Optimal ventilatory strategies and surfactant to protect the preterm lungs

Bronchopulmonary dysplasia (BPD) is a major morbidity among preterm infants treated with invasive ventilation via an endotracheal tube (IVET) and surfactant for respiratory distress syndrome (RDS). Noteworthy, the incidence of BPD varies among different centers: this may be due to different diagnosis criteria and ventilatory strategies used in different centers.
Significant improvements have been made in the use of ventilatory strategies in preterm infants. However, IVET remains as a major contributing factor for BPD. In fact, IVET, even for less than 48 h, is associated with a longer length of stay in hospital. Tidal ventilation using conventional mechanical ventilators and nontidal ventilation using high-frequency ventilators has been extensively studied in preterm infants with RDS: randomized controlled trials comparing conventional mechanical ventilation and high-frequency ventilation, using 'optimal ventilatory strategies', have shown no significant difference in rates of BPD.
A possible alternative could be represented by the use of noninvasive ventilation, such as nasal continuous positive airway pressure (nCPAP) and nasal intermittent positive pressure ventilation (NIPPV). Noninvasive ventilation appears to be beneficial in the management of apnea of prematurity, for prevention of extubation failure, as well as in the initial management of RDS. NIPPV is an alternative option when infants are extubated from IVET or for infants failing nasal continuous positive airway pressure.
NIPPV has been shown to decrease extubation failure significantly compared to nasal continuous positive airway pressure. Moreover, in a retrospective study, it was shown that after the introduction of NIPPV in a unit, following a proper staff education, a significant reduction in BPD occurred. Studies are currently underway in preterm infants with RDS treated with surfactant to further confirm these promising results.
Surfactant therapy has become the standard of care in management of preterm infants with RDS. Two types of surfactants - natural surfactants and synthetic surfactants - have been extensively evaluated in preterm infants. To date natural, modified surfactants, such as beractant, calfactant and poractant alfa, appear to be more effective than synthetic surfactants during the acute phase of RDS. Noteworthy, a recent analysis of a database involving more than 24,000 preterm infants has demonstrated a significant decrease in mortality and cost benefits in infants treated with poractant alfa as compared to those who were given beractant or calfactant. Moreover, poractant alfa is the only natural surfactant that has shown a decreased mortality when compared with a synthetic or natural surfactant and decreased need for additional doses in comparative trials. These differences in outcomes may be related to the fact that poractant alfa contains greater amounts of phospholipids distributed in a smaller volume as well as a greater amount of antioxidant phospholipids, namely plasmalogens.
In conclusion, current evidence suggests that non-invasive ventilation may decrease BPD and that use of non-invasive ventilation as a primary mode or following surfactant administration is associated with improved outcomes in preterm infants with RDS.

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