What is Arterial Gas Embolism?
An arterial gas embolism is a serious condition that happens when air gets into the arteries of the body. It’s critical to detect this problem early because it can be life-threatening. The air can travel to various parts of the body including the brain, spinal cord, heart, kidneys, spleen, and digestive system, causing them to not get the oxygen they need. This can lead to serious complications. Sometimes, there are no initial symptoms, yet at other times signs may be vague, and can ultimately lead to complete breakdown of the heart and blood circulation system.
However, medical professionals have many strategies to reduce the risk of this dangerous condition. This discussion will cover the causes, frequency, symptoms, and treatment of arterial gas embolisms specifically. It will not include other types of embolisms such as those caused by air in the veins, blood clots, carbon dioxide, or fat.
What Causes Arterial Gas Embolism?
When air gets into the blood circulatory system, it’s called an air embolism. The effects of this depend on where the air enters. If air gets into a vein, it could lead to a blockage in the lungs, known as a pulmonary embolism. If air enters an artery, it becomes an arterial gas embolism.
Air can get into your blood circulatory system in one of two main ways. One way is through direct entry, for example, during a surgery in which an incision is made, or through a needle, allowing air from the surroundings into the vessels. Another way is indirectly, as a result of a pressure difference, which can happen during activities like diving.
Arterial gas embolism can also occur directly, when air enters an artery. It can also happen indirectly, when air moves from a vein to an artery. This can be caused by treatments or procedures such as air mistakenly injected into a vessel, inflation of a balloon in the vessel, damage from a blast, lung surgery, or even ventilation machines. It could also occur due to a punctured lung or during certain medical procedures such as spine surgery or hysteroscopy.
Sometimes, things like a rapid decompression during a dive, changes in lung pressure or a hole between the left and right side of the heart—known as a defect—can cause an arterial gas embolism. Procedures like lung biopsy, tumor removal, or during the placement of a thin, flexible tube into a patient’s artery could also unknowingly introduce air into an artery.
Even things like incorrect flushing of a catheter or a damaged arterial catheter balloon during a procedure may lead to an arterial gas embolism. Injuries to the chest, either from blunt force or a penetrating injury, can also cause air to enter the bloodstream. Other causes include the use of a catheter to tail electrical signals in the heart to treat irregular heartbeats.
Being aware of these potential causes is vital for healthcare providers, as it allows them to minimize risks and quickly address any situations where an arterial gas embolism may occur during procedures.
Risk Factors and Frequency for Arterial Gas Embolism
Arterial gas embolism, which is the presence of air in the arteries, is quite rare. This is mostly due to the high pressures in our arteries which naturally protect against this. However, since this condition can have varying symptoms, may not always be recognized or reported, and can be caused by different factors, we don’t know exactly how often it happens. Certain activities or procedures may increase the risk.
- In scuba diving, for example, it can happen in 0.4 to 1 out of 100,000 dives. The risk becomes higher with deeper and longer dives.
- During cardiac bypass surgery, it tends to be very rare, occurring only about 0.003% to 0.007% of the time. But, about half of these cases can lead to serious health problems.
- Based on certain studies, the rate of this condition is about 2.65 per 100,000 hospital stays.
In addition to arterial gas embolism, there are other forms of embolism, such as an intracoronary embolism, which can also happen. Generally, the chance of a serious air embolism happening is about 0.2%. However, this can change based on the specific medical procedure being done, like coronary angioplasty versus diagnostic coronary angiography. The level of training of the healthcare professionals involved can also affect these rates.
Signs and Symptoms of Arterial Gas Embolism
Arterial gas embolism is a condition that occurs when gas bubbles enter your arteries. This can happen during activities like diving, especially if you ascend too quickly. It’s a very serious condition as it can block blood supply to vital organs and can lead to a sudden collapse or even death.
The symptoms of an arterial gas embolism can vary from person to person and are dependent on the affected organs. If this condition affects your brain, symptoms might mimic a stroke and can be very pronounced.
In severe cases, this condition could lead to a sudden drop in blood pressure, irregular heartbeat, and symptoms similar to shock. If the gas bubbles affect your lungs, you might experience symptoms like shortness of breath, fast breathing, chest pain and coughing up blood.
Sometimes, the initial symptoms can be minor and easy to miss. However, if your brain is affected, symptoms can be very pronounced and might include weakness on one side of the body and abnormal coordination. It’s also common to lose consciousness, feel confused, or dizzy. You might also experience paralysis on one side of your body, changes in vision, headache, difficulty speaking, and seizures.
