Chronic lung disease is also known as bronchopulmonary dysplasia. It is a health problem occurs when a baby has damaged tissue in the lungs. Due to that the tissue will be inflamed and may be break down. In that case it will be difficult to that baby to breath, there they need oxygen therapy. It is most common disease in premature babies. The most common symptoms in this disease include fast breath, pale, grey, or blotchy skin, use the neck, chest and belly muscles to breathe, tiring during and after feeding.