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Updated: Jul 16, 2026
A Preterm Rat Model for Pain Studies
Published on: February 9, 2024
Sensitization of cardiac responses to pain in preterm infants
Beth L Pineles1, Curt A Sandman, Feizal Waffarn
1Department of Psychiatry and Human Behavior, University of California, Irvine, California, USA.
Insights
Preterm infants show increased heart rate sensitivity to repeated heelstick pain, indicating potential long-term developmental effects. Neonatal intensive care unit pain management needs enhanced focus on these sensitive responses.
Area of Science:
- Neonatalogy
- Developmental Pediatrics
- Pain Research
Background:
- Neonatal intensive care unit (NICU) care involves repeated painful procedures for preterm infants.
- Early life pain exposure in neonates may lead to lasting developmental consequences.
Purpose of the Study:
- To assess physiological and behavioral changes in preterm infants during serial heelstick procedures.
- To investigate early responses to repeated painful stimuli in a neonatal intensive care unit setting.
Main Methods:
- Evaluated heart rate and behavioral responses in 22 stable preterm infants undergoing three serial heelstick blood draws.
- Infants had less than 48 hours of mechanical ventilation.
Main Results:
- Heart rate and behavioral agitation significantly increased with each heelstick compared to baseline.
- Heart rate response intensified with the third heelstick compared to the first two.
- No significant changes in behavioral responses were observed across the three assessments.
Conclusions:
- Preterm infants demonstrate sensitization to heelstick-induced pain, evidenced by increased heart rate responses.
- These findings highlight the need for increased clinical attention to the impact of repeated pain on neonates.
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.
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