Abstract 67 Poster Session III, Monday, 5/3 (poster 360)

Background: Sweet taste and pacifier sucking are antinociceptive in newborn humans, but the pacifier outcomes are extremely variable. The effects of combining sucking and sweet taste on the well-studied pain caused by heel lance have not been determined.

Objectives: (1). To identify sucking patterns that predict the occurrence of sucking induced analgesia. (2). To evaluate whether sweet taste enhances the analgesia induced by sucking.

Methods: Forty healthy newborns were randomly assigned to received either water or sucrose (12% weight/volume), alone or on a pacifier, (N=10/group) for the 2-min. preceding heel lance for the newborn screening blood test. The pacifier was also kept in the infant's mouth during the procedure that was performed by a phlebotomist uninformed of syringe contents or pacifier fluid. Sessions were videorecorded and analyzed for crying, grimacing and heart rate.

Results: Sucking a plain pacifier induced analgesia relative to water controls, when and only when suck rate exceeded 30 sucks/min. (<30 sucks/min; %Cry=88; %Grimace=97; >30 sucks/minute; %Cry=6; %Grimace=11). Sucrose alone eliminated crying in 7 of 10 infants; sucking a sweetened pacifier eliminated crying and grimacing and blocked heart rate increase regardless of suck rate in 9 of 10 infants. Thus, in conjunction with powerful sweet stimulation, the pacifier can contribute to analgesia even at 'subthreshold' rates of sucking.

Conclusions: Sucking a plain or, especially, a sweetened pacifier is a safe and easily administered intervention against routine pain experienced by newborns in hospital settings. Based on parallel animal studies, the antinociceptive mechanisms engaged here probably act at the level of the spinal cord dorsal horn.

Research funded by NIMH Grants RO-1 MH51705 and KO-5 MH00524