Are there any side effects of taking too much oxygen?

The world we live in cannot exist without oxygen, which is the energy source of life. We can feel oxygen all the time, and it exists in every corner of our lives. Generally speaking, normal breathing of oxygen is healthy and safe and can bring us many benefits. Some people may think that since oxygen has so many benefits, would it be more beneficial to human health if I breathe more?

What are the benefits of breathing oxygen

1. Oxygen inhalation can eliminate fatigue and improve work efficiency. The human brain consumes 20% of the body's oxygen and is particularly sensitive to hypoxia. Insufficient oxygen supply will cause fatigue syndrome such as lack of physical strength, exhaustion, dizziness, insomnia, memory loss and loss of appetite, which will affect people's intelligence and work efficiency. The above symptoms can be significantly improved after oxygen inhalation. Oxygen inhalation is very effective in improving sub-health conditions.

2. Regular oxygen inhalation can improve the body's resistance, eliminate diseases and prevent diseases. Oxygen inhalation can increase the metabolism of human cells, tissues and organs, enhance the functions of various organs and improve the body's immunity.

3. Oxygen inhalation helps to beautify and maintain your skin. Oxygen inhalation can enhance the aerobic metabolism of human cells, strengthen skin nutrition, increase the elasticity of loose skin, and reduce wrinkles; the metabolic function of skin cells is enhanced, which can reduce melanin deposition, reduce ecchymosis, and beautify the skin.

4. Regular oxygen inhalation can resist aging. As we age, our blood vessels become harder and our lung function declines, and the oxygen pressure in our arterial blood gradually decreases, which is more obvious in smokers. Oxygen inhalation can significantly increase the oxygen pressure and prevent the occurrence of many geriatric diseases.

2Is it really good to take oxygen regularly?

Some people say, since the air is polluted, I should breathe oxygen frequently. Yes, in the early 20th century, medical oxygen began to be widely used in the treatment of hypoxia. So-called medical oxygen is oxygen mixed with carbon dioxide, while industrial oxygen is pure oxygen. Pure oxygen cannot be breathed by humans because carbon dioxide can stimulate respiratory function. However, frequent breathing of medical oxygen can also produce toxic reactions because oxygen contains trace amounts of ozone. So the toxicity of medical oxygen

Lungs, eyes, and central nervous system, commonly known as oxygen poisoning. Medical oxygen is a must-have in hospitals. It is a magic weapon for doctors to rescue patients. However, it can only be used for rescue and cannot be abused. Even during emergency treatment, oxygen inhalation must be given intermittently, because frequent use of oxygen will lead to oxygen poisoning. Oxygen poisoning is terrible, and patients will also experience headaches, irritability, and struggles; therefore, oxygen should not be inhaled frequently.

Because medical oxygen contains ozone, premature babies will go blind if they frequently inhale oxygen. This is a common iatrogenic disease in the neonatal intensive care unit of a maternity hospital. One of the main measures in intensive care is to give children oxygen. However, children are prone to retinopathy. The pathogenesis is that premature infants' retinal blood vessels are not mature enough. Long-term oxygen exposure causes the retinal blood vessels to dilate and bend. High concentrations of oxygen can cause abnormal growth of retinal blood vessels.

In severe cases, it can lead to peripheral retinal detachment or even complete retinal detachment. It is said that more than 20 million newborns are born in my country every year, 6% of which are premature babies, and more than 20% of premature babies suffer from retinopathy caused by oxygen poisoning. Therefore, it is worth discussing whether premature babies must be given oxygen.

Since medical oxygen contains ozone, elderly people will develop pulmonary edema if they frequently inhale oxygen. Many children want to show filial piety to their elderly parents, so they bought oxygen machines, oxygen generators, and oxygen cylinders for their elderly parents to breathe oxygen regularly, but many elderly people developed symptoms of coughing up blood. Why is this? This is because long-term inhalation of oxygen can lead to a decrease in alveolar surfactant, causing alveolar infiltration and pulmonary edema. Oxygen poisoning is not easy to detect at the time, and clinical symptoms often occur 2 to 3 days later. Rescue at this time often wastes time. Therefore, even if you really have to use oxygen, you should pay attention to the fact that each time you inhale oxygen, it should be 30 to 40 minutes, 2 to 3 times a day.

3 The dangers of excessive oxygen inhalation

As early as the mid-19th century, British scientist Paul Burt first discovered that if animals were allowed to breathe pure oxygen, it would cause poisoning, and the same was true for humans.

