[1] Childrens Natl Hosp, Div Anesthesiol Pain & Perioperat Med, Washington, DC USA
[2] Childrens Natl Hosp, Joseph E Robert Jr Ctr Surg Care, Washington, DC USA
[3] Eastern Virginia Med Sch, Norfolk, VA USA
[4] George Washington Univ, Sch Med & Hlth Sci, Washington, DC USA
[5] George Washington Univ, Sch Med & Hlth Sci, Childrens Natl Hosp, Div Cardiac Anesthesia, Washington, DC USA
[6] Childrens Natl Hosp, Div Anesthesiol Pain & Perioperat Med, 111 Michigan Ave NW, Washington, DC 20010 USA