Suckling- and sucrose-induced analgesia in human newborns

Pharmacological therapy for analgesia and sedation in the newborn

Rapid advances have been made in the use of pharmacological analgesia and sedation for newborns requiring neonatal intensive care. Practical considerations for the use of systemic analgesics (opioids, non-steroidal anti-inflammatory agents, other drugs), local and topical anaesthetics, and sedative or anaesthetic agents (benzodiazepines, barbiturates, other drugs) are summarised using an evidence-based medicine approach, while avoiding mention of the underlying basic physiology or pharmacology. These developments have inspired more humane approaches to neonatal intensive care. Despite these advances, little is known about the clinical effectiveness, immediate toxicity, effects on special patient populations, or long-term effects after neonatal exposure to analgesics or sedatives. The desired or adverse effects of drug combinations, interactions with non-pharmacological interventions or use for specific conditions also remain unknown. Despite the huge gaps in our knowledge, preliminary evidence for the use of neonatal analgesia and sedation is available, but must be combined with a clear definition of clinical goals, continuous physiological monitoring, evaluation of side effects or tolerance, and consideration of long-term clinical outcomes.

Prevention and management of pain in the neonate: an update

The prevention of pain in neonates should be the goal of all caregivers, because repeated painful exposures have the potential for deleterious consequences. Neonates at greatest risk of neurodevelopmental impairment as a result of preterm birth (ie, the smallest and sickest) are also those most likely to be exposed to the greatest number of painful stimuli in the NICU. Although there are major gaps in our knowledge regarding the most effective way to prevent and relieve pain in neonates, proven and safe therapies are currently underused for routine minor yet painful procedures. Every health care facility caring for neonates should implement an effective pain-prevention program, which includes strategies for routinely assessing pain, minimizing the number of painful procedures performed, effectively using pharmacologic and nonpharmacologic therapies for the prevention of pain associated with routine minor procedures, and eliminating pain associated with surgery and other major procedures.

The polyvagal perspective

The polyvagal theory introduced a new perspective relating autonomic function to behavior, that included an appreciation of the autonomic nervous system as a "system," the identification of neural circuits involved in the regulation of autonomic state, and an interpretation of autonomic reactivity as adaptive within the context of the phylogeny of the vertebrate autonomic nervous system. The paper has two objectives: first, to provide an explicit statement of the theory; and second, to introduce the features of a polyvagal perspective. The polyvagal perspective emphasizes how an understanding of neurophysiological mechanisms and phylogenetic shifts in neural regulation leads to different questions, paradigms, explanations, and conclusions regarding autonomic function in biobehavioral processes than peripheral models. Foremost, the polyvagal perspective emphasizes the importance of phylogenetic changes in the neural structures regulating the autonomic nervous system and how these phylogenetic shifts provide insights into the adaptive function and the neural regulation of the two vagal systems.

The Psychophysical Relationship between Bitter Taste and Burning Sensation: Evidence of Qualitative Similarity

Although it has long been studied as a pure sensory irritant, the ability of capsaicin to evoke, mask, and desensitize bitter taste suggests that burning sensations and bitter taste might be closely related perceptually. The current study investigated the psychophysical relationship between bitterness and burning using 2 different approaches. In Experiment 1, spatial discrimination of 4 taste stimuli was measured in the presence or absence of capsaicin. The subjects' task was to report which of 3 swabs, spaced 1 cm apart and presented to the tongue tip, contained a taste stimulus when 1) water was presented on the other 2 swabs or 2) when 10 muM capsaicin was presented on all 3 swabs. The presence of capsaicin did not change performance on the 3 alternative forced-choice (3-AFC) task for sweet, sour, and salty stimuli, while the localization error for 1.8 mM quinine sulfate (QSO(4)) increased significantly. In Experiment 2, the perceptual similarity/dissimilarity of taste stimuli and capsaicin was measured directly using pairs of stimuli applied to opposite sides of the tongue tip on swabs separated by 2 cm. Multidimensional scaling analyses showed that capsaicin fell nearer to QSO(4) than to any other taste stimulus. Cluster analysis corroborated this finding: capsaicin was closely linked with QSO(4) and the capsaicin-QSO(4) group was separated from the other taste stimuli. The latter result indicated that bitterness was more similar to burning than to the other tastes. These findings imply that despite being mediated by different sensory modalities, bitterness and burn are qualitatively similar. We speculate that this similarity reflects a common function of these 2 sensations as sensory signals of potentially harmful stimuli.

Pode a amamentação promover alívio da dor aguda em recém-nascidos?

Trata-se de um estudo de revisão cujo objetivo foi identificar a eficácia da amamentação e dos aspectos que a congregam (contato, sucção, odor e leite) como medidas não- farmacológicas no alívio da dor aguda em recém-nascidos. Os 14 artigos analisados foram obtidos pelo Medline/PubMed. Verificou-se diferenças metodológicas quanto à amostragem, procedimentos dolorosos, períodos e maneira de administrar o tratamento e variáveis mensuradas. Percebeu-se a eficácia da amamentação e dos aspectos que a congregam, no alívio da dor aguda. Percebe-se a necessidade de estudos que avaliem o seu efeito analgésico antes do procedimento doloroso, até a recuperação, tempo este, suficiente para atingir-se o efeito analgésico pós-absortivo do leite. Deve-se considerar a interação entre todos os componentes que estão contidos na amamentação.

Analgesia and local anesthesia during invasive procedures in the neonate

BACKGROUND

Preterm and full-term neonates admitted to the neonatal intensive care unit or elsewhere in the hospital are routinely subjected to invasive procedures that can cause acute pain. Despite published data on the complex behavioral, physiologic, and biochemical responses of these neonates and the detrimental short- and long-term clinical outcomes of exposure to repetitive pain, clinical use of pain-control measures in neonates undergoing invasive procedures remains sporadic and suboptimal. As part of the Newborn Drug Development Initiative, the US Food and Drug Administration and the National Institute of Child Health and Human Development invited a group of international experts to form the Neonatal Pain Control Group to review the therapeutic options for pain management associated with the most commonly performed invasive procedures in neonates and to identify research priorities in this area.

OBJECTIVE

The goal of this article was to review and synthesize the published clinical evidence for the management of pain caused by invasive procedures in preterm and full-term neonates.

METHODS

Clinical studies examining various therapies for procedural pain in neonates were identified by searches of MEDLINE (1980-2004), the Cochrane Controlled Trials Register (The Cochrane Library, Issue 1, 2004), the reference lists of review articles, and personal files. The search terms included specific drug names, infant-newborn, infant-preterm, and pain, using the explode function for each key word. The English-language literature was reviewed, and case reports and small case series were discarded.

