1 | INTRODUCTION
Nasal continuous positive airway pressure (CPAP) and surfactant replacement have been recommended as the first line treatment for premature infants with respiratory distress syndrome (RDS) [1]. CPAP is the most studied non-invasive respiratory support modality in premature infants. It delivers continuous distending pressure to the airways and alveoli to maintain functional residual capacity [2]. However, CPAP may exert other physiologic effects by introducing positive pressure into the gastrointestinal tract (GIT).
Optimal nutrition is critically important for premature infants, but their gastrointestinal tract motility may be impaired relative to older infants and children [3]. Jaile et al. described benign gaseous distention of the GIT in infants treated with CPAP and devised the term ‘CPAP belly’ [4]. Another study reported improved gastric emptying in infants on machine-derived nasal CPAP (MD-nCPAP) compared to healthy room air controls [5]. However, gastric emptying in preterm infants on other modes of non-invasive respiratory support, including widely-used bubble CPAP (bCPAP), has not been studied. Delayed gastric emptying and large gastric residual volumes have been associated with feeding intolerance and necrotizing enterocolitis (NEC) [6,7].
Our primary objective was to compare ultrasound (US)-estimated gastric emptying rates in premature infants receiving full enteral feedings who are treated with either MD-nCPAP or bubble CPAP (bCPAP). The secondary objective was to determine the relationship between clinically assessed feeding tolerance and US-estimated volumes of residual stomach contents prior to feeding.