Meconium aspiration and neonatal continuous positive airway pressure
THE CONTEXT
The supplied material describes airway injury from aspirated meconium and the mechanism, equipment, indications, and contraindications of continuous positive airway pressure (CPAP).
Meconium aspiration syndrome
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Aspiration of meconium into the lungs can cause respiratory distress, termed meconium aspiration syndrome.
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Meconium can obstruct large and small airways, producing areas of atelectasis and emphysema. These changes can cause air leaks such as pneumothorax.
How CPAP supports breathing
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CPAP provides respiratory support to spontaneously breathing preterm neonates with respiratory distress.
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A compliant chest wall contributes to inadequate functional residual capacity in preterm neonates. Alveoli tend to collapse at the end of expiration, impairing breathing and gas exchange.
Pressure is delivered at the nostrils through binasal prongs or a nasal mask.
Components
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The gas source supplies warm, humidified, blended air and oxygen. The blender can provide oxygen concentrations from 21% to 100%.
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The pressure generator creates positive circuit pressure. In bubble CPAP, the expiratory limb is dipped into a water column to generate the desired pressure.
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The patient interface connects the circuit to the infant's airway.
Indications and contraindications
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Indications include respiratory distress in preterm neonates due to respiratory distress syndrome, transient tachypnea, or pneumonia.
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Other indications include apnea of prematurity despite methylxanthine therapy, support following extubation in preterm very low birth weight infants, and airway instability such as laryngomalacia, tracheomalacia, or bronchomalacia.
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Listed contraindications include severe cardiovascular instability, poor respiratory drive, progressive respiratory failure, and congenital malformations such as tracheoesophageal fistula.