Can adverse neonatal experiences alter brain development and subsequent behavior?

Pain activates cortical areas in the preterm newborn brain

To study the patterns of supraspinal pain processing in neonates, we hypothesized that acute pain causes haemodynamic changes associated with activation of the primary somatosensory cortex. Forty preterm neonates at 28-36 weeks of gestation (mean=32.0) and at 25-42 h (mean=30.7) of age were studied following standardized tactile (skin disinfection) and painful (venipuncture) stimuli. Changes in regional cerebral haemodynamics were monitored by near infrared spectroscopy (NIRS) over both somatosensory cortices in 29 newborns, and over the contralateral somatosensory and occipital areas in 11 newborns. Heart rate (HR) and peripheral oxygen saturation (SaO2) were recorded simultaneously with NIRS parameters: oxygenated [HbO2], deoxygenated, and total hemoglobin. Tactile stimulation produced no changes in HR or SaO2. HR increased in the first 20s (p<0.001), while SaO2 decreased during the 40s after venipuncture (p<0.0001). Following tactile or painful stimulation, [HbO2] increased bilaterally regardless of which hand was stimulated (p<0.0001). Pain-induced [HbO2] increases in the contralateral somatosensory cortex (p<0.05) were not mirrored in the occipital cortex (p>0.1). Pain-related [HbO2] increases were more pronounced in male neonates (p<0.05 on left, p<0.001 on right), inversely correlated with gestational age (r=-0.53 on left, p<0.01; r=-0.42 on right, p<0.05) and directly correlated with postnatal age (r=0.75 on left, p<0.0001; r=0.67 on right, p<0.0001). Painful and tactile stimuli elicit specific haemodynamic responses in the somatosensory cortex, implying conscious sensory perception in preterm neonates. Somatosensory cortical activation occurs bilaterally following unilateral stimulation and these changes are more pronounced in male neonates or preterm neonates at lower gestational ages.

Perinatal corticosteroid effect on amygdala and hippocampus volume during brain development in the rat model

Exposure of the fetus to corticosteroid during brain development has been suggested to cause permanent change in brain structure and has been associated with long term cognitive, behavioral and emotional impairment. We evaluated the effect of perinatal corticosteroid, at a dose similar to that which human fetuses are exposed, on cerebral cortex, corpus collosum, hippocampus, dentate gyrus and amygdala in a rat model. Rat pups were given betamethasone at day 1 (P1). Brain sections from the rat pups at postnatal day 45 (P45) were then analyzed. No differences were noted in the volumes of cerebral cortex, corpus collosum, hippocampus, dentate gyrus, or three nuclei of the amygdala compared to the control and sham groups. We concluded that a single course of betamethasone, at a comparable dose to that which the human fetus is exposed in clinical practice, had no effect on these regional brain volumes at this stage of development.

Summary proceedings from the neonatal pain-control group

Recent advances in neurobiology and clinical medicine have established that the fetus and newborn may experience acute, established, and chronic pain. They respond to such noxious stimuli by a series of complex biochemical, physiologic, and behavioral alterations. Studies have concluded that controlling pain experience is beneficial with respect to short-term and perhaps long-term outcomes. Yet, pain-control measures are adopted infrequently because of unresolved scientific issues and lack of appreciation for the need for control of pain and its long-term sequelae during the critical phases of neurologic maturation in the preterm and term newborn. The neonatal pain-control group, as part of the Newborn Drug Development Initiative (NDDI) Workshop I, addressed these concerns. The specific issues addressed were (1) management of pain associated with invasive procedures, (2) provision of sedation and analgesia during mechanical ventilation, and (3) mitigation of pain and stress responses during and after surgery in the newborn infant. The cross-cutting themes addressed within each category included (1) clinical-trial designs, (2) drug prioritization, (3) ethical constraints, (4) gaps in our knowledge, and (5) future research needs. This article provides a summary of the discussions and deliberations. Full-length articles on procedural pain, sedation and analgesia for ventilated infants, perioperative pain, and study designs for neonatal pain research were published in Clinical Therapeutics (June 2005).

Cuidados centrados en el desarrollo. Situación en las unidades de neonatología de España

INTRODUCTION

Developmental and family centered care (DC) is a framework that aims to enhance the neurodevelopment of the infant. Over the last few years Spanish neonatal units have been working toward introducing this type of care.

OBJECTIVE

To evaluate DC in Spanish neonatal units by assessing certain features of the care provided to very low birth weight infants and their families.

MATERIAL AND METHOD

Spanish hospitals attending infants under 1,500 g were identified. A cross sectional study was performed using a telephone questionnaire with 25 DC-related items.

RESULTS

Of the 100 hospitals attending infants under 1,500 g, 83 hospitals from all the Autonomous Communities in Spain participated in the survey. Of these, 31 % had noise pollution controls, 72 % controlled light intensity, 75 % bound the infants, and 29 % used saccharose as an analgesic. Ten percent allowed unrestricted parental visits. Twenty-two percent used kangaroo care without restriction. Sixty-three percent of the units reported difficulties when introducing DC-related changes.

CONCLUSIONS

Practically all neonatal units have some type of DC activity, although in certain areas, such as unrestricted parental visits, the rate of implementation is low.

Postnatal growth and morphological development of the brain: a species comparison

The objective of this report is to summarize the available literature regarding the postnatal growth and morphological development of the brain and compare the timelines for these events between humans and experimental species. While not the primary focus of this report, in acknowledgement of the evident role of maturation of neurotransmitter systems in development, a brief description of the comparative development of the NMDA receptor is included. To illustrate the challenges faced in estimating developmental toxicity potential in humans, the importance of postnatal experience in CNS development is also briefly reviewed. This review is part of the initial phase of a project undertaken by the Developmental and Reproductive Toxicology Technical Committee of the ILSI Health and Environmental Sciences Institute (HESI) to bring together information on a selected number of organ systems and compare their postnatal development across several species (Hurtt and Sandler: Birth Defects Res Part B 68:307-308, 2003).

Pain relief for neonates in Australian hospitals: a need to improve evidence-based practice

OBJECTIVE

To ascertain the extent to which neonatal analgesia was used in Australia for minor invasive procedures as an indicator of evidence-based practice in neonatology.

METHODS

A cross-sectional telephone survey of hospitals in all Australian states and territories with more than 200 deliveries per year was carried out. Questions were asked regarding awareness of the benefits and the use of analgesia for minor invasive procedures in term and near term neonates. Analysis was undertaken according to state and territory, annual birth numbers and the level of neonatal nursery care available.

RESULTS

Data were available from 212 of 214 eligible hospitals. Of the total respondents, 51% and 70% respectively were aware of the benefits of sucrose and breast-feeding for neonatal analgesia. Eleven per cent of units administered sucrose before venepuncture and 25% of units used breast-feeding. Ten per cent of units used sucrose before heel prick with 49% utilizing breast-feeding. Expressed breast milk was used in 10% of units. Analgesia was given less frequently before intravenous cannulation compared to venepuncture and heel prick. Awareness and implementation of neonatal analgesia varied widely in the states and territories. There was a trend for hospitals providing a higher level of neonatal care to have a greater awareness of sucrose as an analgesic (P < 0.0001) and the use of sucrose for venepuncture (P = 0.029), heel prick (P = 0.025) and intravenous catheter insertion (P = 0.013). Similar trends were found on analysis according to birth number of the maternity units. Smaller units had a greater usage of breast-feeding as an analgesic for heel prick (P = 0.017).

