14 May 2019 The lung is made up of numerous branches (bronchi, bronchioles). The smaller ones are microscopic and end in small sacs called alveoli. On each inhalation, the alveoli expand with air, and oxygen and carbon dioxide are exchanged in the blood circulating in tiny vessels called capillaries around the alveoli. The alveoli are lined with a substance called surfactant, which prevents them from collapsing between breaths. Hyaline membrane disease is an inflammatory process caused by a deficit of surfactant in the alveoli. Immature lungs in infants are associated with a lack of surfactant, among other aspects. A surfactant deficit in immature lungs causes: Difficulty exchanging gases The collapse of the alveoli after exhaling. A collapsed alveolus is difficult to expand at the next inhalation. This may: Cause inflammation and oedema in the alveoli walls Make breathing even harder. Degree of severity Hyaline membrane disease can have varying degrees of severity. If it is very mild , it can be treated only with oxygen. If it is mild to moderate, it can be treated with continuous positive airway pressure (CPAP), a technique in which small tubes in the nose deliver air and oxygen at pressure. If it is severe , the baby must be attached to a ventilator that will help him or her breathe, prevent collapse of the pulmonary alveoli and facilitate gas exchange. Surfactant is administered through an endotracheal tube. This improves lung function and the baby’s clinical condition. Pregnant women with fewer than 34 weeks’ gestation at risk of pre-term delivery may receive treatment to accelerate lung maturity and increase production of surfactant. This significantly reduces the incidence and severity of hyaline membrane disease. This article was written with the support of physicians and other clinical professionals from the Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