If you have any of these symptoms within minutes of surfacing from a dive, particularly loss of consciousness, altered mental state, weakness on one side of the body, seizures, or any other focused neurological changes, you could likely have an arterial gas embolism.
Quick medical attention is imperative. Doctors will want to know how quickly the symptoms started, where they were, how long they lasted, and whether there were any activities that brought on or worsened the symptoms. This can be hard if your brain was affected and you lost consciousness. This condition can also occur due to certain medical procedures. History of recent procedures or trauma to the lung or chest that could cause gas bubbles in your bloodstream is key.
For those diving, symptoms that started after quick ascent should be addressed immediately. Gas bubbles can form in your bloodstream if you ascend too quickly, causing this condition.
During your medical evaluation, doctors will assess your vital signs like your blood pressure, heart rate, breathing rate, and oxygen level. They might listen to your heart and lungs, check for weakness or loss of sensation, assess your level of consciousness, and look for signs of intestinal blockage like pain or tenderness in your abdomen, stiffness, and abnormal bowel sounds.
Testing for Arterial Gas Embolism
An arterial air embolism is mainly determined by a patient’s symptoms and medical history rather than a specific lab test. Nevertheless, certain lab tests can be useful in understanding the impact on various organs and gathering supportive information. Some significant tests include:
- Arterial Blood Gas (ABG) analysis: This will help to check the patient’s oxygen and carbon dioxide levels as well as acid-base balance. Results may reveal low oxygen levels and respiratory alkalosis due to impaired gas exchange created by the embolism.
- Cardiac Enzymes: These enzymes, like troponin, might hint at heart damage or heart attack, especially when coronary arteries are suspected to be involved.
- Complete Blood Count (CBC): A CBC might be done to look for signs of infection or anemia that could be related to specific causes or complications of the embolism.
- Coagulation Profile: This profile might reveal any coagulation issues that could contribute to or result from the embolism.
Imaging tests such as an MRI and a CT scan can offer valuable data when analyzing an arterial gas embolism. However, their ability to specifically identify air embolisms is not very high.
- MRI : While an MRI can evaluate organ damage and identify secondary effects like changes due to lack of blood supply or tissue death, it does not effectively visualize air bubbles.
- CT scan : CT scans might show indirect signs of an embolism, like gas in blood vessels. Its capacity to detect small air bubbles directly, however, is limited.
Other imaging methods, like transthoracic echocardiography, can help assess the presence of air bubbles, evaluate heart function, and detect unusual blood flow patterns. In cases where thoracic procedures have been performed, a chest x-ray can help ensure that the symptoms are not related to lung collapse. Similarly, a chest x-ray or chest ultrasound can help rule out a collapsed lung. A patient’s ECG might show signs of heart attack, slow heart rate, and irregular heart rhythms.
Treatment Options for Arterial Gas Embolism
Treatment for arterial gas embolism, or air bubbles in the arteries, involves three key steps: maintaining steady blood flow, stopping the source of air, and making the air bubbles smaller. If a patient’s condition is unstable, the first things to do are to ensure they can breathe and that their circulation is maintained, as these are essential for survival.
Usually the position suggested for patients with arterial gas embolism is different from that required for venous air embolism. Arterial gas embolism patients are best laid flat on their backs instead of having their head lower than their bodies or lying on their sides, which are positions usually adopted for venous air embolism. This is because the pressure of arterial blood flow pushes the air forward, so these positions could potentially worsen brain swelling and limit air movement through the circulatory system.
Oxygen therapy is essential for patients with suspected arterial gas embolism. By providing a high concentration of oxygen, it supports several functions, as it increases the pressure of oxygen in the blood which aids tissue oxygenation and counters low blood oxygen levels resulting from disruption caused by air bubbles. High oxygen concentration also reduces the amount of nitrogen in the blood, encouraging the absorption of nitrogen gas from the bubbles and helping to reduce their size.
Patients at risk of air embolism, or who are suspected of having one, should not be administered nitrous oxide if they need anesthesia because it can potentially enlarge the size of the gas bubbles.
Stabilizing blood pressure and blood flow in the body is another essential component of arterial gas embolism management, especially when blood pressure drops significantly or if there’s a cardiovascular collapse. This may involve administering intravenous (IV) fluids to improve blood volume and heart function. If these measures are not sufficient, drugs that constrict blood vessels and increase blood pressure may be needed.
Choice of IV fluids may be influenced by various factors such as the patient’s general health condition and the presence of other diseases. Solutions like normal saline or balanced electrolyte solutions are often used to maintain an adequate blood volume and promote good circulation. Drugs to contract blood vessels are only used when fluid administration is insufficient. Choice and dosage of these drugs should be tailored to individual patients and guided by the patient’s response to fluid therapy and ongoing monitoring.
