[1] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Dept Emergency Med, Boston, MA 02114 USA
[2] Harvard Univ, Massachusetts Gen Hosp, Sch Med, Boston MedFlight Crit Care Transport Serv, Boston, MA 02114 USA
[3] Boston Univ, Sch Med, Dept Surg, Boston, MA 02118 USA