Biobehavioral pain responses in former extremely low birth weight infants at four months' corrected age

Sensitivity and Specificity of the Newborn Infant Parasympathetic Evaluation Index in Pain Assessment of Very Low Birth Weight Infants

OBJECTIVE

 This article describes the results of a study investigating the sensitivity and specificity of the Newborn Infant Parasympathetic Evaluation (NIPE) index for detecting the physiological changes resulting from nociception in painful procedures in very low birth weight (VLBW) infants.

STUDY DESIGN

 A prospective observational study was carried on of 44 newborns at 23 to 32 weeks' gestational age. The sensitivity and specificity of the NIPE index are analyzed using a receiver operating characteristic curve. Most of the painful procedures performed were skin-lancing and venipunctures. Nonpainful procedures consist of no intervention, with an interval of at least 1 hour with painful procedures in each newborn.

RESULTS

 The accuracy of the NIPE index to diagnose mild nociceptive stimulation in VLBW newborns is 73.2%.

CONCLUSION

 The NIPE index is a useful technique for assessing nociceptive stimulation in newborns, presenting less observer-dependent variability than other pain assessment scales.

KEY POINTS

· The NIPE index offers an objective assessment of pain.. · Moderate-high sensitivity of the NIPE index in the evaluation of pain in premature newborns.. · Painful procedures in VLBW newborns are reflected as a decrease in the NIPE score..

Classification of Individual Pain Response Trajectories Following Medically Indicated Heel Lances in Preterm Infants During Their NICU Admission

OBJECTIVES

Infants born preterm are exposed to repeated painful procedures during neonatal intensive care unit admission. Particularly in preterm infants, trajectories of pain response are not well understood. The aim of this study was to classify pain response trajectories over 2 minute following medically indicated heel lances in preterm infants.

MATERIALS AND METHODS

This study used existing clinical trial data (NCT01561547) that evaluated the efficacy of kangaroo care and sucrose for infant pain control. Pain was measured using the Premature Infant Pain Profile at 30, 60, 90, and 120 seconds following a heel lance. Group-based trajectory modeling was used to classify pain response in this 2 minute period.

RESULTS

A total of 236 infants with median gestational age of 33 weeks contributed 610 procedures. A model with 5 trajectory classes best fit the data. Three trajectories were stable over time at different levels of intensity from low-mild to low-moderate pain. One trajectory reflected a linear reduction from high-moderate to low-moderate pain. The final trajectory showed variable moderate-high pain. At all times points, 3 classes were at least 1-point different from the overall sample mean pain score. Only 21 (9%) infants maintained the same class for all 3 procedures.

DISCUSSION

In this sample of preterm infants receiving pain relief, most pain trajectories reflected mild to low-moderate pain that was stable over 2 minute after heel lance initiation. Trajectories were not consistent over multiple procedures within infants, and an overall mean pain score for the sample may misrepresent subgroups of pain response.

Available Instruments to Assess Pain in Infants

Pain assessment in newborns and infants is challenging for clinicians. Although behavioral and behavioral-physiological scales are validated pain assessment instruments, their use in this age group has significant limitations. In this review, we summarize the methods currently available for assessing pain in neonates and infants. It is possible that these pain detection methods are also useful for assessing the quality of anesthesia and analgosedation in these populations. Further research should be aimed at confirming the usefulness of these tools in infants and identifying additional pain assessment options for clinical practice.

Local injury and systemic infection in infants alter later nociception and pain affect during early life and adulthood

Newborns in intensive care are regularly exposed to minor painful procedures at developmental time points when noxious stimulation would be normally absent. Pain from these interventions is inconsistently treated and often exists concurrently with systemic infection, a common comorbidity of prematurity. Our understanding of the independent and combined effects of early painful experiences and infection on pain response is incomplete. The main goals of this research therefore were to understand how pain and infection experienced early in life influence future nociceptive and affective responses to painful stimuli. Rat pups were infected with E-coli on postnatal day 2 (PN2) and had left hind paw injury with carrageenan on PN3. Standard thermal tests for acute pain, formalin tests for inflammatory pain, and conditioned place aversion testing were performed at different ages to assess the nociceptive and affective components of the pain response. Early E-coli infection and early inflammatory injury with carrageenan both independently increased pain scores following hind paw reinjury with formalin on PN8, with effects persisting into adulthood in the carrageenan exposed group. When experienced concurrently, early E-coli infection and carrageenan exposure also increased conditioned aversion to pain in adults. Effect of sex was significant only in formalin testing, with males showing higher pain scores in infancy and females showing higher pain scores as adults. These findings demonstrate that infection experienced early in life can alter both the nociceptive and affective components of the pain response and that there is a cumulative effect of local and systemic pro-inflammatory processes on the aversive component of pain.

Self‐reported sensitivity to pain in early and moderately‐late preterm‐born adolescents: A community‐based cohort study

We aimed to compare ratings of self‐reported and parent‐reported pain sensitivity between early preterm (EP), moderately‐late preterm (MLP), and full‐term (FT) adolescents. For EP adolescents, we aimed to determine whether pain sensitivity was associated with early‐life events. EP (n = 68, response rate 47.4%), MLP (n = 128, response rate 33.0%), and FT (n = 78, response rate 31.1%) adolescents and their parents (n = 277) answered an author‐generated question on pain sensitivity at 14‐15 years of age within a community‐based cohort study. Differences between groups were determined using the chi‐square test for trends. For EP adolescents, we assessed associations of treatment modalities (inotrope treatment, mechanical ventilation, and C‐section) and neonatal morbidities (sepsis/necrotizing enterocolitis, small‐for‐gestational age status, asphyxia, and cerebral pathologies) with adolescent pain sensitivity using logistic regression analyses. Increased pain sensitivity was reported by 18% of EP adolescents, compared with 12% of MLP adolescents, and 7% of FT adolescents (P = 0.033). Parent‐reported pain sensitivity did not differ by gestational age group. For EP adolescents, inotrope treatment was associated with increased pain sensitivity (odds ratio, 5.00, 95% confidence interval, 1.23‐20.4, P = 0.025). No other neonatal treatment modalities or morbidities were associated with pain sensitivity in adolescence. In conclusion, we observed higher proportions of increased pain sensitivity for EP and MLP adolescents. Physicians treating preterm adolescents should be aware of altered pain sensitivity.

