Lung protective ventilation in extremely preterm infants.

The lungs of an extremely preterm infant ≤28 weeks gestation are structurally and biochemically immature and vulnerable to injury from positive pressure ventilation. A lung protective approach to respiratory support is vital, aiming to ventilate an open lung, using the lowest pressure settings that maintain recruitment and oxygenation and avoiding hyperinflation with each tidal breath. For infants with severe respiratory distress syndrome and persistent atelectasis, lung protective ventilation requires recruitment using stepwise pressure increments, followed by reduction in ventilator pressures in search of an optimal point at which to maintain ventilation. Several studies, including a single randomised controlled trial, have found this lung protective strategy to be more effectively administered using high-frequency oscillatory ventilation rather than conventional ventilation. Many extremely preterm infants have minimal atelectasis and low oxygen requirements in the first days of life, and the ventilatory approach in this case should be one of avoidance of factors including overdistension that are known to contribute to later pulmonary deterioration. From a practical perspective, this means setting positive end-expiratory pressure at the lowest value that maintains oxygenation and restricting tidal volume using a volume-targeted mode of ventilation.