Decompensated (tension) pneumothorax

Decompensated (tension) pneumothorax is a rapid onset large pneumothorax occurring in a clinically unstable patient (eg with symptoms including severe breathlessness, hypoxaemia, hypotension and cardiovascular collapse). It is a medical emergency and requires urgent needle decompression followed by intercostal catheter drainage.

Decompensated (tension) pneumothorax usually occurs in patients with underlying lung disease or trauma. It is extremely rare in patients with primary spontaneous pneumothorax.

The concept that the effects of a decompensated (tension) pneumothorax relate to supra-atmospheric intrapleural pressure has been questioned; the term decompensated pneumothorax may be preferred over tension pneumothorax.

Diagnosis of decompensated (tension) pneumothorax is clinical, not radiological. Mediastinal shift is often seen in patients with a large pneumothorax; however, in the absence of clinical features of instability, mediastinal shift does not indicate a need for decompression.

Patients on positive pressure ventilation (including continuous positive airway pressure [CPAP] or bilevel positive airway pressure [BPAP]) may develop intrathoracic pressures exceeding atmospheric pressure and deteriorate rapidly. If a patient on positive pressure ventilation deteriorates rapidly, consider decompensated (tension) pneumothorax as a potential cause.