A nurse on a pediatric unit is reviewing her client assignment following the shift report. Which of the following clients should the nurse plan to assess first?

An infant who has pertussis and is receiving oxygen via nasal cannula

An adolescent who was admitted to the unit in sickle cell crisis and is ready for discharge instructions

A school-age child who has diabetes mellitus and requires blood glucose monitoring

A toddler who has both arms in casts and needs to be fed his breakfast