RESULTS

The most commonly performed invasive procedures in neonates included heel lancing, venipuncture, IV or arterial cannulation, chest tube placement, tracheal intubation or suctioning, lumbar puncture, circumcision, and SC or IM injection. Various drug classes were examined critically, including opioid analgesics, sedative/hypnotic drugs, nonsteroidal anti-inflammatory drugs and acetaminophen, injectable and topical local anesthetics, and sucrose. Research considerations related to each drug category were identified, potential obstacles to the systematic study of these drugs were discussed, and current gaps in knowledge were enumerated to define future research needs. Discussions relating to the optimal design for and ethical constraints on the study of neonatal pain will be published separately. Well-designed clinical trials investigating currently available and new therapies for acute pain in neonates will provide the scientific framework for effective pain management in neonates undergoing invasive procedures.

Sucrose and non-nutritive sucking for the relief of pain in screening for retinopathy of prematurity: a randomised controlled trial

BACKGROUND

Screening is necessary for infants at risk of retinopathy of prematurity. Despite local anaesthetic drops, infants find eye examinations distressing, displaying behavioural and physiological changes indicating acute pain. Oral sucrose and non-nutritive sucking reduce pain responses associated with invasive procedures.

OBJECTIVE

To evaluate the use of oral sucrose and/or pacifier for reducing pain responses during eye examinations.

METHODS

Forty infants <32 weeks gestation or <1500 g birth weight, in two neonatal units, were randomised to one of four interventions administered two minutes before their first screening examination: 1 ml sterile water as placebo (group 1, n = 10), 1 ml 33% sucrose solution (group 2, n = 10), 1 ml sterile water with pacifier (group 3, n = 9), or 1 ml 33% sucrose solution with pacifier (group 4, n = 11). Examinations were videotaped. Two observers, blind to the intervention, assessed recordings. Pain responses were scored using the premature infant pain profile (PIPP).

RESULTS

The groups were similar in gestation, birth weight, and age at examination. Mean PIPP scores were 15.3, 14.3, 12.3, and 12.1 for groups 1, 2, 3, and 4 respectively. Analysis of variance showed a significant difference in PIPP score between groups (p = 0.023). Infants randomised to pacifiers scored lower than those without pacifiers (p = 0.003). There was no difference between groups receiving sucrose and those receiving water (p = 0.321).

CONCLUSIONS

Non-nutritive sucking reduced distress responses in infants undergoing screening for retinopathy of prematurity. The difference in response was large enough to be detected by a validated assessment tool. No synergistic effect of sucrose and pacifier was apparent in this group.

Mental health, attachment and breastfeeding: implications for adopted children and their mothers

Breastfeeding an adopted child has previously been discussed as something that is nice to do but without potential for significant benefit. This paper reviews the evidence in physiological and behavioural research, that breastfeeding can play a significant role in developing the attachment relationship between child and mother. As illustrated in the case studies presented, in instances of adoption and particularly where the child has experienced abuse or neglect, the impact of breastfeeding can be considerable. Breastfeeding may assist attachment development via the provision of regular intimate interaction between mother and child; the calming, relaxing and analgesic impact of breastfeeding on children; and the stress relieving and maternal sensitivity promoting influence of breastfeeding on mothers. The impact of breastfeeding as observed in cases of adoption has applicability to all breastfeeding situations, but may be especially relevant to other at risk dyads, such as those families with a history of intergenerational relationship trauma; this deserves further investigation.

Maternal soothing and infant stress responses: Soothing, crying and adrenocortical activity during inoculation

The relation between maternal soothing and infant stress response during inoculation was examined in a sample of 37 mothers and their 3-month-old infants. The mothers' soothing and the infants' cry vocalizations and the mothers' and the infants' salivary cortisol level pre- and post-injection were analysed. There was a positive relation between infants' cry vocalization post-injection and maternal soothing pre- and post-injection. The sample was divided in two sub-groups depending on whether the mothers evidenced most soothing of the infants in the period before (Preparatory group; n=20) or after (Contingent group; n=17) the syringe injection. In the Preparatory group, the duration of infant cry vocalizations was related to amount of maternal soothing before and after the injection, while cry vocalizations in the Contingent group was related to amount of maternal soothing after the injection. The Contingent infants responded to the injection with a significant increase in cortisol, while there was no increase in the Preparatory infants. The Preparatory infants evidenced significantly longer duration of looking at the target stimuli in a visual marking task, suggesting greater difficulties in disengaging attention. These findings indicate that 3-month-olds' stress responses and their mothers' situational behaviour are mutually regulated.

Prenatal, perinatal and neonatal stimulation: A survey of neonatal nurseries

A recent survey was conducted on stimulation of mothers and babies during pregnancy and the neonatal period. The survey was responded to by 82 neonatology staff members from Neonatal Intensive Care Units (NICUs) at hospitals in the United States. Some forms of stimulation were extremely common including (1) skin-to-skin following birth in the delivery room (83% of hospitals); (2) containment (swaddling and surrounded by blanket rolls) in the NICU (86%); (3) music in the NICU (72%); (4) rocking in the NICU (85%); (5) kangaroo care (98%); (6) non-nutritive sucking during tubefeedings in the NICU (96%); and (7) breastfeeding in the NICU (100%). Other forms of stimulation occurred less frequently including (1) pregnancy massage (19%); (2) labor massage (30%); (3) the Doula (assistant who comforts during labor and delivery) (30%); (4) waterbeds in the NICU (23%); and (5) preterm infant massage in the NICU (38%).

Pain assessment and procedural pain management practices in neonatal units in Australia

OBJECTIVE

To identify current pain assessment and procedural pain management practices in neonatal units in Australia.

METHODS

Postal survey conducted during December 2003 and January 2004. The survey comprised questions relating to pain assessment scores, pain reduction strategies for minor painful procedures and the use of articulated policies relating to procedural pain management. Participants were the Nurse Unit Managers or their nominees of neonatal intensive care units, special care units and newborn emergency transport services in Australia.

RESULTS

Surveys were sent to 181 eligible organizations, and 105 of these were returned (58%). Six units (6%) used pain assessment scores on a regular basis, and 16 units (15%) had an articulated policy directing pain management practices during painful procedures. Non-nutritive sucking and various nursing comfort measures were the pain reduction strategies most frequently used during minor painful procedures. Twenty-four units (23%) used sucrose or other sweet-tasting solutions during procedures; however, the reported frequency of their usage was low. Breast-feeding during venepuncture, heel lance and intramuscular or subcutaneous injection was infrequently practised and topical anaesthetic agents were rarely used.

CONCLUSION

This survey demonstrates that the majority of Australian neonatal units have no articulated policy to guide pain management during painful procedures and do not regularly undertake pain assessments. Current evidence-based strategies to reduce procedural pain in hospitalized infants are used infrequently.

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.

