Mechanical ventilation is a useful tool to rescue respiratory failure from various causes and is one of the most basic resuscitation tools in ICU. In order to standardize the application of mechanical ventilation and improve the success rate of mechanical ventilation off-boarding, we propose recommendations and point out the advantages and disadvantages of many key aspects of mechanical ventilation up to off-boarding.
Recommendation 1: Methods of mechanical ventilation to establish an artificial airway: three methods: transnasal, transoral, and tracheotomy, and two methods: fiberoptic bronchoscopy or laryngoscopy. Tracheotomy can be done by traditional or simple methods.
Recommendation 2: Mechanical ventilation establishment should be implemented under the supervision of ECG, blood pressure, and SpO2; it is generally necessary to start ventilator support after the establishment of artificial airway under sedation anesthesia induction.
Recommendation 3: Mechanical ventilation wetting: wetting temperature:34-37°C, wetting canister replacement: 4-5 days. Mechanical ventilation line replacement: 2-4 days.
1, ventilation machine pipeline replacement does not change the infection control, more long time without replacement pipeline does not show greater bad effects. How long should the pipeline be used safely has not been determined.
2, pipeline wetter heating method, pay attention to the pipeline liquid removal, pay attention not to drain the pipeline liquid into the airway or wetting tank, do not contaminate the pipeline.
3, the available evidence is that passive wetting than active wetting has a lower incidence of VAP, the use of passive wetting in infection control simply no evidence.
4, passive wetting does not require daily line changes and can be used safely for at least 48 hours, and in some patients for up to 1 week.
5, VAP prevention strategy should consider the use of closed suction, when using closed suction catheter, do not need to change every day, what time to change has not been determined
6. Clinical care should be alert to VAP risk factors in the treatment of patients with MV.
Recommendation 4: Adjustment of mechanical ventilation parameters (combined with hemodynamic and ventilation and oxygenation monitoring)
The applicable ventilation mode should be determined first, and then the parameters should be adjusted according to different disease types.
Adjustment of parameters during controlled ventilation.
1. Setting of tidal volume: domestic and foreign setting of VT
aSet the VT at the steep and straight section of the P-V curve based on the P-V curve.
bAccording to body weight, 5-10 ml per kg of body weight.
cBased on pulmonary mechanical parameters to maintain VT at the lowest airway pressure, the highest pressure should be lower than Pplat, and the safe pressure resulting from VT should maintain airway pressure <20cmH2O.
dUltimately, plasma PaCO2 should be used as the target for adjustment
2. Setting of RR.
It should be based on changes in pulmonary mechanical parameters, curves and rings, and in principle.
a discard large VT, small f strategy
bWhen pulmonary R and C are poor, their VT settings are small and require larger f (up to 20 times/min)
cGas clamping should be avoided
The final precise adjustment will be based on the changes of PaCO2 and PaO2, and the integrated adjustment of VT and f.
3. Flow rate adjustment.
The gas delivery flow rate is directly related to the change of airway resistance and compliance, reflecting the change of VT and airway pressure, and the use of constant speed
(i.e., square wave) can give us more information, combined with the difference between peak airway pressure and plateau pressure (resistance) to adjust the flow rate, may be at the appropriate flow rate to provide appropriate VT to adapt to the pathophysiological changes in the lungs of this patient, the general flow rate waveform in the clinical commonly used constant flow (square wave) or deceleration wave. Once autoflow is added during capacitance-controlled ventilation, the flow rate cannot be adjusted.
4, trigger sensitivity adjustment: flow rate trigger and pressure trigger, some studies have shown that the flow rate trigger can significantly reduce the patient’s respiratory work than the pressure trigger, while the pressure trigger can reflect the respiratory muscle function. The trigger sensitivity setting is too high because the activity of the pipeline can cause the patient’s own excessive respiratory trigger, the trigger sensitivity setting is too low can make the patient occur too much ineffective respiratory effort, resulting in human-machine confrontation, inducing respiratory muscle fatigue. Therefore, an appropriate trigger sensitivity setting will obviously make the patient more comfortable and promote human-machine coordination.
