[1] Johns Hopkins Sch Med, Dept Emergency Med, Baltimore, MD USA
[2] Beckman Coulter, Brea, CA USA
[3] Johns Hopkins Whiting Sch Engn, Malone Ctr Engn Healthcare, Baltimore, MD USA
[4] Johns Hopkins Sch Med, Dept Med, Div Nephrol, Baltimore, MD USA
[5] Ctr Dis Dynam Econ & Policy, Washington, DC USA