One, the ventilator has a significant air leak, in which case the tidal volume may not go up.
Second, if the patient has a sputum plug blocking the airway, the tidal volume of the ventilator may not go up in this case.
Three, the parameters of the ventilator are not set appropriately, there may also be a low tidal volume of this situation.
Four, some other reasons, such as certain disease states, the tidal volume of the ventilator may not go up. For example, in acute respiratory distress syndrome, there are even times when the tidal volume is artificially small.
The ventilator, as an effective means of artificially replacing the function of voluntary ventilation, has been commonly used in respiratory failure due to various causes, anesthesia respiratory management during major surgery, respiratory support therapy and emergency resuscitation, and occupies a very important position in the field of modern medicine. The ventilator is a medical device that can prevent and treat respiratory failure, reduce complications, and save and prolong the patient's life.
Categorization of ventilators
I. According to the use or application of the type of classification
(a) controlled mechanical ventilation (CMV) 1. Definition: the patient in the spontaneous respiration is weakened or disappeared, completely by the mechanical ventilation machine to produce, control and regulate the patient's respiration. 2. Application: the disappearance or weakening of spontaneous respiration caused by disease; spontaneous respiration is irregular or too fast, mechanical ventilation can not be coordinated with the patient, the spontaneous respiration will be suppressed or weakened by artificial methods.
(ii). Assisted Mechanical Ventilation (AMV) 1. Definition: Ventilator-assisted or augmented spontaneous respiration in the presence of patient's breathing. Various kinds of mechanical ventilation are mainly triggered by the patient's inspiratory negative pressure or inspiratory airflow. 2. Apply to: although the voluntary breathing exists and is more regular, but does not apply to the voluntary breathing is weakened and insufficient ventilation of the patient.
II. According to the use of mechanical ventilation route classification
(a) chest or airway pressure type
(2) extra-thoracic type
three. Classification according to the way of switching between inspiratory and expiratory phases
(I) Fixed-pressure type: after the pressure in the airway reaches the expected value, the ventilator opens the expiratory valve and the thorax and lungs are passively atrophied or the expiration is generated by the negative pressure, and when the pressure in the airway keeps decreasing, the ventilator generates the airflow by the positive pressure once again and causes the inhalation.
(ii) Constant volume type: the predicted tidal volume is delivered to the lungs by positive pressure, and when the predicted tidal volume is reached, the air supply is stopped and the expiratory state is entered.
(3) Timed: Supply air according to the pre-designed inhalation and exhalation times. (d) Hybrid type (multi-function type).
IV. Ventilation according to ventilation frequency
(1) High-frequency ventilation: Ventilation frequency >60 times/minute. 1. Advantages: low airway pressure, low intrathoracic pressure, little interference with circulation, no need to seal the airway. 2. Disadvantages: unfavorable to carbon dioxide elimination. 3. Classification: high-frequency positive pressure ventilation, high-frequency jet ventilation, high-frequency oscillatory ventilation.
(ii) normal frequency ventilation: ventilation frequency <60 times/minute.
V. Classified according to whether there is a synchronization device or performance
(a) synchronization type ventilator: the patient's spontaneous respiration of inhalation can be triggered at the beginning of the ventilator, so that it is supplied to the patient's airway, and to produce the inspiratory action.
(2) Non-synchronized ventilator: the patient's breathing or negative inspiratory pressure can not trigger the ventilator to supply air, generally only used for patients with controlled mechanical ventilation.