Final answer:
After turning the client's head to one side during a seizure, the nurse should immediately place the client in a side-lying position to maintain an open airway and prevent choking or aspiration. Administering IV phenytoin, providing oxygen via face mask, and documenting the duration of the seizure are not the immediate priorities.
Step-by-step explanation:
After turning the client's head to one side during a seizure, the nurse should immediately place the client in a side-lying position (B). This helps prevent choking or aspiration of saliva or vomit by allowing fluids to drain out of the client's mouth. It also helps maintain an open airway. Administering IV phenytoin (A) may be appropriate if the client's seizures are not well-controlled, but it is not the immediate priority in this situation. Providing oxygen via face mask (C) may be necessary if the client is experiencing respiratory distress after the seizure, but it is not the immediate priority. Documenting the duration of the seizure (D) is important for the client's medical record, but it is not the immediate priority.