Definition of oxygen therapy

Oxygen therapy definition (Oxygen therapy): It is a medical treatment measure that corrects the patient’s hypoxic state by increasing the oxygen concentration, which is indicated, targeted, and purely for certain adverse reactions.

Long-term (long-term) home oxygen therapy (LTOT): refers to inhalation of low-concentration oxygen for more than 15 hours a day and night for a longer period of time (60-90 days later, go to the hospital to re-evaluate whether you need to continue long-term oxygen therapy), so that PaO2≥mmHg or SaO2 A method of oxygen therapy that rises to 90%. The concentration is 24%-28%, and the oxygen flow rate is generally 1-2L/min.

The purpose of oxygen therapy

If you want to know how to inhale oxygen, you must know, why do you need oxygen? (Correct the misunderstanding that only inhalation of oxygen when uncomfortable)

What is the role of oxygen therapy (oxygen generator)?

Oxygen therapy has three purposes: 1 to improve hypoxemia; 2 to reduce the work of breathing; 3 to reduce the load on the heart.

Simple analysis: correct the body’s hypoxia (hypoxemia), thereby alleviating a series of physical problems caused by hypoxia.

The ultimate goal: to maintain proper tissue oxygen supply with minimal heart and lung work. Correct hypoxemia, relieve chronic hypoxia symptoms, and reduce the increase in heart load caused by hypoxia.

How can oxygen therapy achieve the above goals?

Oxygen therapy is to correct the hypoxia state of the body, so oxygen therapy is necessary when hypoxia.

Oxygen therapy can maintain proper tissue oxygen supply with minimal heart and lung work, so long-term oxygen inhalation in advance reduces the load on the heart and lungs.

That means long-term home oxygen therapy is needed

The standard oxygen intake time of LTOT in the United States is more than 15 hours a day, and it is the biggest misunderstanding to only inhale oxygen when it is uncomfortable.

Methods of oxygen therapy

Three elements of oxygen therapy: flow rate/wearing time/oxygen therapy course

Long-term (long-term) home oxygen therapy (LTOT): refers to inhalation of low-concentration oxygen for more than 15 hours a day and night for a longer period of time (60-90 days later, go to the hospital to re-evaluate whether you need to continue long-term oxygen therapy), so that PaO2≥mmHg or SaO2 A method of oxygen therapy that rises to 90%. The concentration is 24%-28%, and the oxygen flow rate is generally 1-2L/min.

Refinement: Low flow oxygen inhalation (1-2 liters) / 15 hours or more per day/6 months as a course of treatment

Detection of the effect of oxygen therapy

What effect should be achieved after oxygen therapy? Are there any quantitative testing indicators? Physical condition observation and quantitative data detection:

Observation of the physical condition

Cardiovascular system reaction: After oxygen therapy, the patient’s expression changes from indifferent or restless to quiet, clear mind, slower heart rate, improvement of the peripheral circulatory system (lips/nail caps/fingers, etc.), and the skin is ruddy, dry and warm, and purple disappears. The performance of oxygen therapy is good.

Respiratory system response: After oxygen therapy, dyspnea/shortness of breath is improved, breathing movement is stable, breathing frequency becomes slower, and work of breathing decreases, showing that oxygen therapy has a good effect.

Quantitative data detection:

(1) Transcutaneous oxygen saturation monitoring (SpO2)

The blood oxygen level is above 90% as normal blood oxygen. Pay attention to lung disease accompanied by the symptoms of carbon dioxide retention. When simply inhaling oxygen, the blood oxygen level is not easy to be too high, not exceeding 95%~96%.

(2) Arterial blood gas test (ABG)

The ideal level after oxygen therapy is: 60~80mmHg

Side effects and precautions of oxygen therapy

Oxygen, like all drugs in the hospital, has a therapeutic effect, but if it is used improperly, it will have side effects. In severe cases, oxygen poisoning may occur.

Carbon dioxide retention

The ventilation (breathing) power of COPD patients mainly depends on the stimulation of peripheral chemoreceptors by hypoxia. Once inhaled high-concentration oxygen (greater than or equal to 50%), the stimulation of peripheral receptors by hypoxia is lost, which reduces alveolar ventilation and causes CO2 accumulation. Controlling oxygen therapy can reduce the occurrence of this disease. Therefore, these patients should be given low-concentration oxygen therapy and closely observed to detect changes in the PaCO2 carbon dioxide partial pressure.

Prevention methods: 1 low flow oxygen inhalation; 2 use a ventilator;

Absorptive atelectasis

When breathing air, the lungs contain a lot of nitrogen that is not absorbed by the blood; after the oxygen in the alveoli is absorbed, the nitrogen is left behind to keep the alveoli from collapsing. After inhalation of high-concentration oxygen, the normal mixing ratio of oxygen and nitrogen in the alveoli is changed, so that a large amount of nitrogen in the alveoli is flushed out, and the partial pressure of oxygen in the alveoli gradually rises, and the originally inflated alveoli atrophy and then atelectasis.

Prevention methods: 1. Inhaled oxygen concentration should not exceed 50% as much as possible; 2. Use a ventilator; 3. Expect more sputum and breathe more deeply

Oxygen poisoning

Such as long-term inhalation of high-concentration oxygen (FiO2>50% is high-concentration oxygen), oxygen poisoning may occur, mainly manifested as sternal tightness, chest pain, shortness of breath, dry cough, etc. The characteristics of oxygen poisoning cases: reduction of alveolar surface-active substances, suppression of cilia activity, congestion of pulmonary capillaries, increased permeability, causing effusion in the alveoli, and pulmonary edema.

There are two factors that cause oxygen poisoning: inhaled oxygen concentration and oxygen inhalation time. 

Prevention: Avoid continuous use of 100% oxygen for less than 24 hours, 70% oxygen for more than 2 days or 50% oxygen for more than 5 days.

Dry respiratory tract

Maintaining 37% temperature and 95%-100% humidity in the respiratory tract is a necessary condition for the normal clearance of the mucociliary system. Therefore, pay attention to the humidifying effect of the humidifying bottle during oxygen therapy.

If necessary, add warm water to the humidification bottle to improve the humidification effect. Regularly clean the internal pipeline of the humidification bottle to ensure the smoothness of the micropores at the bottom of the pipeline to ensure the humidification effect.

Retinopathy of prematurity

It mainly occurs from birth to about 1 month. Excessive oxygen partial pressure causes retinal vasoconstriction, leading to vascular necrosis. The proliferating new blood vessels are often fragile and easy to bleed, causing scar formation behind the retina, leading to retinal detachment and blindness. The American Primary Two Association recommends that keeping the newborn’s blood oxygen partial pressure below 80mmHg is the best way to reduce retinopathy.