Assessment of Pain in the Newborn: An Update

Preterm and term neonate pain assessment in neonatal intensive care units is vitally important because of the prevalence of procedural and postoperative pain. Of the 40 plus tools available, a few should be chosen for different populations and contexts (2 have been validated in premature infants). Preterm neonates do not display pain behaviors and physiologic indicators as reliably and specifically as full-term infants, and are vulnerable to long-term sequelae of painful experiences. Brain-oriented approaches may become available in the future; meanwhile, neonatal pain assessment tools must be taught, implemented, and their use optimized for consistent, reproducible, safe, and effective treatment.

The development of pain circuits and unique effects of neonatal injury

Pain is a necessary sensation that prevents further tissue damage, but can be debilitating and detrimental in daily life under chronic conditions. Neuronal activity strongly regulates the maturation of the somatosensory system, and aberrant sensory input caused by injury or inflammation during critical periods of early postnatal development can have prolonged, detrimental effects on pain processing. This review will outline the maturation of neuronal circuits responsible for the transmission of nociceptive signals and the generation of pain sensation-involving peripheral sensory neurons, the spinal cord dorsal horn, and brain-in addition to the influences of the neuroimmune system on somatosensation. This summary will also highlight the unique effects of neonatal tissue injury on the maturation of these systems and subsequent consequences for adult somatosensation. Ultimately, this review emphasizes the need to account for age as an independent variable in basic and clinical pain research, and importantly, to consider the distinct qualities of the pediatric population when designing novel strategies for pain management.

Enhanced Postsynaptic GABAB Receptor Signaling in Adult Spinal Projection Neurons after Neonatal Injury

Clinical and basic science research have revealed persistent effects of early-life injury on nociceptive processing and resulting pain sensitivity. While recent work has identified clear deficits in fast GABAA- and glycine receptor-mediated inhibition in the adult spinal dorsal horn after neonatal tissue damage, the effects of early injury on slow, metabotropic inhibition within spinal pain circuits are poorly understood. Here we provide evidence that neonatal surgical incision significantly enhances postsynaptic GABAB receptor signaling within the mature superficial dorsal horn (SDH) in a cell type-dependent manner. In vitro patch-clamp recordings were obtained from identified lamina I projection neurons and GABAergic interneurons in the SDH of adult female mice following hindpaw incision at postnatal day (P)3. Early tissue damage increased the density of the outward current evoked by baclofen, a selective GABAB receptor agonist, in projection neurons but not inhibitory interneurons. This could reflect enhanced postsynaptic expression of downstream G protein-coupled inward-rectifying potassium channels (GIRKs), as the response to the GIRK agonist ML297 was greater in projection neurons from neonatally incised mice compared to naive littermate controls. Meanwhile, presynaptic GABAB receptor-mediated reduction of spontaneous neurotransmitter release onto both neuronal populations was unaffected by early-life injury. Collectively, our findings suggest that ascending nociceptive transmission to the adult brain is under stronger control by spinal metabotropic inhibition in the aftermath of neonatal tissue damage.

Neonatal Invasive Procedures Predict Pain Intensity at School Age in Children Born Very Preterm

INTRODUCTION

Children born very preterm display altered pain thresholds. Little is known about the neonatal clinical and psychosocial factors associated with their later pain perception.

OBJECTIVE

We aimed to examine whether the number of neonatal invasive procedures, adjusted for other clinical and psychosocial factors, was associated with self-ratings of pain during a blood collection procedure at school age in children born very preterm.

MATERIALS AND METHODS

56 children born very preterm (24 to 32 weeks gestational age), followed longitudinally from birth, and free of major neurodevelopmental impairments underwent a blood collection by venipuncture at age 7.5 years. The children's pain was self-reported using the Coloured Analog Scale and the Facial Affective Scale. Parents completed the Child Behavior Checklist and the State-Trait Anxiety Inventory. Pain exposure (the number of invasive procedures) and clinical factors from birth to term-equivalent age were obtained prospectively. Multiple linear regression was used to predict children's pain self-ratings from neonatal pain exposure after adjusting for neonatal clinical and concurrent psychosocial factors.

RESULTS

A greater number of neonatal invasive procedures and higher parent trait-anxiety were associated with higher pain intensity ratings during venipuncture at age 7.5 years. Fewer surgeries and lower concurrent child externalizing behaviors were associated with a higher pain intensity.

CONCLUSIONS

In very preterm children, exposure to neonatal pain was related to altered pain self-ratings at school age, independent of other neonatal factors. Neonatal surgeries and concurrent psychosocial factors were also associated with pain ratings.

Skin-to-skin care for procedural pain in neonates

BACKGROUND

Skin-to-skin care (SSC), often referred to as 'kangaroo care' (KC) due to its similarity with marsupial behaviour of ventral maternal-infant contact, is one non-pharmacological intervention for pain control in infants.

OBJECTIVES

The primary objectives were to determine the effect of SSC alone on pain from medical or nursing procedures in neonates compared to no intervention, sucrose or other analgesics, or additions to simple SSC such as rocking; and to determine the effects of the amount of SSC (duration in minutes), method of administration (e.g. who provided the SSC) of SSC in reducing pain from medical or nursing procedures in neonatesThe secondary objectives were to determine the safety of SSC care for relieving procedural pain in infants; and to compare the SSC effect in different postmenstrual age subgroups of infants.

SEARCH METHODS

For this update, we used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1); MEDLINE via PubMed (1966 to 25 February 2016); Embase (1980 to 25 February 2016); and CINAHL (1982 to 25 February 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi-randomized trials.

SELECTION CRITERIA

Studies with randomisation or quasi-randomisation, double- or single-blinded, involving term infants (≥ 37 completed weeks' postmenstrual age (PMA) to a maximum of 44 weeks' PMA and preterm infants (< 37 completed weeks PMA) receiving SSC for painful procedures conducted by healthcare professionals.

DATA COLLECTION AND ANALYSIS

The main outcome measures were physiological or behavioural pain indicators and composite pain scores. A mean difference (MD) with 95% confidence interval (CI) using a fixed-effect model was reported for continuous outcome measures. We included variations on type of tissue-damaging procedure, provider of care, and duration of SSC.

