[1] Boston Childrens Hosp, Dept Anesthesiol Crit Care & Pain Med, Boston, MA USA
[2] Harvard Med Sch, Dept Anaesthesia, Boston, MA USA
[3] Childrens Hlth Syst Texas, Dept Pediat Anesthesiol & Pain Management, Dallas, TX 77030 USA
[4] Univ Texas Southwestern Med Ctr, Dept Anesthesiol & Pain Management, Dallas, TX 75390 USA
[5] Childrens Hosp Los Angeles, Dept Anesthesiol Crit Care Med, Los Angeles, CA USA
[6] Ann & Robert H Lurie Childrens Hosp Chicago, Chicago, IL USA
[7] Northwestern Univ, Dept Anesthesiol, Feinberg Sch Med, Chicago, IL USA
[8] Outcomes Res Consortium, Cleveland, OH USA