As doctors increasingly look at COVID-19 patients, they are aware of a strange trend: patients with very low blood oxygen saturation but not breath.
Although these patients are quite ill, their illness does not manifest like the typical acute respiratory distress syndrome (ARDS). This is the outbreak of the SARS coronavirus in 2003 and other Respiratory disease. their lung It’s clear that they’re obviously not pumping oxygen into the blood, but despite the doctor’s debate over whether to place a breathing tube in their throat and intubate, these patients are wary and relatively I feel good.
A concern with this presentation, called “Silent Hypoxia,” is that patients are appearing in hospital in worse health than they understand. But there might be a way to prevent it, New York Times Op-Ed By emergency doctor Richard Levitan. When sick patients are given an oxygen monitor called a pulse oximeter to monitor their symptoms at home, they can seek treatment sooner and ultimately avoid the most invasive treatments. May be possible.
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“This is not a new phenomenon,” said Dr. Mark Moss, director of lung and critical care medicine at the University of Colorado Anschutz Medical School campus. Moss told Live Science that the patient has other conditions that are very low on oxygen but do not feel choking or lack of air. For example, some congenital heart defects result in insufficient oxygenation of the blood because the circulation bypasses the lungs.
However, people with COVID-19 Coronavirus symptoms Doctors’ treatment methods are changing.
Gasping of the air
According to Moss, the normal blood oxygen level is about 97%, and I’m worried if the number falls below 90%. At levels below 90%, the brain does not get enough oxygen and patients may begin to experience confusion, lethargy or other mental disruption. Levels below the 80s increase the risk of damage to vital organs.
However, patients may not feel as dire as they are. Dr Astha Chichra, an emergency care physician at Yale University School of Medicine, appears to be fairly comfortable and alert, although many coronavirus patients appear in hospitals with oxygen saturation in the late 1980s. They may be slightly short of breath, but they are not proportional to the lack of oxygen they are receiving.
According to Moss, there are three main reasons people have difficulty breathing or having difficulty breathing. The first is the obstruction of the airways, which is not a problem with COVID-19. The other is when carbon dioxide accumulates in the blood. A good example of that phenomenon is during exercise. Increased metabolism means the production of more carbon dioxide, leading to intense breathing and exhaling all that CO2.
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The third and most important phenomenon in respiratory illness is poor lung compliance. Lung compliance refers to the easy access of the lungs with each breath. To pneumonia In ARDS, lung fluid fills a microscopic air sac called the alveoli. Alveoli are the places where oxygen from the air diffuses into the blood. When a lung fills with fluid, the lung becomes more tense and stiff, and the human chest and abdominal muscles must work hard to expand and contract the lungs to breathe.
This also happens with the serious COVID-19. However, in some patients, fluid accumulation is not sufficient to make the lungs particularly stiff. Their oxygen levels may be low for unknown reasons without the accumulation of fluid-and those that do not cause the body’s need to hold their breath.
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Work to breathe
It’s still unclear what exactly is happening.
Chicla says some of these patients may have lungs (or elasticity) because they may have fairly healthy lungs. Their lungs are less effective at diffusing oxygen into the blood. Others, especially geriatric patients, may have comorbidities, which means living at low oxygen levels regularly, so they are somewhat lethargic or easily accustomed to wrapping up, she says. Said.
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In New York Times Op-Ed About this phenomenon, Levitan wrote that the lack of gasping may be due to a specific stage of lung failure caused by COVID-19. He says that when lung failure first begins, the virus may attack lung cells to make surfactant, the fatty substance of the alveoli, which lowers lung surface tension and increases compliance. There is. In the absence of a surfactant, increased surface tension causes the alveoli to contract, but when not filled with fluid, it doesn’t feel stiff, Levitan writes. This can explain how the alveoli can’t supply oxygen to the blood without realizing that the patient needs to hold their breath for more air.
The virus also Blood vessel Moss said it would connect to the lungs. Usually, when a patient has pneumonia, small blood vessels around the fluid-filled lungs contract (known as hypoxic vasoconstriction): when the body senses a lack of oxygen in the damaged area, the body It diverts blood to the healthy lungs of the. Because pneumonia fills the lungs with fluid, people run out of air and are short of breath. However, their blood oxygenation remains relatively high when damaged, because their blood vessels carry blood to the most undamaged part of the lungs.
The COVID-19 may be out of balance. The lungs are not filled with fluid and are not stiff, but the blood vessels do not contract and send blood back to the least damaged spots. People are free to inhale and exhale without resistance, but blood is trying to uptake inefficient oxygen that has been damaged in the alveoli.
“The most likely thing here is that the hypoxic vasoconstriction is lost for some reason, which results in blood flowing where there is damage to the lungs,” Moss said. It could be a combination of factors, he added.
“I don’t say that the alveoli are normal and the surfactants are normal, but if someone has hypoxia that is not proportional to what is found in the lungs, it is a problem for lung specialists on the vascular side. Makes me think there is, “he said.
In the New York Times, Levitan proposes to give patients who are not ill enough to be admitted to a hospital with a pulse oximeter, a device that clamps their fingers to measure blood oxygenation. . If their oxygenation number begins to decline, it may be an early warning sign of seeking medical treatment.
“It’s an interesting possibility,” Moss said.
Even without widespread home oxygen monitoring, doctors are now beginning to distinguish between patients with low oxygen levels who are having difficulty breathing and those with low oxygen levels who are breathing comfortably, Chicla said. Said. In the early stages PandemicKnowing that COVID-19 patients can begin to fail soon, doctors tended to put hypoxic people on ventilators right away. According to Chicla, patients who do not suffer from breathing often recover without intubation. They work well with oxygen delivered through the nasal tube or non-rebreathing masks to fit the face and deliver high concentrations of oxygen.
According to Chikla, hypoxic patients with high heart rates and breathing quickly and with effort tend to require mechanical or non-invasive positive pressure ventilation. The latter is an alternative to using a face mask instead of a tube under the throat, but it uses pressure to push air into the lungs.
“The main difference we found between these people is that those who work hard to breathe are those who usually need to be intubated,” Chicla said.
Originally released Live science.
