In modern clinical medicine, the ventilator, as an effective means of energy artificial alternative autonomous ventilation function, has been widely used in respiratory failure caused by various reasons, anesthesia and respiratory management during major surgery, respiratory support therapy and emergency resuscitation It occupies a very important position in the field of modern medicine. The ventilator is a vital medical device that can prevent and treat respiratory failure, reduce complications, save and prolong the lives of patients.
1. Classified by type of use or application
(1) Controlled mechanical ventilation (CMV)
1. Definition: When the patient’s spontaneous breathing weakens or disappears, it is completely generated by the mechanical ventilator to control and regulate the patient’s breathing.
2. Reduction: The automatic breathing caused by the disease disappears or weakens; when the automatic breathing is irregular or the frequency is too fast, and the mechanical ventilation cannot coordinate with the patient, the artificial breathing is suppressed or weakened by artificial methods.
(2). Assisted mechanical ventilation (AMV)
1. Definition: In the presence of patient breathing, the ventilator assists or enhances the patient’s spontaneous breathing. Various types of mechanical ventilation are mainly triggered by the patient’s inspiratory negative pressure or inspiratory airflow.
2. Reasonable: Although spontaneous breathing exists and is more regular, it cannot be used in patients with weakened spontaneous breathing but insufficient ventilation.
(1) Controlled mechanical ventilation (CMV)
1. Definition: When the patient’s spontaneous breathing weakens or disappears, it is completely generated by the mechanical ventilator to control and regulate the patient’s breathing.
2. Reduction: The automatic breathing caused by the disease disappears or weakens; when the automatic breathing is irregular or the frequency is too fast, and the mechanical ventilation cannot coordinate with the patient, the artificial breathing is suppressed or weakened by artificial methods.
(2). Assisted mechanical ventilation (AMV)
1. Definition: In the presence of patient breathing, the ventilator assists or enhances the patient’s spontaneous breathing. Various types of mechanical ventilation are mainly triggered by the patient’s inspiratory negative pressure or inspiratory airflow.
2. Reasonable: Although spontaneous breathing exists and is more regular, it cannot be used in patients with weakened spontaneous breathing but insufficient ventilation.
2. According to the use of mechanical ventilation
(1) Intrathoracic or airway compression type
(2) Chest shape
(1) Intrathoracic or airway compression type
(2) Chest shape
3. According to the switching mode of inhalation and exhalation
(1) Constant pressure type: After the pressure in the respiratory tract reaches a predetermined value, the ventilator opens the exhalation valve, and the thoracic and lungs are passively atrophy or exhaled by negative pressure. When the pressure in the airway continues to fall, the ventilator is again generated by positive pressure Airflow and causing inhalation.
(2) Constant volume type: The positive tidal volume is used to send the estimated tidal volume into the lungs. After reaching the expected tidal volume, the air supply is stopped and the exhaled state is entered.
(3) Timing type: supply air according to the pre-designed inhalation and expiration time. (4) Mixed type (multifunctional type).
(1) Constant pressure type: After the pressure in the respiratory tract reaches a predetermined value, the ventilator opens the exhalation valve, and the thoracic and lungs are passively atrophy or exhaled by negative pressure. When the pressure in the airway continues to fall, the ventilator is again generated by positive pressure Airflow and causing inhalation.
(2) Constant volume type: The positive tidal volume is used to send the estimated tidal volume into the lungs. After reaching the expected tidal volume, the air supply is stopped and the exhaled state is entered.
(3) Timing type: supply air according to the pre-designed inhalation and expiration time. (4) Mixed type (multifunctional type).
4. Supply air according to ventilation frequency
(1) High-frequency ventilation: ventilation frequency> 60 times / min.
1. Advantages: low airway pressure, low intrathoracic pressure, little interference to circulation, no need to close the airway.
2. Disadvantages: Not conducive to the removal of carbon dioxide.
3. Classification: high-frequency positive pressure ventilation, high-frequency jet ventilation, high-frequency oscillatory ventilation.
(2) Normal frequency ventilation: ventilation frequency <60 times / min.
5. According to whether there is a synchronization device or performance
(1) Synchronous ventilator: The inhalation of the patient’s spontaneous breathing can trigger the ventilator to supply air into the patient’s respiratory tract and produce inhalation action.
(2) Non-synchronized ventilator: The patient’s breathing or inspiratory negative pressure cannot trigger the ventilator to supply air, and is generally only used for patients with controlled mechanical ventilation.
6. Classification by applicable objects
(1) Baby ventilator
(2) Infant ventilator
(3) Adult ventilator
7. Classified by working principle
(1) Simple ventilator
(2) Membranous lung
(1) High-frequency ventilation: ventilation frequency> 60 times / min.
1. Advantages: low airway pressure, low intrathoracic pressure, little interference to circulation, no need to close the airway.
2. Disadvantages: Not conducive to the removal of carbon dioxide.
3. Classification: high-frequency positive pressure ventilation, high-frequency jet ventilation, high-frequency oscillatory ventilation.