CONCLUSION

Despite good evidence for the administration of sucrose and breast milk in providing effective analgesia for newborn infants, it is not widely used in Australia. It is imperative that the gap between research findings and clinical practice with regard to neonatal analgesia be addressed.

Maternal separation alters serotonergic transporter densities and serotonergic 1A receptors in rat brain

RATIONALE

The basic mechanisms underlying the association between early life maternal separation and adulthood psychiatric disorders are largely unknown. One possible candidate is the central serotonergic system, which is also abnormal in psychiatric illnesses. Neuroadaptational changes in serotonergic transporter and serotonergic 1A receptors may underlie links between early life stress and adulthood psychiatric disorders.

OBJECTIVE

The aim of this study was to investigate the consequences of a rat model of maternal separation on serotonergic transporter and serotonergic 1A receptor densities and function in adult rat forebrain.

METHODS

Rat pups were separated from dams from postnatal day 2 to postnatal day 14, each day, for zero time, 15 min and 180 min to determine the time-course of effects. A non-handled group was added to control for the effects of handling by an experimenter compared with the animal facility-reared group. Quantitative [(125)I]3beta-(4-iodophenyl)tropan-2beta-carboxylic acid methyl ester and [(125)I]-mPPI autoradiography was used to determine serotonergic transporter and serotonergic 1A densities, respectively. Adult rats were challenged with saline or serotonergic 1A agonist (+) 8-hydroxy-2-(di-n-propylamino)tetralin, 0.4 mg/kg, s.c.) and plasma adrenocorticotropic hormone and corticosterone were determined.

RESULTS

serotonergic transporter and serotonergic 1A densities were significantly lower in the non-handled group in the paraventricular, arcuate, dorsomedial and ventromedial nuclei of the hypothalamus. The non-handled group also displayed lower serotonergic transporter and serotonergic 1A densities in the basolateral anterior, basolateral ventral and basomedial amygdaloid nuclei. Serotonergic transporter densities were also decreased in the CA3 area of the hippocampus in the non-handled group. In contrast, the maternal separation 15 min group displayed the highest serotonergic transporter and serotonergic 1A densities in the basomedial nucleus of amygdala, basolateral anterior nucleus of amygdala, basolateral ventral nucleus of amygdala and basomedial nucleus of amygdala amygdaloid nuclei.

CONCLUSIONS

Early life maternal separation and the extent of handling can alter adult brain serotonergic transporter and serotonergic 1A levels and function in the forebrain. Alterations in these serotonergic systems by early rearing conditions might increase vulnerability for behavioral disorders in adulthood.

State of the science: procedural pain management in the neonate

Neonates in the neonatal intensive care unit experience painful procedures. Over the last 10 years, investigators have examined several pharmacologic and nonpharmacolgic treatment strategies to decrease or eliminate the pain associated with mechanical ventilation, endotrachial intubation, insertion of percutaneous or central venous lines, heel stick, and venipuncture. These procedures and others are addressed as well as the reported severity of pain associated with these procedures. Progress has been made in the past decade to establish evidence-based treatments that will help the clinician more effectively relieve neonatal stress and pain when performing many routine procedures.

Ethanol prevents NMDA receptor reduction by maternal separation in neonatal rat hippocampus

We measured the effects of ethanol on glutamate receptor levels in the hippocampus of neonatal Wistar rats using a vapor chamber model. Two control groups were used; a normal suckle group and a maternal separation group. Levels of NMDA receptors were not significantly altered in ethanol-treated animals compared to the normal suckle control group, as shown by [3H]MK-801 binding and Western blot analysis. However, MK-801 binding and NR1 subunit immunoreactivity were greatly reduced in the hippocampus of separation control animals. Neither ethanol treatment nor maternal separation altered levels of GluR1 or GluR2(4). These results have serious implications for the importance of maternal contact for normal brain development.

Differential effects of glutamate receptor antagonists on dorsal horn neurons responding to colorectal distension in a neonatal colon irritation rat model

AIM: To investigate and compare the effects of spinal D-(-)-2-amino-7-phosphonoheptanoic acid (AP-7) and 6-cyano-7-nitroquinoxaline-2,3-dione disodium (CNQX), two glutamate receptor antagonists, on the responses of dorsal horn neurons to colorectal distension (CRD) in adult rats exposed to neonatal colon irritation (CI).

METHODS: Hypersensitive SD rats were generated by CI during postnatal days 8, 10 and 12. Experiments on adult rats were performed using extracellular single-unit recording. The effects of spinal application of AP-7 (0.001, 0.01, 0.1, 1 mmoL) were tested on the CRD-evoked neuronal responses in 16 controls and 17 CI rats. The effects of CNQX (0.2, 2, 5, 10 μmoL) were also tested on the CRD-evoked responses of 17 controls and 18 CI neurons.

RESULTS: (1) The average responses of lumbosacral neurons to all intensities of CRD in CI rats were significantly higher than those in control rats; (2) In control rats, AP-7（0.01 mmoL）had no significant effect on the neuronal response to all intensities of CRD (20, 40, 60, 80 mmHg); while AP-7 (0.1 mmoL) inhibited the neuronal response to 80-mmHg CRD. By contrast, in CI rats, AP-7 (0.01-1 mmoL) attenuated the CRD-evoked neuronal responses to all distention pressures in a dose-dependent manner; (3) In control rats, CNQX (2 μmoL) had no significantly effect on the neuronal response to all intensities of CRD; however, CNQX (5 μmoL) significantly attenuated the responses to CRD in the 40-80 mmHg range. By contrast, CNQX (2-10 μmoL) significantly decreased the neuronal responses in CI rats to non-noxious and noxious CRD in a dose-dependent manner.

CONCLUSION: Our results suggest that spinal N-methyl-D-aspartate (NMDA) and non-NMDA receptors may contribute to the processing of central sensitivity in a neonatal CI rat model, but they may play different roles in it.

Pain management in the neonatal intensive care unit: a national survey in Italy

BACKGROUND

This study assessed current medical practice in preventative analgesia and sedation for invasive procedures in neonatal intensive care units (NICU) in Italy.

METHODS

A questionnaire was sent to level II and III Italian NICUs to investigate pain management, pharmacological treatment and the use of pain scores during invasive procedures. Main outcome measures were the extent to which analgesia and sedation are currently used for invasive procedures in Italian neonatal units.

RESULTS

The rate of response to the questionnaire was 88%. Written guidelines were available on acute pain control in 25% of the NICUs, and on prolonged pain control in 50%. Routine use of preventative pharmacological and nonpharmacological measures for painful procedures ranged from 13% for elective tracheal intubation to 68% for chest tube insertion. Thirty-six percent of NICUs routinely use sedation with opioids for mechanical ventilation; 14% prevent distress and pain for tracheal suctioning, 44% for heel lancing, 50% for venepuncture and percutaneous venous catheter insertion; 58% use analgesia before lumbar puncture. Validated pain assessment scores were used by 19% of NICUs.

