Sensitization of cardiac responses to pain in preterm infants

Background: Preterm infants are repeatedly exposed to painful experiences as part of their care in the neonatal intensive care unit. There is evidence from both animal and human studies that exposure to pain during the neonatal period may have persisting consequences for development. Objective: To perform serial assessments of three heelstick blood draws to examine early changes both in physiological and behavioral responses to repeated exposure to painful stimuli in preterm infants. Methods: Heart rate and behavioral responses to three serially administered heelstick blood draws were evaluated in 22 medically stable preterm infants with less than 48 h of mechanical ventilation who were admitted to the neonatal intensive care unit. Results: Heart rate and behavioral agitation significantly increased during each heelstick as compared to baseline. The heart rate response was larger to the third heelstick as compared to the first two procedures. Behavioral responses did not change across the three assessments. Conclusions: Healthy preterm infants sensitize to heelstick-induced pain, as measured by their heart rate responses. These data suggest that greater attention to the effects of repeated pain for the neonate is needed. Copyright (c) 2007 S. Karger AG, Basel.