Providing hyperbaric oxygen (HBO) treatment is an important strategy in managing arterial gas embolism. HBO means giving 100% oxygen at pressures higher than that of the atmosphere, typically in a pressurized chamber, to help reduce air bubble size and promote their absorption.
In severe cases where a patient’s condition deteriorates rapidly, chest compressions may be needed as part of cardiopulmonary resuscitation (CPR). Other treatments may also be considered, such as medication to widen the coronary arteries or improve blood flow to the heart, or using special catheters to try to remove the air bubbles if an arterial gas embolism happens during heart artery imaging.
What else can Arterial Gas Embolism be?
Doctors have quite a few different medical conditions they need to consider when diagnosing an arterial air embolism. This is because the symptoms and signs can be similar to an arterial blockage, and the symptoms can vary depending on which organ and specific location in the body is affected. For example:
- In the Central Nervous System, symptoms can appear to be similar to migraines, vertigo, seizures, a mini stroke (TIA), fainting, mental confusion, or spinal cord damage.
- If the inner ear is affected, the patient might experience ear pain during descent, like decreases in altitude or underwater depth.
- Cardiovascular issues might mimic the signs of a heart attack, cardiac arrest, abnormal heart rhythms, blockage of blood flow to limbs, or fluid accumulation in the sac surrounding the heart.
- For the digestive system, a potential symptom might resemble mesenteric ischemia, a condition where the blood flow to the intestines gets blocked.
- If the kidneys are affected, it may present like a disruption of blood supply to the kidneys, or sudden decline in kidney function.
- Metabolic changes might indicate hypoglycemia (low blood sugar) or acid build up in the body.
Given that the symptoms can be so varied and mimic other conditions, it is crucial to get the correct diagnosis.
What to expect with Arterial Gas Embolism
The outlook for patients experiencing a gas blockage in their arteries (arterial gas embolism) largely depends on very limited studies and not much concrete evidence. Most of these studies focus on patients who were chosen to undergo treatment with hyperbaric oxygen (HBO). According to these studies, patients with gas blockages in their veins who received HBO treatment within 6 hours of the symptoms showing up generally have a better outcome.
However, whether or not to use HBO treatment for gas blockages in the arteries is still a matter of much discussion and disagreement among experts. Some studies have shown no noticeable improvement in recovery time, long-term effects, or death rates when considering the timing of starting HBO treatment. However, other past case studies have recorded instances where patients fully recovered neurologically after HBO treatment.
There are certain factors that could indicate a worse outcome for patients with an arterial gas embolism. These factors include:
1. A positive Babinski test when the patient first comes in
2. Specific areas of the brain showing signs of damage
3. Sudden kidney failure
4. Heart attack when the patient first comes in
5. Being older
6. Needing a ventilator to breathe for more than 5 days.
Possible Complications When Diagnosed with Arterial Gas Embolism
Arterial gas embolism, a condition where gas bubbles enter the bloodstream, can lead to different complications depending on which parts of the body are affected. In a study of 119 people who were treated with a high-pressure oxygen therapy for either arterial or venous gas embolisms, long-term recovery was assessed at 6 months and then after a year. Nearly half of the survivors had neurological problems when they left the hospital.
The complications they experienced most often included:
- Visual field deficits
- Motor deficits
- Cognitive issues
- Seizures
However, it’s important to note that many patients saw improvements in their functionality over time. By 6 months, three quarters of those treated had mild or no disability left. This shows that, with proper treatment and management, there’s a potential for recovery and rehabilitation after an arterial gas embolism.
Preventing Arterial Gas Embolism
Preventing air bubbles from entering the arteries, known as arterial gas embolisms, involves recognizing high-risk procedures and taking steps to reduce the chance of this happening. An example of this would be using lung-protective methods when starting mechanical ventilation to lower the chances of lung damage. Additional precautions should also be taken with patients having neck and shoulder vein central lines to decrease the risk of an air embolism during the removal process. These precautions include having the patient lie with their head lower than the rest of their body and asking them to bear down, as if straining and exhaling. Patients with a central line in their thigh don’t need to be in such a position; lying flat is enough.
Extra care should be taken with how a patient is positioned during brain surgery. The “sitting up” position, where the patient is sitting upright, could raise the risk of an air embolism, especially during procedures involving the brain or head blood vessels. A modified version of this, known as the “park bench” position, may be preferable. In this position, the patient is semi-sitting with their head slightly raised to make the surgical procedure easier while reducing the chances of an air embolism.
