Your Patient Is a 60-Year-Old Female with a Sudden Onset

Your patient is a 60-year-old female with a sudden onset of severe difficulty breathing.She has no prior history of respiratory problems.Which of the following should be done before applying oxygen by nonrebreather mask?

A) Listen to the patient's breath sounds.
B) Obtain a history of the present illness.
C) Check the patient's oxygen saturation level.
D) None of the above