How Lucky Do You Feel When an Air Bubble Is In Your Intravenous Line? Part 1/3
By: Gerard J. Myers, RT, CCP Emeritus, Eastern Perfusion International
Part 1 of 3
When was the last time you, or one of your loved ones, was in a hospital bed with an intravenous line attached to your arm and a bag of intravenous fluid hanging from an IV pole beside you? Perhaps when the bag of fluid began to empty, a health care worker entered the room to hang another bag of the lifesaving liquid, or maybe just attach a smaller bag of medication to run into you intravenous line. As she/he changed the bag and adjusted the drips on your IV line you sat silently in deep thought about when you were getting out of the hospital or what you had to do that day. But out of the corner of your eye you noticed a large bubble of air slowly advancing down your IV line toward your arm. You raised the alarm about the bubble to the clinician and were told that ‘there is nothing to worry about, because a little bit of air will never hurt anyone’. This explanation is usually followed by another short explanation about how it would take a massive amount of air to cause you any harm, and that there is nothing to worry about with those little bits of air.
Unfortunately, this scenario is repeated thousands of times by health care workers who still consider venous air bubbles as inconsequential, and subsequently spend their careers disregarding small amounts of air bubbles entering the venous circulation through an intravenous line. In fact, it is almost impossible to estimate how many times air bubbles enter a patient’s blood stream through intravenous lines, in every healthcare setting. These bubbles are often referred as iatrogenic air (coming from the activity of a health care provider). No harm is ever intended, assumed or even imagined, but it is often just a part of the clinician’s training, their routine practice of maintaining an intravenous infusion, and their misinformation around the hazards of air bubbles entering the venous circulation.
The reality is … small amounts of air bubbles entering a person’s blood stream can have adverse consequences and can be harmful. What is interesting is the fact that there is absolutely no reason why any amount of air or air bubbles should be allowed to pass through an intravenous line in any patient. Every clinical protocol for setting up and maintaining an intravenous line, stresses the importance of making sure all of the air is removed from that line before it is attached to a patient’s circulatory system. All air bubbles are foreign to our circulation and the majority can easily be removed from an intravenous line before entering the patient’s circulation. But more importantly, air bubbles have the potential to cause harm and are not in the best interest of the patient … let me explain why.
First of all, regardless of the size of the bubble or its point of entry into our arterial or venous blood streams, bubbles or any particles entering our bloodstream are alien to our circulation and our physiology. Because of this, once a bubble enters the bloodstream, it is immediately attacked and treated like any other foreign substance that enters our body’s natural defense mechanisms. The bubbles are immediately coated by platelets, white blood cells and other proteins as they travel toward the right side of the heart. During their course through the bloodstream, they can damage or degrade the blood vessels delicate lining (called endothelial glycocalyx and its underlying endothelial cells) resulting in endothelial cell edema, inflammation, localized platelet and white cell activation and even blockages in the tiny pulmonary capillary vessels, much in the same manner that a solid or fat embolus would do. Over time, it is believed these bubbles will gradually dissolve in the blood, but not before damaging this endothelial glycocalyx layer as they slip/slide through the microcirculation.
The normal size of our capillaries (microcirculation) is somewhere between 4-9 microns in diameter, but the bubbles trying to pass through these capillaries can be hundreds or thousands of microns larger. If those bubbles break up and enter the arterial blood going to the brain, they have the ability to cause neurocognitive dysfunction (memory loss, emotional upset, etc) or stroke.
© 2017 Gerard Myers