作者单位:Stanford Univ, Sch Med, Dept Anesthesiol Perioperat & Pain, Stanford, CA 94305 USA[1]Stanford Univ, Dept Pediat, Sch Med, Div Crit Care, Stanford, CA 94305 USA[2]Kapiolani Med Ctr Women & Children, Div Crit Care, Dept Pediat, Honolulu, HI USA[3]