What are the steps in a weaning flowchart for mechanical ventilation?

Ventilator Weaning Flowchart

A structured ventilator liberation protocol should be implemented for all mechanically ventilated patients, including daily screening for weaning readiness, spontaneous breathing trials (SBTs), and assessment for extubation if SBT is successful. 1

Step 1: Daily Assessment for Weaning Readiness

• Resolution of underlying respiratory failure
• Oxygenation criteria: FiO₂ ≤ 0.50, PEEP ≤ 5-8 cmH₂O
• Hemodynamic stability: No vasopressors or low-dose stable requirements
• Ability to initiate respiratory effort
• Adequate mental status: Patient able to follow commands
• Adequate cough and secretion management

Step 2: Spontaneous Breathing Trial (SBT)

• Duration: 30-minute trial 1

• Methods:

  • T-piece trial (complete removal of ventilatory support)
  • Low-level pressure support (5-8 cmH₂O)
  • CPAP (5 cmH₂O)

• Monitor for SBT failure signs:

  • Respiratory rate > 35 breaths/min
  • SpO₂ < 90%
  • Heart rate > 140 beats/min or increase by >20%
  • Systolic BP > 180 mmHg or < 90 mmHg
  • Agitation, diaphoresis, or anxiety
  • Paradoxical breathing or accessory muscle use

Step 3: Extubation Readiness Assessment

If SBT successful, assess:

• Airway patency and protection
• Secretion burden: Ability to clear secretions
• Cough strength: Adequate peak expiratory flow
• Mental status: Alert and cooperative
• Hemodynamic stability

Step 4: Decision Point

• If SBT and extubation assessment successful: Proceed to extubation
• If SBT fails: Return to full ventilatory support and address underlying causes

Step 5: Post-Extubation Management

• Monitor closely for 24-48 hours
• Consider prophylactic NIV for high-risk patients
• Oxygen therapy as needed to maintain SpO₂ targets
• Airway clearance techniques if indicated

Step 6: For Difficult-to-Wean Patients

For patients failing initial SBT:

1. Return to full ventilatory support for at least 24 hours
2. Identify and address causes of weaning failure:
   • Respiratory muscle weakness
   • Increased work of breathing
   • Cardiac dysfunction
   • Psychological factors
   • Metabolic disturbances
   • Nutritional status
3. Implement progressive withdrawal techniques:
   • Pressure support ventilation with gradual reduction
   • Daily SBTs with increasing duration
   • Consider tracheostomy if prolonged weaning anticipated (>7 days)

Special Considerations

• COPD patients: May benefit from pressure-augmented SBTs and NIV post-extubation 1
• Neuromuscular disease: Consider NIV to facilitate weaning 2
• Cardiac patients: Monitor for signs of cardiac failure during SBT
• Obesity: Higher PEEP settings (10-15 cmH₂O) may be needed 1

Weaning Classification

• Simple weaning: Successful extubation after first SBT (70% of patients) 1
• Difficult weaning: Requires up to 3 SBTs or up to 7 days (15% of patients) 1
• Prolonged weaning: Requires >3 SBTs or >7 days (associated with poorer outcomes) 1

Protocol Implementation

• Use a protocol-directed approach led by respiratory therapists and ICU nurses
• Perform daily screening for all ventilated patients
• Document weaning progress and outcomes
• Maintain head of bed elevation at 30-45 degrees to reduce VAP risk 1
• Minimize sedation to facilitate weaning 1

This structured approach to ventilator weaning has been shown to reduce duration of mechanical ventilation, ICU length of stay, and associated complications.