Sucrose-induced analgesia is related to sweet preferences in children but not adults

The present study tested the hypothesis that the efficacy of sucrose in reducing pain during the Cold Pressor Test (CPT) was related to its hedonic value. To this aim, we determined the most preferred level of sucrose and the analgesic properties of 24% w/v sucrose during the CPT in 242, 5- to 10-year-old children and their mothers. Outcome measures included pain thresholds (the time at which discomfort was first indicated) and pain tolerance (the length of time the hand was kept in the cold water bath). Although children, as a group, preferred significantly higher sucrose concentrations than adults, there were individual differences that allowed us to group them on the basis of those who preferred sucrose concentrations below that used in the CPT (24% w/v) and those who preferred levels >or=24% w/v sucrose. Regardless of such groupings, sucrose was not an effective analgesic in adult women. Unlike adults, the more children liked sucrose, the better its efficacy as an analgesic. That is, children who preferred >or=24%w/v sucrose exhibited an increased latency to report pain and tolerated pain for significantly longer periods of time when sucrose was held in their mouths relative to water. This effect was more pronounced among normal weight when compared to overweight/at risk for overweight children. The role that dietary habits and individual differences contribute to the preferences for sweet taste and its physiological consequences in children is an important area for future research.

Nutritional aspects modulating brain development and the responses to stress in early neonatal life

Nutrition is one of the critical factors insuring adequate growth and development in all species. In particular, brain development is sensitive to specific nutrient intake such as proteins and lipids, which are important for cell membrane formation and myelinization. Carbohydrate intake insures adequate short-term energy supply, but has important effects on the activity of the hypothalamic-pituitary-adrenal (HPA) axis to regulate stress responsiveness. This review focuses on the effects of carbohydrates and fat on the activity of the HPA axis as well as other brain-related functions such as pain modulation, neuropeptide and neurotransmitters release, and some aspects related to cognitive functions. The role of leptin, DHA and AA as mediators of the effects of fat on the brain is discussed.

Consistent Management of Repeated Procedural Pain With Sucrose in Preterm Neonates: Is It Effective and Safe for Repeated Use Over Time?

OBJECTIVE

Preterm neonates undergo numerous painful procedures in the neonatal intensive care unit (NICU). Sucrose, with and without pacifiers, is effective and safe for relieving pain from single painful events. However, repeated use of sucrose for multiple painful procedures has not been adequately evaluated. The study objectives were to: 1) determine the efficacy and safety of consistent management of repeated procedural pain with sucrose; and 2) explore the impact of consistent pain management on clinical outcomes and neurobiological risk status.

METHODS

Sixty-six preterm infants were randomized to receive standard care (positioning and swaddling; n = 21), sterile water plus pacifier (n = 23), or 24% sucrose plus pacifier (n = 22) prior to all painful procedures in the NICU during the first 28 days of life. Also, at a routine heel lance at 7, 14, 21, and 28 days of life, data were collected to determine efficacy and immediate and long-term adverse events. Data on clinical outcomes and neurobiological risk status were collected at 28 days or NICU discharge.

RESULTS

There was no intervention by time interaction (P = 0.60). There was a significant main effect of intervention (P = 0.03) between the sucrose plus pacifier group, and the standard care group (P = 0.01), but there was no main effect of time (P = 0.72). No group differences existed for adverse events, clinical outcomes, or neurobiological risk status.

DISCUSSION

Consistent management of painful procedures with sucrose plus pacifier was effective and safe for preterm neonates during their stay in the NICU. Further exploration of consistent pain management with sucrose on clinical, developmental, and neurobiological outcomes is required.

Analgesic Effects of Breast-feeding or Pacifier Use With Maternal Holding in Term Infants

OBJECTIVES

First, to compare analgesic effects of breast-feeding versus pacifier use in newborn infants undergoing blood collection via heel sticks. Second, to compare analgesic effects of pacifier use with maternal holding versus nonmaternal holding.

DESIGN

A prospective, randomized, controlled trial.

SETTING

Normal newborn nursery at academic teaching hospital.

PARTICIPANTS

Full-term breast-feeding infants scheduled for routine newborn screening blood test via heel stick (n = 96). Interventions.-Infants randomized to 3 groups for analgesia: 1) breast-feeding, 2) pacifier use while held by mothers, 3) pacifier use while held by research assistants (nonmothers).

OUTCOME MEASURES

Primary outcome was crying (percent of infants who cried during the procedure and mean percent of procedure time that infants cried). Secondary outcomes were physiologic measures.

RESULTS

Fewer breast-feeding infants cried than infants using a pacifier while held by nonmothers both during the procedure (69% vs 100%, P < .01) and after the procedure (28% vs 60%, P = .03). Those infants crying during the procedure cried for less time if held by their mothers either breast-feeding (33%, P < .01) or using a pacifier (45%, P = .03) than those using a pacifier while being held by nonmothers (66%).

CONCLUSION

Breast-feeding is more analgesic than pacifier use with nonmaternal holding. Maternal holding with either breast-feeding or pacifier use is more analgesic than nonmaternal holding with pacifier use, suggesting that maternal holding itself has an analgesic effect. Breast-feeding and maternal holding should be considered as pain-control measures for the neonate during heel-stick procedures.

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.

Sugar Solution Analgesia: The Effects of Glucose on Expressed Mu Opioid Receptors

Glucose or sucrose solutions administered orally provide effective analgesia for procedural pain in neonates. Because analgesia with sugar solutions can be decreased by opioid receptor antagonists, we tested the hypothesis that glucose directly activates opioid receptors. Mu opioid receptors (MOR-1) were expressed in Xenopus oocytes, a well recognized expression system, and glucose was tested for possible agonist, antagonist, and modulatory effects on the receptor. In control experiments, 10 nM of Tyr-D-Ala-Gly-Me-Phe-Gly-ol (DAMGO), a synthetic enkephalin and specific mu agonist, activated the MOR-1, whereas 20 mM of glucose had no effect. In addition, glucose had no effect on the activation of the mu receptor by DAMGO. Finally, glucose did not modulate acute receptor desensitization induced by DAMGO. We conclude that glucose does not directly interact with MOR-1 in an in vitro expression system and that the purported interaction between glucose and the opioid system may be an indirect one, involving release of endogenous opioids.

Les perceptions gustatives chez l'enfant

As soon as the end of gestation, the gustatory system is stimulated by the taste-active compounds carried by the amniotic fluid and its maturation continues until mid-childhood. Facial expressions and relative ingestion methods show that the newborn can discriminate the various taste qualities (bitter, salty, sour, sweet and umami). The range of individual responses is wide. Neonatal reactions to sweet and umami are generally considered to express pleasure. The bitter and sour stimulations lead to hedonically negative reactions. The response to salt taste is less characteristic. Overall, the attraction towards sweet and the rejection of bitter and sour tastes become more pronounced during childhood but tend to decrease in adult life. The early attraction to sweetness is reinforced by exposure to sweet stimulations. With age, the response to salt evolves towards attraction which intensity is dependent on the context and on postnatal exposures to salt. The link between gustatory sensitivity to sweet, salty and sour stimuli and food preferences is far from being clear; the sensitivity to bitter taste better explains the rejection of bitter foods, such as vegetables for instance. The development of gustatory perceptions partly depends upon experience. A better knowledge of the role of experience could help to improve the orientation and the efficacy of nutritionally-oriented food education strategies.