MAIN RESULTS

Twenty-five studies (n = 2001 infants) were included. Nineteen studies (n = 1065) used heel lance as the painful procedure, one study combined venepuncture and heel stick (n = 50), three used intramuscular injection (n = 776), one used 'vaccination' (n = 60), and one used tape removal (n = 50). The studies were generally strong and had low or uncertain risk of bias. Blinding of the intervention was not possible, making them subject to high risk, depending on the method of scoring outcomes.Seventeen studies (n = 810) compared SSC to a no-treatment control. Although 15 studies measured heart rate during painful procedures, data from only five studies (n = 161) could be combined for a mean difference (MD) of -10.78 beats per minute (95% CI -13.63 to -7.93) favouring SSC. Meta-analysis of four studies (n = 120) showed no difference in heart rate following the painful procedure (MD 0.08, 95% CI -4.39 to 4.55). Two studies (n = 38) reported heart rate variability with no significant differences. Two studies (n = 101) in a meta-analysis on oxygen saturation at 30 and 60 seconds following the painful procedure did not show a difference. Duration of crying meta-analysis was performed on four studies (n = 133): two (n = 33) investigated response to heel lance (MD = -34.16, 95% CI -42.86 to -25.45), and two (n = 100) following IM injection (MD = -8.83, 95% CI -14.63 to -3.02), favouring SSC. Five studies, one consisting of two substudies (n = 267), used the Premature Infant Pain Profile (PIPP) as a primary outcome, which favoured SCC at 30 seconds (MD -3.21, 95% CI -3.94 to -2.47), at 60 seconds (3 studies; n = 156) (MD -1.64, 95% CI -2.86 to -0.43), and at 90 seconds (n = 156) (MD -1.28, 95% CI -2.53 to -0.04); but at 120 seconds there was no difference (n = 156) (MD 0.07, 95% CI -1.11 to 1.25). No studies on return of heart rate to baseline level, cortisol levels, and facial actions could be combined for meta-analysis findings.Eight studies compared SSC to another intervention with or without a no-treatment control. Two cross-over studies (n = 80) compared mother versus other provider (father, another female) on PIPP scores at 30, 60, 90, and 120 seconds with no significant difference. When SSC was compared to other interventions, there were not enough similar studies to pool results in an analysis. One study compared SSC (n = 640) with and without dextrose and found that the combination was most effective and that SSC alone was more effective than dextrose alone. Similarly, in another study SSC was more effective than oral glucose for heart rate (n = 95). SSC either in combination with breastfeeding or alone was favoured over a no-treatment control, but not different to breastfeeding. One study compared SSC alone and in combination with both sucrose and breastfeeding on heart rate (HR), NIPS scores, and crying time (n = 127). The combinations were more effective than SSC alone for NIPS and crying. Expressed breast milk was compared to SSC in one study (n = 50) and found both equally effective on PIPP scores. There were not enough participants with similar outcomes and painful procedures to compare age groups or duration of SSC. No adverse events were reported in any of the studies.

AUTHORS' CONCLUSIONS

SSC appears to be effective as measured by composite pain indicators with both physiological and behavioural indicators and, independently, using heart rate and crying time; and safe for a single painful procedure. Purely behavioural indicators tended to favour SSC but with facial actions there is greater possibility of observers not being blinded. Physiological indicators were mixed although the common measure of heart rate favoured SSC. Two studies compared mother-providers to others, with non-significant results. There was more heterogeneity in the studies with behavioural or composite outcomes. There is a need for replication studies that use similar, clearly defined outcomes. Studies examining optimal duration of SSC, gestational age groups, repeated use, and long-term effects of SSC are needed. Of interest would be to study synergistic effects of SSC with other interventions.

Oral glucose efficacy on neonate's pain responses at the NICU: A quasi experimental trial of two clinical procedures

AIM

This research was undertaken with the purpose of testing two research hypotheses regarding the efficacy of 10% oral glucose solution on procedural pain associated with venepuncture and nasopharyngeal suctioning within three neonatal intensive care units (NICU). The hypotheses were formulated from previous conclusions reached by other researchers highlighting the efficacy of sucrose solutions on neonates' pain responses during minor painful procedures.

METHOD

A quasi-experimental trial utilising a time series design with one group was used. Data from a total of 90 neonates included 60 neonates who underwent a venepuncture and 30 neonates who underwent a nasopharyngeal suctioning procedure for clinical purposes. The neonate's pain response for each procedure was scored using the Neonatal Pain Assessment Scale (NPAS) on two separate occasions over three time periods. The pre-procedural score (T₀) when the neonate received no sucrose, the inter-procedural score (T₁) when the neonate was given 2ml of 10% glucose solution two minutes before the procedure (intervention group) or where oral glucose was withheld (control group) and the post-procedural score (T₂) being at the end of the procedure.

RESULTS

The results showed the mean NPAS scores in response to venepuncture or nasopharyngeal suctioning were significantly lower in the intervention group than the control group.

CONCLUSION

This showed that oral glucose (10%) had a positive effect on the pain response during venepuncture and nasopharyngeal suctioning procedures.

ABM Clinical Protocol #23: Nonpharmacological Management of Procedure-Related Pain in the Breastfeeding Infant, Revised 2016

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient. These guidelines are not intended to be all-inclusive, but to provide a basic framework for physician education regarding breastfeeding.

Sensory processing disorder in children ages birth-3 years born prematurely: a systematic review

This systematic review of multidisciplinary literature synthesizes evidence of the prevalence and patterns of sensory processing disorder (SPD) in children ages birth-3 yr born preterm. Forty-five articles including physiological, behavioral, temperament, and SPD research met the inclusion criteria and provided 295 findings related to SPD-130 (44%) positive (evidence of SPD) and 165 (56%) negative (no evidence of SPD). The majority of findings related to sensory modulation disorder (SMD; 43% positive). The most prevalent subcategory of SMD was sensory overresponsivity (82% of findings positive). Evidence of sensory underresponsivity and sensory-seeking SMD, sensory discrimination disorder, and sensory-based motor disorder was limited. This study supports the education of neonatologists, pediatricians, and caregivers about the symptoms and potential consequences of SPD and helps justify the need for follow-up screening for SPD in children ages birth-3 yr born preterm. Research using measures based on sensory processing theory is needed.

