What is an air embolism? Show An air embolism, also called a gas embolism, occurs when one or more air bubbles enter a vein or artery and block it. When an air bubble enters a vein, it’s called a venous air embolism. When an air bubble enters an artery, it’s called an arterial air embolism. These air bubbles can travel to your brain, heart, or lungs and cause a heart attack, stroke, or respiratory failure. Air embolisms are rather rare. An air embolism can occur when your veins or arteries are exposed and pressure allows air to travel into them. This can happen in several ways, such as: Injections and surgical proceduresA syringe or IV can accidentally inject air into your veins. Air can also enter your veins or arteries through a catheter that’s inserted into them. Air can enter your veins and arteries during surgical procedures. This is most common during brain surgeries. According to an article in the Journal of Minimal Access Surgery, up to 80 percent of brain surgeries result in an air embolism. However, medical professionals usually detect and correct the embolism during the surgery before it becomes a serious problem. Doctors and nurses are trained to avoid allowing air to enter the veins and arteries during medical and surgical procedures. They’re also trained to recognize an air embolism and treat it if one does occur. Lung traumaAn air embolism can sometimes occur if there’s trauma to your lung. For example, if your lung is compromised after an accident, you might be put on a breathing ventilator. This ventilator could force air into a damaged vein or artery. Scuba divingYou can also get an air embolism while scuba diving. This is possible if you hold your breath for too long when you’re under water or if you surface from the water too quickly. These actions can cause the air sacs in your lungs, called alveoli, to rupture. When the alveoli rupture, air may move to your arteries, resulting in an air embolism. Explosion and blast injuriesAn injury that occurs because of a bomb or blast explosion can cause your veins or arteries to open. These injuries typically occur in combat situations. The force of the explosion can push air into injured veins or arteries. According to the Centers for Disease Control and Prevention (CDC), the most common fatal injury for people in combat who survive blast injuries is “blast lung.” Blast lung is when an explosion or blast damages your lung and air is forced into a vein or artery in the lung. Blowing into the vaginaIn rare instances, blowing air into the vagina during oral sex can cause an air embolism. In this case, the air embolism can occur if there’s a tear or injury in the vagina or uterus. The risk is higher in pregnant women, who may have a tear in their placenta. Doctors might suspect that you have an air embolism if you’re experiencing symptoms and something recently happened to you that could cause such a condition, such as a surgery or lung injury. Doctors use equipment that monitor airway sounds, heart sounds, breathing rate, and blood pressure to detect air embolisms during surgeries. If a doctor suspects that you have an air embolism, they may perform an ultrasound or CT scan to confirm or rule out its presence while also identifying its exact anatomical location. Treatment for an air embolism has three goals:
In some cases, your doctor will know how the air is entering your body. In these situations, they will correct the problem to prevent future embolisms. Your doctor may also place you in a sitting position to help stop the embolism from traveling to your brain, heart, and lungs. You may also take medications, such as adrenaline, to keep your heart pumping. If possible, your doctor will remove the air embolism through surgery. Another treatment option is hyperbaric oxygen therapy. This is a painless treatment during which you occupy a steel, high-pressurized room that delivers 100 percent oxygen. This therapy can cause an air embolism to shrink so it can be absorbed into your bloodstream without causing any damage. Sometimes an air embolism or embolisms are small and don’t block the veins or arteries. Small embolisms generally dissipate into the bloodstream and don’t cause serious problems. Large air embolisms can cause strokes or heart attacks and could be fatal. Prompt medical treatment for an embolism is essential, so immediately call 911 if you have concerns about a possible air embolism. Over many decades, nurses and other health care practitioners have been under the impression that air in an intravenous line is not harmful or dangerous to the patient, as long as this air volume is less than 50 cc. These same practitioners are also under the impression that volumes of air greater than 50 cc is lethal to the patient. This belief has been passed on and even taught to new generations of graduates, decade after decade, which has resulted in a widespread misinformation and complacency about intravenous line air bubbles. In fact, when patients raise an alarm about air in their IV lines, they are usually told not to worry and that it would take a lot more air than that to hurt anyone. This can cause communication and trust problems between patients and their nurse, especially as the patient repeatedly watches a 1-2 inch air bubble slowly come down the line and enter their arm, or the arm of a loved one. Sources supporting this belief about safe and lethal intravascular air volumes