Does Positive End-Expiratory Pressure (PEEP) maintain thermoregulation and stabilize lung inflation in neonates, particularly premature infants?

PEEP and Neonatal Thermoregulation and Lung Stabilization

PEEP stabilizes lung inflation in premature neonates by establishing and maintaining functional residual capacity during the transition from fluid-filled to air-breathing lungs, but there is no evidence that PEEP directly maintains thermoregulation. 1

PEEP for Lung Stabilization in Premature Neonates

Primary Recommendation

The International Liaison Committee on Resuscitation recommends using PEEP (approximately 5 cm H₂O) for initial ventilation of premature newborns during delivery room resuscitation. 1, 2 This is a weak recommendation based on low-quality evidence, but the physiological rationale is compelling. 1

Mechanism of Lung Stabilization

PEEP provides continuous low positive pressure to the airway that achieves several critical functions:

• Prevents alveolar collapse at end-expiration, which is particularly important in premature lungs that lack stiff chest wall support and have weak breathing efforts 2
• Maintains lung volume during positive pressure ventilation, essential for surfactant-deficient or immature lungs 2
• Improves functional residual capacity establishment during the critical transition from intrauterine to extrauterine life 2, 1
• Enhances oxygenation and lung compliance as demonstrated in animal models 1, 2

Evidence Quality and Strength

The 2020 International Consensus reaffirmed the 2015 recommendation without change, noting that while animal data strongly supports PEEP's physiological benefits, human trial data remains insufficient for high confidence in effect estimates. 1 One small study in preterm infants did not demonstrate reduced intubation rates with PEEP, though animal studies consistently show improved functional residual capacity, oxygenation, and reduced lung injury. 1

Critical Safety Parameters

Avoid excessive PEEP levels (8-12 cm H₂O) as these cause significant harm:

• Reduced pulmonary blood flow 1, 2, 3
• Increased pneumothorax risk 1, 2
• Decreased cardiac output and superior vena cava flow 2
• Potential increased risk of intraventricular hemorrhage 2

No Recommendation for Term Infants

No recommendation can be made for routine PEEP use in term infants due to insufficient data. 1, 2 The evidence base is specific to premature neonates with their unique lung mechanics and surfactant deficiency. 1

PEEP and Thermoregulation: No Direct Evidence

The Evidence Gap

There is no published evidence that PEEP directly maintains thermoregulation in neonates. The guidelines addressing thermoregulation focus on environmental interventions, not respiratory support strategies. 1

Actual Thermoregulation Strategies

The 2015 International Consensus identifies effective thermoregulation approaches for neonates:

• Plastic bag wrapping (legs, torso, and arms) for well babies >30 weeks gestation after drying 1
• Skin-to-skin contact with mother 1
• Kangaroo mother care 1
• These approaches are favored over swaddling or placement in open cots, cribs, or incubators 1

Clinical Context

Hypothermia (temperature <36°C) shows dose-dependent mortality increases, with premature infants demonstrating 12-fold higher mortality compared to term babies when temperatures fall below 36.5°C. 1 However, PEEP is not mentioned as an intervention for thermoregulation in any guideline reviewed. 1

Practical Implementation Algorithm

For Premature Neonates Requiring Respiratory Support:

1. Use PEEP at approximately 5 cm H₂O when providing positive pressure ventilation 2
2. Deliver PEEP using T-piece resuscitator or flow-inflating bag for most reliable and consistent pressure delivery 2, 3
3. If only self-inflating bag available, attach manufacturer-specific PEEP valve set to 5 cm H₂O, recognizing this may not deliver PEEP reliably 2
4. Monitor for adequate chest rise and heart rate response rather than excessive chest wall movement 4, 3
5. Never exceed 8 cm H₂O PEEP to avoid hemodynamic compromise and barotrauma 1, 2

Common Pitfalls to Avoid:

• Do not rely on PEEP for thermoregulation—use proven environmental interventions instead 1
• Do not assume self-inflating bags deliver reliable PEEP even with PEEP valves attached 2
• Do not use high PEEP levels thinking more is better—this causes harm 1, 2
• Do not extrapolate premature infant PEEP recommendations to term infants—the evidence doesn't support this 1, 2