Definition of Massive Haemothorax

A massive haemothorax is a haemothorax >1500 ml, or one-third of the patient's blood volume according to ATLS. It is uncommon, can be blunt or penetrating—usually penetrating—and unlikely to be missed, radiologically.

It creates a problem because of shock (haemorrhagic and impaired venous return from the vena cava) and decreased ventilation (the lung on that side gets compressed).