[1] Virginia Mason Med Ctr, Dept Anesthesiol, Seattle, WA 98101 USA
[2] Univ Washington, Dept Anesthesiol, Seattle, WA 98195 USA
[3] St Lukes Roosevelt Hosp, Dept Anesthesiol, New York, NY USA
[4] Mayo Clin, Dept Anesthesiol, Rochester, MN USA
[5] Mayo Clin, Dept Neurol, Rochester, MN USA
[6] Med Coll Wisconsin, Dept Anesthesiol, Milwaukee, WI 53226 USA
[7] Harvard Univ, Massachusetts Gen Hosp, Dept Anesthesiol, Boston, MA 02115 USA
[8] Northwestern Univ, Childrens Mem Hosp, Dept Anesthesiol, Chicago, IL 60614 USA