injuries and poisoning
Open Pneumothorax
Introduction
An open pneumothorax occurs when air accumulates between the chest wall and the lung as the result of an open chest wound or other physical defect. The larger the opening, the greater the degree of lung collapse and difficulty of breathing. Symptoms include chest pain, shortness of breath, rapid breathing, and a racing heart, sometimes followed by shock. Doctors can diagnose open pneumothorax based on the person's symptoms and examination results. Doctors immediately cover the wound with a three-way dressing and then insert a tube into the chest space to remove air. (See also Introduction to Chest Injuries .) When people with an unsealed opening in the chest wall inhale, the negative pressure generated by the inhalation sucks air into the space between the lung and chest wall (pleural space) from two different sources at once, the trachea (windpipe) and the opening in the chest wall. There is little airflow through small chest wall defects (or wounds), so there are few adverse effects. However, when the opening in the chest wall is about two thirds the diameter of the trachea or larger, more air passes into the pleural space through the chest wall opening than through the trachea, causing the lung to collapse and preventing inhaled air from flowing into the lungs. Larger openings can lead to complete collapse of the lung. 