What are the initial ventilation settings and modes for patients requiring mechanical ventilation?

Initial Ventilation Settings and Modes

Lung-Protective Ventilation Strategy

For all mechanically ventilated patients, initiate lung-protective ventilation immediately with low tidal volumes (4-8 ml/kg predicted body weight), target plateau pressure <30 cmH₂O, and PEEP ≥5 cmH₂O, regardless of whether ARDS is present. 1, 2

Initial Tidal Volume Settings

• Adults: Start with 6 ml/kg predicted body weight (PBW), which may be increased to 8 ml/kg PBW only if the initial volume is not tolerated 1
• Children: Target 3-6 ml/kg PBW initially, which may be increased to 5-8 ml/kg PBW in cases with well-preserved respiratory compliance 1
• Maintain plateau pressure <30 cmH₂O in adults (<28 cmH₂O in children) 1

Initial PEEP and FiO₂ Settings

• Set PEEP ≥5 cmH₂O at minimum to prevent atelectasis 2
• Titrate PEEP based on the FiO₂ required to achieve SpO₂ >90% 1
• Target SpO₂ of 88-95% to prevent hyperoxia 2
• Avoid high FiO₂ strategies; titrate oxygen to the minimum needed for adequate saturation 2, 3

Initial Respiratory Rate

• Set respiratory rate between 20-35 breaths per minute to ensure adequate ventilation 2
• Adjust based on patient's spontaneous respiratory rate and need for minute ventilation 1

Ventilation Modes

Volume Control vs. Pressure Control

• Both modes are acceptable when lung-protective principles are applied 1
• In pressure control mode: Set inspiratory pressure to achieve target tidal volumes while maintaining plateau pressure <30 cmH₂O 1
• In volume control mode: Set tidal volume directly and monitor plateau pressure 1

Spontaneous Breathing Modes

• Transition to assisted modes (pressure support, SIMV with pressure support) as soon as patient recovery allows 4
• For pressure support ventilation: Use 5-8 cm H₂O pressure support for spontaneous breathing trials 5, 4
• Spontaneous breathing modes are preferred in intubated patients when clinically appropriate 1

Backup Rate Settings (ST or Timed Modes)

• Set backup rate equal to or slightly less than the patient's spontaneous sleeping respiratory rate (minimum 10 breaths per minute) 1
• If sleeping respiratory rate is unknown, use the spontaneous awake respiratory rate 1
• Increase backup rate in increments of 1-2 breaths per minute as needed 1

Inspiratory Time Settings

• Initial inspiratory time (IPAP time) should provide %IPAP time of 30-40% of the cycle time 1
• For obstructive lung disease: Use shorter inspiratory time (~30% IPAP time) to allow adequate exhalation 1
• For restrictive lung disease: Use longer inspiratory time (~40% IPAP time) to accommodate decreased compliance 1
• Default inspiratory time is commonly 1.2 seconds 1

Advanced Ventilation Strategies

When to Escalate

• Prone positioning: Consider after 12 hours of ventilator optimization if PaO₂/FiO₂ <150, continuing for 12-16 hours daily 1
• Neuromuscular blockade: Reserve for severe ARDS with ventilator asynchrony, using short-term administration 2
• Permissive hypercapnia: Allow if hemodynamic parameters remain satisfactory to avoid ventilator-induced lung injury 1
• ECMO: Consider for refractory hypoxemia (PaO₂/FiO₂ <100 mmHg) despite optimized lung-protective ventilation 1

Common Pitfalls to Avoid

• Do not use high tidal volumes (>8 ml/kg PBW) even in non-ARDS patients, as this increases risk of ventilator-induced lung injury 2
• Avoid low PEEP/high FiO₂ strategies, which were commonly used but are not evidence-based 3
• Do not delay adjustments: Patients ventilated in the ED for mean of 5 hours often receive few ventilator adjustments, leading to suboptimal settings 3
• Monitor plateau pressure continuously: Patients with stiff chest walls may tolerate higher plateau pressures (~35 cmH₂O), but this requires careful assessment 2
• Avoid excessive sedation: Most patients tolerate lung-protective ventilation without requiring deep sedation 2

Non-Invasive Ventilation Considerations

• CPAP or BiPAP may be considered before intubation in appropriate patients, though these are aerosol-generating procedures requiring infection control precautions 1
• High-flow nasal oxygen (HFNO) is preferred over conventional oxygen therapy when standard oxygen fails 1
• Preoxygenate with 100% FiO₂ for 5 minutes using face mask, bag-valve mask, HFNO, or NIV before intubation 1
• If no improvement or worsening occurs within 1-2 hours of HFNO or NIV, proceed promptly to endotracheal intubation 1