Operations, Patient Care

Bubbles: Air-proofing your IV lines

Issue 2 and Volume 34.

Chances are, when you were a kid, you loved bubbles. Most kids do.

Grown-ups don’t talk much about bubbles, Life-Saver. But they must be important.

I just Googled the word and got 32,300,000 hits. It turns out, life is full of bubbles. Bubbles in the bathtub, bubbles you blow. Spit bubbles. Bubbles at the car wash. Even balloons are bubbles.

For 80 years, there’s been a chewing gum called Dubble Bubble, and it’s been a measure of coolness for generations of kids to pop their first bubble-gum bubble. Of course, you lose some fascination with bubbles about the time you’re old enough to do dishes. That’s when you learn about bubbles in bike tires, too.

But your first Coke teaches you that maybe they’re not so bad. Another 10 years, and you discover the bubbles from those noisy latte machines at Starbucks. Soon enough, it’s Budweiser bubbles, and then maybe champagne bubbles. Of course, we don’t all admit to them, but every one of us learns about methane bubbles. The upper kind, the lower kind, and the kind in between. The silent kind, and the noisy kind. The benign kind, and the kind that can empty a dayroom in two seconds. (They’re flammable, you know. Maybe you’ve run a call or two for the odd young genius who’s just learned that lesson the hard way.)

When you choose a profession, you may learn to regard bubbles as true hazards. Nitrogen bubbles can kill a diver breathing compressed air who surfaces too fast from even a modest depth. Welders go to great lengths to protect their work from the weakening effects of bubbles. Metal in gas (MIG) and Tungsten in gas (TIG) are two techniques of welding in an envelope of inert gas (like argon) to keep bubbles out of welds.

Farmers know all about bovine bubbles, and equestrians quickly learn a special kind of difference between north and south bubbles. As a beginner in medicine, you learned the same lesson: Not all bubbles are benign. One of the risks of cannulating a central vein (or even an external jugular) is the aspiration of air—which, of course, forms bubbles. Hematomatoes are bubbles filled with blood, and so are their deadly cousins, aneurysms.

Bubbles form when you spike an IV bag and allow the fluid to splash down into the open end of that line (especially with a big dripper). Bubbles will keep forming all day, until you eliminate the source. When you first learn to start IVs, your instructors tell you to be careful not to introduce air into a patient’s veins.

The truth is, small bubbles probably won’t do any harm. But who’s to say what’s small? Some people say it takes 50 cc of IV air to kill someone; others say you can do it with as little as 20 cc.

No matter. Keep all the air out of an IV line, and you won’t have to worry about it.

Plenty of us struggle to do that, waiting for an IV line to clear before we connect it to a catheter. And waiting, and waiting. That can be awful when you’re a new first responder, and you have a busy paramedic waiting to plug in the line so they can move on to other things.

Fact is, you don’t need to wait. And you never need to worry about bubbles. There’s an airtight technique you can use to save all that time. I’m amazed at how many people don’t know about it, but you don’t find it in EMS texts, and most instructors forget to mention it. It takes no time at all, and it’s so easy even a fuzzy ol’ cave medic can do it.

Next time you open a drip set, uncoil the tubing to its full length. Grab that little roller valve you use to regulate the flow rate, and run it up the tube until it’s right at the drip chamber. Now close the valve, spike the bag and pinch the drip chamber to put a fluid level in it. Finally, open the valve and clear the line. You won’t see one bubble, even if you squeeze the bag. The only waiting you’ll have to do will be the time it takes for the fluid to get to the open end.

You’ll be so slick.

A side benefit of this technique is, you’ll never have to look for the valve. It’ll be right there at the drip chamber, where you can always find it—again, without wasting time.