What Is Recanalization?
Pulmonary ventilation (pulmonary ventilation) is the process of gas exchange between the lungs and the external environment. Organs that achieve pulmonary ventilation include the respiratory tract, alveoli, and thorax. The respiratory tract is the channel between the alveoli and the outside world; the alveoli are the main place for the exchange of alveolar gas and blood gas; and the rhythmic breathing movement of the thorax is the motivation to achieve ventilation.
Lung ventilation
- Pulmonary ventilation (pulmonary ventilation) is the process of gas exchange between the lungs and the external environment. Organs that achieve pulmonary ventilation include the respiratory tract, alveoli, and
- Complete the transfer of gas from the nasal cavity to the alveoli, and from the alveoli to the nasal cavity, requiring power to overcome
- Lung ventilation needs to overcome lung ventilation
- in
- Tidal Volume
- Each
- Minute ventilation
- The minute ventilation volume refers to the total amount of gas entering or leaving the lungs per minute, which is equal to the breathing frequency times the tidal volume. When breathing calmly, normal adults breathe 12-18 times per minute, with a tidal volume of 500ml, and a ventilation volume of 6-9L per minute. The minute ventilation volume varies with gender, age, size and activity. For comparison, it is best to measure under basic conditions and calculate it in terms of body surface area per square meter.
- During labor and exercise, minute ventilation increases. When you try to breathe deeply and deeply, the maximum volume you can inhale or exhale per minute is the maximum ventilation volume. It reflects the full amount of ventilation in a unit of time and is one of the physiological indicators for estimating how much exercise a person can perform. Measurement
- Time vital capacity
- Ventilation reserve percentage = [(maximum ventilation-minute calm ventilation) / maximum ventilation] × 100%
- A normal value is equal to or greater than 93%.
- Ineffective cavity and alveolar ventilation
- For each inhaled gas, part of the gas will remain in the respiratory tract from the upper respiratory tract to the respiratory bronchioles. This part of the gas does not participate in the gas exchange between the alveoli and the blood, so it is called anatomical dead space. Its volume is about 150ml. The gas that enters the alveoli can also fail to enter the gas exchange with the blood due to the uneven distribution of blood flow in the lungs. The part of the alveolar volume that fails to exchange gas is called the alveolar ineffective cavity. The alveolar void space and the anatomical void space are collectively referred to as a physiological dead space. When a healthy person lies supine, the physiologically ineffective cavity is equal to or close to the anatomical ineffective cavity.
- Due to the presence of ineffective cavities, fresh air inhaled every time cannot reach the alveoli and enter the gas exchange. Therefore, in order to calculate a truly effective gas exchange, alveolar ventilation should prevail. Alveolar ventilation (alveolar ventilation) is the amount of fresh air inhaled into the alveoli per minute, which is equal to (tidal volume-ineffective cavity air volume) × breathing frequency. If the tidal volume is 500ml and the ineffective cavity volume is 150ml, each breath will only update the gas in the alveoli by about 1/7. Changes in tidal volume and breathing frequency have different effects on pulmonary ventilation and alveolar ventilation. When the tidal volume is halved and the respiratory frequency is doubled or the tidal volume is doubled and the respiratory frequency is halved, the lung ventilation remains unchanged, but the alveolar ventilation changes significantly. Therefore, in terms of gas exchange, shallow and fast breathing Adverse.
- High frequency ventilation clinically uses a special form of artificial ventilation in some cases (such as with bronchoscopy, treatment of respiratory failure, etc.), namely high frequency ventilation. This is a kind of artificial ventilation with high frequency and low tidal volume. The frequency can be 60-100 times per minute or higher. The tidal volume is less than the anatomic cavity, but it can maintain effective ventilation and ventilation. It contradicts the above-mentioned view that shallow and fast breathing is not conducive to gas exchange. It is not clear how high-frequency ventilation can maintain effective ventilation and ventilation. The principle of ventilation may be different from the general ventilation principle, and it is believed to be related to the enhancement of gas convection and the acceleration of gas molecular diffusion. The clinical application of high-frequency ventilation and the principle of ventilation need to be further studied.