What are the recommendations for mechanical ventilation in the Intensive Care Unit (ICU) for patients with respiratory failure?

Mechanical Ventilation in the ICU

For all ICU patients requiring mechanical ventilation, implement lung-protective ventilation with tidal volumes of 4-8 ml/kg predicted body weight and maintain plateau pressures ≤30 cmH2O to reduce mortality and ventilator-induced lung injury. 1, 2

Initial Ventilator Setup

Start with these core settings for all mechanically ventilated patients: 2, 3

• Tidal volume: 6-8 ml/kg predicted body weight for most patients; reduce to 4-6 ml/kg for ARDS 2, 3
• Plateau pressure: Maintain <30 cmH2O 1, 4
• PEEP: Start at ≥5 cmH2O minimum 2, 3
• FiO2: Begin at 40% and titrate to target SpO2 88-95% 2, 4
• Respiratory rate: 20-35 breaths/min initially 3

Calculate predicted body weight precisely: Males = 50 + 0.91 × [height (cm) - 152.4] kg; Females = 45.5 + 0.91 × [height (cm) - 152.4] kg 4

ARDS-Specific Management Algorithm

All ARDS Patients (Regardless of Severity)

• Mandatory lung-protective ventilation: 4-8 ml/kg predicted body weight, plateau pressure <30 cmH2O 1, 4
• Accept permissive hypercapnia with pH >7.20 rather than compromise lung protection 4
• Conservative fluid strategy once hemodynamically stable 4

Moderate-to-Severe ARDS (PaO2/FiO2 <200 mmHg)

• Higher PEEP: Use >10 cmH2O (typically 10-15 cmH2O) 1, 2, 4
• Consider recruitment maneuvers (conditional recommendation with low confidence) 1, 2

Severe ARDS (PaO2/FiO2 <150 mmHg)

Implement these interventions immediately: 1, 4

1. Prone positioning: >12-16 hours daily (reduces mortality, RR 0.74) 1, 2, 4
2. Neuromuscular blockade: For up to 48 hours in early severe ARDS 2, 4
3. Systemic corticosteroids: Administer to mechanically ventilated ARDS patients 4
4. VV-ECMO: Consider only in refractory cases at experienced centers 2, 4

Strongly avoid high-frequency oscillatory ventilation in moderate or severe ARDS—this increases harm 1, 2, 4

COPD-Specific Ventilation Strategy

First-Line: Non-Invasive Ventilation

Attempt NIV first for COPD exacerbations with respiratory acidosis: 2

• Bi-level pressure support: IPAP 10-15 cmH2O, EPAP 4-8 cmH2O 2
• Pressure difference: Maintain ≥5 cmH2O between IPAP and EPAP 2
• Backup rate: 10-14 breaths/min 2
• Recheck ABG in 30-60 minutes; intubate if persistent or worsening acidosis 2

If Invasive Ventilation Required

• Tidal volume: 6-8 ml/kg predicted body weight 2, 3
• PEEP: 4-8 cmH2O to offset intrinsic PEEP and improve triggering 2
• I:E ratio: 1:2 to 1:4 to allow adequate expiratory time and prevent air trapping 2, 3
• Monitor for auto-PEEP using pressure-time and flow-time scalars 3

Noninvasive Ventilation Considerations

For less severely ill ARDS patients, noninvasive support with close monitoring is reasonable initially 1

CPAP Indications

• Primary use: Correct hypoxemia by recruiting underventilated lung 2
• Mechanism: Increases mean airway pressure, unloads inspiratory muscles, offsets intrinsic PEEP in COPD 2

Bi-Level Pressure Support

• Most effective NIV mode for COPD patients 2
• IPAP: Provides inspiratory assistance for ventilation 2
• EPAP: Recruits lung, offsets intrinsic PEEP, vents exhaled gas 2

Critical Monitoring Parameters

Obtain arterial blood gas within 1-2 hours of initiating mechanical ventilation 3

Monitor continuously: 3

• Plateau pressure (must remain <30 cmH2O)
• Driving pressure (plateau pressure - PEEP)
• Dynamic compliance
• Auto-PEEP (especially in obstructive disease)

Common Pitfalls to Avoid

• Never prioritize normocapnia over lung protection—accept permissive hypercapnia as necessary 4
• Never use tidal volumes >8 ml/kg PBW even if plateau pressures seem acceptable—both parameters must be optimized 4, 3
• Never delay prone positioning in severe ARDS—early implementation (within 48 hours) improves mortality 4
• Never target excessive oxygen saturation—maintain SpO2 88-95%, not >96% 2, 4
• Never allow inadequate expiratory time in obstructive disease—this causes dynamic hyperinflation and hemodynamic compromise 2, 3
• Never use recruitment maneuvers routinely or for prolonged periods—these are associated with harm 4

Sedation Strategy to Optimize Ventilation

Minimize continuous sedation and target specific endpoints 4

• Avoid benzodiazepines (decrease SWS and REM sleep) 1
• Prefer dexmedetomidine when sedation needed (preserves circadian rhythm, improves sleep efficiency) 1
• Implement spontaneous breathing trials when patients meet weaning criteria 4

Weaning Considerations

• Use a weaning protocol for patients who can tolerate weaning 4
• For tracheostomized patients with prolonged weaning: Reconnect ventilator at night to promote longer sleep 1, 2
• Assess for sleep-disordered breathing after extubation and treat with positive airway pressure if needed 1