The presence of a partial vacuum b/w the pleural membranes in integral to normal breathing movements.?

Question

What would happen if an opening were made into the chest cavity, as with a puncture wound?

How is this condition treated medically?

Answer 1

Is this a homework question?

The answer is yes. I believe the negative pressure is about -3 cmH2O... I'm not sure, it's been a while. So don't quote me on that one.

Basically the pressure allows the lung to stick closely to the chest wall without actually being stuck to the chest wall. Sometimes they do sort of stick it together with talc for certain cancer patients (look under pleuradesis if you want to learn about that).

The pleural fluid normally allows for free movement between surfaces (sort of like a piston being lubricated by motor oil in an engine).

If you make an opening, you'll probably get a pneumothorax. It may not be of the worst kind though (that being the tension pneumothorax). For a tension pneumo, you'd have to throw in a chest tube to equalize the pressure.

In milder cases, you just patch it. Someone wrote something good on the Wiki page, so I'll just quote them... "Penetrating wounds require immediate coverage with an occlusive dressing, field dressing, or pressure bandage made air-tight with petroleum jelly or clean plastic sheeting." That explanation is more for penetrating chest wound, so you'll need a one-way valve OUT, so air can evacuate the pleural space without it getting back in.

Good luck.