REINTRODUCTION OF CONTINUOUS NEGATIVE-PRESSURE VENTILATION IN NEONATES - 2-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 Pa O 2 of ≥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 Pa O 2 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 Pa CO 2 occurred in any group. Significant decreases in ventilator rate, mean airway pressure (Paw) and FI O 2 in peak inspiratory pressure were possible by 12 hours of CNP. CNP and Paw were decreased from −5 cm H2O and 12.8 cm H2O prior to initiation of CNP to −1 cm H2O and 5.0 cm H2O at 72 hours of treatment. FI O 2 at 72 hours was decreased to a mean of 0.57. Combined CNP and IMV ventilator therapy improved oxygenation with lessened Paw in infants with refractory hypoxemia due to MAS and PAH and in larger infants with RDS. While we cannot advocate the routine use of CNP, it would appear to have a role in the management of infants who have failed conventional ventilator therapy. Pediatr Pulmonol 1990; 8:245‐253. Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company