CONCLUSIONS

The need for adequate analgesia is still underestimated. Further information on the safety of analgesics in neonatology is imperative, as is an adequate education of physicians and nurses on the use of pain control guidelines as part of the standard of care in the NICU.

Relationship between significant perinatal events and migraine severity

OBJECTIVE

Nociceptive neuronal circuits are formed during embryonic and postnatal times, so insult during these periods may result in long-term alterations to pain circuitry via synaptic plasticity. One possible long-term result of plasticity is central hyperexcitability, which is suspected to be involved in chronic headache. This study aimed to establish whether there is an association between early pain experiences and the experience of migraines in later childhood.

METHODS

In a retrospective study, we examined the charts of 280 pediatric migraineurs at the Division of Pediatric Neurology at Robert Wood Johnson Medical School and documented their perinatal history and migraine characteristics.

RESULTS

Analysis revealed that there was a significant relationship between patients who had been in the NICU at birth and the type of pain medication prescribed when compared with patients who had not been in the NICU (chi2 test, chi2(2) = 23.304; N = 30250). Findings also suggested that pediatric migraine patients who had been in the NICU at birth had a significantly earlier age of onset of their migraines (chi2 +/- SD = 7.83 +/- 3.23; N = 30) when compared with patients who did not remain in the NICU (chi2 +/- SD = 9.68 +/- 3.57; N = 250; Kolmogorov-Smirnov Test, chi2 = 10.699).

CONCLUSION

On the basis of these findings, we speculate that pain experience as a neonate, through neuronal plasticity and resulting central hyperexcitability, can alter the later experience of pain. However, this observational study cannot validate these links. Other potential explanations that work either synergistically or alone include other forms of stimulation and greater parental vigilance that may occur when neonates spend time in the NICU. This study would prompt additional development of a larger prospective study to establish a link between early pain experience and subsequent pain syndromes and also future investigation into the treatment of pain in neonates as a preventive measure for avoiding long-lasting neuronal alterations.

Venepuncture is preferable to heel lance for blood sampling in term neonates

BACKGROUND

The analgesic effect of oral sucrose in newborn infants undergoing painful procedures is generally accepted. For blood sampling, some studies have shown that venepuncture (VP) is less painful than heel lance (HL).

OBJECTIVE

To determine the least painful and most effective method among blood sampling by VP or HL with or without sucrose.

DESIGN

Randomised, double blind, placebo controlled trial.

SUBJECTS

A total of 100 healthy, full term newborn infants being screened for inborn errors of metabolism were randomly allocated to one of four experimental groups (25 infants in each). Intervention and

OUTCOME MEASURE

Seven specially trained nurses took turns to carry out blood sampling two minutes after administration of oral sucrose or water. Neonatal pain was assessed by the neonatal facial coding system (NFCS), as well as by crying.

RESULTS

Without sucrose, the NFCS score was higher in the HL group than the VP group during blood sampling (median 58 v 23, p<0.001). Oral sucrose significantly reduced the score of the HL group (58 v 47, p<0.01) and also tended to reduce the score of the VP group (23 v 2, p<0.1). However, the HL with sucrose group still had a higher score than the VP without sucrose group (47 v 23, p<0.01). Crying and the total procedure time showed the same trends as the NFCS score.

CONCLUSIONS

VP is less painful and more effective than HL for blood sampling in newborn infants. Although oral sucrose may have an additive analgesic effect, it is not necessarily required if VP is used for blood sampling.

Isoflurane exerts antinociceptive and hypnotic properties at all ages in Fischer rats

BACKGROUND

Some anaesthetic agents exhibit an age-dependent analgesic effect, for example nitrous oxide, which is ineffective in newborn rats. We investigated whether a similar time dependency existed for the responses to the volatile anaesthetic isoflurane.

METHODS

The analgesic and hypnotic properties of isoflurane at various ages was assessed using four cohorts of Fischer rats aged approximately 7, 16, and 28 days and adults (11-12 weeks old). Intraplantar administration of formalin mimicked inflammatory pain, and its effects were assessed using immunohistochemical (c-Fos staining) and behavioural paradigms. The hypnotic properties of isoflurane were assessed using loss of righting reflex.

RESULTS

Formalin administration produced a typical nociceptive response observed both behaviourally and immunohistochemically in all age groups; these nociceptive responses were significantly attenuated by isoflurane 0.5% at each age (P<0.05). Interestingly 7-day-old animals showed a significantly more potent hypnotic response than older animals (P<0.01): with adult rats being most resistant to isoflurane induced hypnosis (P<0.05).

CONCLUSION

In contrast to nitrous oxide, isoflurane is an effective antinociceptive agent in neonatal rats. If the data can be extrapolated to clinical scenarios these results suggest that isoflurane may be analgesic in newborns as well as adult humans. In addition, isoflurane is a potent hypnotic, especially in the very young, which is in contrast to the neonate's relative resistance to anaesthesia as assessed by minimum alveolar concentration.

Microarray analysis of gene expression following the formalin test in the infant rat☆

Injury and pain experienced by the infant results in immediate changes in pain sensitivity that last into adulthood. These long-term changes are likely initiated by altered gene expression. Here we measured how injury alters gene expression in the lumbar spinal cord early and late in the preweaning period of the rat. The expression of large numbers of genes was altered significantly at 3 days of age, when injury has long-term consequences. The functional classes of altered genes included transcription factors, cell death related and metal ion genes. The intensity of the stimulus in the 3-day-old pups induced changes in different classes of genes. Fewer changes were noted at 21 days of age. The increased expression of transcription factors and decreased expression of genes whose products are protective against cell death are hypothesized to underlie the long-term changes that are seen after injury in the neonate.

The impact of emotional stress early in life on adult voluntary ethanol intake-results of maternal separation in rats

The combination of genetic and environmental factors determines the individual vulnerability for excessive ethanol intake, possibly leading to dependence. The environmental influences early in life represent examples of determinant factors for adult behaviour and can be protective as well as risk factors. Maternal separation is one model to examine the long-term consequences of early environmental experiences on neurochemistry and behaviour, including drug-taking behaviour in experimental animals. In the present review, findings from studies using repeated short and prolonged periods of maternal separation, with emphasis on effects on voluntary ethanol intake in rats with or without a genetic predisposition for high voluntary ethanol intake, are summarized. Despite some contradictory results, the general picture emerging shows that short periods of maternal separation during the postnatal period result in a lower adult voluntary ethanol intake in male rats. Prolonged periods of maternal separation were found to induce a high voluntary ethanol intake in male rats, including rats with a genetic predisposition for high ethanol intake. Results from the literature also show that changes were not just related to time of separation but were also related to the degree of handling. Interestingly, in terms of voluntary ethanol intake, female rats were generally not affected by postnatal maternal separation. The reasons for these sex differences need further investigation. In terms of neurobiological consequences of maternal separation, conclusive data are sparse and one of the future challenges will, therefore, be to identify and characterize underlying neurobiological mechanisms, especially in the individual animal.

