1. What clinical conditions should you be most worried about?
Tension pneumothorax, and cardiac tamponade


2. What physical signs should you look for?
Prolonged capillary refill
Hypotension
Absent breath sounds
Hyper-resonance
Tracheal deviation
Distended neck veins
Muffled heart sounds
Surgical emphysema of the chest wall.

3. He is haemodynamically stable. What investigation should he have now (apart from any blood tests)?

CXR, maybe a cardiac echo