system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Where does the air go afterwards that has entered our body during open surgery?

When open surgery has taken place on someone they are opened up and exposed to the 'air'. When they are stitched back up there must be some amount of air that remains inside the body. What happens to this air and/or how does our body get rid of it?
gpt
It goes three places. 
1. Some of it is absorbed into the surrounding tissues. The oxygen gets used, the nitrogen gets used (some of it), and the rest gets excreted as waste through your digestive system, just like any other foreign body.
2. When they stitch you up, it is standard procedure to squeeze you (don't worry it's just a tiny bit), or put pressure on the open wound so that the liquids in your body fill the space and force the air out, rather than leaving a big bubble in you. It's very like turning a syringe upward and pushing the plunger until all the little air bubbles come out and only liquid remains. You also don't generally stop bleeding just because they stitched you up. That's why we wrap you in gauze. Like a ziploc bag with a hole in one side and a tube pouring water in another, eventually, all the air will be pressed out through the hole and only water will remain. Or blood and plasma and such in you.
3. There a literally more capillaries running through your tissues than anyone can count. We know how many veins and arteries we have, but we can never put a number on capillaries, the teeny-tiny vessels that take blood to all your microscopic cells. These capillaries carry blood, and blood is filled with air, (sort of, your red blood cells carry "air"). So your capillaries can absorb some unwanted air in your body, carry it up to the lungs, and eject it that way. 

End of the day? It's nothing to worry about at all. You always see on TV how injecting air into someone's arm will kill them, but that is nonsense. It takes HUGE amounts of air injected DIRECTLY into a vein or artery that passes DIRECTLY through your heart or brain to cause any damage.