The long-term impact of early life pain on adult responses to anxiety and stress: Historical perspectives and empirical evidence

Approximately 1 in 6 infants are born prematurely each year. Typically, these infants spend 25 days in the Neonatal Intensive Care Unit (NICU) where they experience 10-18 painful and inflammatory procedures each day. Remarkably, pre-emptive analgesics and/or anesthesia are administered less than 25% of the time. Unalleviated pain during the perinatal period is associated with permanent decreases in pain sensitivity, blunted cortisol responses and high rates of neuropsychiatric disorders. To date, the mechanism(s) by which these long-term changes in stress and pain behavior occur, and whether such alterations can be prevented by appropriate analgesia at the time of insult, remains unclear. Work in our lab using a rodent model of early life pain suggests that inflammatory pain experienced on the day of birth blunts adult responses to stress- and pain-provoking stimuli, and dysregulates the hypothalamic pituitary adrenal (HPA) axis in part through a permanent upregulation in central endogenous opioid tone. This review focuses on the long-term impact of neonatal inflammatory pain on adult anxiety- and stress-related responses, and underlying neuroanatomical changes in the context of endogenous pain control and the HPA axis. These two systems are in a state of exaggerated developmental plasticity early in postnatal life, and work in concert to respond to noxious or aversive stimuli. We present empirical evidence from animal and clinical studies, and discuss historical perspectives underlying the lack of analgesia/anesthetic use for early life pain in the modern NICU.

Perceptions of health professionals on pain in extremely low gestational age infants

Extremely low gestational age infants (<28 weeks at birth) experience significant pain from repeated therapeutic procedures while hospitalized in the neonatal intensive care unit. As part of a program of research examining pain in preterm infants, we conducted a qualitatively driven mixed-methods design, supplemented with a qualitative and quantitative component, to understand how health care professionals (HCPs) assess and manage procedural pain for tiny and underdeveloped preterm infants. Fifty-nine HCPs from different disciplines across four tertiary-level neonatal units in Canada participated in individual or focus group interviews and completed a brief questionnaire. Four themes from the content analysis were (a) subtlety and unpredictability of pain indicators, (b) infant and caregiver attributes and contextual factors that influence pain response and practices, (c) the complex nature of pain assessment, and (d) uncertainty in the management of pain. The information gleaned from this study can assist in identifying gaps in knowledge and informing unit-based and organizational knowledge translation strategies for this vulnerable population.

Long-Term Persistency of Abnormal Heart Rate Variability following Long NICU Stay and Surgery at Birth

Preterm birth is associated with painful procedures during the neonatal intensive care unit (NICU) stay. Full-term newborns can also experience pain, following surgery. These procedures can have long-lasting consequences. It has been shown that children born preterm show pain responses and cardiac alterations. This study aimed to explore the heart rate reactivity to pain in 107 subjects born either preterm or full-term who were between 7 and 25 years old at testing. We also evaluated the effect of pain experienced at birth, as represented by a longer NICU stay, time under ventilation, and surgery at birth. Participants were asked to immerse their right forearm in 10°C water for 2 minutes. Electrocardiograms were recorded at baseline and during the immersion procedure. Full-term subjects showed a stable increase in heart rate throughout the procedure, whereas preterm ones showed a strong increase at the beginning, which decreased over time. Also, preterm and full-term subjects who experienced pain at birth showed higher resting heart rate, stronger sympathetic activity, and lower cardiac vagal activity. Our study demonstrated a long-term impact of a long NICU stay and surgery at birth on cardiac autonomic activity. This could lead to impaired reactions to pain or stress in later life.

Skin-to-skin care for procedural pain in neonates

BACKGROUND

Skin-to-skin care (SSC), otherwise known as Kangaroo Care (KC) due to its similarity with marsupial behaviour of ventral maternal-infant contact, is one non-pharmacological intervention for pain control in infants.

OBJECTIVES

The primary objectives were to determine the effect of SSC alone on pain from medical or nursing procedures in neonates undergoing painful procedures compared to no intervention, sucrose or other analgesics, or additions to simple SSC such as rocking; and the effects of the amount of SSC (duration in minutes) and the method of administration (who provided the SSC, positioning of caregiver and neonate pair).The secondary objectives were to determine the incidence of untoward effects of SSC and to compare the SSC effect in different postmenstrual age subgroups of infants.

SEARCH METHODS

The standard methods of the Cochrane Neonatal Collaborative Review Group were used. Databases searched in August 2011: Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library); Evidence-Based Medicine Reviews; MEDLINE (1950 onwards); PubMed (1975 onwards); EMBASE (1974 onwards); CINAHL (1982 onwards); Web of Science (1980 onwards); LILACS database (1982 onwards); SCIELO database (1982 onwards); PsycInfo (1980 onwards); AMED (1985 onwards); Dissertation-Abstracts International (1980 onwards). Searches were conducted throughout September 2012.

SELECTION CRITERIA

Studies with randomisation or quasi-randomisation, double or single-blinded, involving term infants (> 37 completed weeks postmenstrual age (PMA)) to a maximum of 44 weeks PMA and preterm infants (< 37 completed weeks PMA) receiving SSC for painful procedures conducted by doctors, nurses, or other healthcare professionals.

DATA COLLECTION AND ANALYSIS

The main outcome measures were physiological or behavioural pain indicators and composite pain scores. A weighted mean difference (WMD) with 95% confidence interval (CI) using a fixed-effect model was reported for continuous outcome measures. We included variations on type of tissue-damaging procedure, provider of care, and duration of SSC.

MAIN RESULTS

Nineteen studies (n = 1594 infants) were included. Fifteen studies (n = 744) used heel lance as the painful procedure, one study combined venepuncture and heel stick (n = 50), two used intramuscular injection, and one used 'vaccination' (n = 80). The studies that were included were generally strong and free from bias.Eleven studies (n = 1363) compared SSC alone to a no-treatment control. Although 11 studies measured heart rate during painful procedures, data from only four studies (n = 121) could be combined to give a mean difference (MD) of 0.35 beats per minute (95% CI -6.01 to 6.71). Three other studies that were not included in meta-analyses also reported no difference in heart rate after the painful procedure. Two studies reported heart rate variability outcomes and found no significant differences. Five studies used the Premature Infant Pain Profile (PIPP) as a primary outcome, which favoured SCC at 30 seconds (n = 268) (MD -3.21, 95% CI -3.94 to -2.48), 60 seconds (n = 164) (MD -1.85, 95% CI -3.03 to -0.68), and 90 seconds (n = 163) (MD -1.34, 95% CI -2.56 to -0.13), but at 120 seconds (n = 157) there was no difference. No studies provided findings on return of heart rate to baseline level, oxygen saturation, cortisol levels, duration of crying, and facial actions that could be combined for analysis.Eight studies compared SSC to another intervention with or without a no-treatment control. Two cross-over studies (n = 80) compared mother versus other provider on PIPP scores at 30, 60, 90, and 120 seconds with no significant difference. When SSC was compared to other interventions, there were not enough similar studies to pool results in an analysis. One study compared SSC with and without dextrose and found that the combination was most effective and that SSC alone was more effective than dextrose alone. Similarly, in another study SSC was more effective than oral glucose for heart rate but not oxygen saturation. SSC either in combination with breastfeeding or alone was favoured over a no-treatment control, but was not different to breastfeeding. There were not enough participants with similar outcomes and painful procedures to compare age groups or duration of SSC. No adverse events were reported in any of the studies.

