Upon auscultation of a rub, the nurse must determine if it is of cardiac or pulmonary origin. Therefore, the nurse instructs the patient to hold their breath; if the rub is no longer auscultated, then it is likely of pleural origin. If the rub persists, then it is likely a pericardial friction rub. Then, the nurse can contact the provider for assessment. Coughing and clearing the throat can cause rhonchi to cease, but not a friction rub. Breathing through the nose will not be helpful in differentiating a pleural and pericardial friction rub.