Question

explain how significantly increased volume and pressure in the pleural cavity could affect the structures in the mediastinum to produce hypotension

Answer 1

In pneumothorax where air accumulates in the pleural cavity, the pressure and volume of pleural cavity increases.As a result the intrathoracic pressure also increases, The lungs will collapse, as more air is entering the pleural cavity.And blood return to heart decreases, due to increased pressure and cardiac filling decreases, cardiac output decreases.

Blood pressure is determined by cardiac output. When cardiac output decreases blood pressure also decreases producing hypotension.