A bubble study is a noninvasive test that lets healthcare providers look at the flow of blood through the heart. It is done as part of a medical imaging study called anechocardiogram(echo) that shows the heart’s structure. A bubble study is also known as an agitated saline contrast study.
A bubble study is often done to help diagnosepatent foramen ovale(PFO), which is a hole between the upper chambers of the heart.During the bubble study test, saline mixed with air is put into a vein. Overall, it takes about 30 minutes to do a bubbly study test.
This article goes over what a bubble study is used for, how it’s done, and what risks you should know about before you have the test.
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How a Bubble Study Is Done
A bubble study works because sound waves bounce around and create “echo waves” when they are near physical substances like gas or liquid. The echo waves show up on an echocardiogram as increased density.
How to PrepareUsually, there is no preparation needed before a bubble study. Check with your healthcare provider about what you need to do to get ready for the test.
How to Prepare
Usually, there is no preparation needed before a bubble study. Check with your healthcare provider about what you need to do to get ready for the test.
In a typical bubble study, a salty (saline) solution is shaken to make tiny bubbles and is injected into a vein.As the bubbles travel through the vein and into the right side of the heart, the increased density they produce on the echocardiography image allows a provider to watch the bubbles move through the heart chambers.
If the heart is working normally, the bubbles will be seen going into the right atrium, then the right ventricle. Then, they go out of the pulmonary artery and into the lungs. Once in the lungs, they can be filtered out through circulation.
Commercial forms of “bubbles” are available to be used during bubble studies. These new agents usually are made of tiny protein orphospholipidcasings with gas in them. They are safe in most cases and may provide better echo imaging. However, they are much more expensive than a shaken saline solution.
Are There Risks With a Bubble Study?
The bubble study test is considered safe.While your provider will want you to be aware of any serious complications, these are not common.
The more serious risks of a bubble study include reduced blood flow and an airmicroembolism, which is when air enters a vein and causes a blockage.Research has shown that if a bubble study causes a microembolism, it could trigger a stroke.
A less serious but more common risk of having a bubble study is that you’ll have some discomfort in the part of your arm where the cannula is put in.
Bubble Study for Patent Foramen Ovale
The most common reason for needing a bubble study is to look for a PFO. While the bubbles are being injected into the vein, the patient is asked to bear down like they are trying to have a bowel movement (theValsalvamaneuver).
Doing this temporarily raises the pressures inside the right side of the heart. If there is a PFO, the bubbles can often be seen going into the left atrium. Bubbles appearing in the left atrium during the test confirm there is a PFO.
Why Are PFOs a Problem?The main reason healthcare providers worry about PFOs is that they could allow blood clots to cross into the left side of the heart, where they could enter the circulation of the brain and lead to an embolic stroke.
Why Are PFOs a Problem?
The main reason healthcare providers worry about PFOs is that they could allow blood clots to cross into the left side of the heart, where they could enter the circulation of the brain and lead to an embolic stroke.
While PFOs are common (occurring in up to 25% of adults), they only rarely lead to a stroke.While a positive bubble study might confirm you have a PFO, it does not tell your healthcare provider very much about your risk of having a stroke.
Most experts think that a better way to assess whether a PFO is likely to produce a stroke is to do a transcranial Doppler study (TCD) with a bubble study.
For this test, echo techniques are used to look at the bubbles traveling through the blood vessels of the brain. The TCD study can show whether the bubbles that were injected into a vein are actually getting into the brain circulation.
If they are, having a PFO could be more likely to increase a person’s risk of stroke. Therefore, a provider will be more likely to recommend anticoagulation therapy, or if a stroke has already happened, possibly the surgical closure of the PFO.
Summary
A bubble study can be done to see how the blood flows through the heart. It is done as part of an echocardiogram. You may need a bubble study to diagnose a heart problem like a patent foramen ovale (PFO).
A bubble study usually does not take long. A bubble study is safe but there are risks involved with any test. Your provider will talk to you about the risks of having a bubble study done and explain why they think the risk is worth the benefit for your condition.
