When it comes to medical devices, few are as vital as intravenous lines (IV). While IV lines continue to save countless lives, in rare cases they can cause severe harm or death if air bubbles are allowed to enter a patient’s body through them. Why? Because air bubbles can cause a blood vessel blockage called an air or gas embolism. Air embolisms present a serious threat to human life. To understand the true severity of such a situation, let’s break down how air embolisms occur, and what can be done to prevent them.

What Happens When Air Bubbles Enter The Human Body?

Gerard J. Myers describes it best when he states that bubbles or any particles entering our bloodstream are alien to our circulation and our physiology. When bubbles enter the body, they are not welcomed with open arms; rather, they are treated as foreign invaders that must be extinguished. In response to this “invasion,” our bodies coat the bubbles with platelets, white blood cells, and other proteins. If the bubbles make their way through the bloodstream, they will often damage our endothelial glycocalyx cells, which are what lines our blood vessels.  

After damaging the lining of the blood vessels, the air bubbles will try to pass through our capillaries, but even tiny bubbles won’t be big enough. The bubbles can then break up into smaller bubbles that can get inside the capillary walls, which will cause a blockage. In the most severe cases, a capillary blockage will prevent blood from getting from the heart to the rest of the body.

In more severe cases, when a lot of air is injected into a patient’s bloodstream, an air embolism can completely block the passage of blood through a vein or artery, denying vital parts of the body of necessary blood flow.

Symptoms of an air embolism can include anything from pain in joints, anxiety, and chest pain, to paralysis of extremities, loss of consciousness, and death. If the embolism blocks blood from getting to the brain, stroke or death become a real possibility.

The Venous Vs. The Arterial System: 2 Dangerous Paths With Equally Scary Outcomes

Depending on the medical procedure, an air bubble can enter the circulatory system through either the venous system or the arterial system. The main difference between the venous and arterial system is that the venous system carries blood to the heart, while the arterial system carries blood away from the heart. For a detailed explanation, watch the video below:

Generally speaking, air bubbles in the arterial system present a greater threat than air bubbles in the venous system because arterial air can travel to the brain and cause a stroke. However, it is estimated that 30% of the population have what’s called a patent foramen ovale (PFO), meaning there is a hole in the heart between the right atrium and the left atrium. In this case, a venous embolism can become a much more problematic arterial embolism.

How Much Air is Too Much?

Injecting a large amount of air in the circulatory system is well known to cause severe complications, including stroke or death. The risks are even greater in small children where the total blood volume is much smaller than in adults.

Historically, it has always been thought that a small amount of air (say, hundreds of microliters) is safe because there aren’t typically any immediate, obvious symptoms. However recent research is showing that this may not be the case. As described above, even small amounts of air can damage the endothelial glycocalyx, the lining of blood vessels. Several recent studies support the hypothesis that disturbance of the glycocalyx accelerates atherosclerosis, which can increase long term risks for heart attack and stroke. If localized near the brain, these microbubbles can cause damage to the blood-brain barrier that can cause both acute and chronic neurologic injury [Stump DA: Semin Cardiothorac Vasc Anesth 2005; 9(2):151-2]. Microembolisms are one of the hypothesized causes of cognitive defects in cardiopulmonary bypass patients, which can affect as many as 60% of patients 8 days postoperative [Taylor KM: Brain damage during cardiopulmonary bypass,. Ann Thorac Surg 65(4 Suppl):S20-26, 1998.]

Treatment for Air Embolism

The next logical question, of course, is whether air embolism can be cured. In short, yes, but only in certain situations. Possible treatments include administration of 100% oxygen to the patient, which can reduce the volume of the embolism by eliminating nitrogen, or hyperbaric oxygen therapy, which compresses existing air bubbles. Additionally, if large air bubbles are trapped in the patient’s heart via the venous system, then the patient could lay on their back with their pelvis above their head (the trendelenburg position), or they could try to trap the air next to the right ventricular apex by lying on their side. Unfortunately, in many cases, patients won’t know that they’ve received a harmful amount of air until it’s too late. The best thing to do is to prevent air embolisms from occurring in the first place.

Prevention Is The Best Medicine: How Our Bubble Sensors Can Help Detect and Exterminate Air In IV Lines, Infusion Pumps, and Fluid Warmers

ClearLine MD's IVAny medical device that is designed to deliver liquid to a patient’s circulatory system is equipped with at least one bubble sensor to trigger an alarm and stop the device whenever air is detected. Bubbles can be introduced into an IV line through things such as syringes, fluid warmers, and infusion pumps. In fact, a recently released FDA Safety Communication stresses the importance of following proper procedures to prevent air bubbles when using these kinds of devices.

However, even when proper protocols are followed, bubbles are often introduced into the IV line and when they’re detected, they can be extremely disruptive to the medical procedure. In an air alarm event, the practitioner is required to stop the procedure and re-prime the tubing, wasting precious minutes that would otherwise be used on providing care to the patient and contributing to the serious problem of alarm fatigue.

This can lead to a balancing act in medical device design and the SMD Sensors engineering team takes special care while working with our customers to design and validate bubble sensors that will detect dangerous amounts of air while ignoring what are typically considered “nuisance” bubbles. Our engineers have the experience to help guide you through the custom design process and optimize your medical device. We have the capability to generate precise bubbles in house and can calibrate each sensor to the desired bubble detection range.

To further improve patient safety, SMD Sensors teamed up with ClearLine MD to help create something special: an FDA-cleared product that automatically detects and removes air from IV lines, which is created by Infusion Pumps, Fluid Warmers, infusion bags, and connector malfunctions without intervention from the caregiver or a disruption to the procedure. We are proud to say that our calibrated custom bubble sensors empower this device with hawk-like vigilance. When air bubbles enter the ClearLine IV, our bubble detectors trigger an immediate response: the air gets diverted to a separate waste collection bag before it can reach the patient’s circulatory system. Without a doubt, the integrated capabilities of this product is revolutionary, offering a solution that protects patients against air embolisms while significantly reducing alarm fatigue.

If you’re a practitioner interested in a device that will automatically remove air from IV lines without intervention then schedule a demo with ClearLine MD.

If you’re an engineer interested in integrating custom sensors into a device that could help save lives, contact us below.