(SOUNDBITE OF WALKIE-TALKIE)
MICHAEL BELL: Tiffany, how much oxygen are you on?
UNIDENTIFIED PERSON: Sixty percent.
BELL: You can probably come down substantially.
UNIDENTIFIED PERSON: Potassium 3.4, calcium 1.25.
LULU GARCIA-NAVARRO, HOST:
Dr. Michael Bell is on a walkie-talkie advising a group of medical staff treating a young girl in the pediatric intensive care unit at Children's National Hospital here in Washington, D.C.