The respiratory system is a very important life system of the entire human body. The respiratory center is in the medulla oblongata. Once respiratory failure occurs, it is easy to cause great harm and even affect life. The hazards of respiratory failure are everywhere. Symptoms such as difficulty breathing, shortness of breath, and cyanosis may appear, and may even be insane, manic, twitching, or comatose. So what should we do if someone have symptoms of respiratory failure?
Respiratory failure is caused by lung ventilation and / or ventilation dysfunction caused by various reasons, which can not maintain sufficient gas exchange at rest, resulting in hypoxemia with (or without) hypercapnia Syndrome that causes a series of pathophysiological changes and corresponding clinical manifestations. Its clinical manifestation lacks specificity, and a clear diagnosis depends on arterial blood gas analysis: at sea level, resting state, and breathing air, the arterial blood oxygen partial pressure (PaO2) <60 mmHg, with or without carbon dioxide partial pressure (PaCO2)> 50mmHg, can be diagnosed as respiratory failure.
1. Classification of respiratory failure
In clinical workers, respiratory failure is usually divided into two types, type I and type II, according to arterial blood gas, as follows:
①Type I respiratory failure Hypoxia without CO2 retention, or with reduced CO2 (Type I), is seen in cases of ventilation dysfunction (disorder of ventilation / blood flow, impaired diffuse function, and pulmonary arteriovenous shunt) Such as severe pulmonary infectious diseases, interstitial lung diseases, acute pulmonary embolism, etc.
②Type Ⅱ respiratory failure is caused by the lack of O2 and CO2 retention caused by inadequate alveolar ventilation. The degree of simple ventilation is insufficient. The degree of O2 and CO2 retention is parallel. If the ventilation function is impaired, the O2 deficiency is more serious. Only increase alveolar ventilation, if necessary, oxygen therapy to correct. If accompanied by ventilation dysfunction, hypoxemia is more serious, such as COPD.
2. Classification by disease course
According to the course of disease, it can be divided into two kinds of acute and chronic, as follows:
①Acute respiratory failure refers to the sudden causes of the aforementioned five types of causes, causing ventilation or severe damage to ventilation function, and clinical manifestations of sudden respiratory failure, such as cerebrovascular accidents, drug poisoning to suppress the respiratory center, respiratory muscle paralysis, pulmonary infarction, If ARDS is not rescued in time, it will endanger the patient's life.
②Chronic respiratory failure is more common in chronic respiratory diseases, such as chronic obstructive pulmonary disease and severe tuberculosis. Its respiratory function damage gradually increases. Although it lacks O2 or is accompanied by CO2 retention, it can still engage in daily activities through the body's compensatory adaptation.
3. The oxygen concentration of type Ⅰ and type Ⅱ respiratory failure is different
The treatment principle of respiratory failure points out: enhance respiratory support, including airway patency, correct hypoxia and improve co-ventilation, etc. It can be seen that oxygen inhalation is an important link in the treatment of respiratory failure, and the hypoxic state of patients can be corrected by increasing the concentration of inhaled oxygen .
The principle of determining the oxygen concentration is to reduce the oxygen concentration as much as possible on the premise of ensuring that PaO2 rapidly increases to 60 mmHg or the pulse volume oxygen saturation (SPO2) reaches more than 90%.
①Type Ⅰ respiratory failure is hypoxic respiratory failure. A higher concentration (> 35%) of oxygen can quickly relieve hypoxemia without causing CO2 retention.
②Type Ⅱ respiratory failure is hypercarbonated respiratory failure. Patients often have notification dysfunction. It is necessary to keep oxygen concentration low (<35%) during oxygen therapy to prevent excessive blood oxygen content.
Chronic respiratory failure (referred to as chronic respiratory failure) is often caused by bronchial-pulmonary diseases, which is complicated by many conditions, difficult to treat, and has a high mortality rate. Oxygen therapy is one of its important treatment methods. The years of experience and lessons in the course of oxygen therapy for chronic respiratory failure patients are summarized as follows:
1. Improper concentration of oxygen therapy
Chronic respiratory failure is mostly type Ⅱ, which has both hypoxia and carbon dioxide retention. At this time, the respiratory center is not sensitive to carbon dioxide stimulation, and it mainly depends on hypoxia to maintain its excitability. Therefore, restrictive oxygen supply should be used, usually using low-flow continuous nasal catheter (or nasal congestion) to inhale oxygen, the oxygen concentration is 24% to 28%, and the oxygen flow is 1L / min to 2L / min.If the concentration of oxygen therapy and the way of oxygen inhalation are improper, oxygen therapy will fail.
(1) Intermittent oxygen inhalation at high concentration. The patient or his family often do not understand the knowledge of oxygen therapy for chronic respiratory failure, causing the patient to adjust the oxygen device to inhale high-concentration oxygen when he suffers from aggravation. This method can not only prevent carbon dioxide retention, but also increase hypoxia. The patient's hypoxic symptoms temporarily improved when oxygen was inhaled. Ventilation was suppressed and PaCO2 increased. After the interruption of oxygen inhalation, alveolar ventilation and PACO2 returned to the level before oxygen inhalation, and PAO2 was lower than the value before oxygen inhalation, which promoted hypoxia Exacerbated.
⑵ Continuous oxygen inhalation at high concentration. Due to poor conditions in primary hospitals and inexperience of medical staff, patients with chronic respiratory failure and acute myocardial infarction are sometimes placed in the same room, using the same oxygen delivery pipeline to give high flow and high concentration of continuous oxygen inhalation; or because patients and their families adjust the oxygen flow Caused by. Although this method of oxygen therapy can temporarily increase PaO2, the patient's respiratory central excitability is reduced and respiratory depression is reduced, which makes the hypoxia and carbon dioxide retention worse, and even the occurrence or exacerbation of pulmonary encephalopathy.
2. Inhaled oxygen temperature is too low
Chronic respiratory failure patients are mostly based on chronic obstructive pulmonary disease, which often occurs or worsens when the climate is cold in winter, and there is severe obstructive ventilation dysfunction. During oxygen therapy, if oxygen is inhaled directly or only through distilled water, the inhaled oxygen is too cold and too dry, which will stimulate the airway, make it contract and spasm, at the same time make the sputum more viscous, the airway obstruction is more serious, and breathing is increased Failure and heart failure. Therefore, it is necessary to pay attention to the warming and humidification of inhaled oxygen during oxygen therapy for patients with chronic respiratory failure. 75% -95% alcohol can also be injected into the humidification bottle to reduce the surface tension of the foam in the lungs, which is conducive to gas exchange.
3. How to inhale oxygen
Normal pressure saturated oxygen inhalation or positive pressure oxygen supply from ventilator (oxygen concentration 100%): 4-6 times / day, 20-30 minutes / time is recommended. Due to the high partial pressure of oxygen inhaled, it can quickly correct hypoxia and reduce Inflammatory exudation, intermittent high partial pressure oxygen inhalation is conducive to the recovery of the disease, fully considering the risk of oxidative damage and oxygen poisoning.
Nebulization of oxygen: Germany reported the use of nebulization to cure 4 patients with new coronary pneumonia in a short time. If nebulized oxygen therapy is used, it may bring more benefits to patients. Drugs can be delivered directly to the respiratory tract and alveoli by nebulization.
High-flow oxygen inhalation: It is suitable for severely breathed patients, and has achieved ideal results in the treatment of new coronary pneumonia. It may be better to take a 5-minute break every 1 to 2 hours.