Page 33 - Physiological based CPAP for preterm infants at birth Tessa Martherus

Introduction
Lung aeration at birth plays a key role in initiating the major physiological changes that are
required for survival after birth (1-3). Most very preterm infants have difficulty aerating their
lungs and establishing functional residual capacity, for which respiratory support is often
needed (4, 5). Respiratory support has to be provided with care as preclinical studies in premature lambs have shown that inadequate or improper respiratory support can easily
injure the premature lung and brain via haemodynamic instability and activation of inflammatory pathways (6, 7) Previously, all infants were intubated and mechanical 1 ventilation was given; however, clinical trials (8, 9) have shown that nasal continuous positive
airway pressure (CPAP) instead lowers the combined risk of death or oxygen requirement at 28 days after birth and reduces the duration of ventilation. The focus has therefore shifted (10) to non-invasive ventilation in the form of CPAP and positive pressure ventilation (PPV).
While most very preterm infants breathe spontaneously at birth, their respiratory drive is insufficient to achieve lung aeration (3, 4) and their spontaneous breathing is often missed (11). PPV is therefore initiated via facemask, however observational clinical studies have shown that PPV is often inadequate to deliver tidal volumes between 4 and 8 mL/kg due to pressure settings, mask leak and obstruction. Meanwhile, PPV can also generate potentially injurious high tidal volumes due to high positive inspiratory pressures (PIP) or when spontaneous breathing coincides with inflations (5, 6) Given the fact that infants often breathe spontaneously, although insufficient, and PPV is often inadequate and/or injurious, optimising respiratory effort of very preterm infants with CPAP may represents an improved approach. While CPAP has been adopted worldwide and several studies have described the technique and equipment to use this technique (12), there is little evidence for the optimal pressure strategy and which devices and interfaces that should be used to best support breathing in very preterm infants (13).
In this review, we summarise the currently available evidence for why PPV can be insufficient and what is known about the effect of different CPAP strategies in very preterm newborns at birth. We searched on PubMed for (pre)clinical studies comparing different pressure support levels, CPAP supplying devices or pressure delivering interfaces specifically used in the delivery room. The reference list of included articles was checked to identify articles not included in the primary search.
Supporting breathing of preterm infants at birth
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