I. Principle of CPAP ventilator treatment:

Ordinary CPAP can keep the upper airway from collapsing during breathing by providing a proper constant pressure in the mask. Therefore, CPAP is not a "blower" that many people understand, but in the process of breathing patients must be able to quickly change speed to "repair" the fluctuation of human breathing, so that the pressure in the mask is stable. This requires that CPAP motors have fast speed change capability, sensors have high sensitivity and accuracy, and CPAP has a high level of control technology. If CPAP is made into a common "blower", the pressure in the mask will decrease significantly when the patient breathes in, causing a certain degree of "collapse" of the upper airway; when exhaling, the pressure in the mask will rise significantly, hindering the discharge of carbon dioxide, and the patient will feel the "top" of the exhalation obviously. Therefore, the use of uncomfortable CPAP, the treatment effect is often not good. Medical insurance systems in Europe and America have strict requirements for CPAP performance. For example, in Germany, CPAP that can enter the health insurance system must simulate 500 ml breathing volume and 12-16 breathing frequencies per minute. Under 250 pxH2O pressure, the pressure fluctuation in the mask must be within the range of <12.5 pxH2O.

This technology of common CPAP is also the basic technology of other types of household ventilators (such as automatic ventilator, dual-level ventilator, etc.).

2. Treatment principle of AutoCPAP automatic ventilator:

When the patient is tired during the day or drinks before bedtime, the pressure set by CPAP can not meet the treatment needs because of the more relaxed muscles. In severe cases, the patient will open his mouth because of breathing suffocation, and then be blown awake by the ventilator. After using CPAP for half a year or a year, many physiological changes have taken place in patients. The pressure of CPAP treatment often needs to be re-measured and adjusted, which increases the demand for family medical services. As a result, automatic ventilator came into being. At present, most automatic ventilators deduce the change of upper airway resistance according to the change of flow rate and pressure during breathing. If the machine changes the pressure when the patient has obvious insufficiency of ventilation or even suffocation, the therapeutic effect of the patient will obviously be bad. A good automatic ventilator must detect "traces" in the early stage of airway changes and adjust the pressure as soon as possible to ensure that patients'upper respiratory tract remains unobstructed. In addition, central apnea is caused by abnormal brain respiratory center. For such apnea and hypopnea, the machine can not blindly adjust the pressure. Automatic ventilators need to be able to identify this situation. It can be seen from this that the technical content of the automatic ventilator is high, and the technical level will determine the treatment effect. Of course, the difference between good and bad often requires comparison.

3. The therapeutic principle of bi-level ventilator:

Bi-level ventilators can be divided into two categories, one for sleeping patients and the other for chronic respiratory failure patients. There are obvious differences in performance standards and prices between the two types of machines. Machines for sleeping patients are still designed to maintain airway patency through appropriate pressures. Breathing two pressures, mainly for the treatment of patients with high pressure, make it easier to breathe out more conducive to carbon dioxide emissions. Machines for patients with slow expiratory failure have high performance requirements: high susceptibility to inhalation, can adapt to the patient's weak breathing when the patient's condition is serious; the speed of rising and lowering blood pressure can be very fast (especially starting speed, because the patient is the most laborious when starting inhalation), should be able to adapt to about 30 times per minute of shallow and fast breathing. In addition, the above two types of machines require that the pressure in the mask be as stable as possible during the process of inhalation and exhalation.

It can be seen from this that although the volume of household ventilator is small, its technical content is very high. Despite the global demand of millions of units per year, there are very limited manufacturers who can enter the health insurance system in Europe and the United States.

4. Common knowledge about maintenance of household ventilators

Home ventilator mainframe is composed of motor, CNC circuit (including sensors), driving circuit, display module, power supply and other components. Maintenance usually involves replacing related components. When the main parts are replaced, the final calibration of pressure gauge and flowmeter is enough. Because of the huge sales of household appliances, localized maintenance has been achieved in developed countries many years ago.