AUTHORS' CONCLUSIONS

SSC appears to be effective, as measured by composite pain indicators and including both physiological and behavioural indicators, and safe for a single painful procedure such as a heel lance. Purely behavioural indicators tended to favour SSC but there remains questionable bias regarding behavioural indicators. Physiological indicators were typically not different between conditions. Only two studies compared mother providers to others, with non-significant results. There was more heterogeneity in the studies with behavioural or composite outcomes. There is a need for replication studies that use similar, clearly defined outcomes. New studies examining optimal duration of SSC, gestational age groups, repeated use, and long-term effects of SSC are needed.

Neonatal injury rapidly alters markers of pain and stress in rat pups

Less than 60% of infants undergoing invasive procedures in the neonatal intensive care unit receive analgesic therapy. These infants show long-term decreases in pain sensitivity and cortisol reactivity. In rats, we have previously shown that inflammatory pain experienced on the day of birth significantly decreases adult somatosensory thresholds and responses to anxiety- and stress-provoking stimuli. These long-term changes in pain and stress responsiveness are accompanied by two-fold increases in central met-enkephalin and β-endorphin expression. However, the time course over which these changes in central opioid peptide expression occur, relative to the time of injury, are not known. The present studies were conducted to determine whether the observed changes in adult opioid peptide expression were present within the first postnatal week following injury. The impact of neonatal inflammation on plasma corticosterone, a marker for stress reactivity, was also determined. Brain, spinal cord, and trunk blood were harvested at 24 h, 48 h, and 7 d following intraplantar administration of the inflammatory agent carrageenan on the day of birth. Radioimmunoassay was used to determine plasma corticosterone and met-enkephalin and β-endorphin levels within the forebrain, cortex, midbrain, and spinal cord. Within 24 h of injury, met-enkephalin levels were significantly increased in the midbrain, but decreased in the spinal cord and cortex; forebrain β-endorphin levels were significantly increased as a result of early life pain. Corticosterone levels were also significantly increased. At 7 d post-injury, opioid peptides remained elevated relative to controls, suggesting a time point by which injury-induced changes become programmed and permanent.

Assessment of pain in the neonate

Accurate pain assessment in preterm and term neonates in the neonatal intensive care unit (NICU) is of vital importance because of the high prevalence of painful experiences in this population, including both daily procedural pain and postoperative pain. Over 40 tools have been developed to assess pain in neonates, and each NICU should choose a limited number of pain assessment tools for different populations and contexts. Only two pain assessment tools have a metric adjustment to account for differences of pain assessment in prematurity. Preterm neonates do not display behavior and physiologic indicators of pain as reliably and specifically as full term infants, and preterm infants are vulnerable to long term sequelae of painful experiences. "Brain-oriented" approaches for more objective measurement of pain in neonates may become available in the future. In the meantime, neonatal pain assessment tools need to be taught, implemented, and their ongoing use optimized to form a consistent, reproducible basis for the safe and effective treatment of neonatal pain.

[Impact of cocooning and maternal voice on the autonomic nervous system activity in the premature newborn infant]

INTRODUCTION

Discomfort, pain, and stress have an adverse impact on the psychomotor development in the premature newborn infant. Recent studies indicate that pain and stress are associated with a reduction of parasympathetic outflow. We hypothesized that cocooning associated with the human voice has a favorable impact on parasympathetic activity in the premature newborn infant.

METHOD

We compared heart rate variability (HRV) before and after standardized cocooning phases associated with the human voice and carried out: 1) by the mother and 2) by a third person. HRV was assessed and expressed as an index reflecting the parasympathetic tone.

RESULTS

Ten children were included (median gestational age, 33 weeks (30(+4)-33(+2))). We observed a higher HRV index after the period of cocooning associated with the human voice compared with the baseline measurement (P<0.05), whether the procedure was carried out by the mother or a third person.

CONCLUSION

This study shows that cocooning associated with the human voice enhances HRV in the preterm newborn infant, indicating an increase in parasympathetic activity after cocooning associated with the human voice. However, the impact is similar whether the cocooning associated with the human voice is performed by the mother or a third person. This result suggests that cocooning associated with the human voice carried out either by the mother or a third person contributes to decreasing stress and discomfort in the premature newborn infant.

Pain evaluation after a non-nociceptive stimulus in preterm infants during the first 28days of life

BACKGROUND

Protective mechanisms that modulate and lead to habituation to pain are immature in preterm newborn infants.

AIMS

To evaluate if a routine non-painful handling will be perceived as painful throughout the neonatal period in newborn infants with 28-32 weeks of gestational age.

STUDY DESIGN

Prospective cohort study.

SUBJECTS

36 preterm infants without malformations evaluated for pain during a diaper change.

OUTCOME MEASURES

Patients were studied at three times (5 min prior, during, and 3 min after the diaper change) during five moments (72 h, 7, 14, 21 and 28 days of life) by evaluation of heart rate, oxygen saturation and 3 validated pain assessment tools: the Neonatal Infant Pain Scale (NIPS), the Behavioral Indicators of Infant Pain (BIIP) and Premature Infant Pain Profile (PIPP). Results were analyzed by repeated measures ANOVA adjusted for gender, gestational age at birth, number of painful procedures and use of opioids.

RESULTS

Patients had, at birth, mean gestational age of 30.2±1.4 weeks, birthweight of 1257±238g, with 50% males. Analysis of pain assessment tools did not show increase of pain presence or pain scores at the five sequential evaluation moments. The variation of oxygen saturation during the three study times was similar at the different post-natal ages, but heart rate variation increased significantly from 72 h until the 28th day of life.

CONCLUSIONS

In preterm infants, the non-nociceptive handling does not trigger pain responses even after 28 days of neonatal care, which includes the experience of repetitive procedural pain.

