Developmental changes in the responses of preterm infants to a painful stressor

Abstract

The purpose of this investigation was to examine longitudinally gestational age and developmental differences in preterm infants' self-regulatory abilities in response to a painful stressor, as well as associations between behavioral and cardiovascular responses. Participants included 49 healthy premature infants. Behavioral and cardiovascular responses to a heel stick blood draw were compared between infants of 28-31 and 32-34 weeks gestational age at birth. Both gestational age groups displayed behavioral and cardiovascular indications of stress in response to the blood draw. However, both shortly after birth and several weeks later, infants born at younger gestational ages (28-31 weeks) were more physiologically reactive. Evidence that the behavioral stress responses of 28-31 weeks gestational age group preterm infants do not reflect their physiological responses suggests that evaluation of preterm infants' experiences and risk require assessments of both physiology and Corresponding Author: Elysia Poggi Davis, Address: Department of Psychiatry and Human Behavior and Pediatrics, University of California, Irvine, City Tower 333 City Boulevard West, Suite 1200, Orange, CA 92628, Email: edavis@uci.edu, Fax: (714) 940-1939, Telephone: (714) 940-1924. Requests for reprints may be sent to Elysia Poggi Davis, Department of Psychiatry and Human Behavior, University of California Irvine, City Tower, 333 City Boulevard West, Orange, CA, 92868; edavis@uci.edu Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. behavior. The greater stress vulnerability of the 28-31 relative to the 32-34 week gestation infants and the implications of this for subsequent development are discussed. NIH Public Access KeywordsStress; Prematurity; Self-regulation; Physiological reactivity Medical and technological breakthroughs over the last few decades have increased the survival rates of infants born at the youngest viable gestational ages. Yet many of the procedures that are a necessary part of their post-natal care can be, by nature, painful and stressful. In a Canadian survey, Johnston, Collinger, Henderson, and Anand (1997) found that infants residing in a NICU had an average of two invasive procedures a day, with some infants having as many as eight. One common procedure is the heel stick blood draw (Barker & Rutter, 1995). Although at one point the prevailing belief was that preterm infants could not feel the pain of invasive medical procedures, more recent research has indicated that premature infants have the anatomic and brain structures necessary for nociception (Stevens, Johnsto...

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“…Due to their CNS immaturity, preterm infants may not reliably demonstrate behavioral responses to pain until after 30 weeks (Lucas-Thompson et al, 2008). Yet, behavioral indicators correlate with increases in HR and decreases in oxygen saturation in response to painful procedures (Holsti, Grunau, Oberlander, & Osiovich, 2008), suggesting that both physiologic and behavioral indicators contribute to pain assessment.…”