(2) Normal frequency ventilation: ventilation frequency <60 times / min.
5. According to whether there is a synchronization device or performance
(1) Synchronous ventilator: The inhalation of the patient’s spontaneous breathing can trigger the ventilator to supply air into the patient’s respiratory tract and produce inhalation action.
(2) Non-synchronized ventilator: The patient’s breathing or inspiratory negative pressure cannot trigger the ventilator to supply air, and is generally only used for patients with controlled mechanical ventilation.
6. Classification by applicable objects
(1) Baby ventilator
(2) Infant ventilator
(3) Adult ventilator
7. Classified by working principle
(1) Simple ventilator
(2) Membranous lung
Main mechanical ventilation function
(1) Holding the breath at the end of inhalation
1. After the end of inhalation and before the start of the exhalation, the ventilator does not supply air, and the exhalation valve continues to close and close to maintain the lung pressure at a certain level.
2. Clinical application:
(1) The inspiratory time is extended, which is beneficial to the distribution of gas.
(2) Conducive to the dispersion of gas
(3) The distribution and dispersion of the inhaled drugs in the lungs
3. It can increase the burden on the heart.
(2) Positive end-expiratory pressure ventilation
1. At the end of expiration, the airway pressure does not drop to zero, and still maintains a certain positive pressure level.
2. Clinical application: suitable for hypoxemia caused by shunt in the lung, such as ARDS PEEP breakthrough ARDS mechanism
(1) Reduce alveolar collapse, reduce lung shunt, and correct hypoxemia caused by lung shunt
(2) Reduce alveolar collapse and increase FRC, which is conducive to the full exchange of alveolar-capillary catheter gas.
(3) The increase in alveolar pressure makes the alveolar-arterial oxygen partial pressure increase, which is beneficial to the diffusion of oxygen to the capillaries.
(4) Increased inflation of the alveoli can increase the compliance of the lungs, and can also reduce breathing work.
1. After the end of inhalation and before the start of the exhalation, the ventilator does not supply air, and the exhalation valve continues to close and close to maintain the lung pressure at a certain level.
2. Clinical application:
(1) The inspiratory time is extended, which is beneficial to the distribution of gas.
(2) Conducive to the dispersion of gas
(3) The distribution and dispersion of the inhaled drugs in the lungs
3. It can increase the burden on the heart.
(2) Positive end-expiratory pressure ventilation
1. At the end of expiration, the airway pressure does not drop to zero, and still maintains a certain positive pressure level.
2. Clinical application: suitable for hypoxemia caused by shunt in the lung, such as ARDS PEEP breakthrough ARDS mechanism
(1) Reduce alveolar collapse, reduce lung shunt, and correct hypoxemia caused by lung shunt
(2) Reduce alveolar collapse and increase FRC, which is conducive to the full exchange of alveolar-capillary catheter gas.
(3) The increase in alveolar pressure makes the alveolar-arterial oxygen partial pressure increase, which is beneficial to the diffusion of oxygen to the capillaries.
(4) Increased inflation of the alveoli can increase the compliance of the lungs, and can also reduce breathing work.
4. The main symptoms of PEEP
(1) Influence on hemodynamics
(2) Barotrauma to lung tissue
(3) Capable of compressing pulmonary capillaries. Decreases lung blood flow and may increase ineffective ventilation
(4) It can reduce the alveolar surfactant.
(1) Influence on hemodynamics
(2) Barotrauma to lung tissue
(3) Capable of compressing pulmonary capillaries. Decreases lung blood flow and may increase ineffective ventilation
(4) It can reduce the alveolar surfactant.
5. Selection of the best PEEP: keeping preset of FiO2 <60%, the lowest PEEP level of PaO2> 60mmHg can be achieved.
6. Endogenous PEEP: due to the short expiratory time or high dyspnea, the gas in the alveoli is retained, which can maintain the positive pressure of the alveolar pressure throughout the exhalation cycle. Application of ventilator artificially caused.
(3) Prolonged expiratory breath and end-expiratory breath-hold: suitable for patients with COPD and cardiovascular retention.
(4) Sigh: 1-3 deep breaths equivalent to 1.5 times-2 times the tidal volume in every 50-100 breathing cycles, so that the alveoli at the bottom of the lungs that are prone to collapse can expand regularly, and improve the Gas exchange to prevent atelectasis.
(5) Inverse Ventilation (IRV)
1. Advantages: Prolonged inhalation time is conducive to the diffusion and distribution of gas, and is helpful to correct hypoxia.
2. Disadvantages: great interference to circulation, great pressure injury to lung tissue
(4) Sigh: 1-3 deep breaths equivalent to 1.5 times-2 times the tidal volume in every 50-100 breathing cycles, so that the alveoli at the bottom of the lungs that are prone to collapse can expand regularly, and improve the Gas exchange to prevent atelectasis.
(5) Inverse Ventilation (IRV)
1. Advantages: Prolonged inhalation time is conducive to the diffusion and distribution of gas, and is helpful to correct hypoxia.
2. Disadvantages: great interference to circulation, great pressure injury to lung tissue
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