Barotrauma is physical damage to body tissues caused by a difference in pressure between a gas space inside, or contact with, the body and the surrounding gas or liquid. The initial damage is usually due to over-stretching the tissues in tension or shear, either directly by an expansion of the gas in the closed space or by pressure difference hydrostatically transmitted through the tissue. Tissue rupture may be complicated by the introduction of gas into the local tissue or circulation through the initial trauma site, which can cause blockage of circulation at distant sites or interfere with the normal function of an organ by its presence. The term is usually applied when the gas volume involved already exists prior to decompression. Barotrama can occur during both compression and decompression events.
Salt water aspiration syndrome is a rare diving disorder suffered by scuba divers who inhale a mist of seawater, usually from a faulty demand valve, causing irritation of the lungs. It is not the same thing as aspiration of salt water as a bulk liquid, i.e. drowning. It can usually be treated by rest for several hours. If severe, medical assessment is required. First described by Carl Edmonds.
Pemberton's sign was named after Hugh Pemberton, who characterized it in 1946.
Dysbarism refers to medical conditions resulting from changes in ambient pressure. Various activities are associated with pressure changes. Underwater diving is the most frequently cited example, but pressure changes also affect people who work in other pressurized environments, and people who move between different altitudes.
Superior vena cava syndrome (SVCS), is a group of symptoms caused by obstruction of the superior vena cava ("SVC"), a short, wide vessel carrying circulating blood into the heart. The majority of cases are caused by malignant tumors within the mediastinum, most commonly lung cancer and non-Hodgkin's lymphoma, directly compressing or invading the SVC wall. Non-malignant causes are increasing in prevalence due to expanding use of intravascular devices, which can result in thrombosis. Other non-malignant causes include benign mediastinal tumors, aortic aneurysm, infections, and fibrosing mediastinitis.
The mediastinum is the central compartment of the thoracic cavity. Surrounded by loose connective tissue, it is an undelineated region that contains a group of structures within the thorax, namely the heart and its vessels, the esophagus, the trachea, the phrenic and cardiac nerves, the thoracic duct, the thymus and the lymph nodes of the central chest.
Esophageal rupture is a rupture of the esophageal wall. Iatrogenic causes account for approximately 56% of esophageal perforations, usually due to medical instrumentation such as an endoscopy or paraesophageal surgery. In contrast, the term Boerhaave syndrome is reserved for the 10% of esophageal perforations which occur due to vomiting.
Pneumoperitoneum is pneumatosis in the peritoneal cavity, a potential space within the abdominal cavity. The most common cause is a perforated abdominal organ, generally from a perforated peptic ulcer, although any part of the bowel may perforate from a benign ulcer, tumor or abdominal trauma. A perforated appendix seldom causes a pneumoperitoneum.
Mediastinitis is inflammation of the tissues in the mid-chest, or mediastinum. It can be either acute or chronic. It is thought to be due to four different etiologies:
Pneumomediastinum is pneumatosis in the mediastinum, the central part of the chest cavity. First described in 1819 by René Laennec, the condition can result from physical trauma or other situations that lead to air escaping from the lungs, airways, or bowel into the chest cavity. In underwater divers it is usually the result of pulmonary barotrauma.
Hamman's sign is a crunching, rasping sound, synchronous with the heartbeat, heard over the precordium in spontaneous mediastinal emphysema. It is felt to result from the heart beating against air-filled tissues.
A mediastinal tumor is a tumor in the mediastinum, the cavity that separates the lungs from the rest of the chest. It contains the heart, esophagus, trachea, thymus, and aorta. The most common mediastinal masses are neurogenic tumors, usually found in the posterior mediastinum, followed by thymoma (15–20%) located in the anterior mediastinum. Lung cancer typically spreads to the lymph nodes in the mediastinum.
Mediastinal germ cell tumors are tumors that derive from germ cell rest remnants in the mediastinum. Germ cell tumors most commonly occur in the gonad but occasionally elsewhere.
Pneumopericardium is a medical condition where air enters the pericardial cavity. This condition has been recognized in preterm neonates, in which it is associated with severe lung pathology, after vigorous resuscitation, or in the presence of assisted ventilation. This is a serious complication, which if untreated may lead to cardiac tamponade and death. Pneumomediastinum, which is the presence of air in the mediastinum, may mimic and also coexist with pneumopericardium.
Subcutaneous emphysema occurs when gas or air accumulates and seeps under the skin, where normally no gas should be present. Subcutaneous refers to the subcutaneous tissue, and emphysema refers to trapped air pockets. Since the air generally comes from the chest cavity, subcutaneous emphysema usually occurs around the upper torso, such as on the chest, neck, face, axillae and arms, where it is able to travel with little resistance along the loose connective tissue within the superficial fascia. Subcutaneous emphysema has a characteristic crackling-feel to the touch, a sensation that has been described as similar to touching warm Rice Krispies. This sensation of air under the skin is known as subcutaneous crepitation, a form of crepitus.
Tracheobronchial injury is damage to the tracheobronchial tree. It can result from blunt or penetrating trauma to the neck or chest, inhalation of harmful fumes or smoke, or aspiration of liquids or objects.
Pneumoparotitis, is a rare cause of parotid gland swelling which occurs when air is forced through the parotid (Stensen) duct resulting in inflation of the duct.
Pneumatosis is the abnormal presence of air or other gas within tissues.
Emphysema is any air-filled enlargement in the body's tissues. Most commonly emphysema refers to the enlargement of air spaces (alveoli) in the lungs, and is also known as pulmonary emphysema.
Orbital emphysema is a medical condition that refers to the trapping of air within the loose subcutaneous around the orbit that is generally characterized by sudden onset swelling and bruising at the impacted eye, with or without deterioration of vision, which the severity depends on the density of air trapped under the orbital soft tissue spaces.
