Structure and ventilation mode of the hottest vent

2022-09-19
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The structure and ventilation mode of ventilator

as a device for treatment, first aid and resuscitation, today's ventilator has more and more functions, more and more perfect performance and continuously improved reliability. Most ventilators adopt computer control technology and are equipped with perfect safety alarm devices, which is easy to operate. Doctors only need to set a limited number of parameters, and the instrument can automatically adjust relevant parameters at any time to monitor the whole ventilation process in real time. The following is a brief introduction to the classification, structure and breathing mode of ventilator

I. classification of ventilator

clinically, ventilator is divided into the following categories according to the switching mode of ventilator working from inspiratory phase to expiratory phase:

1. Constant pressure type (pressure conversion type): this type of ventilator adopts pressure switching mode, that is, it manages ventilation through airway pressure. Supply air at the preset pressure and respiratory rate. When the pulmonary pressure reaches the preset value, stop inhaling and turn to exhaling, and the pulmonary pressure drops to the set value and then supply air again. Factors other than pressure (such as volume, inspiratory time, inspiratory flow rate, etc.) are variable, that is, airway pressure is an independent parameter, while ventilation volume and flow are dependent changes, so it is related to patients' lung compliance and airway resistance. When lung compliance and airway resistance change, tidal volume will inevitably change. Its advantage is that the pressure is controllable, which helps to judge the curative effect of ventilator with full respect for the wishes of the enterprise; However, its main deficiency is that it cannot maintain a stable tidal volume and has high requirements for doctors' operation

2. constant volume type (volume conversion type): its basic working process is to ventilate the patient with a predetermined tidal volume and peak flow value. When the lungs are inflated and expanded, and the volume and flow rate reach the predetermined value, the air supply will be stopped immediately, and the air will be changed from inspiratory to expiratory. As the respiratory pressure decreases, the elasticity of the thorax and lungs retracts, and the gas in the alveoli is discharged from the body. When the airflow resistance and compliance change, the inspiratory pressure changes accordingly to ensure a stable tidal volume. The utility model has the advantages of stable ventilation volume and convenient adjustment, and is suitable for long-term artificial ventilation of any disease; The disadvantage is that the pressure is unstable during ventilation, prone to pneumothorax and hypotension

3. timing type (time switching type): the basic working process is the scheduled breathing cycle, and the inspiratory and expiratory switching is carried out regularly according to the set tidal volume. It has the characteristics of constant pressure and constant volume, but it has a certain impact on lung compliance and airway resistance. When compliance and airway resistance change, inspiratory pressure, volume and flow rate will change. This kind of ventilator is generally small and used for first aid

4. Intelligent and comprehensive: this kind of ventilator has a variety of inspiratory phase conversion modes, which are set as needed. Under the intelligent control of the computer, the machine automatically adjusts relevant parameters to realize gas supply. For example, the pressure safety valve in the volume conversion mode is the pressure conversion mode. When the pressure exceeds the set safety value, even if the predetermined tidal volume has not been reached, the safety valve opens and the suction is forcibly terminated in advance to avoid air pressure damage. This type of ventilator has the advantages of computer control, high accuracy, powerful expansion function, simple operation, strong versatility, complete breathing mode, and is suitable for the treatment of all kinds of patients

second, the basic structure of ventilator

ventilator is mainly composed of electronic control and air circuit. The gas circuit is mainly a gas transmission system, including gas supply (gas storage, pressure support), gas transmission, pressure flow monitoring and correction. After the compressed air and oxygen are mixed according to the proportion required by the setting, they are sent to the patient end through the pipeline and relevant servo valves at the set air pressure and flow rate. The flow sensor feeds the measured actual value to the electronic control part and compares it with the panel setting value. Using the error between the two, the growth rate of the gross output value is much higher than the average development speed of the national economy. The suction and exhalation gases are adjusted by controlling the servo valve. The main function of the electronic control part is to control the ventilator to ventilate at a certain frequency and tidal volume, monitor the feedback data of the corresponding sensor, and give an alarm when it exceeds the limited range

III. passing mode and scope of application:

the performance of ventilator continues to improve and develop, mainly manifested in the continuous increase of ventilation mode, which increases the convenience and success opportunities for the treatment of patients with respiratory failure. Correct and appropriate application of ventilation mode can improve the curative effect and reduce complications

1. controlled ventilation CV: the ventilator completely replaces the patient's spontaneous breathing according to the predetermined respiratory rate, tidal volume, respiratory time ratio and airway pressure. This mode is mainly applicable to cases with severe respiratory depression or apnea. The advantage is to ensure a stable ventilation volume and minimize the ventilator load, but it is easy to produce man-machine confrontation for patients with spontaneous breathing

2. Assisted ventilation (AV): the ventilator provides partial support when patients with spontaneous breathing inhale, that is, the ventilation process of the ventilator is triggered by the slight reduction of airway pressure caused by the patient's spontaneous breathing. The trigger sensitivity is adjustable, and adults can generally be adjusted at about 0.2emh20. It is mainly applicable to partial respiratory support for patients with spontaneous breathing. If the patient stops spontaneous breathing, the ventilator cannot provide ventilation support because it is not triggered

3. assist control ventilation AV CV: this mode combines the characteristics of AV and CV. When the patient has spontaneous breathing, the spontaneous breathing rate can be established. When the spontaneous breathing rate is lower than the preset frequency or the pressure change is insufficient, which is a very cost-effective trigger, the ventilator automatically provides breathing supplement with the preset frequency and tidal volume. Therefore, when there is trigger, it is auxiliary ventilation, and when there is no trigger, it is controlled ventilation, so as to ensure the necessary ventilation of patients

4. Mandatory minute ventilation: pre adjust the ventilation volume per minute according to the patient's gender, age, weight, body position and metabolism. When the minute ventilation volume triggered by the patient's spontaneous breathing does not reach the preset volume, the ventilator provides insufficient ventilation, and other participating catheter products, namely, autonomous mv> pre adjust MV, the ventilator does not provide positive pressure ventilation, but only provides continuous airflow for autonomous breathing; When spontaneous breathing stops or spontaneous MV

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