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.

Ontogeny of analgesia elicited by non-nutritive suckling in acute and persistent neonatal rat pain models

Significant analgesic and calming effects in human infants and neonatal rodents are produced by orogustatory and orotactile stimuli associated with nursing. These naturally occurring analgesic stimuli may help to protect the vulnerable developing nervous system from the long-term effects of neonatal tissue injury. However, the efficacy of orotactile-induced analgesia across the pre-weaning period, as well as its effects on persistent inflammatory pain, is unknown. Here, we investigated the developmental profile of analgesia produced by orotactile stimulation during non-nutritive suckling in rats. The effects of suckling, as compared to non-suckling littermates, on nocifensive withdrawal responses to thermal and mechanical stimuli were examined at postnatal (P) days P0, P3, P10, P17 and P21. In some rats, Complete Freund's adjuvant (CFA) was injected in a fore- or hindpaw to produce inflammation. For thermal stimuli, suckling significantly increased forepaw withdrawal latencies at P3, P10 and P17, while hindpaw responses were increased at P3 and P10, but not at P17. In inflamed pups, suckling increased fore- and hindpaw response latencies at P10 and P17, but not at P0 or P21. Suckling-induced analgesia was naloxone-insensitive. For mechanical stimuli, suckling-induced analgesia was present at P3, P10 and P17, but not at P21, for both fore- and hindpaws in naïve and inflamed animals. Additionally, suckling had a small but significant effect at P0 for the forepaw in inflamed pups. In nearly all experiments, the peak effect of suckling for thermal and mechanical stimuli occurred at P10. These results indicate that orotactile analgesia, like orogustatory analgesia, is absent or minimal at P0, appears consistently at approximately P3 and is maximal at P10. Unlike gustatory analgesia in rats however, orotactile analgesia persists at least to P17. Orotactile stimulation during suckling effectively reduces transient pain elicited by thermal and mechanical stimuli, as well as persistent hyperalgesia and allodynia caused by inflammation.

Oral fructose solution as an analgesic in the newborn: a randomized, placebo-controlled and masked study

BACKGROUND

Pain in the newborn child can be associated with various risks. For this reason, as well as for ethical reasons, it seems essential to find a simple and acceptable method for reducing pain. Pharmacological agents are not recommended because of their side-effects. Glucose and sucrose solutions were administered, and were found effective for pain relief in minor procedures in previous studies. Fructose solution has not been tried in human neonates before now. For this study, fructose solution for pain relief was tried during heel lancing in term neonates, and to compare its effect with glucose and placebo, using a validated behavioral acute pain rating scale.

METHODS

In total, 34 healthy full-term neonates were studied. Randomized, masked, placebo-controlled and crossover trial were used. Each infant was assessed three times, receiving 0.5 mL of 30% fructose, 0.5 mL of 30% glucose or 0.5 mL of sterile water orally by syringe in random order, 2 min before heel lancing.

RESULTS

Pain scores were significantly lower in 30% fructose and 30% glucose groups as compared with the placebo group. No statistically significant difference in pain scores was found between 30% fructose and 30% glucose groups.

CONCLUSION

A small dose of 0.5 mL of 30% fructose solution has an equal analgesic effect with 0.5 mL of 30% glucose solution.

Effet analgésique de la crème Emla®, du saccharose et de leur association pour les injections sous-cutanées chez le nouveau-né prématuré : étude prospective de 265 injections

OBJECTIVE

To compare the analgesic effects of non nutritive pacifier sucking, oral administration of a 30% saccharose solution, local application of Emla and their association for subcutaneous injection of erythropoietin (EPO) in preterm infants.

METHODS

Our study was a randomised, prospective study conducted over 5 months. Neonates with a gestational age below 33 weeks of gestation and older than 8 days of life were included if they were treated with EPO (three subcutaneous injections per week during 6 weeks). For each consecutive EPO injection, patients were randomised between four groups of intervention: non nutritive pacifier sucking (T), oral administration of 0.2-0.5 ml of a 30% saccharose solution with non nutritive pacifier sucking (S), local application of Emla with non nutritive pacifier sucking (E), and oral administration of 0.2-0.5 ml of a 30% saccharose solution with local application of Emla and with non nutritive pacifier sucking (S + E). Each child was its own control. Pain was assessed with the Newborn Acute Pain scale (DAN) and with the Neonatal Facial Coding System (NFCS).

RESULTS

Thirty-three neonates were included, representing 265 injections. Distribution was: 41 in group T, 71 in group E, 86 in group S and 67 in group E + S. Mean DAN and NFCS scores were statistically different between groups T, E and S. Analgesic effect of saccharose (-1.05) was greater than Emla (-0.56). Used together, effects were adding up without potentialisation.

CONCLUSION

This study shows that the association of non nutritive pacifier sucking with oral administration of saccharose and local application of Emla has a better analgesic effect than each of these three interventions alone for subcutaneous injection of EPO.

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

OBJECTIVES

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

METHODS

Seventy-six infants, 54 preterm (< or =32 weeks' GA at birth) and 22 term-born infants who were seen at 8 months CCA composed the study sample, after excluding those with major sensory, motor, or cognitive impairment. Salivary cortisol was measured before (basal) and 20 minutes after introduction of novel toys (post 1) and after developmental assessment (post 2).

RESULTS

Salivary cortisol was significantly higher in ELGA infants at 8 months, compared with the VLGA and term groups before and after introduction of visual novelty. Term-born and VLGA infants showed a slight decrease in cortisol when playing with novel toys, whereas the ELGA group showed higher basal and sustained levels of cortisol. After controlling for early illness severity and duration of supplemental oxygen, higher basal cortisol levels in preterm infants at 8 months' CCA were associated with higher number of neonatal skin-breaking procedures. In contrast, cortisol responses to novelty were predicted equally well by neonatal pain or GA at birth. No relationship between morphine dosing and cortisol response was demonstrated in these infants.

CONCLUSIONS

ELGA preterm infants show a different pattern of cortisol levels before and after positive stimulation of visual novelty than more maturely born, VLGA preterm and term-born infants. Exposure to high numbers of skin-breaking procedures may contribute to "resetting" basal arousal systems in preterm infants.