If a person is in a pure oxygen environment greater than 0.05MPa (half an atmospheric pressure), it will be toxic to all cells. If the inhalation time is too long, "oxygen poisoning" may occur. The capillary barrier in the lungs is destroyed, leading to pulmonary edema, pulmonary congestion and bleeding, which seriously affects the respiratory function and causes hypoxia and damage to various organs. In a pure oxygen environment of 0.1MPa (1 atmosphere), a person can only survive for 24 hours before developing pneumonia, which will eventually lead to respiratory failure and death from suffocation. A person can stay in a 0.2MPa (2 atmospheres) high-pressure pure oxygen environment for a maximum of one to two hours. If the stay exceeds this time, it will cause brain poisoning, life rhythm disorder, mental confusion, and memory loss. If 0.3MPa (3 atmospheres) or even higher oxygen is added, the brain cells will degenerate and die within minutes, and the person will convulse and become comatose, leading to death.

In addition, excessive oxygen intake can also promote aging. Oxygen that enters the human body reacts with oxidase in cells to produce hydrogen peroxide, which then turns into lipofuscin. This lipofuscin is a harmful substance that accelerates cell aging. It accumulates in the myocardium, causing myocardial cell aging and decreased heart function; it accumulates on the blood vessel walls, causing blood vessel aging and hardening; it accumulates in the liver, weakening liver function; it accumulates in the brain, causing a decline in intelligence, memory loss, and people becoming demented; it accumulates on the skin, forming age spots.

4 Indications for oxygen therapy

1. Hypoventilation: Hypoxia caused by hypoventilation for any reason (often accompanied by CO2 retention) is suitable for oxygen therapy, but oxygen administration cannot replace the treatment of the cause. For those with respiratory center depression, in addition to oxygen, respiratory stimulants should be added, and assisted ventilation should be used when necessary to increase ventilation volume; for those with obstructive hypoventilation, the obstruction of the respiratory tract must be eliminated first, such as relieving bronchospasm, promoting expectoration, removing foreign bodies, etc. Otherwise, the oxygen therapy will not be effective. If necessary, endotracheal intubation or tracheotomy can be performed.

2. Ventilation/perfusion (V/Q) ratio imbalance: The V/Q ratio of a normal person is 0.8. V/Q imbalance may be due to normal blood perfusion but insufficient lung ventilation (V/Q<0.8), or normal ventilation but insufficient or interrupted blood perfusion (such as pulmonary infarction, V/Q>0.8). Both can cause insufficient Hb oxygenation (functional shunt) and hypoxemia. Increasing the oxygen concentration of the inspired air increases the oxygen concentration in the alveolar gas, which can improve the V/Q imbalance caused by hypoventilation and increase the diffusion of oxygen. High-concentration oxygen administration has a better effect, but for those with obvious CO2 retention and abnormal respiratory regulation, high-concentration oxygen administration can cause respiratory depression, which not only fails to improve hypoxia but also aggravates CO2 retention.

3. Diffusion barrier: Oxygen must diffuse from the alveoli into the blood through the alveolar-capillary membrane, including the alveolar epithelium, basement membrane, interstitium and alveolar capillary endothelium. Thickening of the alveolar membrane, edema of lung tissue, thickening of the capillary wall, and reduced gas diffusion area can all reduce the diffusion function and cause hypoxia. Any lung disease with thickening of the alveolar capillary membrane and resulting in hypoxemia is commonly known as "alveolar capillary block syndrome", which is common in pulmonary interstitial fibrosis and pulmonary edema. For such patients, inhalation of pure oxygen can achieve good results. Due to the strong diffusion capacity of CO2, diffusion barriers are mostly caused by hypoxia, and there is often no obvious retention of CO2.

4. Right-to-left shunt: This type of hypoxia is caused by part of the venous blood entering the left heart or arterial system directly without pulmonary oxygenation. It is seen in congenital heart disease, arteriovenous fistula (anatomical shunt) or atelectasis (functional shunt). Inhalation of pure oxygen or high-pressure oxygen therapy can increase the amount of dissolved oxygen in the blood and improve this type of hypoxia.

5. Heart failure, myocardial infarction, cerebral ischemia, and peripheral circulatory failure: These patients have poor tolerance to hypoxia. When PaO2 drops to 6.7 kPa (50 mmHg), it can be life-threatening; when PaO2 reaches 8.0 kPa (60 mmHg), it can still induce arrhythmias and decreased cardiac output. Therefore, for such patients, oxygen therapy should be given as long as PaO2 drops to 9.3 kPa (70 mmHg).

