system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is it okay for IV drips to have air bubbles running through the lines?

I've always heard of the horrendous things that happen if air gets in the veins. What's the safe guard here? I about freaked out last time I had an IV because I saw air bubbles running towards my hand. The nurse just said, "nah, that's fine."

* To clarify: I saw large gaps of air in the IV line throughout the time I was hooked up to it. I'm sure I'm fine as this was almost a year ago, but out of curiosity I've done a bit of research and keep finding contradictory reports. One side seems to believe that a bit of air through an IV won't kill anybody so it's completely fine. The other, claims that it still does damage to certain cells and systems of the body, and there's no reason for air bubbles to be in the lines in the first place. They claim it's a product of lazy medical practice and it should really stop. I, on the other hand, am a landscaper, machinist, and gunsmith in training, who can't understand half of what either side is saying, hence the ELI5.

*I just can't type today. Anymore typos in this awfully written post will just have to be ignored. I'm not usually illiterate I promise.
gpt
RN here. There are two main types of IV lines. Peripheral IVs and central lines. Peripheral IVs are typically inserted into a small vein of the arm or hand and have a tiny diameter. This is what most people think of as an IV. Central lines (google PICC ) have a much larger diameter and are inserted in larger veins and terminate in one of the body's large vessels -e.g Superior Vena Cava very close to the heart. The real danger of air in the circulatory system is that if a bubble is large enough and makes it to the brain it can cause a blockage called an embolism in one of the smaller vessels supplying blood to the brain. This would essentially cause a stroke. A small amount of air passing (<10ml-about the size of a test tube from HS chemistry) passing through a peripheral IV just simply can't form a large enough bubble to pose a danger. In fact it has been estimated that you would need as much as 100ml of air pushed through a peripheral IV to do harm. Those tiny bubbles just get dissolved in your blood very quickly. A central line however is a much different situation. Because they have a much larger diameter and are placed in larger vessels with larger volumes of blood then it doesn't take much air for a large bubble to form. A few tiny bubbles of air that you would typically see in IV tubing is not likely to do any harm but as little as 2-3ml air pushed in all at once with a medication for instance could easily be dangerous in a central line. That's why nurses trained to clear all the air from syringes used for central lines.  It all about how big of  bubble can form in your blood. So if you have peripheral IV in your arm or hand and you see a few bubbles in your IV tubing don't let it concern you it's just not enough to hurt you.