Neonatal pain in very preterm infants: long-term effects on brain, neurodevelopment and pain reactivity

Effects of early life psychosocial adversity have received a great deal of attention, such as maternal separation in experimental animal models and abuse/neglect in young humans. More recently, long-term effects of the physical stress of repetitive procedural pain have begun to be addressed in infants hospitalized in neonatal intensive care. Preterm infants are more sensitive to pain and stress, which cannot be distinguished in neonates. The focus of this review is clinical studies of long-term effects of repeated procedural pain-related stress in the neonatal intensive care unit (NICU) in relation to brain development, neurodevelopment, programming of stress systems, and later pain sensitivity in infants born very preterm (24-32 weeks' gestational age). Neonatal pain exposure has been quantified as the number of invasive and/or skin-breaking procedures during hospitalization in the NICU. Emerging studies provide convincing clinical evidence for an adverse impact of neonatal pain/stress in infants at a time of physiological immaturity, rapidly developing brain microstructure and networks, as well as programming of the hypothalamic-pituitary-adrenal axis. Currently it appears that early pain/stress may influence the developing brain and thereby neurodevelopment and stress-sensitive behaviors, particularly in the most immature neonates. However, there is no evidence for greater prevalence of pain syndromes compared to children and adults born healthy at full term. In addressing associations between pain/stress and outcomes, careful consideration of confounding clinical factors related to prematurity is essential. The need for pain management for humanitarian care is widely advocated. Non-pharmacological interventions to help parents reduce their infant's stress may be brain-protective.

Heart rate dynamics during acute pain in newborns

Autonomic nervous system modulation of heart rate is significantly altered during painful procedures in newborns. Most studies investigating pain employed only linear-based analysis methods, thus ignoring the complex, non-linear nature of heart rate control mechanisms. The emergences of dynamic, nonlinear analysis methods enable us to uncover information embedded in the fluctuations of heart rate not otherwise noticeable. Our objective was to examine how cardiac dynamics change in newborns who undergo heel lancing by analyzing linear and nonlinear characteristics of heart rate fluctuations. We used dynamic nonlinear analyses methods to reveal heart rate variability and complexity alterations during painful stimulus in newborns. Poincaré plots were applied to examine the dynamics of the system, sample entropy to investigate the complexity of the system, and detrended fluctuation analysis, to reveal the fractal properties of the system. Heart rate significantly increased (165 vs.123 beats per minute, p < 0.001) while variability decreased. Sample entropy and the quantitative measures of the Poincaré plots (SD1 and SD2) significantly decreased during heel lancing (0.75 vs. 1.0, p < 0.01; 6.4 vs. 12.8, p < 0.001; and 30.4 vs. 50.5, p < 0.01, respectively). Detrended fluctuation analysis showed a significant decrease in the short-term scaling exponent α1 (1.06 vs. 1.3, p < 0.001), and an increase in the long-term scaling exponent α2 (1.5 vs. 1.1, p < 0.001). Our results indicate altered complexity of heart rate variability during painful stimulus in newborns and disruption of the mechanisms that regularly control it. Such alterations resemble certain pathological conditions and may represent stress reaction.

Heart rate variability analysis for newborn infants prolonged pain assessment

Pain management is a general concern for healthcare quality. In the particular context of neonatal care, it's well known that an efficient pain management will decrease mortality and morbidity of newborn infants. Furthermore, the plasticity of developing brain is vulnerable to pain and/or stress, that in turn may cause long term neurodevelopmental changes, including altered pain sensitivity and neuroanatomic and behavioural abnormalities. During neonatal intensive care stay, large number of painful procedures are performed, the majority of which are not accompanied by adequate analgesia. Optimal management requires competent pain assessment which can be especially difficult to perform in this non verbal population. We have developed an instantaneous heart rate variability (HRV) analysis method, non intrusive and user-friendly, based on the ECG signal acquisition. This analysis method enabled us to design parameters related to the influence of pain on the Autonomic Nervous System (ANS) activity. This paper presents the application of this method, previously validated for adults under general anesthesia, to the domain of newborn infants prolonged pain assessment.

Effects of skin-to-skin contact on autonomic pain responses in preterm infants

The purpose of this randomized crossover trial was to determine the effects on autonomic responses in preterm infants of longer Kangaroo Care (30 minutes, KC30) and shorter KC (15 minutes, KC15) before and throughout heel stick compared with incubator care (IC). Beat-to-beat heart rate (HR) and spectral power analysis of heart rate variability, low frequency power (LF), high frequency power (HF), and LF/HF ratio were measured in 26 infants. HR changes from Baseline to Heel Stick were significantly less in KC30 and KC15 than in IC, and more infants had HR decrease in IC than in 2 KC conditions. In IC, LF and HF significantly increased from Baseline to Heel Stick and dropped from Heel Stick to Recovery; in 2 KC conditions, no changes across study phases were found. During Heel Stick, LF and HF were significantly higher in IC than in KC30. In all 3 conditions, LF/HF ratio decreased from Baseline to Heel Stick and increased to Recovery; no differences were found between IC and two KC conditions. Both longer and shorter KC before and throughout heel stick can stabilize HR response in preterm infants, and longer KC significantly affected infants' sympathetic and parasympathetic responses during heel stick compared with incubator care.

PERSPECTIVE

This study showed that KC has a significant effect on reducing autonomic pain responses in preterm infants. The findings support that KC is a safe and effective pain intervention in the neonatal intensive care unit.

Warmth is analgesic in healthy newborns

This study identifies a behavioral and nonpharmacologic means of preventing and reducing newborn pain. Our objective was to determine whether warmth is analgesic in newborn infants undergoing vaccination-a routine painful hospital procedure. We used a prospective randomized controlled trial of 47 healthy full-term newborn infants. Infants were randomized into 1 of 3 conditions prior to vaccination: warmth exposure, pacifier suckling, or sucrose taste. Crying, grimacing, and heart rate differences were analyzed between groups before, during, and after vaccination as outcome measures. Warmer infants cried significantly less than sucrose taste or pacifier suckling after vaccination. Heart rate patterns reflected this analgesia. Core temperature did not differ between study groups. Providing natural warmth to newborn infants during a painful procedure decreases the crying and grimacing on par with the "gold" standard treatments of sucrose or pacifier.

Maternal touch and talk for invasive procedures in infants and toddlers in the pediatric intensive care unit

The aim of this single-blind, randomized, crossover trial was to test the effect of Touch & Talk (T&T) for infants and toddlers less than 36 months of age (N = 65) in the pediatric intensive care unit on their physiological stability and recovery to an invasive procedure. In the T&T condition, mothers touched, sang, or told stories or rhymes to their child during an invasive procedure. In the control condition, the mothers did not have contact with their child. Physiological measures included heart rate, heart rate variability, and oxygen saturation range during the procedure and change from baseline. Time from the end of the procedure until the heart rate returned to baseline levels gave the recovery time. Analysis was conducted using repeated-measures analysis of covariance. There were no significant differences on any of the physiological parameters by condition during the procedure. However, when controlling for severity of illness, recovery was faster with mothers.

