What is the approach to PEEP (Positive End-Expiratory Pressure) titration and recruitment maneuvers in patients with Pediatric Acute Respiratory Distress Syndrome (PARDS)?

PEEP Titration and Recruitment Maneuvers in PARDS

Initial PEEP Settings

Start with PEEP of 5-8 cmH₂O in all PARDS patients, then titrate upward based on disease severity while continuously monitoring hemodynamics and oxygenation. 1 This baseline range prevents alveolar collapse while minimizing cardiovascular compromise in the pediatric population.

Disease Severity-Based Approach

• Mild PARDS: Maintain PEEP 5-10 cmH₂O 2
• Moderate PARDS: Target PEEP 10-15 cmH₂O 2
• Severe PARDS: Consider PEEP 15-20 cmH₂O, though higher PEEP may be necessary 1, 2

The 2017 Paediatric Mechanical Ventilation Consensus Conference emphasizes that higher PEEP is often required in severe disease to restore end-expiratory lung volume and improve respiratory system compliance without impairing hemodynamics. 1

PEEP Titration Strategy

Use incremental PEEP titration rather than fixed tables, balancing oxygenation improvement against hemodynamic stability and avoiding overdistension. 1 There is no single defined method to determine "best PEEP" in children, but several approaches can guide decision-making. 1

Practical Titration Method

• Monitor these parameters during PEEP changes: 1

  • Peak inspiratory pressure and plateau pressure (keep Pplat ≤28-30 cmH₂O) 1, 3
  • Respiratory system compliance (Crs) 1
  • SpO₂ and PaO₂/FiO₂ ratio 1
  • Central venous saturation as marker for cardiac output 1
  • Pressure-time and flow-time scalars 1, 3

• Consider transpulmonary pressure monitoring in complex cases with chest wall compliance issues to avoid under-inflation despite adequate airway pressures 4

Oxygenation Targets During PEEP Titration

• When PEEP <10 cmH₂O: Target SpO₂ 92-97% 1, 3
• When PEEP ≥10 cmH₂O: Accept SpO₂ 88-92% 1, 3

This tiered approach acknowledges that higher PEEP requirements indicate more severe disease where slightly lower saturations are acceptable to avoid excessive airway pressures.

Critical Pitfall: Mechanical Power and Driving Pressure

Increasing PEEP beyond 10 cmH₂O can significantly increase mechanical power (by ~60%) and driving pressure (by ~33%), potentially worsening ventilator-induced lung injury. 5 A 2024 study in children with mild-to-moderate PARDS demonstrated that PEEP levels of 10-12 cmH₂O caused substantial increases in these injury-associated variables. 5 This underscores the importance of:

• Carefully evaluating respiratory system mechanics during each PEEP increment 5
• Assessing lung recruitability before assuming higher PEEP will be beneficial 5
• Recognizing that not all PARDS patients have recruitable lung 2

Recruitment Maneuvers

Consider recruitment maneuvers cautiously in PARDS, but recognize there is insufficient evidence to routinely recommend any specific recruitment maneuver in children. 1 The consensus guidelines explicitly state strong agreement that data are lacking to support routine use. 1

Evidence-Based Limitations

• Recruitment maneuvers may resolve atelectasis and improve gas exchange temporarily 1
• No outcome data demonstrate improved mortality or morbidity 1
• No evidence supports one recruitment method over another (sustained inflation vs. incremental PEEP) 1
• Do not perform routine recruitment maneuvers after endotracheal suctioning 1

Adult ARDS Data (Relevant Context)

The 2024 American Thoracic Society guidelines for adult ARDS strongly recommend against prolonged recruitment maneuvers (PEEP >35 cmH₂O for >60 seconds) in moderate-to-severe ARDS due to lack of mortality benefit and potential harm. 1 While pediatric-specific data are limited, this suggests caution with aggressive recruitment strategies.

When to Consider Recruitment Maneuvers

If attempting recruitment in PARDS:

• Use stepwise/incremental PEEP titration rather than sustained inflation maneuvers 2
• Limit to patients with potentially recruitable lung (early disease, diffuse infiltrates) 2
• Monitor hemodynamics closely during the maneuver 1
• Assess response by improvement in oxygenation and compliance 2
• Recognize that recruitment should occur within lung-protective ventilation context, not solely to improve oxygenation 2

Monitoring During PEEP Optimization

Continuously assess these parameters to avoid complications: 1

• Arterial blood gases (PaO₂, PaCO₂, pH) in moderate-to-severe disease 1
• Lactate and central venous saturation 1
• Intrinsic PEEP in patients with air-trapping 1, 3
• Dynamic compliance changes 1
• Signs of hemodynamic compromise (decreased cardiac output, hypotension) 1

Special Considerations

Cardiac patients: The same PEEP principles apply as for non-cardiac children, as PEEP ≤15 cmH₂O does not impair venous return or cardiac output after cardiac surgery. 1

Obstructive airway disease: Add PEEP when air-trapping is present to facilitate triggering, but assess intrinsic PEEP and plateau pressure to guide external PEEP settings. 1

Airway malacia: Use higher PEEP to stent airways open, but titrate carefully to avoid cardiovascular compromise. 1