Page 143 - Physiological based CPAP for preterm infants at birth Tessa Martherus

Which CPAP levels to use for PB-CPAP
In Chapter 1, we summarize the available literature of (pre)clinical studies on CPAP levels. We found that there was only one study investigating the effect of CPAP levels at birth and because CPAP and positive end-expiratory pressure (PEEP) are used interchangeably in guidelines (16, 23), we also included studies on PEEP levels at birth. When interpreting these studies, it is important to note that PEEP applied during positive pressure ventilation is substantially different from CPAP during spontaneous breathing (Figure 3). When infants are supported with CPAP, the CPAP level is effectively the highest external pressure applied to the airways as the pressure in the lower airways only transiently increases above the CPAP level to effect expiration. With each breath, the intrathoracic pressure decreases thereby reducing the mean airway pressure (MAP) below the CPAP level. However, when infants are ventilated, PEEP is the lowest pressure applied to the airways as the peak inspiratory pressure increases the MAP. Therefore, the MAP is substantially higher during ventilation with PEEP than with a similar CPAP level used during spontaneous breathing and this may have a different effect on preterm infants. Nevertheless, this was the best available evidence at the time and therefore was still included in our search strategy.
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General discussion
Figure 3. Differences in mean airway pressure during CPAP and iPPV.
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