[1] Duke Univ, Med Ctr, Dept Anesthesiol, Div Cardiothorac Anesthesiol & Crit Care Med, Durham, NC USA
[2] Univ Virginia, Sch Med, Dept Anesthesiol, Charlottesville, VA 22908 USA
[3] Duke Univ, Med Ctr, Dept Surg, Div Cardiovasc & Thorac Surg, Durham, NC 27710 USA
[4] Duke Univ, Med Ctr, Div Cardiol, Durham, NC 27710 USA
[5] Univ Washington, Dept Anesthesiol & Pain Med, Div Cardiothorac Anesthesiol, Seattle, WA 98195 USA