Skin-to-Skin Contact (Kangaroo Care) Analgesia for Preterm Infant Heel Stick

The purpose of the study was to compare a heel stick conducted during Kangaroo Care (skin-to-skin contact) with the mother to a heel stick in a warmer in reducing premature infant physiologic and behavioral pain responses. Twenty-four premature infants in a university-based neonatal intensive care unit were recruited and randomized to 2 sequences: sequence A group received 3 hours of Kangaroo Care (with a heel stick in Kangaroo Care) followed by 3 hours in a warmer (with a heel stick in the warmer). Sequence B group had warmer care and a heel stick (in the warmer) before Kangaroo Care and a heel stick (in Kangaroo Care). Heart rate, respiratory rate, oxygen saturation, crying time, and behavioral state were measured before, during, and after heel stick. Repeated measures ANOVA and Mann Whitney U statistics were performed. Heart rate and length of crying in response to pain were significantly reduced during Kangaroo Care and the Kangaroo Care heel stick as compared to when infants were in the warmer and had a heel stick in the warmer. Three infants did not cry at all during the Kangaroo Care heel stick; infants slept more during Kangaroo Care than in the warmer. Kangaroo Care positioning before and during heel stick is a simple and inexpensive analgesic intervention to ameliorate pain in stable premature infants.

Alterations in stress-associated behaviors and neurochemical markers in adult rats after neonatal short-lasting local inflammatory insult

Recently, there has been a growing interest in long-term consequences of neonatal pain because modern neonatal intensive care units routinely employ procedures that cause considerable pain and may be followed by local inflammation and hyperalgesia lasting for several hours or even days. To address this question, we developed a rat model of short lasting (<2 days) early local inflammatory insult produced by a single injection of 0.25% carrageenan (CAR) into the plantar surface of a hindpaw. Previously, we demonstrated that rats receiving this treatment within the first week after birth grow into adults with a global reduction in responsiveness to acute pain. Here, we report that these animals also manifest a low anxiety trait associated with reduced emotional responsiveness to stress. This conclusion is based in the following observations: (a) rats in our model display reduced anxiety on an elevated plus-maze; (b) in the forced swim test, these rats exhibit behavioral characteristics associated with stronger ability for stress coping; and (c) these animals have reduced basal and stress-induced plasma levels of such stress-related neuroendocrine markers as corticotropin-releasing factor, vasopressin, and adrenocorticotrophic hormone. In addition, we used DNA microarray and real-time reverse-transcriptase polymerase chain reaction to profile long-term changes in gene expression in the midbrain periaqueductal gray (PAG; a region involved in both stress and pain modulation) in our animal model. Among the affected genes, serotonergic receptors were particularly well represented. Specifically, we detected increase in the expression of 5-HT1A, 5-HT1D, 5-HT2A, 5-HT2C and 5-HT4 receptors. Several of these receptors are known to be involved in the anxiolytic and analgesic activity of the PAG. Finally, to determine whether neonatal inflammatory insult induces elevation in maternal care, which may play a role in generating long-term behavioral alterations seen in our model, we examined maternal behavior for 3 days following CAR injection. Indeed, we observed a substantial increase in maternal attention to the pups at the time of inflammation, but this increase was not without its cost: a period of significant maternal neglect afterward.

Morphine does not provide adequate analgesia for acute procedural pain among preterm neonates

BACKGROUND

Morphine alleviates prolonged pain, reduces behavioral and hormonal stress responses induced by surgery among term neonates, and improves ventilator synchrony and sedation among ventilated preterm neonates, but its analgesic effects on the acute pain caused by invasive procedures remain unclear.

OBJECTIVE

To investigate the analgesic efficacy of intravenously administered morphine on heel stick-induced acute pain among preterm neonates.

DESIGN

This study was nested within a prospective, randomized, double-blind, multicenter, placebo-controlled trial (the NEOPAIN Trial).

SETTING

A tertiary-care NICU in a teaching hospital.

PARTICIPANTS

Forty-two preterm neonates undergoing ventilation.

INTERVENTIONS

Neonates were randomized to either the morphine (loading dose of 100 microg/kg, followed by infusions of 10-30 microg/kg per hour according to gestation, N = 21) or placebo (5% dextrose infusions, N = 21) group. Pain responses to 3 heel sticks were evaluated, ie, before the loading dose (T1), 2 to 3 hours after the loading dose (T2), and 20 to 28 hours after the loading dose (T3).

MAIN OUTCOMES MEASURES

Pain was assessed with the Douleur Aiguë Nouveau-né (DAN) scale (behavioral pain scale) and the Premature Infant Pain Profile (PIPP) (multidimensional pain scale); plasma morphine levels were measured at T3.

RESULTS

Infants in the placebo and morphine groups had similar gestational ages (mean +/- SD: 27.2 +/- 1.7 vs 27.3 +/- 1.8 weeks) and birth weights (972 +/- 270 vs 947 +/- 269 g). Mean +/- SD DAN pain scores at T1, T2, and T3 were 4.8 +/- 4.0, 4.6 +/- 2.9, and 4.7 +/- 3.6, respectively, for the placebo group and 4.5 +/- 3.8, 4.4 +/- 3.7, and 3.1 +/- 3.4 for the morphine group. The within-group factor (pain at T1, T2, and T3) was not statistically different over time. The between-group analysis (infants receiving placebo versus those receiving morphine) showed no significant differences. Mean +/- SD PIPP pain scores at T1, T2, and T3 were 11.5 +/- 4.8, 11.1 +/- 3.7, and 9.1 +/- 4.0, respectively, for the placebo group and 10.0 +/- 3.6, 8.8 +/- 4.9, and 7.8 +/- 3.6 for the morphine group. The within-group factor was statistically different over time. The between-group analysis showed no significant differences. Mean +/- SD plasma morphine levels at T3 were 0.44 +/- 1.79 ng/mL and 63.36 +/- 33.35 ng/mL for the placebo and morphine groups, respectively. There was no correlation between plasma morphine levels and pain scores at T3 (DAN, R = -0.05; PIPP, R = -0.02).

CONCLUSIONS

Despite its routine use in the NICU, morphine given as a loading dose followed by continuous intravenous infusions does not appear to provide adequate analgesia for the acute pain caused by invasive procedures among ventilated preterm neonates.