Oral glucose before venepuncture relieves neonates of pain, but stress is still evidenced by increase in oxygen consumption, energy expenditure, and heart rate

Oral glucose was recommended as pain therapy during venepuncture in neonates. It is unclear whether this intervention reduces excess oxygen consumption (o(2)), energy loss, or cardiovascular destabilization associated with venepuncture, and whether <2 mL glucose solution is effective. We tested the hypothesis that oral glucose solution attenuates the increases in neonatal oxygen consumption, energy expenditure (EE), and heart rate associated with venepuncture for two different volumes of glucose solution (2 and 0.4 mL). In this prospective, randomized, controlled, double-blind trial, 58 neonates (gestational age, 31-42 wk; postnatal age, 1-7 d) were randomized to 2 mL glucose 30%, 0.4 mL glucose 30%, or 2 mL water by mouth before venepuncture. The videotaped behavioral pain reactions were scored with the Premature Infant Pain Profile. Cry duration, o(2), EE (indirect calorimetry), and heart rate were measured. The 2 mL glucose solution reduced pain score and crying after venepuncture compared with controls [median pain score, 5.5 (interquartile range, 4-9) versus 11 (7-12), p = 0.01; median duration of first cry, 0 s (0-43 s) versus 13 s (2-47 s), p < 0.05, respectively]. The 0.4 mL glucose solution had no effect. The 2 mL glucose solution did not attenuate the o(2) increase during venepuncture (1.5 +/- 0.2 mL/kg min (water) versus 1.7 +/- 0.5 (0.4 mL glucose) versus 1.1 +/- 0.2 (2 mL glucose) (mean +/- SEM) nor EE nor heart rate. We conclude that oral administration of 2 mL glucose 30% before venepuncture reduced pain expression and crying, but did not prevent the rise in o(2), EE, or heart rate. Alternative therapies against the stress of nonpainful handling during venepuncture should be explored.

Sucrose consumption enhances the analgesic effects of cigarette smoking in male and female smokers

RATIONALE

Nicotine has analgesic actions in experimental animals and humans. Moreover, the analgesic properties of nicotine in experimental animals are increased by intake of sweet-tasting nutritive fluids. It is important to determine if the effects of diet on nicotine-induced analgesia are limited to experimental animals, or if these effects can be translated from the laboratory to clinical research situations.

OBJECTIVE

This study investigated whether intake of a sweet-tasting sucrose solution would enhance the pain relieving actions of nicotine, administered in the form of cigarette smoking, in male and female college-aged students. The effects of smoking and sucrose intake on mood were also examined.

METHOD

Using the cold pressor test, pain thresholds and pain tolerance were determined in 24 male and 25 female smokers. Each participant was tested 4 times. On 2 of the test days, participants drank a sucrose-containing beverage, and on 2 of the days, drank water. Twenty-five minutes later, participants either smoked a cigarette or did not smoke. Participants were tested 5 min later for their responses on the cold pressor test. To determine if mood was altered by smoking or sucrose intake, the Profile of Mood Scale was administered immediately preceding and following experimental manipulations.

RESULTS

Cold threshold and cold tolerance were greater when participants were allowed to smoke than when they were not allowed to smoke. While men and women responded in a similar manner to the experimental manipulations, men displayed significantly greater cold threshold and cold tolerance than women. Sucrose consumption augmented the effects of smoking on cold threshold, but not on cold tolerance. Men reported feeling significantly more vigorous and less angry, and women reported feeling significantly less tense after they had smoked than when they had not smoked. Sucrose consumption did not alter self-reports of mood in either men or women.

CONCLUSION

These findings suggest that sucrose augments the analgesic properties of nicotine in humans, as well as in experimental animals, and suggest that diet could serve as an adjunct in the control of pain.

Sucrose for analgesia in newborn infants undergoing painful procedures

BACKGROUND

Management of pain for neonates is less than optimal. The administration of sucrose with and without non-nutritive sucking (pacifiers) has been the most frequently studied non-pharmacological intervention for relief of procedural pain in neonates.

OBJECTIVES

To determine the efficacy, effect of dose, and safety of sucrose for relieving procedural pain as assessed by validated individual pain indicators and composite pain scores.

SEARCH STRATEGY

Standard methods as per the Neonatal Collaborative Review Group. A MEDLINE search was carried out for relevant randomized controlled trials (RCTs) published from January 1966 - March 2004, EMBASE from 1980-2004 and search of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2004). Key words and (MeSH) terms included infant/newborn, pain, analgesia and sucrose. Language restrictions were not imposed. Bibliographies, personal files, the most recent relevant neonatal and pain journals and recent major pediatric pain conference proceedings were searched manually. Unpublished studies, or studies reported only as abstracts, were not included. Additional information from published studies was obtained.

SELECTION CRITERIA

RCTs in which term and/or preterm neonates (postnatal age maximum of 28 days after reaching 40 weeks corrected gestational age) received sucrose via oral syringe, NG-tube, dropper or pacifier for procedural pain from heel lance or venepuncture. In the control group, water, pacifier or positioning/containing were used. Studies in which the painful stimulus was circumcision were excluded.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed according to the methods of the Neonatal Collaborative Review Group. Quality measures included blinding of randomization, blinding of intervention, completeness of follow up and blinding of outcome measurement. Data were abstracted and independently checked for accuracy by the three investigators.

STATISTICAL ANALYSIS

The statistical package (RevMan 4.2) of the Cochrane Collaboration was used. For meta-analysis, a weighted mean difference (WMD) with 95% confidence intervals (CI) using the fixed effects model was reported for continuous outcome measures.

MAIN RESULTS

Forty-four studies were identified for possible inclusion in this review. Seven studies reported only as abstracts, and sixteen additional studies were excluded, leaving 21 studies (1,616 infants) included in this review. Sucrose in a wide variety of dosages was generally found to decrease physiologic (heart rate) and behavioural (the mean percent time crying, total cry duration, duration of first cry, and facial action) pain indicators and composite pain scores in neonates undergoing heel stick or venepuncture. When pain scores (Premature Infant Pain Profiles) were pooled across 3 studies (Gibbins 2001; Johnston 1999a; Stevens 1999), they were significantly reduced in infants who were given sucrose (dose range 0.012 g to 0.12 g) compared to the control group, [WMD -1.64 (95% CI -2.47,- 0.81); p = 0.0001] at 30 seconds and [WMD -2.05, (95% CI -3.08, -1.02); p = 0.00010] at 60 seconds after heel lance. When results for change in heart rate were pooled for two studies (Haouari 1995, Isik 2000), there were no significant differences between changes in heart rate for infants given sucrose (dose range 0.5 g to 0.6 g) compared to the control group, [WMD 0.90 (95% CI -5.81, 7.61); p = 0.8] at one minute and [WMD -6.20 (95% CI -15.27, 2.88); p = 0.18] at three minutes after heel lance.

REVIEWERS' CONCLUSIONS

Sucrose is safe and effective for reducing procedural pain from single painful events (heel lance, venepuncture). There was inconsistency in the dose of sucrose that was effective (dose range of 0.012 g to 0.12 g), and therefore an optimal dose to be used in preterm and/or term infants could not be identified. The use of repeated administrations of sucrose in neonates needs to be investigated as does the use of sucrose in combination with other behavioural (e.g., facilitated tucking, kangaroo care) and pharmacologic (e.g., morphine, fentanyl) interventions. Use of sucrose in neonates who are of very low birth weight, unstable and/or ventilated also needs to be addressed.

