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.