Altitude Adaptation Insufficiency
Introduction
Introduction to plateau insufficiency The area above 3000m above sea level is called the plateau area. It is characterized by low air pressure and corresponding decrease in oxygen partial pressure, which is easy to cause hypoxia in human body. Plateau builders, border guards, mountaineers, etc., if they do not take preventive measures, can cause highaltitudesickness or plateau insufficiency, also known as mountainickness (mountainickness). Foreign scholars divide the high altitude disease into five types of syndromes: acute high altitude disease, high altitude pulmonary edema, high altitude cerebral edema, high altitude retinal hemorrhage and chronic high altitude disease. Chinese scholars divide plateau disease into two categories: acute high altitude disease and chronic high altitude disease. When you first enter the plateau, you should eat more carbohydrates, multivitamins and digestible foods. High-carbohydrate foods provide glucose and enhance lung dispersal for heavy physical work on the plateau. Drinking is prohibited. basic knowledge The proportion of sickness: 10% (more common in residents living in the plains) Susceptible people: no specific population Mode of infection: non-infectious Complications: acute high altitude disease, hypertension, high altitude polycythemia
Cause
Plateau adaptation to insufficiency
For a long time in the plateau, the body gradually adapts to the special natural conditions of the plateau. The reason for the adaptation is that under the regulation of the neurohumoral fluid, the various functions of the body have changed accordingly, especially the respiratory and circulatory systems are more obvious. The difference between the partial pressure of oxygen in the alveoli and the height of the alveolar decreases, which directly affects the alveolar gas exchange, the rate of oxygen-carrying oxygen and the release of oxygen in the tissue, resulting in insufficient oxygen supply to the body, resulting in hypoxia. Due to hypoxia, through peripheral chemoreceptors (mainly carotid body), indirect stimulation of the respiratory center causes an increase in early ventilation, and the body can inhale more oxygen for compensation. This process is the adaptation process of the human body to low altitude hypoxia. It takes about 1-3 months to gradually transition to stable adaptation. It is called altitude training. The individual's adaptation is very different. Generally, it can adapt quickly within 3000m above sea level. 42005330m is only part of the people, and it takes a long time. Adaptation, about 5330m is the artificial height of adaptation, prone to hypoxia reaction, the higher the altitude, the lower the partial pressure of oxygen in the atmosphere, the degree of hypoxia Corresponding increase, climbing speed and intensity of labor also can affect the degree of altitude sickness. In addition, psychological stress, fatigue, infections, malnutrition, and low temperature and other factors also have an impact on the incidence.
Prevention
Plateau adaptation to insufficiency prevention
1. For personnel entering the plateau area, a comprehensive physical examination should be carried out. Generally, those who are healthy are more likely to adapt to the hypoxic environment. All pregnant women have obvious heart, lung, liver, kidney and other diseases, hypertension II, suffering from epilepsy, severe nerves. Debilitating, active period of digestive tract ulcers, severe anemia, are not suitable for entry into the plateau.
2, usually should strengthen physical exercise, the implementation of the ladder rise, so that gradually adapt, mountain climbing speed is important, domestic reports within 3 days from the plain to the elevation of 4200m, the incidence of acute high altitude sickness is 83.5%, and by 2261m through the ladder in 7 ~ When the 4200m was reached within 15 days, the incidence rate was only 52.7% (P<0.001).
3, drug prevention, in order to prevent acute altitude sickness caused by hypoxia, appropriate drug prevention, such as diuretics, sedatives, adrenocortical hormones, vitamins, etc.
4. Those who enter the plateau should reduce physical labor, and gradually increase the amount of labor according to the degree of adaptation. The working environment of the plateau is mostly below 4000m, and its impact on labor capacity is 30% to 50% lower than that of the plain; therefore, in high altitude areas. The labor quota (above 3500m) should be reduced accordingly. At 2300m above sea level, the electrocardiographer of the electric furnace is more changed than the control group. It may be due to the combination of excessive physical labor and low-oxygen environment. Prevent acute upper respiratory tract infections.
5, when entering the plateau should eat more carbohydrates, multivitamins and digestible foods, high-carbohydrate foods can provide glucose and enhance the ability of the lungs to diffuse, so that heavy physical labor in the plateau, alcohol consumption, mountain sickness symptoms It is best to take a semi-recumbent position during sleep to reduce right venous return and pulmonary capillary congestion.
Complication
Plateau adaptation to complications Complications, acute high altitude disease, high altitude, erythrocytosis
Acute altitude sickness:
Plateau response, many clinical symptoms of high altitude coma are caused by hypoxia and elevated intracranial pressure.
Chronic high altitude disease:
High altitude heart disease, high altitude hypertension and high altitude hypotension, high altitude polycythemia.
Symptom
Plateau adaptation symptoms of insufficiency Common symptoms Difficulty of breathing, increased intracranial pressure, irritability, high blood pressure, convulsions, coma, shortness of breath, fatigue, dizziness, erythrocytosis
Plateau disease occurs mostly in the first mountain climbing, especially in the first few days, called acute reaction. Those who do not regress in the altitude sickness for more than 3 months are called chronic reactions.
