Abstract 1287 Poster Session I, Saturday, 5/1 (poster 6)

Effective suckle feeding is an integral part of successful development and demands efficient coordination of the rhythmic processes of suckle, swallow, and respiration. While it is clear that infants become more efficient suckle feeders over time, the precise strategy whereby greater feeding efficiency is achieved has not been studied. Accordingly, to determine which parameters of a feeding episode might be most useful in describing developmental changes in rhythmic suckle feeding, we studied 16 fullterm infants at 1-4 days of age and again at 4 weeks using simultaneous recording of pharyngeal and nipple pressures to assess suckle and swallow and nasal thermistor and thoracic strain gauge readings to assess respiration.

Results: The mean interval between swallows in runs (defined as ≥ 3 swallows with ≤ 2 seconds between swallow peaks) was 1.315 ± 0.036 (S.E.M.) seconds in the immediate neonatal period vs. 1.201 ± 0.04 seconds at one month of age (p<.05). Over the first month the percentage of swallows in runs increased significantly, from 56.8 ± 4.6% to 78.3 ± 3.7% (p<.001). Stability of swallow rhythm (defined as s.d./mean run-swallow interval) was equivalent (≈25%) at the two time points studied. The percentage of "apneic swallows" (run-swallows uninterrupted by breathing efforts), a measure previously shown to inversely correlate with post-conceptual age in preterm infants, also did not change over the first month of life (18% and 22%, respectively). The most common swallow-respiration interactive pattern was [inspiration-swallow-expiration], representing 33.3± 4.5% of the swallows; the phase of respiration following the swallow was expiration (or pause) 86% of the time, suggesting that the babies were effectively protecting their airways. Efficiency of feeding, as measured by volume of formula/swallow significantly increased with time (0.24 ±0.03 vs. 0.45 ± 0.04 cc/swallow; p<.001).

Conclusions: Feeding efficiency improves over the first month post-term by the increased aggregation of swallows into runs and by an increase in rhythmic swallow rate. Stability of swallow rhythm and avoidance of apneic runs is already established shortly after birth. Knowledge of normal maturational patterns of suckle feeding may allow earlier identification of variations in central bulbar regulation of feeding and of infants at risk of neurodevelopmental delay and feeding disorders.

Supported by a grant from United Cerebral Palsy.