PICC Lines And Air Bubble

The consequences and risks of air embolism depends more on the individual patient and less on the access type.

If a patient has no shunt between the left and right sides of the heart then the air will end up in the pulmonary vasculature. It takes a relatively large amount of air to cause serious harm in the pulmonary vasculature or cause cavitation in the RA/RV.

If the patient has a shunt (such as a PDA, PFO, ASD, VSD, single ventricle pathology, surgical shunt, or any other communication) diagnosed or not, and the air can enter the left side of the circulation and result in injury to the heart, brain, or other left sided vasculature. These are typically more debilitating than right sided insults.

There is some additional risk with a CVC (including PICCs) that they could migrate through a PFO/ASD, although this is pretty rare, especially with good placement and good radiographic confirmation.

When in doubt we add an inline air filter to the line.

For a venous air embolism, you would need about 100 cc of air injected to the heart in about the course of 1 second. It basically couldn't happen through a picc line (though it can theoretically happen if you remove an IJ or subclavian central line with poor technique and the patient creates enough negative pressure via breathing to quickly pull in that much air - this is why you lay the patient flat, have them breathe in an hold their breath before you pull said central line, etc).

However, an arterial air embolism can be dangerous at about 1 cc of air. Thats enough to cause a stroke or MI if it gets into the arterial blood and travels to the wrong place. Most air bubbles in the venous blood are harmlessly removed from the blood when that venous blood travels to the lungs. However a patient with much of a shunt can be in more danger. I've read that a shocking 30 percent of us actually have a patent foramen ovale, though because left sided pressures are higher than right sided pressures in the heart, a PFO seldom causes much of a shunt anyway in adults. Still, its possible when coughing, during mechanical ventilation, etc. Or the patient can have a shunt caused by damaged lung tissue, etc. They would have to be pretty unlucky for a small venous air bubble to cause a damaging arterial air embolism, but it can happen.

With all that said, most bubbles you see in iv tubing are substantially smaller than 1 cc anyway. Ever watched a bubble study during an echocardiogram? They fill the heart with thousands of tiny air bubbles, and it's not considered dangerous. You don't have to sweat the tiny bubbles, whether in a picc or otherwise.

Been a nurse for 40 years. Was a PICC nurse for 15 years, have put in approx 10,000 PICCs. NEVER have seen a single patient (or heard of a single patient) that was harmed by air bubbles. I did have one patient when I was doing home health who had a faulty pump (unbeknownst) to me. When it alarmed "air" she kept pushing the button to override it. So she pumped herself full of air. Her mom called me in a panic because patient was SOB. I happened to be close by and rushed over there, and could remember one thing from school "in case of air embolism put patient on left side" Which I did. DIdn't know what else to do. Called provider. They said place on left side. OK then what? Provider had no idea. So patient layed on left side for about 30 minutes. I looked things up later and what this does it allows the air to rise up into a little corner of the atrium and then it just slowly reabsorbs. Which is what happened and patient was fine. So do be vigilant, but relax, you'll be fine.

OP, the likelihood that you would even have a syringe with more than, say, 1mL of air inside is pretty small. The pre- filled saline flushes at my hospital have about 1mL and I either squirt it out before flushing or purposely hold the syringe with the plunger up (so the air is away from the luerlock) and only flush with about 9mL (basically, watching what I'm doing). When I draw a med out of a vial I always draw out the whole volume, shake the syringe a couple of times to make the air rise to the luerlock, squirt it out, and then waste appropriately if I don't actually need the whole volume. I don't want to say a mistake could *never* happen, but I can't envision a time where I would accidentally draw up 5mL of air, not realize it, and give to via a PICC.

These are all reasons to be focused during med preparation and med pass, but I think as you get more comfortable with the psychomotor skills, you'll develop a method that works for you.

Other good habits to build now: use clean gloves and handle the line aseptically, make sure the clave is secure on the hub, clamp the line when not in use, and use protective caps if your institution uses them.

On 12/18/2019 at 11:11 AM, Cowboyardee said:

For a venous air embolism, you would need about 100 cc of air injected to the heart in about the course of 1 second. It basically couldn't happen through a picc line (though it can theoretically happen if you remove an IJ or subclavian central line with poor technique and the patient creates enough negative pressure via breathing to quickly pull in that much air - this is why you lay the patient flat, have them breathe in an hold their breath before you pull said central line, etc).

However, an arterial air embolism can be dangerous at about 1 cc of air. Thats enough to cause a stroke or MI if it gets into the arterial blood and travels to the wrong place. Most air bubbles in the venous blood are harmlessly removed from the blood when that venous blood travels to the lungs. However a patient with much of a shunt can be in more danger. I've read that a shocking 30 percent of us actually have a patent foramen ovale, though because left sided pressures are higher than right sided pressures in the heart, a PFO seldom causes much of a shunt anyway in adults. Still, its possible when coughing, during mechanical ventilation, etc. Or the patient can have a shunt caused by damaged lung tissue, etc. They would have to be pretty unlucky for a small venous air bubble to cause a damaging arterial air embolism, but it can happen.

With all that said, most bubbles you see in iv tubing are substantially smaller than 1 cc anyway. Ever watched a bubble study during an echocardiogram? They fill the heart with thousands of tiny air bubbles, and it's not considered dangerous. You don't have to sweat the tiny bubbles, whether in a picc or otherwise.

You sound well informed. I am curious about where you got the 100 CCs from.

And, for frame of reference for folks who don't know what 1cc of air looks like in tubing:

Let's say your tubing is 80 inches long, and has a priming volume of 20 ml. In order to have 1cc of air in the tubing, the bubble would be 4 inches long.

Many nurses know very little about stuff like priming volumes. For a primer on priming volumes:

https://infusionnurse.org/2015/02/11/iv-administration-sets-priming-volume-vs-residual-volume/

There is zero evidence to support the "tiniest" amount of air would impact a PICC line.

When I still worked the floor, I used to infuse into PICCs regularly and if there were a few bubbles of air here and there scattered throughout the line when new bags of lipids were hung, we all just let it go. Nothing ever happened. What you don't want is a large amount of air infusing at once.