A couple of things with occlusive dressings:

Keep the occlusive dressing just slightly larger than the wound. If the occlusive dressing is too large, you essentially create a secondary pleural space.

Check for exit wounds. If found, apply an occlusive dressing to any additional sites.

Try to apply and seal the occlusive dressing when the patient exhales.

If possible transport with the injured side down, but monitor patient’s condition constantly.

If the patient complains of an increase in difficultly to breath, a decrease in the level of conscious and/or distension (enlargement/engorgement) of the jugular veins (large veins in the neck), you may have “burp” the occlusive dressing to relive trapped air and/or blood.

Pete