With the large-scale infection of the new coronavirus pneumonia in the world in the past two years, the number of critically ill patients in the ICU has increased significantly. The ICU ventilator that sends oxygen-containing air into the lungs and expels carbon dioxide gas from the body to improve the ventilation of the respiratory system has become an important medical material, but many medical workers are not familiar with the principles and precautions of ventilator use.
As an important means of mechanical ventilation, China transport ventilator can relieve respiratory failure caused by severe hypoxemia and hypercapnia, increased intracranial pressure, neuromuscular paralysis and other diseases, buy time and conditions for rescue, and ultimately make patients resume effective spontaneous breathing.
With the advancement of modern mechanical ventilation technology, there is no absolute contraindication to the use of ventilators, but the ventilation pressure should be reduced and the frequency should be increased in the application of diseases such as bullae, pneumothorax, hypovolemic shock, and myocardial infarction.
There are multiple parameters displayed on the control panel of the ventilator, and clinicians set appropriate thresholds to intervene in patient ventilation according to the patient's condition and respiratory function.
1. Tidal Volume (TV): The amount of gas delivered by the ventilator to the patient each time, the set value is 6-8mL/kg.
2. Respiratory rate (RR/RF): The number of breaths a patient takes on a ventilator per minute, expressed in units of breaths per minute.
3. Inspiratory ratio (IE): the ratio of inspiratory and expiratory time, generally set to 1:1.5~2.
4. Minute ventilation (MV): The amount of gas the ventilator delivers to the patient every minute. MV=RR×TV.
5. Oxygen concentration: the percentage of oxygen in the gas output by the ventilator, and the oxygen concentration should ensure that the patient's blood oxygen saturation (SpO₂) is >96%.
6. Positive end-expiratory pressure (PEEP): Maintaining a level higher than atmospheric pressure in the airway at the end of expiration can prevent alveolar collapse and promote oxygenation. The general ventilator setting value is 15cmH2O.
7. Peak airway pressure (P-Peak): The highest pressure during the ventilation process of the ventilator. The higher the airway pressure, the greater the P-Peak.
1. Controlled ventilation: for patients with severe respiratory depression or apnea
However, this mode completely "ignores" the patient's spontaneous breathing, which can easily lead to human-machine confrontation, that is, the abnormal human-machine relationship caused by the different rhythms of the two breathing pumps of the ventilator and spontaneous breathing, aggravating the underlying cardiopulmonary diseases.
2. Assisted ventilation: It is used for patients whose respiratory center function gradually recovers as a transitional measure for ventilator weaning
In this mode, the China ICU ventilator machine delivers air at the actual air demand of the patient, and the human inhalation is synchronized with the ventilator delivery, also known as synchronous ventilation.
However, when the patient breathes very slowly, the ventilation rate of the ventilator is also very small, and the ventilation is insufficient; and when the patient breathes quickly, the assisted breathing rate of the ventilator will also increase, and the ventilation is excessive.
3. Spontaneous ventilation: used for patients recovering from spontaneous breathing as a preparation for weaning
The patient breathes spontaneously, and the ventilator detects that the airway pressure is lower than expected and triggers the inspiratory start, and provides ventilation support by default. Unlike assisted ventilation, the patient can decide to switch between inhalation and exhalation.
During the initial setting of the ventilator, the doctor can select the appropriate ventilation mode according to the needs of the patient. All ventilation modes are derived from three modes: controlled ventilation, assisted ventilation, and spontaneous ventilation.