Prior pain induces heightened motor responses during clustered care in preterm infants in the NICU

Acute pain is a significant stressor for preterm infants in neonatal intensive care units (NICU); however, little is known about the effects of acute pain on subsequent motor responses during clusters of tactile handling.

Neonatal procedural pain exposure predicts lower cortisol and behavioral reactivity in preterm infants in the NICU

Data from animal models indicate that neonatal stress or pain can permanently alter subsequent behavioral and/or physiological reactivity to stressors. However, cumulative effects of pain related to acute procedures in the neonatal intensive care unit (NICU) on later stress and/or pain reactivity has received limited attention. The objective of this study is to examine relationships between prior neonatal pain exposure (number of skin breaking procedures), and subsequent stress and pain reactivity in preterm infants in the NICU. Eighty-seven preterm infants were studied at 32 (+/-1 week) postconceptional age (PCA). Infants who received analgesia or sedation in the 72 h prior to each study, or any postnatal dexamethasone, were excluded. Outcomes were infant responses to two different stressors studied on separate days in a repeated measures randomized crossover design: (1) plasma cortisol to stress of a fixed series of nursing procedures; (2) behavioral (Neonatal Facial Coding System; NFCS) and cardiac reactivity to pain of blood collection. Among infants born

Neonatal procedural pain and preterm infant cortisol response to novelty at 8 months

Stress systems may be altered in the long term in preterm infants for multiple reasons, including early exposure to procedural pain in neonatal intensive care. This question has received little attention beyond hospital discharge. Stress responses (cortisol) to visual novelty in preterm infants who were born at extremely low gestational age (ELGA; <or =28 weeks), very low gestational age (VLGA; 29-32 weeks), and term were compared at 8 months of age corrected for prematurity (corrected chronological age [CCA]). In addition, among the preterm infants, we evaluated whether cortisol levels at 8 months were related to neonatal exposure to procedural pain and morphine in the neonatal intensive care unit.

Specific Newborn Individualized Developmental Care and Assessment Program movements are associated with acute pain in preterm infants in the neonatal intensive care unit

The Newborn Individualized Developmental Care and Assessment Program (NIDCAP) is widely used in neonatal intensive care units and comprises 85 discrete infant behaviors, some of which may communicate infant distress. The objective of this study was to identify developmentally relevant movements indicative of pain in preterm infants.

Does prone or supine position influence pain responses in preterm infants at 32 weeks gestational age?

The purpose of this study was to examine the influence of prone and supine position in preterm infants during acute pain of blood collection.

Are there developmentally distinct motor indicators of pain in preterm infants?

The aims of this study were to examine preterm infant reactions to pain in detail over prolonged time periods using multiple measures, and to assess the value of including specific body movements of the Neonatal Individualized Developmental Care and Assessment Program (NIDCAP) system to evaluate pain. Ten preterm infants born at 31 weeks mean gestational age (GA) and mean birth weight 1676 g were studied during a routine blood collection in a Level III neonatal intensive care unit (NICU). At 32-week post-conceptional age, computerized physiologic and video recordings were obtained continuously for 60 min (prior to, during and after lance). Motor and facial behaviors were coded independently, using the NIDCAP and the NFCS (Neonatal Facial Coding System), respectively, and compared with heart rate (HR) and oxygen saturation responses. Of the movements hypothesized to be stress cues in the NIDCAP model, extension of arms and legs (80%) and finger splay (70%) were the most common following lance. Contrary to the model, most infants (70%) had lower incidence of twitches and startles post-lance compared to baseline. Whereas all infants showed some NFCS response to lance, for three infants, the magnitude was low. HR increased and oxygen saturation decreased post-lance. Infants with more prior pain exposure, lower Apgar, and lower GA at birth, displayed more motor stress cues but less facial activity post-lance. Extension of extremities and finger splay, but not twitches and startles, from the NIDCAP, appear to be stress cues and show promise as clinical pain indicators to supplement facial and physiological pain measures in preterm infants.

