作者单位:Intermt Med Ctr, Dept Med, Div Pulm, Murray, UT USA[1]Stanford Univ, Dept Anesthesia, Stanford, CA 94305 USA[2]Beth Israel Deaconess Med Ctr, Dept Anesthesia, Boston, MA 02215 USA[3]Stanford Univ, Dept Med, Div Cardiovasc Med, Stanford, CA 94305 USA[4]Univ Chicago, Dept Anesthesia, Chicago, IL 60637 USA[5]