Does PEEP Remove Fluid in Neonates?
No, PEEP does not remove fluid from the lungs in neonates—instead, it prevents alveolar collapse and maintains lung volume by providing continuous positive airway pressure at end-expiration. 1
Mechanism of Action: What PEEP Actually Does
PEEP works through mechanical support rather than fluid removal:
- PEEP provides low positive pressure to the airway that prevents lung collapse at the end of expiration, maintaining functional residual capacity rather than actively removing fluid 1
- The mechanism maintains lung volume during positive pressure ventilation, which is particularly critical in surfactant-deficient or immature lungs of preterm infants 1, 2
- In animal studies, PEEP improves functional residual capacity, oxygenation, and lung compliance by preventing atelectasis, not by clearing fluid 1
Clinical Application in Neonatal Resuscitation
The International Liaison Committee on Resuscitation recommends using PEEP at approximately 5 cm H₂O for initial ventilation of premature newborns during delivery room resuscitation (weak recommendation, low-quality evidence). 2
For Preterm Infants:
- Use PEEP during initial stabilization of apneic preterm infants requiring positive-pressure ventilation 1, 3
- Set PEEP at approximately 5 cm H₂O when administering PPV to preterm newborns 2
- PEEP prevents alveolar collapse in lungs not supported by a stiff chest wall, especially when breathing efforts are weak 1, 2
For Term Infants:
- No recommendation can be made for routine PEEP use in term infants due to insufficient data 1, 2
- There is no evidence to support or refute the value of PEEP during resuscitation of term infants 1, 4
Critical Safety Considerations
Avoid excessive PEEP levels (8-12 cm H₂O) as these may reduce pulmonary blood flow, decrease cardiac output, and increase the risk of pneumothorax. 1, 2, 3
- High PEEP may decrease superior vena cava flow, potentially increasing intraventricular hemorrhage risk 2, 5
- In one study of 50 ventilated newborns, increasing PEEP from 5 to 8 cm H₂O caused a significant reduction in right ventricular output of 17 ml/kg/min, though SVC flow changes were not statistically significant 5
- 36% of infants experienced clinically important changes in blood flow (±25%) with PEEP increases, highlighting individual variability 5
Common Misconception: PEEP vs. Fluid Clearance
The confusion likely stems from PEEP's role in improving oxygenation in fluid-filled or collapsed lungs:
- PEEP improves gas exchange by recruiting collapsed alveoli and maintaining functional residual capacity, not by removing pulmonary edema or fetal lung fluid 1, 6
- The beneficial effects include improved ventilation/perfusion ratio and decreased intrapulmonary shunt, which are mechanical rather than fluid-clearing mechanisms 7
- Fluid clearance in neonates occurs through active sodium transport and lymphatic drainage, processes that are independent of PEEP application 6
Strength of Evidence and Limitations
- The recommendation for PEEP in preterm infants carries only weak recommendation strength with low-quality evidence 1, 2
- Strong animal data supports physiological benefits, but human trial data remains insufficient 1, 8
- A 2019 Cochrane review found insufficient evidence to guide PEEP level selection for preterm infants on conventional mechanical ventilation for RDS or BPD 8