Comparison of sucrose, expressed breast milk, and breast-feeding on the neonatal response to heel prick

Newborns endure many heel pricks and other uncomfortable procedures during their first hospital stay. The aim of this study was to investigate the effectiveness of breast-feeding in reducing pain in newborns undergoing heel prick tests. One hundred thirty healthy term infants requiring a heel prick blood sampling for the Guthrie test were studied. Infants were randomly allocated to 1 of the following treatment groups: group 1, 25% sucrose (n = 35); group 2, breast milk (n = 33); group 3, sterile water (n = 34); and group 4, breast-feeding (n = 28). The median values of crying and recovery time and percent change in heart rate at 1, 2, and 3 minutes were recorded. A behavioral pain scale was applied according to the infant body coding system. The median crying time was 36, 62, 52, and 51 seconds in groups 1, 2, 3, and 4, respectively (P =.002). Similarly, there was a significant overall difference among groups for the duration of recovery time (P =.006) and the percent change in heart rate at 1 (P =.03), 2 (P =.01), and 3 (P =.009) minutes favoring the sucrose group. But when we compared the groups, the significance remained for the sucrose versus breast milk (P =.007) and water (P =.001) groups for the recovery time and sucrose versus all other groups for the percent change in heart rate at 3 minutes. The infant body coding system showed that babies in the sucrose group had significantly lower scores followed by the breast-fed and breast milk groups (P =.0001). Our study revealed that 25% sucrose is superior to breast-feeding in pain relief, which is reflected mainly in crying time and behavioral variables. The behavioral effects of breast-feeding did not provide any additional benefit.

Hard-food mastication suppresses complete Freund's adjuvant-induced nociception

The effect of food hardness during mastication on nociceptive transmission in the spinal cord was studied by analyzing complete Freund's adjuvant (CFA) induced nocifensive behavior and Fos expression. The behavioral study showed that the shortening of the withdrawal latency following CFA injection into the hind paw was depressed after a change in the given food hardness from soft to hard. The depression of nocifensive behavior in the rats with hard food was reversed after i.v. injection of naloxone. Fos protein-like immunoreactive cells (Fos protein-LI cells) were expressed in the superficial and deep laminae of the L4-6 spinal dorsal horn after s.c. injection of CFA into the hind paw during soft food mastication. The number of Fos protein-LI cells was decreased in the rats with hard food mastication followed by soft food. This reduction of Fos protein-LI cells following change in food hardness was reversed after i.v. application of naloxone. Furthermore, the depression of Fos protein-LI cells following hard food intake was significantly inhibited after bilateral inferior alveolar nerve transection or bilateral ablation of the somatosensory cortex. These findings suggest that the change in food hardness during mastication might drive an opioid descending system through the trigeminal sensory pathway and somatosensory cortex resulting in an antinociceptive effect on chronic pain. However, IAN transection and cortical ablation did not induce 100% reversal of Fos expression, suggesting other than trigeminal sensory system may be involved in this phenomena, such as the pathway through the brainstem reticular formation.

Sucrose attenuates a negative electroencephalographic response to an aversive stimulus for newborns

Reports that sweet taste calms crying in newborns and is analgesic against the pain caused by a heel lance served as the basis for this study. Electroencephalographic (EEG) activity, heart rate activity, and infants' facial behaviors were recorded before and after a noninvasive, but noxious, heelstroke (procedure from the Brazelton Neonatal Behavior Assessment Scale). In a randomized and controlled trial, 34 newborns were administered 2 mL of water or sucrose solution before the heelstroke. Frontal EEG asymmetry scores were computed, and power in the 3 to 6 Hz frequency band was analyzed. Infants who received water showed increased relative right frontal EEG activation from baseline to the post-heelstroke phase, a pattern that typifies negative affect. The EEG of infants in the sucrose group did not change. Heart rate increased rapidly in both groups during the heelstroke phase. However, after the heelstroke, the heart rate of infants who received sucrose returned to baseline, whereas the heart rate of infants who tasted water remained elevated. During the heelstroke, the infants in the water group cried and grimaced twice as long as the infants in the sucrose group. These findings add to the growing literature showing that sucrose attenuates newborns' negative response to aversive or noxious stimuli.

Effects of chewing gum on responses to routine painful procedures in children

In infants, sweet taste and sucking on a pacifier both have analgesic effects. Animal studies suggest that sweet taste may involve opioids, while rhythmic oral movements, as with a pacifier, increase the release of serotonin, which is involved in the gating of nociceptive afferents. The present study was designed to see if these effects produce an analgesic effect in children. Two studies were performed, during blood draws in a pediatric test center in 7- to 12-year-old children, and during vaccination at school in 9- to 11-year-old children. Using unsweetened or sweetened chewing gum, there were four groups: control, sweet, chew, and sweet plus chew. Overall, there was no effect of either sweet taste or chewing on pain responses. However, in boys sweet taste tended to increase pain ratings, but only in conjunction with chewing, while in girls sweet taste tended to decrease pain ratings in conjunction with chewing and increased them in the absence of chewing. Ratings of pain intensity and affective state were correlated. Affective state before the painful stimulus was related to pain response in the girls and in the boys in the test center, but not in the schools. In the schools, the presence of peers may have influenced the ratings.

Pain management in nursing procedures on premature babies

BACKGROUND

Pain can be caused to premature babies when nursing and other procedures are carried out. Procedural pain management for these babies raises challenging questions for health care professionals. Optimal pain management for premature babies can be reached by using and further developing existing pharmacological and non-pharmacological pain alleviation methods for procedural pain before, during, and after procedures.

AIMS

The aims of this study were to describe the environment of pain management in nursing procedures and examinations with premature babies; to describe preparation of the baby for the procedure; to describe non-pharmacological pain alleviation methods during and after the procedures; and to develop a process describing procedural pain management in premature babies.

METHOD

The material for this study consisted of journal articles on non-pharmacological procedural pain alleviation in infants published between 1994 and 2002. During this period knowledge of pain management in premature babies has improved considerably. The study was based on the method of content analysis.

FINDINGS

Procedural pain management in premature babies was described by researchers as a process comprising: (1) an environment that is favourable to effective pain management, (2) safe preparation of the baby for the procedure, (3) pain alleviation during the procedure, and (4) restoring the baby's sense of security after the procedure. Pain management is recommended to be used alone or together with pharmacological interventions. Additionally, systematic pain management requires documentation of the whole pain management process.

CONCLUSION

Pain management can be described as a process. It is important to test and assess this process and individual non-pharmacological pain management methods in practical nursing situations. The findings of this review can be used to improve pain management methods in premature babies.