Foreign scholars divide the high altitude disease into five types of syndromes: acute high altitude disease, high altitude pulmonary edema, high altitude cerebral edema, high altitude retinal hemorrhage and chronic high altitude disease.
Chinese scholars divide plateau disease into two categories: acute high altitude disease and chronic high altitude disease.
First, acute altitude sickness
1. Acute altitude sickness
If you enter the plateau above 3000m in a short period of time, or when the residents of the plateau area return to the plateau after living in the plain for a period of time, they can all have reactions, headache, dizziness, palpitations, shortness of breath, heavy loss of appetite, nausea, vomiting, insomnia, Fatigue, bloating and chest tightness, check for mild cyanosis and facial swelling.
Acute altitude sickness occurs more than 24 hours after climbing, usually within 1 to 2 weeks, the symptoms disappear on their own, and the symptoms can be treated symptomatically. The dose of acetazolamide is 0.25g orally, 2 to 4 times a day. 3 days after going up to the mountain, 3 days after going to the plateau, the drug acts as a diuretic, which can reduce the incidence and severity of acute high altitude disease, and can reduce the hypoxia during sleep. Acetazolamide can increase arterial oxygen. Concentration and improve the oxygenation of arterial blood to prevent further damage to the gas exchange in the lungs; also reduce proteinuria and peripheral edema, prednisone 5 ~ 10mg, 2 times a day orally, 3 days after going uphill to help alleviate symptoms In addition, an appropriate amount of sedatives, various vitamins and aminophylline can be used.
2, high altitude pulmonary edema
The incidence rate is about 3%. On the basis of acute altitude sickness, when the altitude is above 4000m, it will occur, but it can also occur in 2500m fast climbers. Therefore, there are rapid onsets 3 to 48 hours after climbing, and there are also 3 cases late. 10 days of onset, symptoms such as headache, chest tightness, cough, difficulty breathing, can not be supine, etc., some severe cases may have oliguria, a lot of bloody foam, even unconscious, signs of purpura and lungs breath sounds reduced X-ray wet sound, X-ray shows that the lungs have a lighter density, flaky cloud-like fuzzy shadows, most obvious next to the hilum, the right side is often heavier than the left side.
According to research, hypoxia can cause pulmonary venous vasoconstriction, increased resistance, leading to pulmonary hypertension; can also increase pulmonary capillary permeability, coupled with lymphatic dysfunction caused by hypoxia, and ultimately promote pulmonary edema, pathological examination The lungs are scattered in the flaky hemorrhage area, fibrin exudation and transparent membrane formation in the alveoli, capillary expansion, hyperemia, and microthrombus formation in it, cold and respiratory infections can aggravate hypoxia, cough or fatigue Important incentives.
Comprehensive treatment effect is good, early oxygen is fully absorbed, the flow rate of oxygen is about 6-8L per minute, there is pulmonary edema, absolute bed rest, keep warm, prevent upper respiratory tract infection, prohibit drinking plenty of water, furosemide (furosemide) available 20 ~40mg immediately intravenous or 40 ~ 80mg orally, 2 times a day, for 2 to 3 days, during the diuretic should be potassium supplementation and observation of dehydration, when there is irritability, a small amount of sedative can be used, can also be used 0.25g aminophylline Slowly inject 40ml of 50% glucose solution to reduce pulmonary artery pressure. Oral prednisone or intravenous drip of hydrocortisone can reduce capillary exudation and relieve bronchospasm. When there is respiratory and heart failure, immediately take appropriate Treatment, after the condition is stable, go to the lower altitude.
3, high altitude cerebral edema
Also known as high altitude coma or high altitude encephalopathy, the incidence is low, but it is easy to cause death, seen in the rapid entry into the plateau above 4000m, the incidence is acute, mostly at night, the main cause of acute hypoxia, causing small blood vessels and permeability of the brain Increased, resulting in cerebral edema, in addition to the symptoms of early acute altitude sickness, accompanied by increased intracranial pressure, such as severe headache, vomiting, etc., may also appear mental illness, depression or excitement, paralysis and other mental symptoms, individual patients with convulsions After sleepiness, drowsiness and even coma, the patient's pulse rate increases, the breathing is extremely irregular, the pupil is slow to respond to light, sometimes pathological reflex and optic nerve head edema and hemorrhage occur, the cerebrospinal fluid is normal, and the pressure may be slightly higher.
Second, chronic altitude sickness
According to the clinical manifestations, there are five types, but the performances of each type intersect with each other. Most cases are mixed types with pulmonary hypertension and cardiac changes.
1. Chronic altitude sickness
Some patients live in the plateau for a certain period of time, but the symptoms of altitude sickness are always prolonged. Symptoms of neurasthenia often occur. Sometimes there may be arrhythmia or transient fainting. Pay attention to physical exercise and improve the ability to adapt to hypoxia. Vitamin B6, bromine, etc.
