[1] Univ Texas Southwestern Med Ctr Dallas, Dept Otolaryngol Head & Neck Surg, 2350 N Stemmons Fwy,F6-221, Dallas, TX 75207 USA
[2] Childrens Med Ctr Dallas, Dept Pediat Otolaryngol, Dallas, TX USA
[3] Childrens Hosp Philadelphia, Dept Anesthesiol & Crit Care Med, Philadelphia, PA 19104 USA
[4] Univ Penn, Dept Anesthesiol & Crit Care, Perelman Sch Med, Philadelphia, PA 19104 USA
[5] Childrens Hosp Philadelphia, Div Otolaryngol, Philadelphia, PA 19104 USA
[6] Univ Penn, Dept Otorhinolaryngol Head & Neck Surg, Perelman Sch Med, Philadelphia, PA 19104 USA