Background. Previous reports have suggested that healthy, full-term newborn infants who are in more aroused behavioral states tend to respond more robustly to painful events. Others have shown that acutely ill premature and full-term infants who undergo significant handling and immobilization as part of required nursery procedures respond less robustly to concurrent painful events. Purpose. To investigate, using an experimental manipulation, the effect of arousal associated with handling and immobilization on response to acute pain in generally healthy, premature and full-term newborn infants. Methods. Infants were randomly assigned to a group that underwent a series of handling and immobilization procedures before a heelstick or to a group that underwent the heelstick without previous handling and immobilization. Heart rate, behavioral state, and facial activity were compared between the handled (n = 21) and nonhandled (n = 27) infants during an undisturbed baseline, a preparatory, and a standard heelstick procedure. Results. In the handled group, heart rate increased over baseline levels in response to the handling but promptly returned to prehandling levels. There were no significant differences between handled and nonhandled groups in mean heart rate, behavioral state, or facial activity during the baseline or preparatory periods before the heelstick. However, in response to the heelstick, handled infants had a higher mean heart rate, greater behavioral arousal, and displayed more facial activity as compared with nonhandled infants. Conclusions. Healthy premature and full-term newborn infants who undergo common nursery experiences such as handling and immobilization as part of their routine care can exhibit greater physiologic and behavioral reactivity to subsequent painful procedures. The effects of the previous handling may be undetectable, using conventional indices of reactivity, until the painful event. These findings emphasize the importance of identifying reliable markers of previous stress, particularly for newborn infants who may become clinically compromised as a result of the physiologic instability associated with response to pain.
- Newborn infant