Treatment

Consider the following:

Insert a nasogastric tube gently to drain stomach content. The insertion of the chest drain is to drain any associated pneumo/haemothoraces.
A cautiously placed chest drain using the traditional open technique, not Seldinger, is indicated
Surgical repair needs to be considered in the context of associated injuries
Examine the CT carefully in patients who have sustained a (blunt) abrupt increase in intra-abdominal pressure
Diaphragmatic injury needs excluding by your surgical colleagues in cases of penetrating injury requiring theatre.