[1] Univ Tubingen, Dept Anesthesia & Intens Care Med, D-72074 Tubingen, Germany
[2] Harvard Univ, Brigham & Womens Hosp, Sch Med, Dept Anesthesiol,Perioperat & Pain Med,Div Card, Boston, MA USA
[3] Univ Colorado, Hlth Sci Ctr, Dept Anesthesiol,Perioperat & Pain Med, Denver, CO 80202 USA