Integration of suck and swallow rhythms during feeding in preterm infants with and without bronchopulmonary dysplasia

The aim of this study was to define quantitative measures for assessing the integration and maturation of suck and swallow rhythms in preterm infants as they relate to each other. Fourteen preterm infants (eight males, six females; gestational age range 26 to 32 weeks) with bronchopulmonary dysplasia (BPD) and an age-matched cohort of 20 infants (10 males, 10 females; gestational age range 26 to 33 weeks) without BPD were studied weekly from time of initiation of oral feeding using simultaneous recordings of nipple and pharyngeal pressure. The integration of suck and swallow rhythms was quantified by using the coefficient of variation (COV) of the suck-swallow dyad interval. Infants without BPD had a significant correlation between increasing postmenstrual age (PMA) and decreasing COV of the dyadic interval (increasing stabilization; r=0.45; p=0.008). In the non-BPD cohort 35 weeks or less PMA, the mean dyadic COV was 0.42 (SD 0.12) versus 0.34 (SD 0.09) in those more than 35 weeks PMA (p=0.039). In contrast, dyadic stability in infants with BPD was not correlated with PMA. Infants with BPD of more than 35 weeks PMA had less dyadic stability (0.45, SD 0.10) than did age-matched controls (p<0.001). Dyadic stability was also correlated with feeding efficiency in the non-BPD group (r=0.46; p=0.007) but not in the BPD cohort. Therefore, ontogeny of rhythmic suckle feeding can be described quantitatively in preterm infants, allowing comparison with at-risk populations. Infants with BPD do not follow predicted maturational patterns of suck-swallow rhythmic integration.