Pneumothorax Tension Pneumothorax and Pneumomediastinum

A pneumothorax may occur in patients with trauma, or it may be iatrogenic (e.g., central line insertion or aspiration of pleural effusion) or spontaneous. Spontaneous pneumothoraces are most likely to occur in patients who are tall and thin and smoke cigarettes. Spontaneous pneumothoraces also are associated with Marfan's syndrome, smoking crack cocaine, and Pneumocystis carinii pneumonia. Other severe injuries or conditions can mask all symptoms.

Pneumomediastinum may present in the same way as pneumothorax (spontaneous or traumatic), but it is sometimes accompanied by throat pain or dysphagia.

Tension pneumothorax is caused by the buildup of pressure outside of the lung, compressing the mediastinum and limiting venous return and cardiac output. Tension pneumothorax should be suspected in trauma patients who are hypoxic or hypotensive, patients who have a known pneumothorax (or if having a procedure that may cause one), and those receiving mechanical ventilation who deteriorate clinically.

Causes

• The main cause of pneumothorax is Trauma. Tension pneumothorax may be the result of blunt trauma with or without associated rib fractures.
• Several factors that may cause tension pneumothoraces such as unrestrained head-on motor vehicle accidents, falls, and altercations involving laterally directed blows.
• Pneumothorax may also cause by some diseases such as asthma, chronic obstructive pulmonary disease, pneumonia, pertussis, tuberculosis, lung abscess, and cystic fibrosis.

Symptoms

• Acute onset of chest pain or discomfort (often pleuritic) ++++ .
• Dyspnea +++
• Both chest pain and dyspnea +++

Signs

Pneumothorax

• A healthy patient with a small pneumothorax (usually less than 15% to 20% volume) may have no physical signs.
• Tachypnea
• Tachycardia
• Decreased breath sounds
• Hyperresonance to percussion (may be masked by hemothorax)
• Subcutaneous emphysema
• Patients with preexisting cardiopulmonary disease or other
  associated injuries may be cyanotic or in shock.

Tension pneumothorax

• Hypotension
• Tracheal deviation (later finding)
• Distended neck veins (later finding)

Pneumomediastinum

• Hamman's sign (crepitance heard over the heart during systole) +++
• Subcutaneous emphysema +++

Treatment

• Initial treatment, In which treatment it involves the insertion of a large bore cannula or needle into the second intercostal space on the mid-clavicular line known as "needle thoracostomy", or more commonly, "needle decompression", thereby releasing the pressure in the pleural cavity and converting the tension pneumothorax to a simple pneumothorax.
• After the initial treatment, the another treatment for Pneumothorax is Chest tube placement. In most centres, chest tubes should be immediately available in the resuscitation room and placement is usually rapid. The controlled placement of a chest tube is preferable to blind needle thoracostomy. This is provided the patient's respiratory and haemodynamic status will tolerate the extra minutes it takes to perform the surgical thoracostomy.