Changing determinants of crying termination in 6- to 12-week-old human infants

Developmental change in human infant crying termination was studied in 60 infants who were 6, 9, and 12 weeks of age. They qualified by spontaneously crying for at least 30 s during the study's first minute. Infants then received either 0.8 ml sucrose (12% w/v) by syringe or sucked a pacifier dipped in the 12% solution for a total of 3.5 min. Crying was substantially reduced by pacifier-sucking at all three ages tested. Sucrose too was effective at 6 and 9 weeks of age but did not reduce crying in 12-week-olds. These data suggest different schedules in the decline of sweet taste and pacifier sucking as agents of crying termination. These differential rates argue for multiple systems that govern crying reduction and argue against a single central target that changes ontogenetically in sensitivity and control. Whether the continuation of sucking effectiveness is sustained by infant sucking experience or reflects a slower rate of decline cannot be determined at present.

Analgesic effect of breast feeding in term neonates: randomised controlled trial

OBJECTIVES

To investigate whether breast feeding is effective for pain relief during venepuncture in term neonates and compare any effect with that of oral glucose combined with a pacifier.

DESIGN

Randomised controlled trial.

PARTICIPANTS

180 term newborn infants undergoing venepuncture; 45 in each group.

INTERVENTIONS

During venepuncture infants were either breast fed (group 1), held in their mother's arms without breast feeding (group 2), given 1 ml of sterile water as placebo (group 3), or given 1 ml of 30% glucose followed by pacifier (group 4). Video recordings of the procedure were assessed by two observers blinded to the purpose of the study.

MAIN OUTCOME MEASURES

Pain related behaviours evaluated with two acute pain rating scales: the Douleur Aiguë Nouveau-né scale (range 0 to 10) and the premature infant pain profile scale (range 0 to 18).

RESULTS

Median pain scores (interquartile range) for breast feeding, held in mother's arms, placebo, and 30% glucose plus pacifier groups were 1 (0-3), 10 (8.5-10), 10 (7.5-10), and 3 (0-5) with the Douleur Aiguë Nouveau-né scale and 4.5 (2.25-8), 13 (10.5-15), 12 (9-13), and 4 (1-6) with the premature infant pain profile scale. Analysis of variance showed significantly different median pain scores (P<0.0001) among the groups. There were significant reductions in both scores for the breast feeding and glucose plus pacifier groups compared with the other two groups (P<0.0001, two tailed Mann-Whitney U tests between groups). The difference in Douleur Aiguë Nouveau-né scores between breast feeding and glucose plus pacifier groups was not significant (P=0.16).

CONCLUSIONS

Breast feeding effectively reduces response to pain during minor invasive procedure in term neonates.

Oral Administration of a 12% Sucrose Solution Did Not Decrease Behavioural Indicators of Distress in Piglets Undergoing Tail Docking, Teeth Clipping and Ear Notching

Sucrose has been shown to attenuate the behavioural response to painful procedures in human infants undergoing circumcision or blood collection via heelstick. Sucrose has also been found to have a behaviour-modifying effect in neonatal rats exposed to a hot plate. The effect was abolished in neonatal rats by injection of the opioid antagonist naltrexone, suggesting that it was mediated by endogenous opioids. In this experiment, the behaviour of 571 newborn Large White x Landrace hybrid piglets in a specific-pathogen-free piggery of the University of Queensland was recorded during and after the routine management practices of tail docking, ear notching and teeth clipping. Piglets were randomly assigned to receive 1.0 ml of a 12% sucrose solution (treatment group) or a placebo (1.0 ml of air) administered via syringe in the mouth, 60 s before commencement of one of the management procedures. Behaviours were recorded at the time of the procedure, and then 2 min after completion of the procedure. Piglets that received the sucrose solution did not behave significantly differently from piglets receiving the placebo. Regardless of whether sucrose or placebo was administered, piglets undergoing the routine management procedures showed significantly greater behavioural responses than piglets undergoing no procedure. It was concluded that under commercial conditions, a 12% sucrose solution administered 1 min prior to surgery was not effective in decreasing the behavioural indicators of distress in piglets undergoing routine management procedures. Further research into methods of minimising distress caused to piglets by these procedures is recommended.

Intra-oral administration of sweet-tasting substances and infants' crying response to immunization: a randomized, placebo-controlled trial

The analgesic effects of four solutions administered intra-orally (25 and 50% sucrose solutions, hydrogenated glucose, and a sterile water placebo) were tested in groups of babies receiving routine DTP (diphtheria, tetanus, and pertussis) and HIB (Haemophilus influenzae type B) injections at the first, second, or third immunization. The duration of the baby's cry during 3 min following DTP and HIB injections was measured as main outcome. For all three immunization groups, the babies receiving the placebo generally spent most time crying. For both the DTP and HIB injections, the difference between 50% sucrose and placebo was most evident in the group receiving the 3rd immunization. Intra-oral administration of the 50% sucrose solution, compared to placebo, appeared to reduce the cry response to painful experiences in babies beyond the neonatal period.

Routine sucrose analgesia during the first week of life in neonates younger than 31 weeks' postconceptional age

OBJECTIVE

To determine the efficacy of sucrose analgesia for procedural pain during the first week of life in preterm neonates in neonatal intensive care units on enhancing later clinical outcomes.

METHODS

A total of 107 preterm neonates who were born at <31 weeks' postconceptional age (PCA) entered this double-blind, randomized, controlled trial within 48 hours of birth at 3 level III university-affiliated neonatal intensive care units in Canada, and 103 completed the study. Sucrose (0.1 mL of 24%) or sterile water was administered orally up to 3 times, 2 minutes apart, for every invasive procedure during a 7-day period. Motor development and vigor, and alertness and orientation components of the Neurobehavioral Assessment of the Preterm Infant were measured at 32, 36, and 40 weeks' PCA; Score for Neonatal Acute Physiology was measured on the last day of intervention; and Neuro-Biological Risk Score (NBRS) was measured at 2 weeks of age and at discharge. Primary analyses of covariance were applied for each outcome to compare group differences followed by secondary analyses using standard linear regression within each group to determine predictors of outcomes.

RESULTS

Although there were no differences between the groups on any outcomes, there were significant dose-related effects within each group. In the sucrose group only, higher number of doses of sucrose predicted lower scores on motor development and vigor, and alertness and orientation at 36 weeks', lower motor development and vigor at 40 weeks', and higher NBRS at 2 weeks' postnatal age. Higher number of invasive procedures was predictive of higher NBRS both times in the water group.

CONCLUSIONS

Repeated use of sucrose analgesia in infants <31 weeks' PCA may put infants at risk for poorer neurobehavioral development and physiologic outcomes. Additional study is needed to determine the most appropriate age and duration of sucrose analgesia in preterm infants.

