The main pathogenesis of new coronavirus pneumonia (referred to as covid-19) is that a large amount of inflammatory secretions or exudates flood the interstitial lung and alveoli, which prevents fresh air from entering the alveoli and exchanging carbon dioxide in the body, leading to hypoxia, even multiple organ failure and death. At present, there are no specific anti-neo coronavirus drugs, and more symptomatic support therapy is adopted. Among them, oxygen inhalation is a very important symptomatic treatment measure throughout the treatment of neo-coronary pneumonia.
1.Why does it cause hypoxia?
The main function of the lung: complete the gas exchange of oxygen and carbon dioxide.
The lungs are the first entry point for fresh oxygen from the outside world. Oxygen enters the lungs with breathing, and is exchanged with carbon dioxide through the capillary network of the alveolar wall. This exchange is a physical diffusion process under the action of oxygen or partial pressure of carbon dioxide. It enters the heart from the pulmonary veins (pulmonary circulation) and then the aorta (systemic circulation). Deliver oxygen-rich blood to various organs and tissues in the body. A healthy adult's steady breathing volume is 450 ~ 500ml once, about 9 liters of air per minute, and about 12,960 liters of air per day, equivalent to 16.8 kg. The purpose of inhaling so much air is to ingest about 3.5 kg of oxygen. . The quality of lung function directly determines how much gas is exchanged. The larger the vital capacity, the more oxygen is inhaled, the stronger the alveolar diffusion function, and the healthier the person.
SaO2 refers to the proportion of oxygen and hemoglobin, it is the most widely used and easiest available data at present. SaO2 reflects the combined amount of oxygen, its advantage is that it can be continuously monitored, but it is easy to be interfered by external factors. Theoretically it never can reach 100% saturationration, normal people are generally 95% -100%, and less than 94% can be regarded as hypoxia, SaO2 <80%, can basically be diagnosed as hypoxemia, SaO2: 60% -80%, which indicates obvious hypoxemia, SaO2 <60%, suggesting severe hypoxemia.
2. Arterial blood gas analysis
Arterial oxygen partial pressure (PaO2) refers to the physical dissolved oxygen content in the blood. After combining oxygen into the body, it must first dissociate into dissolved oxygen before it can be used by tissue cells. It can objectively reflect the state of hypoxia at the time, but it cannot be continuously and dynamically observed，and need to draw blood to complete. The normal value is 80-100mmHg, usually PaO2 <60mmHg can be diagnosed as hypoxemia, PaO2 <50mmHg indicates the presence of respiratory failure, PaO2 <40mmHg indicates severe hypoxia, and PaO2 <30mmHg indicates life dying. PaO2 will decrease with age, and it can be considered hypoxemia when PaO2 is lower than the limit of peers.
3.Advice for oxygen inhalation:
1. The purpose of oxygen inhalation includes four aspects:
1) Maintaining normal blood oxygen saturation physiological indicators;
2) Protecting important organ functions;
3) Repairing organ damage caused by hypoxia;
4) Reducing inflammatory exudation;
5) Enhancing human immunity.
2.How to inhale oxygen?
Nebulization of oxygen: Germany reported that the application of nebulization method could cure 4 patients with neo-coronary pneumonia in a short time. If nebulization oxygen therapy is used, it may bring more benefits to patients. Drugs can be delivered directly to the respiratory tract and alveoli through aerosolization.
High-flow oxygen inhalation: It is suitable for severely ill patients with weak breathing. It has achieved ideal results in the treatment of new type of coronary pneumonia. It may be better to rest for 5 minutes every 1-2 hours.
3. Covid-19 patients must still adhere to oxygen therapy after recovery
Most patients think that everything will be fine after recovery and discharge. In fact, the body organs of covid-19 patients have been damaged during treatment. Especially after lung injury, it will indirectly affect the hypoxia of other organs. If oxygen is not supplied in time, it will cause organ dysfunction and even inflammation or failure. Therefore, after discharge from the hospital, the patients still need to insist on oxygen therapy. The homecare oxygen concentrator has become an essential medical device for family health.