Use of opioids in asphyxiated term neonates: effects on neuroimaging and clinical outcome

Perinatal asphyxia is a common cause of neurologic morbidity in neonates who are born at term. Asphyxiated neonates are frequently treated with analgesic medications, including opioids, for pain and discomfort associated with their care. On the basis of previous laboratory studies suggesting that opioids may have neuroprotective effects, we conducted a retrospective review of medical records of 52 neonates who were admitted to our neonatal intensive care unit between 1995 and 2002 and had undergone magnetic resonance imaging (MRI) of the brain. Our review revealed that 33% of neonates received morphine or fentanyl. The neonates who received opioids also had experienced hypoxic/ischemic insults of greater magnitude as suggested by higher plasma lactate levels and lower 5-min Apgar scores. It is interesting that the MRI studies of neonates who were treated with opioids during the first week of life demonstrated significantly less brain injury in all regions studied. More important, follow-up studies of a subgroup of opioid-treated neonates whose MRI scans were obtained in the second postnatal week had better long-term neurologic outcomes. Our results suggest that the use of opioids in the first week of life after perinatal asphyxia have no significant long-term detrimental effects and may increase the brain's resistance to hypoxic-ischemic insults.

Pain management in children: developmental considerations and mind-body therapies

One of the most challenging roles of medical providers serving children is to appropriately assess and treat their pain. Pain is one of the most misunderstood, underdiagnosed, and undertreated/ untreated medical problems, particularly in children. New JCAHO regulations regard pain as "the fifth vital sign" and require caregivers to regularly assess and address pain. This review focuses on the clinical assessment of pain, based on a developmental model and addresses common beliefs and myths that affect the management of pain in children. We provide a review of the pain literature that focuses on the integration of mind-body therapies into the management of procedure-related pain, headache, and recurrent abdominal pain in children.

Modulation of adult rat benzo(a)pyrene (BaP) metabolism and DNA adduct formation by neonatal diethylstilbestrol (DES) exposure

This study seeks to elucidate the role of diethylstilbestrol (DES), a synthetic estrogen on benzo(a)pyrene (BaP) metabolism in the male rat reproductive tissues. Offspring of timed-pregnant Sprague-Dawley rats were neonatally treated on days 2, 4, and 6 post-partum with 1.45 micromol/kg of DES. Ten weeks after birth, the adult rats were challenged with radiolabeled benzo(a)pyrene (3H BaP) (10 micromol/kg) and the rats were sacrificed 2 h after BaP exposure. Prostrate, testis, lung, liver, urine and feces samples were collected and extracted using a mixture of H2O, MeOH and CHCl3. The extracts were analyzed by reverse phase HPLC. The concentrations of BaP organic metabolites in DES rats were lower compared to controls (vehicle-treated rats). On the other hand, concentrations of aqueous metabolites were significantly increased in DES treated animals. The toxication to detoxication ratios were significantly decreased in DES rats compared to controls. This trend is also reflected in the decreased concentrations of BaP-DNA adducts in DES rats. Collectively these results suggest that DES is capable of modulating the metabolic pathway of BaP towards detoxification thereby preventing the manifestation of toxicity.

Predictors of internalizing symptoms among very low birth weight young women

As part of a longitudinal study of the outcomes of very low birth weight children (<1.5 kg), we sought to examine the perinatal, childhood, and young adult predictors of internalizing symptoms among very low birth weight young women and their normal birth weight controls. The cohort included 125 very low birth weight and 124 normal birth weight 20-year-old subjects. Perinatal, childhood, and young adult predictors were examined via stepwise multivariate analyses. Results revealed very low birth weight to be a significant predictor of parent-reported internalizing symptoms of their daughters but only among white subjects who had mothers with high levels of psychological distress. Additional significant predictors of 20-year internalizing symptoms included child I.Q. and internalizing symptoms at age 8 years and family expressiveness. When the results were analyzed according to the young adult self-report, additional predictors of internalizing symptoms included a history of asthma and exposure to violence. Perinatal risk factors were not found to be predictive of internalizing symptoms at age 20 years. Future studies should prospectively examine social and environmental factors associated with the neonatal intensive care experience that might explain the effect of very low birth weight on later psychopathology.

Long-term effects of fluoxetine or vehicle administration during pregnancy on behavioral outcomes in guinea pig offspring

RATIONALE

Assessment of the benefits versus risks associated with antidepressant use during pregnancy must include an analysis of possible drug effects on fetal development. Human studies indicate that prenatal fluoxetine exposure is associated with adverse neonatal outcomes. Animal modeling may provide useful information concerning possible long-term effects of prenatal fluoxetine exposure. Limitations in previous such studies using rat models may be overcome using a guinea pig model in which fluoxetine is delivered by osmotic pump throughout pregnancy.

METHODS

Initial experiments measured the half-life of fluoxetine and dosing required to achieve human therapeutic blood levels in the guinea pig. In subsequent experiments, guinea pigs received fluoxetine or vehicle via osmotic pump or no treatment throughout pregnancy. Outcome measures included: pregnancy characteristics, weight gain, and, in offspring as adults, pain threshold, acoustic startle responses and prepulse inhibition.

RESULTS

There was no effect of treatment group on gestation length, number of live-births or still-births, maternal or offspring weight gain, and acoustic startle responses. In adult offspring, pain threshold was decreased by vehicle treatment during gestation. Prenatal fluoxetine increased pain threshold, relative to vehicle controls. Prepulse inhibition of startle was increased in adult offspring treated prenatally with either vehicle or fluoxetine compared to no treatment.

CONCLUSIONS

The guinea pig provides a practicable and clinically relevant model of prenatal fluoxetine exposure. Adult guinea pigs exposed to fluoxetine prenatally showed increased thermal pain thresholds but no change in prepulse inhibition, indicating selective long-term effects of prenatal fluoxetine on serotonin-modulated behaviors. Further studies on long-term effects of prenatal fluoxetine on nociception are warranted.

Analgesic effects of oral sucrose and pacifier during eye examinations for retinopathy of prematurity

Oral sucrose reduces pain during heel sticks and venipunctures in preterm infants, but no studies have been done to determine the effectiveness of sucrose during eye examinations for retinopathy of prematurity. Therefore, the purpose of this study was to determine the effectiveness of local anesthetic eye drops and a pacifier, plus repeated doses of 24% sucrose, to relieve pain associated with eye examinations for retinopathy of prematurity. In this double-blind randomized controlled trial, 30 preterm infants were randomly assigned to one of two treatments, in which they received either local anesthetic eye drops, a pacifier, plus three doses of sterile water or local anesthetic eye drops, a pacifier, plus three doses of 24% sucrose during the eye examination. Treatment effectiveness was determined using a validated infant pain measure, the Premature Infant Pain Profile (PIPP), which includes measures of facial expressions, heart rate, and oxygen saturation and takes behavioral state and gestational age into consideration. Data were collected before, during, and following an examination of the left eye. Statistically significant differences in mean PIPP scores were found between the sucrose and water groups during the left eye examination. The mean PIPP score was 8.8 for the sucrose group and 11.4 for the water group ( t = 2.87, p = .008 two-tailed). No significant differences were found in PIPP scores immediately following the procedure. Sucrose and a pacifier may be beneficial for minimizing pain during eye examinations in preterm infants and should be considered as a part of evidence-based guidelines for relieving pain during this procedure.

