[1] Univ Maryland, Sch Med, Dept Surg, Div Cardiac Surg, Baltimore, MD 21201 USA
[2] Univ Maryland, Sch Med, Dept Surg, Program Trauma, Baltimore, MD 21201 USA
[3] Univ Maryland, Sch Med, Dept Anesthesiol, Baltimore, MD 21201 USA
[4] Univ Maryland, Med Ctr, R Adams Cowley Shock Trauma Ctr, Baltimore, MD 21201 USA