Mr. emmet, age 65, is admitted to the hospital with cough, fever, chill, malaise, and headache. he is diagnosed with influenza. examination reveals shortness of breath at rest, course crackles throughout the lung fields, and cough productive of thick yellow sputum. the physician has prescribed guaifenesin to the patient mobilize the secretions in the lungs. what would be an important nursing intervention to enhance the guaifenesin drug therapy?