[1] Stanford Univ, Sch Med, Ctr Adv Technol Surg, Stanford, CA 94305 USA
[2] Stanford Univ, Sch Med, Div Emergency Med, Stanford, CA 94305 USA
[3] Stanford Univ, Sch Med, Dept Anesthesia, Stanford, CA 94305 USA
[4] Stanford Univ, Sch Med, Dept Surg, Stanford, CA 94305 USA
[5] VA Palo Alto Hlth Care Syst, Patient Safety Ctr Inquiry, Palo Alto, CA USA