The efficacy of non-pharmacological interventions in the management of procedural pain in preterm and term neonates

BACKGROUND

Neonates in a neonatal intensive care unit are exposed to a high number of painful procedures. Since repeated and sustained pain can have consequences for the neurological and behaviour-oriented development of the newborn, the greatest attention needs to be paid to systematic pain management in neonatology. Non-pharmacological treatment methods are being increasingly discussed with regard to pain prevention and relief either alone or in combination with pharmacological treatment.

AIMS

To identify effective non-pharmacological interventions with regard to procedural pain in neonates.

METHODS

A literature search was conducted via the MedLine, CINAHL, Cochrane Library databases and complemented by a handsearch. The literature search covered the period from 1984 to 2004. Data were extracted according to pre-defined criteria by two independent reviewers and methodological quality was assessed.

RESULTS

13 randomised controlled studies and two meta-analyses were taken into consideration with regard to the question of current nursing practice of non-pharmacological pain management methods. The selected interventions were "non-nutritive sucking", "music", "swaddling", "positioning", "olfactory and multisensorial stimulation", "kangaroo care" and "maternal touch". There is evidence that the methods of "non-nutritive sucking", "swaddling" and "facilitated tucking" do have a pain-alleviating effect on neonates.

CONCLUSIONS

Some of the non-pharmacological interventions have an evident favourable effect on pulse rate, respiration and oxygen saturation, on the reduction of motor activity, and on the excitation states after invasive measures. However, unambiguous evidence of this still remains to be presented. Further research should emphasise the use of validated pain assessment instruments for the evaluation of the pain-alleviating effect of non-pharmacological interventions.

Long-term consequences of early infant injury and trauma upon somatosensory processing

Long-term consequences of early infant injury upon somatosensory processing were tested in school aged children. The aim was to test whether the long-term changes in sensitivity reported in animal models, in regions both local to and distant from the injury site, could be observed in humans. To do this we used quantitative sensory testing (QST) in children aged 9-12 years who had undergone cardiac surgery in infancy. Cutaneous mechanical and thermal thresholds were measured at the thoracic scar region and at control contralateral thoracic and reference thenar areas in this early surgery group (n=9), and compared with thresholds at the same regions in age and gender-matched controls (n=9). The results showed that the cardiac surgery group was significantly less sensitive to von Frey hair tactile stimulation in the non-injured thenar area than the control group; mean threshold 5.02, SD+/-1.59 compared to 2.76, SD+/-0.79 (von Frey hair number, p=0.04). In addition, their lateral thoracotomy scar areas were significantly less sensitive to von Frey hair stimulation (mean=9.82, SD+/-1.97, p<0.001) and to cooling and warming than any other site tested. Eight of the nine children in the early surgery group did not perceive warmth on their scars and were only able to detect uncomfortable heat as the temperature was raised. Three of these children felt a paradoxical cold prior to the hot sensation and all reported subtle abnormalities in everyday sensations. Questionnaires revealed perceived differences in pain perception, individual aberrant sensations and pain interfering with daily life that warrant further study. We conclude that tissue injured in early infancy remains measurably altered to mechanical and thermal stimulation in later life. These findings are consistent with the results of animal studies that early infant injury has not only local, but also global long-term consequences upon sensory processing.

Skin conductance measurements as pain assessment in newborn infants born at 22-27 weeks gestational age at different postnatal age

BACKGROUND

To assess pain or stress in newborn infants submitted to intensive care is important but difficult, as different observational pain scales are not always reliable in premature infants. As an indicator of pain, skin conductance (SC) measurements have detected increased sweating in newborn infants >28 gestational age (GA) submitted to heel lancing.

OBJECTIVE

To measure SC during heel lancing and routine care in newborn infants, born at 22 to 27 GA, with special relation to postnatal age (PNA).

METHODS

In six infants <28+0 GA and 4 infants ≥28+0 GA spontaneous SC activity and behavioural state (Neonatal Pain Agitation and Sedation Scale (N-PASS)) was measured before, during and after each intervention. Measurements were repeated in each patient at different PNA.

RESULTS

Baseline SC prior to intervention took longer time to stabilise and was higher in <28 than in ≥28+0 PNA. The combination of heel lancing and squeezing gave an increased SC in <28 PNA, whereas heel lancing alone gave the same SC response in ≥28+0 PNA. A possibly continued immature response in SC measurements was not observed. Oral glucose admission prior to heel lancing increased SC. Routine care did not give any changes in SC. Except during orogastric tube placement no signs of discomfort or pain could be detected by the neonatal pain, agitation and sedation scale (N-PASS) in <28 PNA.

CONCLUSION

Changes in SC could be detected in infants at <28+0 PNA and related to the combination of heel lancing and squeezing. A maturational development of the SC was observed in infants born <28 GA. SC seems to be able to differentiate between pain and discomfort.

Early life adversity as a risk factor for fibromyalgia in later life

The impact of early life events is increasingly becoming apparent, as studies investigate how early childhood can shape long-term physiology and behaviour. Fibromyalgia (FM), which is characterised by increased pain sensitivity and a number of affective co-morbidities, has an unclear etiology. This paper discusses risk factors from early life that may increase the occurrence or severity of FM in later life: pain experience during neonatal life causes long-lasting changes in nociceptive circuitry and increases pain sensitivity in the older organism; premature birth and related stressor exposure cause lasting changes in stress responsivity; maternal deprivation affects anxiety-like behaviours that may be partially mediated by epigenetic modulation of the genome—all these adult phenotypes are strikingly similar to symptoms displayed by FM sufferers. In addition, childhood trauma and exposure to substances of abuse may cause lasting changes in developing neurotransmitter and endocrine circuits that are linked to anxiety and stress responses.

