A. remind the patients to take a deep breath several times until they get used to it

B. breathe through the patient 's nose rather than his mouth

C. before wearing oronasal mask, make sure the patient 's faces are clean

D. Use a humidifier to deal with such problems as the patient 's sneezing , rhinobyon or rhinorrhea

E. Change the water in the humidifier every day to keep it within the waterline