In order to improve the average airway pressure in constant frequency mechanical ventilation, the parameters should be adjusted first.

In order to improve the average airway pressure in constant frequency mechanical ventilation, the parameters to be adjusted are as follows:

A, ventilator tidal volume settings:

Adult tidal volume is generally 5 ~15ml [karaoke], and 8 ~12ml [karaoke] is the most commonly used range. The following factors should be considered in the setting of tidal volume: thoracic and pulmonary compliance, airway resistance, compressible volume of ventilator pipeline, oxygenation state, ventilation function and risk of barotrauma.

Ventilator-related injuries, such as barotrauma, are caused by improper application of mechanical ventilation. In order to prevent air pressure injury during tidal volume setting, it is generally required that the pressure of airway platform should not exceed 35 ~ 40 cmH2O.

For pressure-controlled ventilation, tidal volume mainly depends on the preset pressure level, patient's inspiratory intensity and airway resistance. In general, the tidal volume level should not be higher than 8 ~ 12 ml.

Second, the ventilator inspiratory-expiratory ratio setting:

During mechanical ventilation, the inspiratory-expiratory ratio of ventilator should consider the influence of mechanical ventilation on hemodynamics, oxygenation state and spontaneous breathing level of patients.

1. For patients who breathe spontaneously, when the ventilator assists breathing, the ventilation of the ventilator should be coordinated with the inhalation of the patient to ensure synchronization. Generally, it takes 0.8 ~ 1.2 seconds to inhale, and the ratio of inhalation to exhalation is 1: 1.5 ~ 1: 2.

2. For patients with controlled ventilation, long inspiratory time and high inspiratory rate can increase the average airway pressure and improve oxygenation. However, to prolong the inspiratory time, we should pay attention to monitoring the hemodynamic changes of patients.

3. Inhalation time is too long, patients are not easy to tolerate, and often need to use sedatives or even muscle relaxants. Moreover, short expiratory time will lead to endogenous positive end-expiratory pressure, which will aggravate the interference to circulation. Attention should be paid in clinical application.