can be traced all the way back to publications from 1809, 1953 and 1963, when experiments were done on small dogs and rabbits to see how much air would block the chambers of the heart and cause death. But even today, that lethal amount of air in a human is still unknown. However, modern health care providers are still under the impression that as long as the air volumes are less than 50 cc, then venous air will not harm the patient. More recent reports have demonstrated a link between venous air and strokes. Although some suggest these morbidity causing events are rare, intravenous air (regardless of amount) still has the potential to pass from the venous circulation, into the arterial circulation through what is called right to left shunting (undetected PFO's, ASD's, VSD's and Intra-pulmonary R>L Shunts). In fact, venous air bubbles can go directly to the cerebral circulation (called a retrograde path) through the superior vena cava if the patient is in a sitting position when the air enters the peripheral or central IV line. What is interesting is the fact that most reported strokes in the USA are ischemic and embolic in nature (87%), but there are still many of these ischemic strokes that have an unknown origin (called cryptogenic strokes). In fact, in a study of 287 young adults with ischemic strokes, 43% of these strokes were found to be cryptogenic in nature. There are several other sources of strokes beside air, but intravenous air is an iatrogenic event, which for the most part is preventable. More to the point, intravenous air (in my opinion) should be a 'never event'. Unfortunately, the lack of knowledge about hazards associated with venous air is sadly lacking in health care, not only with the public, but with health care practitioners as well. Over the past 30 years as a Cardiovascular Perfusionist I have been researching, writing and speaking about arterial air emboli during cardiac surgery. But over the last decade I became more aware of the clinician complacency and misinformation that hovers around the issue of intravenous air associated with central and peripheral IV lines. As a result, I have talked on venous emboli in many countries, given webinars and published articles indicating the physiology, hazards and morbidity associated with intravenous air. We need to stop being so cavalier and dismissive about IV air with patients and future health care practitioners, who are ultimately responsible for preventing/eliminating air in an intravenous line. We need to stop telling concerned patients that “a little air will never hurt you” or “it would take much more air than that to kill you”. The topic needs to be more deeply addressed at a didactic level of education, not during clinical rotations. Until that time comes, we need to pay more attention to procedures that intentionally put air bubbles into the venous circulation (air bubble studies, foam sclerotherapy), we have to be more receptive and diligent to removal of air bubbles from an IV line, and we have to make more frequent use of current medical devices that are designed to remove IV air, or encourage the medical industry to develop new or better technology to do so. To help understand these 7 attached .jpg slides a little better; Slide 1. When a bolus of air (regardless of amount) enters the venous circulation, it is immediately coated by proteins, platelets and white cells in the blood, and quickly enters the cardiac chambers on the right side of the heart. Air bubbles in the blood have been described as 'solid emboli with compressible gas cores'. Slide 2. A couple of well know authors describe the dangers associated with air bubbles when they get into the arterial circulation. Slide 3. Briefly explains why and how air bubbles can damage the microcirculation. Slide 4. A slide showing air bubbles lodged and trapped in cerebral capillaries during a postmortem investigation. Slide 5. This is a 20-micron lipid embolus stuck in a cerebral arteriole. Also, on this slide are the accepted lumen diameters for arterioles, metarterioles and capillaries. Slide 6. A bolus of air entering a cardiac chamber is vigorously agitated by the contractions of a beating heart, which subsequently break that air bolus into thousands of smaller microbubbles. This slide demonstrates what happens when an air bolus enters circulating blood and is immediately broken into many thousands of small gas bubbles of varying diameters (keep in mind the diameters of blood vessels on slide 5). Slide 7. Summarizes some of the myths and realities. To get a better understanding of the many ways air emboli can get into the venous circulation, please read a previous post I put on LinkedIn (November 2014). The title of the post was “How Luck Do You Feel When Air Bubbles Are in Your Intravenous Line”. Also, the following link will bring you to my Editorial in a peer reviewed scientific journal called Perfusion out of England. The title of the Editorial is; “Air in Intravenous Lines: a need to review old opinions”. https://journals.sagepub.com/doi/full/10.1177/0267659117706834 After reading the above, ask yourself a personal question; What would you do if you seen a large air bubble coming down the IV line towards you or your child’s arm? Better still, discuss this issue with your educational or health care programs or share this article with others who may one day have an IV line during their hospital stay. |