Pediatric procedural pain

Pain is subjective. The pain response is individual and is learned through social learning and experience. Early pain experiences may play a particularly important role in shaping an individual's pain responses. Painful medical procedures such as immunizations, venipunctures and dental care, and minor emergency department procedures such as laceration repair, compose a significant portion of the average child's experience with painful events. Inadequate relief of pain and distress during childhood painful medical procedures may have long-term negative effects on future pain tolerance and pain responses. This article reviews the evidence for long-term negative effects of inadequately treated procedural pain, the determinants of an individual's pain response, tools to assess pain in children, and interventions to reduce procedural pain and distress. Future research directions and a model for conceptualizing and studying pediatric procedural pain are proposed.

The Assessment of Preterm Infants' Behavior (APIB): furthering the understanding and measurement of neurodevelopmental competence in preterm and full-term infants

The Assessment of Preterm Infants' Behavior (APIB) is a newborn neurobehavioral assessment appropriate for preterm, at risk, and full-term newborns, from birth to 1 month after expected due date. The APIB is based in ethological-evolutionary thought and focuses on the assessment of mutually interacting behavioral subsystems in simultaneous interaction with the environment. The subsystems of functioning assessed include the autonomic (respiration, digestion, color), motor (tone, movement, postures), state organization (range, robustness, transition patterns), attention (robustness, transitions), and self-regulation (effort, success) systems as well as the degree of facilitation required to support reorganization and subsystem balance. The environment is represented by a sequence of distal, proximal, tactile, and vestibular challenges, derived from the BNBAS. The APIB conceptualizes infant competence as the degree of differentiation of subsystem function and degree of modulation of subsystem balance at any stage in infant development. Infants are understood as actively seeking their next differentiation, while counting on good enough environments to assure progressing developmental competence. In the case of interference such as premature birth, the mismatch of expectation and actual experience causes misalignment, which may become developmentally costly. The assessment is a finely tuned dialogue between examiner and infant, which requires training, skill and self-knowledge. The APIB has well established inter-rater-reliability, concurrent and construct validity, and is clinically relevant for behavioral intervention and individually appropriate and supportive care.

Pain assessment in the neonate using the Bernese Pain Scale for Neonates

BACKGROUND

Neonates who require treatment in the neonatal intensive care unit (NICU) are subjected to many invasive painful procedures.

AIMS

Assessment of pain in preterm and term neonates with or without ventilation on continuous positive airway pressure using the Bernese Pain-Scale for Neonates (BPSN). The validity and the reliability of the BPSN was established.

STUDY DESIGN AND SUBJECTS

Pain assessments (n=288) were performed by 6 health care workers in different situations of term and preterm neonates. Each neonate (n=12) was observed in four given situations (after feeding, while a foot was being warmed, while a routine capillary blood sample was taken and 15 min after the blood sample was taken). Pain assessments were made by two nurses at the bedside using the BPSN, the Visual-Analogue Scale (VAS) and the Premature Infant Pain Profile (PIPP). At the same time, a video sequence was made which was shown later to four different nurses to assess pain using the BPSN, the PIPP, and the VAS.

RESULTS

The construct validity of the BPSN was very good (F=41.3, p<0.0001). Moreover, concurrent and convergent validity of the BPSN compared to VAS and PIPP was r=0.86, and r=0.91, p<0.0001, respectively. Finally, the study demonstrated high coefficients for interrater (r=0.86-0.97) and intrarater reliability (r=0.98-0.99).

CONCLUSION

The BPSN was shown to be a valid and reliable tool for assessing pain in term and preterm neonates with and without ventilation.

The relationship between physiological and behavioral measures of stress in preterm infants

OBJECTIVE AND DESIGN

The purpose of this exploratory descriptive analysis was to explore relationships among physiological stress, behavioral stress, and motor activity cues in preterm infants when they were not being handled or disturbed, and to determine whether there were differences between younger and older preterm infants in these variables or relationships.

SETTING AND PARTICIPANTS

The convenience sample included 42 preterm infants who had been 27 to 33 weeks gestational age at birth and were from 6 to 19 days old at the time of data collection in the neonatal intensive-care unit.

MEASURES

In each 10-minute observation, heart rate (HR) and oxygen saturation (O2 sat) levels were recorded every 5 seconds, and observational measures of behavioral distress and motor activity were recorded twice a minute. The physiological data were coded to reflect the percentage of each 10-minute period during which HR levels were less than 100 bpm or more than 200 bpm or O2 sat levels were abnormally low (less than 90 mg%). Data were analyzed with correlational and general linear mixed models procedures.

RESULTS

Stress cues and motor activity were more often related to low levels of O2 sat than to low or high HR. Physiological status was more often related to motor activity than to stress cues. Few differences in the relationships were observed between younger and older preterm infants.

CONCLUSION

Although these results are preliminary, they suggest that neonatal nurses should monitor preterm infants' behavioral stress and motor activity cues in response to caregiving and minimize stimuli that evoke stress responses linked to physiological instability.

Early experience alters brain function and structure

OBJECTIVE

To investigate the effects of early experience on brain function and structure.

METHODS

A randomized clinical trial tested the neurodevelopmental effectiveness of the Newborn Individualized Developmental Care and Assessment Program (NIDCAP). Thirty preterm infants, 28 to 33 weeks' gestational age (GA) at birth and free of known developmental risk factors, participated in the trial. NIDCAP was initiated within 72 hours of intensive care unit admission and continued to the age of 2 weeks, corrected for prematurity. Control (14) and experimental (16) infants were assessed at 2 weeks' and 9 months' corrected age on health status, growth, and neurobehavior, and at 2 weeks' corrected age additionally on electroencephalogram spectral coherence, magnetic resonance diffusion tensor imaging, and measurements of transverse relaxation time.

RESULTS

The groups were medically and demographically comparable before as well as after the treatment. However, the experimental group showed significantly better neurobehavioral functioning, increased coherence between frontal and a broad spectrum of mainly occipital brain regions, and higher relative anisotropy in left internal capsule, with a trend for right internal capsule and frontal white matter. Transverse relaxation time showed no difference. Behavioral function was improved also at 9 months' corrected age. The relationship among the 3 neurodevelopmental domains was significant. The results indicated consistently better function and more mature fiber structure for experimental infants compared with their controls.

CONCLUSIONS

This is the first in vivo evidence of enhanced brain function and structure due to the NIDCAP. The study demonstrates that quality of experience before term may influence brain development significantly.

Analgesic effect of expressed breast milk in procedural pain in neonates

Prevention, treatment and assessment of neonatal pain have been of major clinical and scientific interest the last decades. Non-pharmacological interventions such as sweet oral solutions are successful in pain relief. Whether breast milk, with its lactose content of 7%, has any effect on the prevention of pain has been debated.

CONCLUSION

Randomized studies of breast milk in prevention and treatment of neonatal pain are needed.

Gastric suction at birth associated with long-term risk for functional intestinal disorders in later life

OBJECTIVE

To test the hypothesis that noxious stimulation at birth may increase the long-term risk for developing psychosomatic or functional disorders during later life.

STUDY DESIGN

Matched case-control study using sibling controls. The birth records were retrieved for the offspring of 494 mothers who, after uncomplicated pregnancies, had delivered two or more children with birth weights at least 2500 g, if at least one child was exposed to a perinatal complication or birth asphyxia. Among their offspring (N=1110), the 108 cases hospitalized for functional intestinal symptoms were identified from nationwide hospital discharge records. Of these, 96 cases were compared with 116 unaffected sibling controls.

