What is the protocol for weaning a patient off mechanical ventilation (MV) support?

From the Guidelines

Weaning a patient off ventilator support should be done using a spontaneous breathing trial (SBT) with inspiratory pressure augmentation of 5-8 cm H2O, as this approach has been shown to be effective in liberating patients from mechanical ventilation. The process of weaning a patient off ventilator support involves a systematic approach that begins with assessing readiness through specific criteria, including adequate oxygenation, hemodynamic stability, appropriate mental status, and sufficient respiratory muscle strength 1.

Key Considerations

• The patient should demonstrate adequate oxygenation (PaO2/FiO2 > 200), hemodynamic stability, appropriate mental status, and sufficient respiratory muscle strength (negative inspiratory force > -20 cmH2O) before starting the weaning process.
• SBTs involve placing the patient on minimal ventilator support (T-piece or CPAP of 5 cmH2O) for 30-120 minutes while monitoring for signs of intolerance such as respiratory rate > 35/min, SpO2 < 90%, heart rate increase > 20%, or visible distress.
• Pressure support ventilation (PSV) weaning gradually reduces pressure support from 15-20 cmH2O to 5-8 cmH2O before extubation.
• Synchronized intermittent mandatory ventilation (SIMV) weaning decreases mandatory breath rates by 2-4 breaths/minute every 1-2 hours until reaching 4 breaths/minute.

Monitoring and Preparation

• Throughout the process, careful monitoring of vital signs, arterial blood gases, and work of breathing is essential.
• Extubation follows successful weaning trials, with preparation including suctioning, pre-oxygenation, and having emergency equipment ready.
• For patients at high risk for extubation failure, extubation to preventative noninvasive ventilation (NIV) is recommended 1.

Evidence-Based Recommendations

• The American College of Chest Physicians and the American Thoracic Society recommend using SBTs with inspiratory pressure augmentation to liberate patients from mechanical ventilation 1.
• The guidelines also suggest protocols attempting to minimize sedation and recommend extubation to preventative NIV for patients at high risk for extubation failure 1.

From the Research

Weaning Protocol

The protocol for weaning a patient off ventilator support involves several steps, including:

• Categorizing patients into three groups based on the difficulty and duration of the weaning process 2
• Considering weaning as early as possible 2, 3
• Conducting a spontaneous breathing trial (SBT) as the major diagnostic test to determine whether patients can be successfully extubated 2, 3
• Using low levels of pressure support or T-tube breathing for the initial SBT, which should last 30 minutes 2
• Favouring pressure support or assist-control ventilation modes in patients failing an initial trial/trials 2

Weaning Strategies

Several strategies have been shown to be effective in promoting timely and successful weaning, including:

• Weaning protocols 4
• Use of spontaneous breathing trials 4
• Bundling of spontaneous breathing trials with sedation and delirium monitoring/management 4
• Early mobility 4
• Use of automated weaning systems and modes that improve patient-ventilator interaction 4
• Mechanical insufflation-exsufflation as a weaning adjunct 4
• Early extubation to non-invasive ventilation and high flow humidified oxygen 4

Spontaneous Breathing

Maintaining spontaneous breathing during mechanical ventilation has been shown to have several benefits, including:

• Improvements in pulmonary gas exchange, systemic blood flow, and oxygen supply to the tissue 5
• Redistribution of ventilation and end-expiratory gas to dependent, juxtadiaphragmatic lung regions, promoting alveolar recruitment 5
• Prevention of cyclic alveolar collapse in dependent lung regions 5
• Decreased duration of mechanical ventilator support, length of stay in the intensive care unit, and overall costs of care giving 5