Common abnormal breath sounds in lung auscultation are as follows: 1) Alveolar breath sounds are diminished or absent: seen in restricted thoracic activity, respiratory muscle disease, bronchial obstruction, compressive lung expansion insufficiency, and abdominal massive ascites, huge tumors, etc. 2) Enhanced alveolar breath sounds: occurs due to increased oxygen demand of the organism, hypoxia excites the respiratory center, and increased blood acidity stimulates the respiratory center, resulting in enhanced respiratory movements. (3) Prolonged expiratory sounds: due to partial obstruction, spasm or narrowing of the lower airway, resulting in increased respiratory resistance, or due to decreased elasticity of lung tissue, resulting in weakened respiratory drive. 4) Intermittent breath sounds: Local inflammation in the lungs or bronchial stenosis, which prevents air from entering the alveoli evenly, can cause intermittent breath sounds, which are also called cogwheel breath sounds because they are accompanied by short irregular intervals. Commonly seen in tuberculosis and pneumonia. 5) Rough breath sounds: for the bronchial mucosa mild edema or inflammatory infiltration caused by unsmooth or narrow, so that the airflow in and out of the poor formation. It is seen in the early stage of bronchial or lung inflammation. 2, abnormal bronchial breath sounds: If bronchial breath sounds are heard at the site of normal alveolar breath sounds, they are abnormal bronchial breath sounds, medical|schooling.com collects and organizes or called tube-like breath sounds. 3, abnormal bronchoalveolar breath sounds: bronchoalveolar breath sounds heard in the area of normal alveolar breath sounds. The mechanism of production is because the lung solid area is small and mixed with normal air-containing lung tissue, or the lung solid area is deeper and covered by normal lung tissue.