Procedural pain management for neonates using nonpharmacological strategies: Part 1: sensorial interventions

Neonates who are born preterm and are admitted to neonatal intensive care units endure frequent procedures that may be painful. Nonpharmacological interventions that have been studied to relieve their pain may be categorized in 2 main groups according to their nature: interventions that focus on creating a favorable environment and offering pleasant sensorial stimuli and interventions that are centered on maternal care. These interventions may be considered within the philosophy of developmental care, since they are aimed at adjusting the environment to the needs of the neonate and involve family-centered care. In this article, the first of a 2-part series, we will synthesize the evidence from experimental studies of interventions that focus on the environment and on tactile and gustatory stimulation. The mechanisms suggested by researchers as possible explanations for the efficacy of these interventions are pointed, and the implications for procedural pain management in neonatal care are drawn.

Poincaré plot descriptors of heart rate variability as markers of persistent pain expression in freely moving rats

Evaluation of pain is a critical issue in human pathologies but also in animal experimentation. In human studies there is growing evidence that cardiovascular outputs such as heart rate variability (HRV) might be of interest to detect and measure pain expression. Indeed, systems controlling cardiovascular function are closely coupled to the perception of pain. To demonstrate the interest of HRV, we have combined radiotelemetry and remote-controlled nociceptive tests in rats submitted to various situations of acute and persistent inflammatory pain. We found the Poincaré plot descriptor SD1 and pNN18 to represent robust indicators of pain, especially in the case of persistent inflammatory states. Further studies will be performed in order to understand by which mechanisms pain-related increases in HRV are produced and if these descriptors can be used for other persistent pain states.

Endpoints in pediatric pain studies

Assessing pain intensity in (preverbal) children is more difficult than in adults. Tools to measure pain are being used as primary endpoints [e.g., pain intensity, time to first (rescue) analgesia, total analgesic consumption, adverse effects, and long-term effects] in studies on the effects of analgesic drugs. Here, we review current and promising new endpoints used in pediatric pain assessment studies.

Assessment of acute pain in children: development of evidence-based guidelines

AIM

Detecting children's pain in a healthcare setting can be improved by facilitating pain expression in ways that are appropriate to the child's cognitive development and that can be recognised by their carers. To ensure up-to-date guidance on assessing pain in children, the Royal College of Nursing undertook an evidence-based update of pain assessment guidelines, initially published in 2000.

METHODS

Following systematic review of the psychometric testing literature, a two-stage critical appraisal process was developed to derive a list of robust tools that could be recommended for use in a variety of settings to assess the intensity of a child's acute pain. Studies were appraised on the basis of their relevance to this topic and according to prespecified quality criteria. Tools were assessed for inclusion in guideline recommendations according to minimum validity and reliability thresholds.

RESULTS

Overall the quality of literature was poor, limited by small samples, lack of control groups, unblinded raters and convenience sampling. Twenty-four tools are recommended for use with infants and verbal children without cognitive impairment, 11 of which are purely self-report tools. Eight tools are recommended for use with neonates, some of which require concurrent physiological measures. Four tools are considered valid for use in children with cognitive impairment. All of these tools had shown reliability and validity according to the criteria established for this review.

CONCLUSION

The tools are presented in user-friendly tables that include a guide to their key features and the setting and age groups in which they have been validated. They are accompanied by good practice recommendations from experts and recommendations relating to timing and triggers for pain assessment. These outputs are some of those associated with the full guidelines and supporting material published on the Royal College of Nursing website (http://www.rcn.org.uk/childrenspainguideline).

Contextual factors influencing pain response to heelstick procedures in preterm infants: what do we know? A systematic review

Major efforts to develop objective measurement tools for neonatal pain assessment have been made. However, the challenge of measuring pain in neonates remains suggesting that contextual factors (cFs) might alter their responses to pain. Although the role of cFs is increasingly discussed as crucial for pain assessment, they are not well described in the literature and are rarely considered in the clinical setting despite their importance.

AIM

To systematically examine studies investigating the impact of cFs on pain response in preterm infants.

METHOD

A literature search was undertaken for the period from 1990 to 2009. Studies reporting the relation between one or more cFs and pain response in preterm infants during a heelstick procedure were considered for inclusion.

RESULTS

Twenty-three studies satisfied inclusion criteria. The studies varied relative to their design, sample, analysis procedures, and variables examined. Six categories of cFs emerged: age, pain exposure, health status, therapeutic interventions, behavioral status, and demographic factors. The examined cFs varied in the strength of their association with pain response, although none were invariably related, as evidenced by contradictory findings. In some cases the inconsistencies appeared attributable to methodological limitations in studies. Behavioral and physiological pain responses were not always in agreement as would be expected.

CONCLUSION

This review supports the influence of some cFs on pain response. However, the results remain inconclusive which may be, in part, related to the heterogeneity of the studies. Contextual factors need further investigation for a better understanding of the magnitude of their effect on pain response.

Cortisol, behavior, and heart rate reactivity to immunization pain at 4 months corrected age in infants born very preterm

OBJECTIVE

Pain response may be altered in infants born very preterm owing to repeated exposure to procedures in the neonatal intensive care unit. Findings have been inconsistent in studies of behavioral and cardiac responses to brief pain in preterm versus full-term infants following neonatal intensive care unit discharge. To our knowledge, cortisol reactivity to pain has not been compared in preterm and full-term infants. We examined pain reactivity to immunization in preterm and full-term infants.

METHOD

Cortisol, facial behavior, and heart rate reactivity before, during, and after immunization were examined in infants born preterm at extremely low gestational age (ELGA 24 to 28 wk), very low gestational age (VLGA 29 to 32 wk), and full-term, at corrected age 4 months.

RESULTS

In all groups, cortisol, behavior, and heart rate increased during immunizations. Cortisol concentrations were lower in preterm ELGA and VLGA boys, compared with full-term boys. In contrast, facial and heart rate responses to immunization did not differ between preterm and full-term infants.

DISCUSSION

Although earlier reports found differences in pain processing in preterm infants earlier and later in development, the present findings indicate that pain responses, indexed by behavior and heart-rate, do not seem to differ in preterm compared with full-term infants at 4 months corrected age. Importantly, however, stress regulation seems altered in preterm male infants. As cortisol impacts development and functioning of the brain, altered stress regulation has important implications beyond pain systems.

ABM clinical protocol #23: Non-pharmacologic management of procedure-related pain in the breastfeeding infant

A central goal of The Academy of Breastfeeding Medicine is the development of clinical protocols for managing common medical problems that may impact breastfeeding success. These protocols serve only as guidelines for the care of breastfeeding mothers and infants and do not delineate an exclusive course of treatment or serve as standards of medical care. Variations in treatment may be appropriate according to the needs of an individual patient. These guidelines are not intended to be all-inclusive, but to provide a basic framework for physician education regarding breastfeeding.