[1] Michael E DeBakey VA Med Ctr, Med Care Line, Houston, TX USA
[2] Baylor Coll Med, Dept Med, Sect Pulm Crit Care & Sleep Med, Houston, TX 77030 USA
[3] Baylor Coll Med, Dept Med, Infect Dis Sect, Houston, TX 77030 USA
[4] Baylor Coll Med, Allied Hlth Sci, Houston, TX 77030 USA
[5] DoD VA Vis Ctr Excellence, Bethesda, MD USA