Abstract 279

In prior studies we and others have shown that heart rates (HR) and systemic blood pressures (BP) of newborn infants increase during feeding. In bottle feeding babies we found that the overall increase in BP from lying quietly in the crib to being held and fed was substantial; however, increases from being held just prior to feeding to the first few minutes of feeding were quite small. In that study, infants were allowed to suck on a pacifier (PAC) immediately before feeding. In this current study we tested the hypothesis that sucking on a pacifier before bottle feeding influences responses that are specific to feeding. Thirty-four healthy term infants were tested between 16 and 40 hours of age. Changes in BP and HR (via Dinamap) from resting in the crib to being held for 3 min, and changes from being held to the first 3 min of being fed were computed. Half of the infants were allowed to suck on a pacifier while being held prior to feeding. The overall changes in systolic (SYS) and diastolic (DIA) BP from crib to feeding were significant (p<.01) and similar in the two groups (PAC SYS-BP +16±2 vs NO-PAC SYS-BP +15±3mmHg; PAC DIA-BP +10±1vs NO-PAC DIA-BP +10±2mmHg). Overall changes in HR were also significant in both groups (p<.01) but increases were larger in the pacifier group (PAC +18±3 vs NO-PAC +9.0±3bpm). Systolic BP and HR changes from crib to being held were greater in the infants given a pacifier (PAC SYS-BP +15±1 vs NO-PAC SYS-BP +8±2mmHg, p<.02; PAC HR +11±3 vs NO-PAC HR +2±2bpm, p<.01). Changes in diastolic BP from crib to being held were significant (p<.01) but did not differ in the two groups (PAC DIA-BP +11±1 vs NO-PAC DIA-BP +8±2mmHg, ns). BP changes in response to feeding were significant only in the NO-PAC group (p<.05) and only for systolic pressure (PAC SYS-BP +2±1 vs NO-PAC SYS-BP +7±2, p<.06). These results indicate that overall cardiovascular response to feeding in newborn infants are comprised of components associated with changes in body position, sucking, and nutrient intake and that sucking on a pacifier before feeding leads to smaller BP responses that are specifically associated with nutrient intake.

Supported by a research grant from NICHD: RO3-HD35567