7 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Maggiore P, Bellinge J, Chieng D, et al.Ischaemic stroke and the echocardiographic “Bubble Study”: Are we screening the right patients?.Heart Lung Circ. 2019;28(8):1183-1189. doi:10.1016/j.hlc.2018.07.007NHS.Bubble contrast echocardiogram.Powers AY, Selvaraj V.Bubbles in the brain: A rare complication following transthoracic echocardiography.R I Med J (2013). 2018;101(6):37-39. Published 2018 Aug 1.Bassett G, Lin J, Tran M, Sistino J.Evaluating the potential risks of bubble studies during echocardiography.Perfusion. 2015;30(3):219-223. doi:10.1177/0267659114539182National Neuroscience Institute.Transcranial doppler bubble study.Dia A, Cifu AS, Shah AP.Management of patients with a patent foramen ovale with history of stroke or tia.JAMA. 2021;325(1):81. doi:10.1001/jama.2020.22176Komar M, Olszowska M, Przewłocki T, et al.Transcranial Doppler ultrasonography should it be the first choice for persistent foramen ovale screening?.Cardiovasc Ultrasound. 2014;12:16. doi:10.1186/1476-7120-12-16Additional ReadingParker JM, Weller MW, Feinstein LM, et al.Safety of ultrasound contrast agents in patients with known or suspected cardiac shunts.Am J Cardiol2013;112:1039. doi:10.1136/jnnp.2010.219733
7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Maggiore P, Bellinge J, Chieng D, et al.Ischaemic stroke and the echocardiographic “Bubble Study”: Are we screening the right patients?.Heart Lung Circ. 2019;28(8):1183-1189. doi:10.1016/j.hlc.2018.07.007NHS.Bubble contrast echocardiogram.Powers AY, Selvaraj V.Bubbles in the brain: A rare complication following transthoracic echocardiography.R I Med J (2013). 2018;101(6):37-39. Published 2018 Aug 1.Bassett G, Lin J, Tran M, Sistino J.Evaluating the potential risks of bubble studies during echocardiography.Perfusion. 2015;30(3):219-223. doi:10.1177/0267659114539182National Neuroscience Institute.Transcranial doppler bubble study.Dia A, Cifu AS, Shah AP.Management of patients with a patent foramen ovale with history of stroke or tia.JAMA. 2021;325(1):81. doi:10.1001/jama.2020.22176Komar M, Olszowska M, Przewłocki T, et al.Transcranial Doppler ultrasonography should it be the first choice for persistent foramen ovale screening?.Cardiovasc Ultrasound. 2014;12:16. doi:10.1186/1476-7120-12-16Additional ReadingParker JM, Weller MW, Feinstein LM, et al.Safety of ultrasound contrast agents in patients with known or suspected cardiac shunts.Am J Cardiol2013;112:1039. doi:10.1136/jnnp.2010.219733
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Maggiore P, Bellinge J, Chieng D, et al.Ischaemic stroke and the echocardiographic “Bubble Study”: Are we screening the right patients?.Heart Lung Circ. 2019;28(8):1183-1189. doi:10.1016/j.hlc.2018.07.007NHS.Bubble contrast echocardiogram.Powers AY, Selvaraj V.Bubbles in the brain: A rare complication following transthoracic echocardiography.R I Med J (2013). 2018;101(6):37-39. Published 2018 Aug 1.Bassett G, Lin J, Tran M, Sistino J.Evaluating the potential risks of bubble studies during echocardiography.Perfusion. 2015;30(3):219-223. doi:10.1177/0267659114539182National Neuroscience Institute.Transcranial doppler bubble study.Dia A, Cifu AS, Shah AP.Management of patients with a patent foramen ovale with history of stroke or tia.JAMA. 2021;325(1):81. doi:10.1001/jama.2020.22176Komar M, Olszowska M, Przewłocki T, et al.Transcranial Doppler ultrasonography should it be the first choice for persistent foramen ovale screening?.Cardiovasc Ultrasound. 2014;12:16. doi:10.1186/1476-7120-12-16
Maggiore P, Bellinge J, Chieng D, et al.Ischaemic stroke and the echocardiographic “Bubble Study”: Are we screening the right patients?.Heart Lung Circ. 2019;28(8):1183-1189. doi:10.1016/j.hlc.2018.07.007
NHS.Bubble contrast echocardiogram.
Powers AY, Selvaraj V.Bubbles in the brain: A rare complication following transthoracic echocardiography.R I Med J (2013). 2018;101(6):37-39. Published 2018 Aug 1.
Bassett G, Lin J, Tran M, Sistino J.Evaluating the potential risks of bubble studies during echocardiography.Perfusion. 2015;30(3):219-223. doi:10.1177/0267659114539182
National Neuroscience Institute.Transcranial doppler bubble study.
Dia A, Cifu AS, Shah AP.Management of patients with a patent foramen ovale with history of stroke or tia.JAMA. 2021;325(1):81. doi:10.1001/jama.2020.22176
Komar M, Olszowska M, Przewłocki T, et al.Transcranial Doppler ultrasonography should it be the first choice for persistent foramen ovale screening?.Cardiovasc Ultrasound. 2014;12:16. doi:10.1186/1476-7120-12-16
Parker JM, Weller MW, Feinstein LM, et al.Safety of ultrasound contrast agents in patients with known or suspected cardiac shunts.Am J Cardiol2013;112:1039. doi:10.1136/jnnp.2010.219733
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