[1] Univ N Carolina, Dept Med, Div Pulm & Crit Care Med, Chapel Hill, NC 27515 USA
[2] Shanxi Med Univ, Hosp 1, Dept Resp & Crit Care Med, Taiyuan, Peoples R China
[3] Univ N Carolina, UNC Sch Med, Chapel Hill, NC 27515 USA
[4] Wake Forest Univ, Wake Forest Sch Med, Winston Salem, NC USA
[5] Univ N Carolina, Marsico Lung Inst, Chapel Hill, NC 27515 USA