Early pain in preterm infants. A model of long-term effects

There are multiple lines of evidence suggesting that in vulnerable prematurely born infants, repeated and prolonged pain exposure may affect the subsequent development of pain systems, as well as potentially contribute to alterations in long-term development and behavior. Multiple factors cumulatively contribute to altered developmental trajectories in such infants. These include characteristics of the developing organism (low tactile threshold, sensitization, rapid brain development), characteristics intrinsic to the infant (gestation, illness severity), characteristics of the experience in the neonatal intensive care unit (pain exposure and cumulative stress), and characteristics of the caregivers within their family and social context. This article provides a model for examining long-term effects of pain in the newborn period embedded in a developmental context framework.

Relations between behavioral and cardiac autonomic reactivity to acute pain in preterm neonates

The purpose of this study was to assess relations and concordance between behavioral and physiologic reactivity to pain in preterm neonates at 32 weeks postconceptional age as a function of gestational age at birth.

Pain sensitivity and temperament in extremely low-birth-weight premature toddlers and preterm and full-term controls

High-technology medical care of extremely low-birth-weight (ELBW) infants (<1001 g) involves repeated medical interventions which are potentially painful and may later affect reaction to pain. At 18 months corrected age (CCA), we examined parent ratings of pain sensitivity and how pain sensitivity ratings related to child temperament and parenting style in 2 groups of ELBW children (49 with a birth weight of 480-800 g and 75 with a birth weight of 801-1000 g) and 2 control groups (42 heavier preterm (1500-2499 g) and 29 full-birth-weight (FBW) children (> 2500 g). Both groups of ELBW toddlers were rated by parents as significantly lower in pain sensitivity compared with both control groups. The relationships between child temperament and pain sensitivity rating varied systematically across the groups. Temperament was strongly related to rated pain sensitivity in the FBW group, moderately related in the heavier preterm and ELBW 801-1000 g groups, and not related in the lowest birth-weight group (<801 g). Parental style did not mediate ratings of pain sensitivity. The results suggest that parents perceive differences in pain behavior of ELBW toddlers compared with heavier preterm and FBW toddlers, especially for those less than 801 g. Longitudinal research into the development of pain behavior for infants who experience lengthy hospitalization is warranted.

Pain in the preterm neonate:behavioural and physiological indices

The impact of invasive procedures on preterm neonates has received little systematic attention. We examined facial activity, body movements, and physiological measures in 56 preterm and full-term newborns in response to heel lancing, along with comparison preparatory and recovery intervals. The measures were recorded in special care and full-term nurseries during routine blood sampling. Data analyses indicated that in all measurement categories reactions of greatest magnitude were to the lancing procedure. Neonates with gestational ages as short as 25-27 weeks displayed physiological responsivity to the heel lance, but only in the heart rate measure did this vary with gestational age. Bodily activity was diminished in preterm neonates in general, relative to full-term newborns. Facial activity increased with the gestational age of the infant. Specificity of the response to the heel lance was greatest on the facial activity measure. Identification of pain requires attention to gestational age in the preterm neonate.

Prenatal and postnatal inflammation in relation to cortisol levels in preterm infants at 18 months corrected age

Objective

To examine whether early inflammation is related to cortisol levels at 18 months corrected age (CA) in children born very preterm.

Study Design

Infants born ≤ 32 weeks gestational age were recruited in the NICU, and placental histopathology, MRI, and chart review were obtained. At 18 months CA developmental assessment and collection of 3 salivary cortisol samples were carried out. Generalized least squares was used to analyze data from 85 infants providing 222 cortisol samples.

Results

Infants exposed to chorioamnionitis with funisitis had a significantly different pattern of cortisol across the samples compared to infants with chorioamnionitis alone or no prenatal inflammation (F[4,139] = 7.3996, P <.0001). Postnatal infections, necrotizing enterocolitis and chronic lung disease were not significantly associated with the cortisol pattern at 18 months CA.

Conclusion

In children born very preterm, prenatal inflammatory stress may contribute to altered programming of the HPA axis.

Keywords: preterm, chorioamnionitis, funisitis, premature infants, hypothalamic-pituitary-adrenal axis, infection, cortisol, stress