Respiratory alkalosis

Introduction to respiratory alkalosis Respiratory alkalosis refers to a decrease in plasma H2CO3 concentration or PaCO2 due to excessive pulmonary ventilation, resulting in an increase in pH (>7.45). According to the incidence of the disease is also divided into two major categories of acute and chronic. In the acute case, the PaCO2 decreased by 10 mmHg (1.3 kPa), the HC03- decreased by about 2 mmol/L, and the chronic HCO3- decreased to 4-5 mmol/L. Respiratory alkalosis is characterized by a decrease in blood PaCO2 and an increase in pH, also known as hypocapnia. The main reason is excessive ventilation of the lungs, and the body loses too much CO2. Can be seen in shock, high fever, craniocerebral injury, recall disease. basic knowledge The proportion of illness: 0.3% Susceptible people: no specific population Mode of infection: non-infectious Complications: acute respiratory distress syndrome

Cause of respiratory alkalosis

Abnormal metabolic process (30%):

When hyperthyroidism and fever occur, ventilation can significantly increase beyond the amount of CO ₂ that should be excreted, which can lead to respiratory alkalosis, but it is generally not serious, but it indicates that ventilation is not solely dependent on [H+] and PCO in body fluids. ₂ , also related to metabolic intensity and aerobic conditions, at this time the hyperventilation may be caused by increased pulmonary blood flow through a reflective response.

Hypoxia and hypoxia (30%):

Hyperventilation in hypoxic hypoxia is a compensation for hypoxia, but at the same time it can cause excessive CO ₂ excretion and respiratory alkalosis, which is common in people who enter the plateau, mountains or high altitude; thoracic and lung lesions such as pneumonia Pulmonary embolism, pneumothorax, pulmonary congestion, etc. cause thoracic, pulmonary vascular or lung tissue afferent nerves are stimulated by patients with increased reflex ventilation; in addition, some patients with congenital heart disease, due to increased right to left shunt Hypoxemia can also cause hyperventilation, which causes a decrease in plasma H ₂ CO ₃ and respiratory alkalosis.

Pregnancy (30%):

There is a moderate increase in ventilation, which exceeds CO ₂ production. It is currently believed to be a stimulating effect of progesterone on the respiratory center. Some synthetic progesterone preparations also have this effect. During pregnancy, vomiting may occur due to vomiting and insufficient diet. Respiratory alkalosis can occur after the pregnancy reaction period, sometimes causing hand, foot and ankle.

Pathogenesis

Respiratory acidosis caused by airway obstruction may have obtained a considerable degree of compensation after more than 6-8 hours. Plasma HCO ₃ - has increased correspondingly, and it has a proper ratio with accumulated CO ₂ if the airway is blocked. Suddenly removed, a large amount of CO ₂ is exhaled from the lungs, and the arterial blood PCO ₂ suddenly decreases. The already increased HCO ₃ - has not yet reached the kidneys, so the proportion of [BHCO ₃ ] / [HHCO ₃ ] suddenly increases, and the alkalinity occurs. Poisoning, although this phenomenon is called excessively compensated respiratory acidosis, its essence is due to the sudden decrease in PCO ₂ causing the blood pH to rise, still belongs to the category of respiratory alkalosis.

Respiratory alkalosis prevention

The best measure for prevention is to actively deal with the primary disease, cover the nose and mouth with paper bags, increase the dead space of the respiratory tract, reduce the exhalation and loss of CO ₂ to increase blood PCO ₂ , and also inhale oxygen containing 5% CO ₂ . If the ventilation is excessive due to improper use of the ventilator, the ventilator should be adjusted. Intravenous calcium gluconate can eliminate hand and foot convulsions.

Respiratory alkalosis complications Complications, acute respiratory distress syndrome

A common complication of this disease is acute respiratory distress syndrome.

Symptoms of respiratory alkalosis Common symptoms Respiratory alkalosis Chest tightness Chest pain convulsions High ventilation Dizziness Metabolic alkalosis Hyperventilation syndrome

1, hands, feet, facial, especially the numbness of the mouth and acupuncture-like feeling.

2, chest tightness, chest pain, dizziness, fear, and even limb convulsions.

3, breathing shallow and slow.

4, respiratory alkalosis occurred within 6h, the kidney still shows significant compensatory function, called acute respiratory alkalosis, arterial blood PCO ₂ decreased, AB blood PH value may be within the normal range, such as PCO ₂ in 4 Below 3KPA, the blood pH is higher than 7,43.

After 6 to 18 hours of respiratory alkalosis, when the kidney has shown compensatory function, it is called persistent respiratory alkalosis, or chronic respiratory alkalosis. At this time, although the arterial blood PCO ₂ is still low, most of them have been Get fully compensated, the pH is mostly in the normal range.

Examination of respiratory alkalosis

1, blood gas analysis and testing.

2. Detection of electrolyte sodium, potassium, calcium, chlorine and magnesium.

3, liver and kidney function tests.

According to the condition, the clinical symptoms are selected as electrocardiogram, B-ultrasound, X-ray examination and so on.

Diagnosis and identification of respiratory alkalosis

diagnosis

According to medical history, physical signs and blood gas analysis, the diagnosis of acute or chronic respiratory alkalosis can be obtained.

Acute respiratory alkalosis, about 1.33 kPa (10 mmHg) for PCO ₂ reduction, and about ₂ mmol/L for plasma HCO ₃ -, the formula for calculating the compensation limit is:

[HCO ₃ -] = 0.2 × PCO ₂ ± 2.5.

[HCO ₃ -] = 24-0.2 × PCO ₂ ± 2.5.

Chronic respiratory alkalosis, about 1.33 kPa (10 mmHg) for PCO ₂ reduction, and about 5 mmol/L for plasma HCO ₃ -, the formula for calculating the compensation limit is:

[HCO ₃ -] = 0.5 × PCO ₂ ± 2.5.

[HCO ₃ -] = 24-0.5 × PCO ₂ ± 2.5.

1. If the measured AB24-0.5×PCO ₂ ±2.5, the chronic respiratory alkalosis has been fully compensated.

2. If the measured AB>24-0.5×PCO ₂ ±2.5, it may be chronic respiratory alkalosis with metabolic alkalosis, or respiratory alkalosis due to short time not fully compensated.

3. If the measured AB<24-0.5×PCO ₂ ±2.5, it may be chronic respiratory alkalosis with metabolic acidosis or excessively compensated respiratory alkalosis.

The diagnosis of this disease is clear, no need to identify.

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