2. Determination of hypoxia degree and oxygen supply indicators

1. Mild hypoxemia: no cyanosis, SaO2 above 80%, PaO2 above 6.7 kPa (50 mmHg), PaCO2 below 6.7 kPa (50 mmHg), generally no oxygen therapy is required. Oxygen therapy may be meaningful for patients with heart or brain diseases, those with peripheral circulatory failure, or when hypoxemia is expected to worsen, and can be given as appropriate. Such patients do not have CO2 paralysis and do not need to rely on hypoxia to drive breathing, and oxygen therapy will not cause respiratory depression.

2. Moderate hypoxemia: obvious cyanosis, SaO2 60% to 80%, PaO2 4.0 to 6.7 kPa (30 to 50 mmHg), oxygen therapy can alleviate hypoxemia and improve symptoms. If PaCO2>7.3 kPa (55

Improper oxygen administration may cause respiratory depression, and the oxygen concentration should be controlled at 24% to 28%.

3. Severe hypoxemia: Severe cyanosis, SaO2 <60%, PaO2 <4.0 kPa (30 mmHg), oxygen therapy should be performed immediately. Such patients often have severe CO2 retention and central CO2 paralysis due to low ventilation. Low-concentration oxygen should be given at the beginning, and the oxygen concentration should be controlled at 24%, and then gradually increased. If there is no CO2 retention, high concentration oxygen can be given.

5. Complications that may occur during oxygen therapy

Overview

Oxygen therapy, like other drug treatments, can have therapeutic effects but can also cause toxic side effects if used improperly, and this should be taken seriously. The harm of oxygen therapy to the body mainly includes the following aspects:

CO2 retention

Patients with respiratory failure accompanied by increased PaCO2 often experience further increase in PaCO2 after oxygen therapy. For patients with respiratory failure mainly caused by hypoventilation, when FiO2 increases to 25-30%, PaCO2 of some patients may increase by 20-40 mmHg. The occurrence of CO2 retention is mainly related to factors such as the reduced excitatory effect of hypoxia on the respiratory center after oxygen therapy, the decrease in minute ventilation and the further imbalance of the ventilation/blood flow ratio. At this time, FiO2 should be reduced as much as possible (i.e., low-flow oxygen inhalation should be used, limiting the oxygen flow rate to 1-2L/min), while strengthening the observation of the condition and blood gas monitoring. When PaCO2 increases rapidly, mechanical ventilation treatment should be adopted in time.

Absorption atelectasis

For patients with incomplete airway obstruction, after inhaling higher concentrations of oxygen, the oxygen in the local alveoli is absorbed, causing alveolar collapse and atelectasis. The main preventive measures include: keeping FiO2 less than 60% as much as possible, adding PEEP if mechanical ventilation is performed, and encouraging patients to expectorate to maintain local airway patency.

Oxygen toxicity

Oxygen poisoning is the most important toxic side effect of oxygen therapy. Although the incidence is very low, the harm after it occurs is serious and should be taken seriously. Oxygen poisoning leads to acute lung injury and ARDS-like changes. The main clinical manifestations are tracheobronchitis, ARDS, airless atelectasis, and effects on children's lung development. It can also affect the central nervous system, erythropoietic system, endocrine system and retina. There is no early diagnosis for oxygen poisoning, and there is also a lack of effective treatment. Oxygen poisoning is an iatrogenic disease. The best treatment is prevention. Limiting high-concentration oxygen inhalation is an effective clinical method to prevent oxygen poisoning. The only cause of oxygen poisoning is long-term high-concentration oxygen inhalation, but there is still no consensus on the safe limit of oxygen concentration. It is generally believed that oxygen inhalation concentration below 60% under normal pressure is safe and will not cause oxygen poisoning. Clinical observations have shown that inhaling pure oxygen for 6 hours at normal pressure may cause damage to the respiratory mucosa, and typical changes of oxygen poisoning may occur if inhaling pure oxygen for more than 24 hours. When non-invasive oxygen therapy is performed clinically, FiO2 is difficult to exceed 60-80%. At the same time, studies have shown that the lungs of critically ill patients may be better able to tolerate the damaging effects of oxygen than normal lungs. Therefore, there is no need to worry about oxygen poisoning during conventional oxygen therapy (such as nasal or mask oxygen therapy). However, during mechanical ventilation, since FiO2 can be effectively guaranteed at this time, FiO2 should be controlled below 60-80% as much as possible to prevent 60-80% oxygen poisoning.