Reintroduction of continuous negative pressure ventilation in neonates: two-year experience

Continuous negative pressure ventilation utilizes subatmospheric pressure around the thorax to improve oxygenation. It has not been routinely used since the mid-1970s. We treated 37 infants with the combination of continuous negative pressure (CNP) and intermittent mandatory ventilation (IMV), after failing to attain a PaO2 of greater than or equal to 50 torr on IMV alone. Lung diseases included pulmonary interstitial emphysema (PIE), respiratory distress syndrome (RDS), and pulmonary artery hypertension (PAH) due either to meconium aspiration syndrome (MAS) or other causes (non-MAS). All infants had evidence of severe parenchymal pulmonary disease, or pulmonary artery hypertension resulting in persistent hypoxemia and hypotension. In the PIE group, CNP was started later in the course of the disease, and both positive pressure and oxygen were maintained for a longer period. The group of infants with non-MAS PAH required CNP and positive pressure ventilation for the shortest period of time. The infants with PIE also had a greater incidence of bronchopulmonary dysplasia (BPD) and intraventricular hemorrhage (IVH). In addition, three patients with PIE died. In the non-MAS patients with PAH, no complications and no deaths occurred. The response to CNP was a rapid improvement in oxygenation in all groups with the greatest increase of PaO2 in the non-MAS PAH infants: from 30 torr prior to the initiation of CNP to 140 torr within 30 minutes. No significant changes in pH or PaCO2 occurred in any group. Significant decreases in ventilator rate, mean airway pressure (Paw) and FIO2 in peak inspiratory pressure were possible by 12 hours of CNP.(ABSTRACT TRUNCATED AT 250 WORDS)