Objective measurement
1.Appropriate oxygen PaO2≥60mmHg,FiO2≤04,
2, stable cardiovascular function (e.g. HR≤140 beats/min, stable blood pressure, no or small amount of vasoactive drugs.
3.Mild fever or no fever (e.g. T38℃)
4.No significant acid replacement
5, appropriate hematocrit (e.g. HB ≥ 8-10g/dl)
6, good mental status (such as the ability to wake up GCS ≥ 13, no sedative infusion)
7, stable metabolic status (e.g., normal electrolytes)
Subjective clinical evaluation.
1, pain relief in the acute phase
2, ICU physicians believe that interruption of the ventilator is possible
3, adequate coughing capacity
Recommendation 5: Patients receiving mechanical ventilation for respiratory failure should meet the following criteria to undergo formal evaluation for interruption of ventilator support.
1. Some resolution of the underlying cause of respiratory failure
2. Adequate oxygenation (e.g., PaO2/FiO2 > 200 mmHg, PEEP ≤ 5 cmH2O, FiO2 ≤ 0,4 and pH ≥ 7,25)
3, hemodynamic stability, no myocardial ischemia and clinical hypotension (i.e., no vasopressors or only small doses of vasoactive drugs such as dobutamine and dobutamine)
4. Initial inspiratory capacity
Recommendation 6: Assessment of formal deconditioning of patients on mechanical ventilation in respiratory failure should be performed during the autonomic breathing pattern rather than while still on controlled ventilatory support, with initial simple autonomic breathing used to evaluate the ability to perform continuous formal SBT. Criteria for assessing patient endurance during formal SBT are type of breathing, adequate gas exchange, hemodynamic stability, and subjective sensation. 30-120 minutes of SBT tolerance should be attempted to consider permanent ventilator withdrawal.
Recommendation 7: Successful extraction of the patient’s artificial airway should be based on the state of airway opening and the patient’s ability to protect the airway.
Recommendation 8: Management of patients with failed SBT
Which mode of mechanical ventilation should be provided after SBT? Should a constant high level or a gradual decrease in support (i.e., low assisted support) be applied?
Evidence-based medicine focus: The aspect of MV support strategy is a difficult one. This is due to comparing two or more ventilation treatments, not only in terms of the mode of ventilation but also in terms of how to use these modes. Ideally, trials developed to reduce the handling of invasive ventilation support are similar in evaluating each strategy.
Recommendation 9: SBT in mechanically ventilated patients should determine the cause of SBT failure, and once the reversible cause of SBT is corrected, SBT should be followed within 24 hours if the patient still fits the criteria of recommendation 10.
Recommendation 10: Patients with failed SBT for expiratory failure should receive a stable non-fatiguing and comfortable ventilation support.
Recommendation 11: Anesthesia and sedation strategies aimed at early decannulation and extubation should be used for post-surgical patients.
The application of sedation in surgical patients suppresses the respiratory center and pain is a major cause of ventilator dependence. Ventilation strategies with appropriate sedation and pain relief shorten the duration of ventilator support.
Recommendation 18: The role of tracheotomy in ventilator-dependent patients
Providing long-term assisted ventilation in critically ventilator-dependent patients often requires a tracheotomy. These advantages include improved patient comfort, better airway management, reduced airway resistance, increased patient activity, facilitation of patient articulation and speech, and the ability to eat by mouth safely.
Recommendation 19: Tracheotomy should be considered for patients who need to be on a ventilator for a long period of time after the start of stabilization, and patients will benefit more from a tracheotomy.
Recommendation 20: Except in patients with definite irreversible disease (e.g., high spinal cord injury or advanced amyotrophic lateral sclerosis) requiring prolonged MV support, permanent ventilator dependence should be considered only after more than 3 months of off-board failure.
Recommendation 21: The deconditioning strategy for patients on prolonged mechanical ventilation should be slow and should include progressively longer trials of spontaneous breathing.
Recommendation 22: Short-term evaluation of successful and unsuccessful deconditioning time 24-48 hours.