Mediastinal Displacement | Tension pneumothorax

Mediastinal Displacement

Mediastinal shift describes a shift of the mediastinum towards the side of the healthy lung. The mediastinum is the center of the thorax, where the heart and its blood vessels are located. The increasing pressure in the pleural gap leads to a compression of the supplying vessels of the heart (veins), as a result of which the heart is no longer supplied with sufficient blood and the blood pressure drops. This also leads to congestion of the neck veins, which is an important symptom in diagnostics. In the course of the disease, the increasing pressure also causes compression of the heart and consequent cardiac arrest.

How is a tension pneumothorax treated?

There are several different ways to relieve a tension pneumothorax. It is important to release the pressure that builds up through the trapped air and thus counteract the mediastinal displacement. This is made possible either by a so-called relief puncture or by a thoracic drainage.

A relief puncture counteracts a tension pneumothorax and prevents the life-threatening condition. In contrast to a thoracic drainage, where a tube is inserted into the pleural gap and restores the original negative pressure, a relief puncture is only an emergency measure and not a final therapy. Accordingly, a relief puncture is only used under enormous time pressure or in emergency situations.

A needle is used to create a connection between the pleural gap and the outside air. The needle is inserted either at the upper edge of the second or third rib at the front of the chest (according to Monaldi) or at the upper edge of the fifth or sixth rib at the side of the chest (according to Bülau). It is important not to puncture the lower edge of the rib, as nerves and blood vessels run there.

Duration and prognosis

The duration and prognosis of a tension pneumothorax depends on when a valve mechanism has formed, how pronounced it is and how soon therapy has been or can be started. With a fully developed valve mechanism, a tension pneumothorax develops within a few minutes, as about 500 ml of air enters the pleural gap with each breath. Without therapy, a tension pneumothorax is usually fatal, as it leads to cardiac arrest. If a tension pneumothorax is treated in time and without complications, it heals completely after a few days. However, this depends on accompanying injuries and the patient’s state of health.