The nurse is caring for a comatose client who has suffered a closed head injury. What intervention should the nurse implement to prevent increases in intracranial pressure (ICP) ？（）
A．Suction the airway every hour and as needed.
B．Elevate the head of the bed 15 to 30 degrees.
C．Turn the client and change his position every 2 hours.
D．Maintain a well-lit room.
