A pediatric expert said surveillance footage of an 8-year-old East Texas girl choking at school highlights warning signs adults may overlook. The expert also said the footage shows why quick response matters during a medical emergency.

Dr. Scott Hadland, chief of adolescent medicine at Mass General Brigham for Children, reviewed footage of Adrian Thompson's final moments at Velma Penny Elementary School with CBS19's Emily Trevino. Adrian began choking during lunch on April 15 and died the following day at Cook Children's hospital in Fort Worth.

Her parents gave CBS19 surveillance footage obtained through the Texas Rangers' investigation. They said they hoped to raise awareness and get answers about the response to their daughter's emergency.