Fine crackles are brief, discontinuous, popping lung sounds that are high-pitched. Fine crackles are also similar to the sound of wood burning in a fireplace, or hook and loop fasteners being pulled apart or cellophane being crumpled.
Crackles, previously termed rales, can be heard in both phases of respiration. Early inspiratory and expiratory crackles are the hallmark of chronic bronchitis. Late inspiratory crackles may mean pneumonia, CHF, or atelectasis.