Clinical Contributors to this Story
Adrian Pristas, M.D. contributes to topics such as Sleep Medicine.
A problem with any of these factors — for example, high altitude, asthma or heart disease — might result in hypoxemia, particularly under more extreme conditions, such as exercise or illness. When your blood oxygen falls below a certain level, you might experience shortness of breath, headache, and confusion or restlessness. A normal SpO2 level is vital to maintaining the health of all tissue in the body. As previously mentioned, hypoxemia is low oxygen saturation in the blood. Hypoxemia is directly related to hypoxia, which is low oxygen saturation in the body’s tissue. Hypoxemia often causes hypoxia, if the oxygen levels are quite low, and remain so.
Blood oxygen levels may be measured using a pulse oximeter. A normal blood oxygen level varies between 75 and 100 millimeters of mercury (mm Hg). A blood oxygen level below 60 mm Hg is considered. When oxygen saturation levels fall below 92%, the pressure of the oxygen in your blood is too low to penetrate the walls of the red blood cells. It is a matter of gas laws. Your insurance company may not pay for oxygen unless your levels fall to 88% oxygen saturation.
There has been a recent spike in sales for pulse oximeters, the small device used to measure the level of oxygen in your blood. Apple also just announced that the new Apple Watch Series 6 comes with a blood oxygen sensor and app. So, why is the spotlight on this health metric?
To get the inside scoop on blood oxygen levels and pulse oximeters and why there’s growing interest in both, we spoke to Adrian Pristas, M.D., pulmonologist and corporate medical director, Centers for Sleep Medicine at Hackensack Meridian Health.
Q: What does “blood oxygen level” mean?
Dr. Pristas: “Blood oxygen level” describes the amount of oxygen you have circulating in your blood. Our bodies need oxygen to function. Oxygen enters the body through the nose and mouth and passes through the lungs into the bloodstream. Once in the bloodstream, oxygen helps replace cells that wear out, provides energy for our bodies, supports the way our immune system functions and more. Low blood oxygen levels indicate that there may be an issue with your lungs or circulation.
Q: Why is there increased interest in blood oxygen levels?
Dr. Pristas: People started to buy pulse oximeters to measure blood oxygen levels at home when they learned that low levels could be a sign of COVID-19. Shortness of breath is a well-known symptom of COVID-19, but it’s not always easy to detect. Candy crush free download for macbook pro. Some thought this device could be a tool to help self-assess for signs and symptoms. There have also been reports of “silent hypoxia” where peoples’ oxygen levels are dangerously low, but they don’t necessarily experience shortness of breath.
Q: What’s a normal blood oxygen level, and when should I be concerned?
Dr. Pristas: If you’re using a pulse oximeter to measure your blood oxygen level, a normal reading is a Sp02 level that’s between 95 and 100 percent. However, this may vary for people with certain medical conditions, such as lung disease. Speak with your doctor to determine what ‘normal’ is for you and keep in mind that while these at home devises are handy and non-invasive, they are not always 100% accurate. In fact, Apple says its new blood oxygen feature should only be used for general fitness and wellness purposes and should not be used to diagnose, monitor or treat any medical conditions. Other tests, performed by health care providers, include blood draws or breathing tests to accurately measure blood oxygen levels. If your Sp02 is below 95% you should consult with your health care provider.
Normal Human Oxygen Level Range
Q: Can a pulse oximeter detect COVID-19?
Dr. Pristas: A pulse oximeter cannot detect COVID-19, however, it can help you monitor for signs and symptoms associated with the virus. Having a low blood oxygen level could be a sign of COVID-19, but it can also be a sign of other health issues that need to be discussed with your health care provider. Either way, if you are monitoring your blood oxygen levels at home with a pulse oximeter, contact your health care provider if your Sp02 drops below 90-95%.
Q: How does a pulse oximeter work?
Dr. Pristas: Using a pulse oximeter is painless. The small device simply clips on to your finger, and beams of light measure the amount of oxygen in your blood, as well as your heart rate. The small beams of light analyze the color and movement of your blood cells. Dark red blood cells indicate a lack of oxygen, while bright red blood cells indicate the right amount of oxygen. If 95% of the blood cells are bright red, while 5% are dark red, your Sp02 would be 95%.
You can also attach a pulse oximeter to your toe, earlobe or nose, but it is commonly used on your finger. Once the Sp02 reading appears, you can remove it.
Q: Should I monitor my blood oxygen levels at home?
Dr. Pristas: There are some scenarios when your doctor might recommend you monitor your blood oxygen levels at home. If you have an underlying health condition, like heart or lung disease, or you are in the process of recovering from COVID-19, it could be helpful for you to keep an eye on your blood oxygen levels. However, if you do choose to monitor from home, talk to you doctor first about how to properly use the device, understand your reading and interpret the results. For example, if your hand is not steady during the reading you could see varying saturations from a faulty reading.
If you’re otherwise healthy, it’s not necessary to have a pulse oximeter or any other device to monitor your blood oxygen levels at home. If you’re unsure, ask your doctor for personal advice.
Next Steps & Resources:
- Meet our clinical contributor: Adrian Pristas, M.D.
- To make an appointment with Dr. Pristas or a doctor near you, call 800-822-8905.
