, R Adams Cowley Shock Trauma Ctr, Div Trauma Anesthesiol,Dept Anesthesiol,Educ, 22 South Greene St, Baltimore, MD 21201 USA
[3] Univ Maryland, Sch Med, Div Crit Care Med, Baltimore, MD 21201 USA