RESULTS

Functional intestinal symptoms occurred more commonly among the 1110 subjects (9.5%) than in the general population (3.4%, chi(2)=124, P<10(-6)). Gastric suction at birth occurred more frequently among the cases compared with their siblings (22.9% vs 11.2%). There were no differences in the number of cases and controls exposed to perinatal trauma or birth asphyxia. Multivariate logistic regression analyses showed that gastric suction at birth was associated with functional intestinal disorders during later life (odds ratio, 2.99; 95% confidence interval, 1.32-6.79; P=.009), whereas maternal, perinatal, or other confounding variables were not significant.

CONCLUSIONS

Noxious stimulation caused by gastric suction at birth may promote the development of long-term visceral hypersensitivity and cognitive hypervigilance, leading to an increased prevalence of functional intestinal disorders in later life.

Neonatal ethanol exposure produces a hyperalgesia that extends into adolescence, and is associated with increased analgesic and rewarding properties of nicotine in rats

RATIONALE

Drug exposure during CNS development may alter subsequent dependence liability. We postulated that early alcohol exposure might produce persistent alterations in responses to noxious stimuli. Because relief of physical discomfort may be negatively reinforcing, changes in responses to noxious stimuli produced by early alcohol exposure may increase the rewarding properties of nicotine, a potent analgesic. Such factors may contribute to the high level of alcohol and nicotine co-abuse in humans.

OBJECTIVES

The purpose of this study was to determine whether neonatal ethanol exposure in rats altered responses to noxious stimuli, and whether nicotine would then be more rewarding to the alcohol-exposed offspring, perhaps via its analgesic actions.

METHODS

Neonatal rats received ethanol by gavage (5.0 or 6.5 g/kg) on postnatal days (PND) 9-13. An iso-caloric control group was also included. Rats were then tested to assess responsiveness to a mild noxious heat stimulus, as measured in the tail-flick assay (PND 14 and PND 28), for their response to acute analgesic injections of either nicotine or ethanol (PND 28), and for nicotine induced conditioned place preference (CPP) (PND 36).

RESULTS

Neonatal ethanol exposure produced hyperalgesia during the first 24 h after alcohol withdrawal (PND 14) that continued through PND 28. The analgesic effects of 12.5 microg/kg nicotine were enhanced approximately 2-fold in adolescent rats with previous ethanol histories, relative to controls. These ethanol-exposed rats also showed a significant CPP to nicotine, whereas controls showed no CPP.

CONCLUSIONS

Persistent decreases in tail-flick response latencies suggestive of hyperalgesia were observed following neonatal ethanol exposure in the rat. These changes were accompanied by increases in the analgesic and place-conditioning effects of nicotine in adolescence. If similar effects occur in humans, prenatal alcohol exposure may play a role in an increased risk for the rewarding effects and dependence liability of nicotine later in life.

A three-center, randomized, controlled trial of individualized developmental care for very low birth weight preterm infants: medical, neurodevelopmental, parenting, and caregiving effects

Medical, neurodevelopmental, and parenting effects of individualized developmental care were investigated in a three-center, randomized, controlled trial. A total of 92 preterm infants, weighing less than 1250 g and aged less than 28 weeks, participated. Outcome measures included medical, neurodevelopmental and family function. Quality of care was also assessed. Multivariate analysis of variance investigated group, site, and interaction effects; correlation analysis identified individual variable contributions to significant effects. The results consistently favored the experimental groups. The following contributed to the group effects: shorter duration of parenteral feeding, transition to full oral feeding, intensive care, and hospitalization; lower incidence of necrotizing enterocolitis; reduced discharge ages and hospital charges; improved weight, length, and head circumferences; enhanced autonomic, motor, state, attention, and self-regulatory functioning; reduced need for facilitation; and lowered family stress and enhanced appreciation of the infant. Quality of care was measurably improved. Very low birth weight infants and their parents, across diverse settings, may benefit from individualized developmental care.

Influence of sex and experimental protocol on the effect of maternal deprivation on rectal sensitivity to distension in the adult rat

Neonatal maternal separation induces visceral hyperalgesia before and after stress in male rats. This study compares the effects on sensitivity to rectal distension in adult male and female rats, using two protocols of deprivation. Between postnatal days 1 and 14, maternal deprivation was performed for 2 h per day according to a protocol of type M (removal of all pups from home cage) or type P (separation of half of littermates). Visceral sensitivity was assessed at 12 weeks of age by the number of abdominal contractions induced by rectal distension before and after restraint stress. Calcitonin gene-related peptide (CGRP) was identified in the rectal wall by immunohistochemistry. In basal conditions, both separation protocols induced hyperalgesia, that was greater after type M than type P, and in females than in males for type P separation. Acute restraint stress induced hyperalgesia in control females only, and this effect was similarly enhanced by both type P and M separation. No difference was found between controls and deprived rats in rectal CGRP immunoreactivity which was greater in females and increased after rectal distension. These results indicate that long-term visceral hyperalgesia depends upon the type of maternal deprivation and that females are more sensitive than males.

Myths and facts about pain in neonates

THE PURPOSE OF THIS COLUMN is to examine some of the common myths and misconceptions about neonatal pain and to present facts found in clinical and evidence-based nursing research. Research shows that pain and stress in the preterm infant have both immediate and long-range deleterious effects.Nociceptionis the term frequently used to describe the neonate’s nerve perception of painful stimuli.1

Pilot study of a pain assessment tool in the Neonatal Intensive Care Unit

OBJECTIVES

To develop and validate a pain assessment tool to assess procedural pain experienced by mechanically ventilated neonates.

METHODS

Assessment of ventilated infants, before, during and after a known routine traumatic procedure using the Nepean Neonatal Intensive Care Unit Pain Assessment Tool (NNICUPAT). This tool scores physiological and behavioural responses to pain. Variables used in the NNICUPAT included facial expression, body movement, skin colour, saturation, respiratory rate, heart rate and nurses' perception of pain. To test the validity of the NNICUPAT, it was compared to a visual analogue scale (VAS), which is a unidimesional observation measure, where zero equals no pain and 10 equals severe pain.

RESULTS

Thirty ventilated neonates (mean gestation 28 +/- 3.3 standard deviation (SD)) weeks) were enrolled in the pilot study over a 9-month period. The total score before the procedure was: 0.26 +/- 0.14 (mean +/- standard error of the mean (SEM)) range 0-3; total score during the procedure 5.1 +/- 2.2 (mean +/- SD) range 1-10; and the total score after the procedure was 0.26 +/- 0.15 (mean +/- SEM) range 0-3. There was a significant correlation between the NNICUPAT and the VAS during the procedure (r = 0.825, P = < 0.01) and after the procedure (r = 0.375, P = < 0.05). Inter-rater reliability was calculated between the principle coder and other coders (using the NNICUPAT) and showed a significant correlation before (r = 0.88, P < 0.01) and during (r = 0.88, P < 0.01) the procedure.

