Neonatal CPAP setup and complications; meconium ball valve effect
THE CONTEXT
This target continues guidance on continuous positive airway pressure (CPAP) and explains how a meconium plug can trap air within alveoli.
CPAP initiation and escalation
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Congenital diaphragmatic hernia is listed as a contraindication to CPAP.
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Initiate CPAP at 5 cm H₂O and titrate the inspired oxygen fraction to maintain oxygen saturation at 90–95%.
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Escalate pressure in steps of 1–2 cm H₂O to a maximum of 7–8 cm H₂O. Increase the inspired oxygen fraction in steps of 5% up to 80%.
Failure and weaning
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CPAP failure includes worsening respiratory distress, arterial oxygen pressure below 50 mm Hg, and arterial carbon dioxide pressure above 60 mm Hg despite CPAP of 7–8 cm H₂O and an inspired oxygen fraction of 80%.
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For weaning, first reduce the inspired oxygen fraction in steps of 5% to 40%, then reduce pressure in steps of 1–2 cm H₂O until 4 cm H₂O.
Complications
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CPAP complications include nasal injury, pulmonary air leaks, decreased cardiac output, and gastric distension, also called CPAP belly syndrome.
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Excessive CPAP can increase pulmonary vascular resistance.
Meconium plug and air trapping
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A meconium plug can act as a ball valve: air enters the alveoli during inspiration but cannot escape through the main airway during expiration, leading to rupture of small alveoli.