A 12-year-old child has had a traumatic head injury from playing in a football game. He is admitted to the emergency department and transferred to the pediatric intensive care unit. He has an I.V. of dextrose 5% in water at a 'keep-open' rate and nasal oxygen at 2 L/minute. The nurse is assessing the child at the beginning of the shift (11:00 p.m.) and reviews the Glasgow Coma Scale flow sheet. The nurse notes that the child responds to pain, is making incomprehensible sounds, and has abnormal flexion of the limbs. What should the nurse do first?