CONCLUSIONS

The NNICUPAT does show validity in the assessment of procedural pain in the ventilated neonate. Further evaluation of both inter- and intra-rater reliability will be necessary to establish the ongoing validity of the NNICUPAT.

Long-term effects of maternal separation on ethanol intake and brain opioid and dopamine receptors in male wistar rats

Accumulating evidence indicates that an animal's response to a drug can be profoundly affected by early environmental influences. The brain opioid and dopamine systems may play a critical role in these effects, since various types of stress and drugs of abuse promote alterations in these brain systems. To study this further, we investigated long-term behavioural and neurochemical effects of repeated maternal separation in male Wistar rats. The pups were separated in litters daily from their dams for either 15 min (MS15) or 360 min (MS360) from postnatal days 1-21. Analysis of the kappa- and delta-opioid, dopamine D(1)- and D(2)-like receptors with receptor autoradiography revealed long-term neurochemical changes in several brain areas. D(1)-like receptor binding was affected in the hippocampus and D(2)-like receptor binding in the ventral tegmental area and the periaqueductal gray, whereas minor changes were seen in opioid receptor density after maternal separation. At 10-13 weeks of age, MS15 rats had a lower ethanol intake whereas, the MS360 rats consumed more 8% ethanol solution compared with MS15 and animal facility-reared rats. Ethanol consumption altered kappa-receptor density in several brain areas, for example the amygdala, substantia nigra and the periaqueductal gray. D(1)-like receptor binding was affected in distinct brain areas, including the nucleus accumbens, where also delta-opioid receptor density was changed in addition to the frontal cortex. Ethanol-induced changes were observed in D(2)-like receptor density in the ventral tegmental area in MS360, and in the ventral tegmental area and frontal-parietal cortex in animal facility-reared rats. These findings show that early experiences can induce long-lasting changes in especially brain dopamine receptor density and that ethanol consumption induces alterations in opioid and dopamine receptor density in distinct brain areas. It is also suggested that changes induced by repeated MS15 may provide protection against high voluntary ethanol intake.

Nursing assessment of infant pain

This study compared how nurses perceived their assessment of infant pain and how the pain was actually assessed in an intensive care unit. A descriptive design was used to collect data about nurses beliefs and documentation practices related to pain assessment in infants. An anonymous subset of the unit nurses (n = 24) responded to a questionnaire regarding infant pain assessment. Pain assessment documentation of the unit nurses was examined in a retrospective chart review (n = 107). Results showed an inconsistency between what nurses believe about infant pain as sessment and the documentation practice in the unit. According to the questionnaire, the nurses believed that pain assessment was important to providing effective pain relief and that nurses are capable of assessing infant pain. However, it was not evident in the documentation that nurses used pain tools or other means to document their evaluations of infant pain or the infant's response to pain medication interventions.

CONCLUSION

Greater consistency of nurses in documenting pain assessment, thereby improving care provider communication of an infant's pain experience, is needed to improve the standard of care in managing infant pain.

[Multicentric study on neonatal medical pain management in the Nord-Pas-de-Calais]

The aim of this study was to describe pain management for newborn infants in neonatal intensive care units and neonatal units in the Nord-Pas-de-Calais.

PATIENTS AND METHODS

A questionnaire was distributed to the 52 physicians practising in the six neonatal intensive care units and six neonatal units. The questions were in reference to pain assessment, treatment and prevention.

RESULTS

Forty questionnaires were completed (77%). Eleven units proclaimed an interest in neonatal pain management. The tool for assessing pain was the EDIN scale (Echelle Douleur Inconfort Nouveau-né, neonatal pain and discomfort scale). Analgesic treatment was administered in 100% of cases for the insertion of chest tube, in 92% of cases for the insertion of percutaneous central catheter in a ventilated newborn infant and in 91% of cases for necrotizing enterocolitis requiring a mechanical ventilation. Prescribed analgesic drugs were propacetamol, nalbuphin or fentanyl; a sedation by midazolam or diazepam was occasionally associated. Emla cream was used before lumbar puncture in 80% of cases in the neonatal intensive care units and in 92% of cases in the neonatal units. Three neonatal intensive care units and four neonatal units administered a sucrose solution for blood samples.

CONCLUSION

At the time of study, the interest in the pain of the physicians working in neonatal intensive care units and neonatal units was inadequate to guarantee an optimum management of pain in newborn infants. Physicians' approach remained heterogeneous.

Repetitive acute pain in infancy increases anxiety but does not alter spatial learning ability in juvenile mice

We assessed the long-term behavioural effects of a single acute or repetitive inflammatory pain experienced during infancy. Groups of male and female CD1 mice were subjected to either an acute single pain, i.e. a tail clip or sham pain at P8, or acute repetitive pain in the form of needle pricks or sham pain from P8 to P14. All of the subjects were tested in the elevated plus maze at P30 and in the Morris Water Maze from P31 to P38. Mice in the acute single pain and sham groups did not differ on measures of anxiety in the plus maze. Mice in the repetitive pain group demonstrated significantly more anxious behaviours than controls in the elevated plus maze as they spent less time in the open arms, made fewer open arm entries, displayed fewer head dips and showed more stretch attend postures. There were no effects of single or repetitive pain treatments in the latency to find the hidden platform in the Morris Water Maze. Overall, these data suggest that acute repetitive pain experienced during infancy may increase anxiety later in life but it does not influence spatial learning as measured in the Morris Water Maze. The origin of the anxiogenic profile shown in the acute repetitive pain mice may be a result of changes in neural circuitry or context dependent learning and is currently under further investigation with this paradigm.

Follow-up data their use in evidence-based decision-making

Experience with certain perinatal interventions, such as supplemental oxygen and dexamethasone, leads to the conclusion that follow-up data are needed to be well informed about the safety of certain perinatal interventions. Experience with indomethacin suggests that follow-up data also are regarded by some clinicians as a necessary aspect of evidence about effectiveness. Ideally, clinical trials of perinatal interventions might involve collection of data about neonatal predictors of outcome (such as a neuroimaging study and a standardized neurologic assessment); several developmental and neurologic assessments before school entry; a comprehensive evaluation of the child's cognitive function, behavioral competencies, and academic performance at 7 to 8 years of age; serial detailed assessments of the family psychosocial functioning; and an inventory of resources available for the child. Many clinical trials have not included follow-up after the neonatal period, and in such cases information about the effect of the intervention on participants' HRQL is incomplete. The approach taken in several recent trials, in which the outcome of interest is neurodevelopmental outcome at 18 months, attempts to strike a balance between a theoretical ideal (a comprehensive, longitudinal follow-up through school age) and a follow-up regimen that is not prohibitively expensive. Such trials include follow-up during the first 1 to 3 years of life, when major disabilities can be identified reliably, thereby providing moderately informative data about participants' eventual quality of life, related to the presence or absence of major disability. If, however, there is reason to suspect that the intervention has effects on the developing brain, follow-up after school entry may provide additional evidence pertinent to the risks and benefits of the intervention.