Chilean Andes disease (Monge's or Andes disease), also known as secondary chronic high altitude disease, occurs in some residents who were originally able to adapt to the plateau. Due to chronic hypoxia, the sensitivity of peripheral chemoreceptors to hypoxia is reduced. , resulting in low alveolar ventilation, its pathological features are reduced arterial oxygen saturation, increased hemoglobin and hematocrit, pulmonary hypertension is higher than the original healthy residents, clinical manifestations are similar to general chronic high altitude disease, oxygen inhalation can increase arteries Oxygen saturation, and improve neuropsychiatric symptoms, can be cured by transferring to lowlands.
2, high altitude heart disease
It is more common in children, because of the poor compensatory ability to hypoxia, hypoxia caused pulmonary vasospasm, hardening, increased pulmonary artery pressure, right ventricular enlargement due to excessive overload, leading to right heart failure, in addition, blood pressure Increased and increased blood viscosity also affect the left ventricle, resulting in heart hypertrophy and heart failure, hypoxia can also lead to turbidity of myocardial cells, focal necrosis and myocardial fiber break, etc. Clinical symptoms of children with purpura, shortness of breath , edema, paroxysmal cough, nightingale, mental wilting, etc.; adults have heart palpitations, cough, cyanosis, edema, physical decline, etc., because the heart enlargement is mainly the right ventricle, so the X-ray examination, the pediatric heart is often diffuse Sexual or spherical expansion, adult pulmonary artery is prominent, the diameter of the main trunk of the pulmonary artery is often greater than 1.5cm, autopsy see right heart myocardial degeneration, extensive rupture of muscle fibers, interstitial hyperplasia, thickening of the middle layer of pulmonary arterioles, disappearance of pulmonary arterial fibers After turning to low ground, symptoms and signs are alleviated or disappeared. The focus of treatment is to control infection and correct heart failure.
3, high altitude polycythemia
For a long time in the plateau, the increase of red blood cells and hemoglobin is a compensatory function. The higher the altitude, the longer the residence time, the more red blood cells there are, the more red blood cells increase, the higher the blood viscosity, the hematocrit and the whole blood ratio in Yinchuan area. The viscosity is higher than that in the plain area, and the male is higher than the female. Due to the increase of the whole blood specific viscosity, the cyclical resistance increases, the cardiac load and the tissue hypoxia increase, resulting in a series of symptoms. In the Han nationality who moved to Lhasa, the prevalence rate is up. 13%, according to the study, erythropoietin increased after hypoxia stimulation; also found that 2-adrenergic receptors participate in the production of erythropoietin, the diagnostic criteria are generally more than 7 million/mm3 red blood cells, hemoglobin more than 17g/dl, The hematocrit is as high as 80%, and the venous bleeding 300-400ml can only temporarily relieve the symptoms, so it is better to turn to low-lying treatment.
4, high altitude hypertension
The first high blood pressure in the plateau is mainly due to hypoxia, which causes small blood vessels to contract, sputum, increased peripheral resistance, accelerated heart rate, and shortened cycle time. The plateau migrates to the unstable period within one year, and the blood pressure fluctuates significantly. Most of them have a significant reduction in aldosterone secretion in long-term and high-level plateaus, resulting in lower blood pressure, increased renin secretion, and increased blood viscosity. These may have an effect on the formation of hypertension, and clinical manifestations are similar to chronic altitude sickness. It is mainly a neurasthenic syndrome, which rarely causes heart and kidney damage. After returning to the low ground, the blood pressure quickly returns to normal.
5, high altitude hypotension
The prevalence rate in China is about 10%. The clinical manifestation is neurasthenic syndrome. The cause of the disease is related to the increase of histamine content caused by long-term hypoxia and adrenal insufficiency. Most of them do not require special treatment. .
Examine
Examination of plateau insufficiency
Proteinuria and peripheral edema, arterial oxygenation decreased.
The purpura and lungs have lower respiratory sounds and are covered with wet rales. The X-ray shows that the lungs have a lighter density, and the flake-like cloud-like blurred shadows are most obvious at the hilum, and the right side is often heavier than the left side.
The pulse rate is increased, the breathing is extremely irregular, the pupil is unresponsive to light, and sometimes pathological reflexes and optic nerve head edema and hemorrhage occur.
Diagnosis
Diagnosis and differentiation of plateau adaptation syndrome
diagnosis
Plateau disease occurs mostly in the first mountain climbing, especially in the first few days, called acute reaction. Those who do not regress in the altitude sickness for more than 3 months are called chronic reactions.
Differential diagnosis
Foreign scholars divide the high altitude disease into five types of syndromes: acute high altitude disease, high altitude pulmonary edema, high altitude cerebral edema, high altitude retinal hemorrhage and chronic high altitude disease.
Chinese scholars divide plateau disease into two categories: acute high altitude disease and chronic high altitude disease.