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The material provided through HealthU is intended to be used as general information only and should not replace the advice of your physician. Always consult your physician for individual care
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Researchers have begun to solve one of COVID-19’s biggest and most life-threatening mysteries: how the virus causes “silent hypoxia,” a condition where oxygen levels in the body are abnormally low.
Those low oxygen levels can can irreparably damage vital organs if gone undetected for too long.
More than six months since COVID-19 began spreading in the US, scientists are still solving the many puzzling aspects of how the novel coronavirus attacks the lungs and other parts of the body.
Despite experiencing dangerously low levels of oxygen, many people infected with severe cases of COVID-19 sometimes show no symptoms of shortness of breath or difficulty breathing.
Hypoxia’s ability to quietly inflict damage is why health experts call it “silent.” In coronavirus patients, researchers think the infection first damages the lungs, rendering parts of them incapable of functioning properly. Those tissues lose oxygen and stop working, no longer infusing the blood stream with oxygen, causing silent hypoxia. But exactly how that domino effect occurs has not been clear until now.
“We didn’t know [how this] was physiologically possible,” says Bela Suki, professor of biomedical engineering and of materials science and engineering at Boston University and one of the coauthors of the study in Nature Communications.
Some coronavirus patients have experienced what some experts have described as levels of blood oxygen that are “incompatible with life.” Disturbingly, Suki says that many of these patients showed little to no signs of abnormalities when they underwent lung scans.
To help get to the bottom of what causes silent hypoxia, biomedical engineers used computer modeling to test out three different scenarios that help explain how and why the lungs stop providing oxygen to the bloodstream.
They found that silent hypoxia is likely caused by a combination of biological mechanisms that may occur simultaneously in the lungs of COVID-19 patients, says lead author Jacob Herrmann, a biomedical engineer and research postdoctoral associate in Suki’s lab.
How healthy lungs work
Normally, the lungs perform the life-sustaining duty of gas exchange, providing oxygen to every cell in the body as we breathe in and ridding us of carbon dioxide each time we exhale.
Healthy lungs keep the blood oxygenated at a level between 95 and 100%—if it dips below 92%, it’s a cause for concern and a doctor might decide to intervene with supplemental oxygen. (Early in the coronavirus pandemic, when clinicians first started sounding the alarm about silent hypoxia, oximeters flew off the shelves as many people, worried that they or their family members might have to recover from milder cases of coronavirus at home, wanted to be able to monitor their blood oxygen levels.)
The researchers first looked at how COVID-19 affects the lungs’ ability to regulate where blood is directed. Normally, if areas of the lung aren’t gathering much oxygen due to damage from infection, the blood vessels will constrict in those areas. This is actually a good thing that our lungs have evolved to do, because it forces blood to instead flow through lung tissue replete with oxygen, which is then circulated throughout the rest of the body.
But Herrmann says preliminary clinical data has suggested that the lungs of some COVID-19 patients had lost the ability of restricting blood flow to already damaged tissue and, in contrast, were potentially opening up those blood vessels even more—something that is hard to see or measure on a CT scan.
Using a computational lung model, Herrmann, Suki, and their team tested that theory, revealing that for blood oxygen levels to drop to the levels observed in COVID-19 patients, blood flow would indeed have to be much higher than normal in areas of the lungs that can no longer gather oxygen—contributing to low levels of oxygen throughout the entire body, they say.
Next, they looked at how blood clotting may affect blood flow in different regions of the lung. When the lining of blood vessels get inflamed from COVID-19 infection, tiny blood clots too small to be seen on medical scans can form inside the lungs. They found, using computer modeling of the lungs, that this could incite silent hypoxia, but alone it is likely not enough to cause oxygen levels to drop as low as the levels seen in patient data.
Silent hypoxia hides in lungs
Normal Human Body Oxygen Level
Last, the researchers used their computer model to find out if COVID-19 interferes with the normal ratio of air-to-blood flow that the lungs need to function normally.
This type of mismatched air-to-blood flow ratio is something that happens in many respiratory illnesses such as with asthma patients, Suki says, and it can be a possible contributor to the severe, silent hypoxia that has been observed in COVID-19 patients.
The models suggest that for this to be a cause of silent hypoxia, the mismatch must be happening in parts of the lung that don’t appear injured or abnormal on lung scans.
Altogether, the findings suggest that a combination of all three factors are likely to be responsible for the severe cases of low oxygen in some COVID-19 patients.
By having a better understanding of these underlying mechanisms, and how the combinations could vary from patient to patient, clinicians can make more informed choices about treating patients using measures like ventilation and supplemental oxygen.
Researchers are currently studying a number of interventions, including a low-tech intervention called prone positioning that flips patients over onto their stomachs, allowing for the back part of the lungs to pull in more oxygen and evening out the mismatched air-to-blood ratio.
“Different people respond to this virus so differently,” Suki says. For clinicians, he says it’s critical to understand all the possible reasons why a patient’s blood oxygen might be low, so that they can decide on the proper form of treatment, including medications that could help constrict blood vessels, bust blood clots, or correct a mismatched air-to-blood flow ratio.
The National Heart, Lung, and Blood Institute supported the work.
Normal Blood Oxygen Level By Age
Normal Oxygen Level In Human Body In Hindi
Source: Boston University