Pneumomediastinum (synonym of mediastinoscopy) is the method of roentgenologic examination of the mediastinum, contrastirovania through the introduction of gas. Air, oxygen or other gas injected into the mediastinum through a puncture. After this, the patient is placed in such a position that the gas had accumulated predominantly in the underlying investigation Department of the mediastinum and 2-3 hours doing x-ray in different projections, and if necessary tomography (see).
Pneumomediastinum is a valuable method of diagnostics of tumors and cysts of the mediastinum. Pneumomediastinum used to identify enlarged lymph nodes and other pathological formations, to clarify, whether grows in the mediastinum malignant tumor of the lung. In contrast examination of the esophagus , pneumomediastinum allows you to examine the state of its inner and outer walls (see Paleography).
Pneumomediastinum produce at stationary examination of the patient, as within two days after the studies he should be under the supervision of medical personnel.

Pneumomediastinum (from the Greek. pneuma - air, pozdnee. mediastinum - mediastinum and Greek. grapho - writing, depict; a synonym for mediastinoscopy) is the method of roentgenologic examination of the mediastinum, the image contrast is increased by the artificial introduction of gas. Mediastinal organs, about the same delay of x-rays, are portrayed as almost homogeneous median shadows on the background which is very difficult, and in many cases impossible to detect pathological education. Pneumomediastinum, contributing to the fragmentation of the middle shade into its component parts, can significantly improve the diagnosis of diseases of the mediastinum.
Pneumomediastinum shown only in cases where conventional x-ray examination does not reveal the pathological education, which is supposed on the basis of clinical symptoms. It is also used to Refine the shape, size and syntopia formations found in fluoroscopy and radiography. Contraindications to pneumomediastinum are inflammatory processes of fiber mediastinum, compression syndrome, febrile condition, decompensated heart diseases.
Important this method for the solution of the issue of intra - or location pathological education. If you enter into the mediastinum gas envelops the pathological education from all sides, can be considered proven its vnutriepetelialnaya location (Fig. 1, 2 and 3). On the contrary, if the pathological education together with a light separates light layer of gas from the shadow of the mediastinum, we are talking about internal-lung education. For lung cancer and cancer of the esophagus P. used to clarify the issue of tumor invasion into the mediastinum, as well as about the presence of lymph node metastases this area.
Methods of introduction of gas into the mediastinum different. It is accepted to divide them into direct and indirect. The most efficient direct methods, characterized by the direct introduction of gas fibre in the mediastinum. These methods allow to create high contrast mediastinum with relatively small amounts entered gas. The most common chest method Condorelli - Kazan (gas is injected into a puncture in the field jugular fossa); parasternal (intercostal-chest) method of Rozenstrauha - Ender (gas
enter through 8 points - in the II, III, IV and V of the intercostal space on the left of the sternum; direct summing of gas to pathological education has received the name of directed pneumomediastinum); subcritically method bulma-Tevine in the modification of the E. C. Krivenko (gas is injected through an incision under the xiphoid process) and paravertebral method Paolucci - Jacobini in modification E. C. Potemkina (gas is injected in the posterior mediastinum by puncture chest wall for paravertebral line, mainly in the IV intercostal space).

Fig. 1. Coelomic cyst pericardium: 1 - before the introduction of gas; 2 - after the introduction of gas.
Fig. 2. Cancer of the upper lobe of the left lung. Visible sharply increased paratracheal lymph nodes.
Fig. 3. Ceratoides education anterior mediastinum.

Among the indirect methods, some widely proactively (more precisely paracoccidioides) method Rivas, which consists in the introduction of gas fibre in the pelvis, where he moved in the retroperitoneal space, and then in the mediastinum.
After the introduction of gas into the mediastinum produce mnogoproektsionnoe x-ray examination, including imaging.
To contrast the mediastinum can be used air, oxygen, carbon dioxide, nitrous oxide and mixtures of these gases. The introduction of these gases are well tolerated. The rate of resorption different.
When using direct methods overlay pneumomediastinum (see), the quantity of injected gas ranges from 200 to 700 ml. Indirect methods require more gas (up to 2500-3000 ml). The introduction of gas directly into the mediastinum should be under periodic radiological control; it allows to avoid many of the complications associated with the imposition pneumomediastinum. The choice of the place puncture caused by the requirement to feed gas to the lower pole of pathological formations, as due to the ease gas moves upward and better embraces these formations.
For proper interpretation of pneumomediastinum when those or other diseases should be studied in detail picture of normal mediastinum in conditions pneumomediastinum. Gas is distributed in the mediastinum unevenly; most of the gas is usually collected in the top-front and bottom rear sections of this area. The least amount of gas usually found in the back-to upper division of the mediastinum, where the amount of fiber is minimal.
Primary mediastinal organs in conditions pneumomediastinum okutyvaya gas, which seemed to rasslaivath these bodies and creates between them a light background, contributing to the detection of those or other pathological formations. The most visible periesophageal, perioralny, majortopicyn, pericardial, retrosternal layer.
The lack of gas in a particular Department mediastinum may be due to spikes and other phenomena. In particularly difficult cases it is advisable to combine pneumomediastinum with imaging, kinografika, electromyographya, film, angiocardiography, etc.