What is pneumothorax?

Causes and Symptoms

Pneumothorax is the result of anything that causes air or fluid, such as blood, to leak into the space between the two layers of pleura, which line the chest wall (parietal) and the lung tissue (visceral). For normal lung function there is negative pressure in this space. When air enters, the negative pressure is disrupted, and the atmospheric pressure presses on the lung tissue, deflating it. A pneumothorax can be mild and self-limiting, but a severe pneumothorax can collapse the whole lung and cause a shift in the location of the heart and great vessels. This is a life-threatening situation.

Pneumothorax is caused by trauma to the lung, medical procedures performed on the lungs, infant prematurity, existing lung disease, endometriosis in the chest, and bullae. Trauma includes anything that penetrates the chest wall, such as a stabbing, gunshot wound, or excessive blunt trauma to the chest. Medical procedures such as a bronchoscopy, cardiopulmonary resuscitation (CPR), liver or lung biopsy, chest surgery, and the insertion of chest tubes can cause a pneumothorax. Premature infants or infants who swallow meconium, newborn stool, can rupture their lungs attempting to breathe despite lung tissue that is sticking together. The presence of existing lung disease can increase the risk of developing a pneumothorax. These diseases include emphysema, asthma, chronic infections, tuberculosis, cystic fibrosis, cancer, and chronic obstructive pulmonary disease (COPD). An unusual cause of pneumothorax is the presence of endometriosis in the chest. This condition causes pneumothorax at the time of the menstrual
cycle, when the endometrial tissue bleeds. Bullae develop due to local weakness in the lung tissue and can rupture with changes in atmospheric pressure, such as when scuba diving, flying, and mountain climbing. Most often bullae rupture for no apparent reason. Bullae are more common in cigarette smokers.

The symptoms of pneumothorax are shortness of breath, sharp pain in the chest, a feeling of tightness, cyanosis, dry cough, rapid heart rate, subcutaneous emphysema, and the sound of air moving through a penetrating chest wound. A primary pneumothorax is diagnosed by the symptoms; pulse oximetry, which measures oxygen saturation of the blood; auscultation, or listening to the lobes of the lungs through a stethoscope; and chest x-ray. A traumatic pneumothorax is related to a traumatic injury and a postmedical pneumothorax to a medical procedure.

Treatment and Therapy

A small pneumothorax will resolve on its own. It is treated with watchful waiting and repeated chest x-rays. If there is shortness of breath, then oxygen can be administered. If a pneumothorax does not resolve on its own, then a needle can be inserted through the chest wall into the pneumothorax (thoracentesis), and the air or fluid can be extracted. Another common treatment is the insertion of a chest tube with its tip in the intrapleural space. An airtight dressing is placed around the tube and the tube is drained into a system that includes a water seal in order to prevent the reintroduction of air. Gentle suction may be used to remove the air or any drainage present. Usually, the pneumothorax will resolve within two to three days, and then the tube can be removed. If the pneumothorax reoccurs after the suction is removed from the chest tube, then there is a more portable system called a Heimlich valve that can be used to continue chest drainage. This valve permits air or fluid to leave the interpleural space without permitting air to reenter.

If the pneumothorax does not improve, or if it reoccurs, then surgery may be required. Pleurodesis may be performed, particularly for ruptured bullae. In this procedure, a chemical irritant is used to create scar tissue to heal weakened spots in the lung. Surgery in the form of video-assisted thoracic surgery (VATS) can be performed to close the lung with staples. Open chest surgery is less commonly used to treat pneumothoraces.

In an emergency, a sucking or traumatic chest wound should be treated with an occlusive dressing to prevent the introduction of additional air into the chest. Ideally, this dressing should be sterile and have either petroleum jelly gauze or plastic to seal the wound.

Perspective and Prospects

Pneumothorax was first identified by Jean Marc Gaspard Itard, a student of Rene Laennec, in 1803. Laennec, himself, described the clinical picture of pneumothorax, in 1819. The first treatment of pneumothorax was thoracentesis. Both thoracentesis and chest tubes generally led to empyema, an infection in the pleural space because of the absence of aseptic technique. After the discovery of germ theory and aseptic technique by Ignaz Semmelweiss (1818–1865), Louis Pasteur
(1822–1895), and Joseph Lister
(1827–1912), pneumothorax could be treated with aseptic thoracentesis, or with surgery. Semmelweis discovered that hand washing between patients could limit the spread of infection after childbirth. Pasteur tested germ theory, and wrote about the microscopic germs that cause infection, both in the presence of air and in anaerobic tissue. Lister is referred to as the father of surgery because he introduced the use of chemicals to sterilize surgical instruments and to clean wounds. In 1875, G. E. Playfair developed water seal drainage for removing fluids from the chest, and in 1876, F. Cresswell Hewett used water seal drainage with chest tubes.

Tuberculosis was a scourge in the nineteenth century, and it frequently created a pneumothorax by eating through the lung. There were no antibiotics at this time, so treatment was limited, and most persons who developed tuberculosis died from it. In 1882, Italian physician Carlo Forlanini began to use pneumothorax for treatment of tuberculosis in an effort to rest the lung. This treatment was continued into the early twentieth century.

Bibliography

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