Crossover trial of analgesic efficacy of glucose and pacifier in very preterm neonates during subcutaneous injections

OBJECTIVE

Very preterm newborns undergo multiple invasive procedures. Nonpharmacological interventions are valuable alternatives for pain relief during minor procedures in neonates. Oral sucrose analgesia has been widely studied in term and preterm neonates during painful procedures. The analgesic effect of oral glucose in very preterm infants has not yet been reported. The objectives of this study were to assess the analgesic effect of orally administered glucose and to determine the synergetic analgesic effect of glucose and pacifiers during subcutaneous injections in very preterm neonates using a validated behavioral acute pain rating scale.

DESIGN

Two crossover trials.

SETTING

One neonatal intensive care unit in a community-based general hospital.

METHODS

A prospective study was conducted in 40 very preterm neonates. Each infant received 2 treatments in a crossover manner during 2 consecutive subcutaneous injections of erythropoietin. The first trial (25 infants) was intended to compare oral 30% glucose (0.3 mL) versus placebo (0.3 mL of sterile water); the second trial (15 infants) compared oral 30% glucose (0.3 mL) versus oral 30% glucose (0.3 mL) followed by sucking a pacifier. The primary outcome measure was the evaluation of pain induced by a subcutaneous injection of erythropoietin, using Douleur Aiguë Nouveau-né scale (0 no pain, 10 maximum pain).

RESULTS

Twenty-four infants completed the study in the first trial and 15 in the second one. Mean (95% confidence interval [CI]) gestational age, birth weight, postnatal age, and weight at inclusion for neonates in the first and second trial were, respectively, 28.1 (95% CI: 27.3-29.0) and 29.1 (95% CI: 27.8-30.4) weeks, 1036 (95% CI: 944-1128) and 995 (95% CI: 848-1141) g, 26.4 (95% CI: 22.4-30.3) and 26 (95% CI: 22.0-29.9) days, and 1234 (95% CI: 1120-1348) and 1209 (95% CI: 1059-1359) g. In the first trial, median (interquartile) pain scores for placebo and 30% glucose, respectively, were 7 (2.5-9.75) and 4.5 (1-6). In the second trial, median (interquartile) pain scores for 30% glucose and for 30% glucose plus pacifier, respectively, were 4 (2-7) and 4 (1-6).

CONCLUSIONS

A small dose of 0.3 mL of 30% oral glucose has an analgesic effect in very preterm neonates during subcutaneous injections. This effect is clinically evident because it can be detected by a behavioral pain rating scale. The synergetic analgesic effect of glucose plus sucking a pacifier is less obvious in very preterm neonates as opposed to what other studies have showed in full-term infants.

A theoretical framework for understanding self-report and observational measures of pain: a communications model

Self-report and observational measures of pain are examined from the perspective of a model of human communication. This model examines the experience of pain as affected by intrapersonal and contextual factors, the process whereby it is encoded into expressive behaviour, and the process of decoding by observers prior to their engaging in action. Self-report measures primarily capture expressive pain behaviour that is under the control of higher mental processes, whereas observational measures capture behaviour that is less subject to voluntary control and more automatic. Automatic expressive behaviours are subject to less purposeful distortion than are behaviours dependent upon higher mental processes. Consequently, observational measures can be used and have clinical utility as indices of pain when self-report is not available, for example, in infants, young children, people with intellectual disabilities or brain damage, and seniors with dementia. These measures are also useful when the credibility of self-report is questioned and even when credible self-report is available. However, automatic behaviours may be more difficult for observers to decode. The model outlined herein takes into account the role of various human developmental stages in pain experience and expression and in understanding the utility of self-report and observational measures. We conclude that both observational and self-report measures are essential in the assessment of pain because of the unique information that each type contributes.

Breastfeeding is analgesic in healthy newborns

CONTEXT

This study identifies a behavioral and nonpharmacologic means of preventing newborn pain.

OBJECTIVE

To determine whether breastfeeding is analgesic in newborn infants undergoing heel lance-a routine, painful, hospital procedure.

DESIGN

A prospective, randomized, controlled trial.

SETTING

Hospital maternity services at Boston Medical Center, Boston, Massachusetts, and Beverly Hospital, Beverly, Massachusetts.

PARTICIPANTS

A random sample of 30 full-term, breastfed infants.

INTERVENTIONS

Infants in the intervention group were held and breastfed by their mothers during heel lance and blood collection procedures for the Newborn Screening Program Blood Test. Infants in the control group experienced the same blood test while receiving the standard hospital care of being swaddled in their bassinets.

OUTCOMES MEASURES

Crying, grimacing, and heart rate differences were analyzed between the breastfeeding and the control infants before, during, and after blood collection.

RESULTS

Crying and grimacing were reduced by 91% and 84%, respectively, from control infant levels during the blood collection. Heart rate was also substantially reduced by breastfeeding.

CONCLUSIONS

Breastfeeding is a potent analgesic intervention in newborns during a standard blood collection.

Effect of multisensory stimulation on analgesia in term neonates: a randomized controlled trial

Many attempts have been made to obtain safe and effective analgesia in newborns. Oral glucose-water has been found to have analgesic properties in neonates. We investigated whether other sensory stimulation added to oral glucose provided more effective analgesia than oral glucose alone. In a randomized prospective double-blind trial, we studied 120 term newborns during heel prick. The babies were divided randomly into six groups of 20, and each group was treated with a different procedure during heel prick: A) control; B) 1 mL 33% oral glucose given 2 min before the heel prick; C) sucking; D) 1 mL 33% oral glucose plus sucking; E) multisensory stimulation including 1 mL 33% oral glucose (sensorial saturation); F) multisensory stimulation without oral glucose. Sensorial saturation consisted in massage, voice, eye contact, and perfume smelling during heel prick. Each heel prick was filmed and assigned a point score according to the Douleur Aiguë du Nouveau-né (DAN) neonatal acute pain scale. Camera recording began 30 s before the heel prick, so it was impossible for the scorers to distinguish procedure A (control) from B (glucose given 2 min before), C (sucking water) from D (sucking glucose), and E (multisensory stimulation and glucose) from F (multisensory stimulation and water) from the video. Procedure E (multisensory stimulation and glucose) was found to be the most effective procedure, and the analgesia was even more effective than that produced by procedure D (sucking glucose). We conclude that sensorial saturation is an effective analgesic technique that potentiates the analgesic effect of oral sugar. It can be used for minor painful procedures on newborns.

Effects of colostrum in newborn humans: dissociation between analgesic and cardiac effects

This study evaluates the effects of colostrum, delivered via syringe or on a pacifier, on the pain and heart rate reactions of newborns undergoing routine heel-lance. This was achieved by following a quasi-randomized, controlled trial in which 60 newborn infants at Boston Medical Center, Boston, MA, were randomly assigned to receive colostrum, sucrose, or water, by syringe or on a pacifier, for a total of 6 groups (n = 10 per group). The effectiveness of an intervention was determined by comparing crying, grimacing, and heart rate differences among groups during and following blood collection. We report that colostrum, delivered by syringe or on a pacifier, did not reduce crying or grimacing relative to control infants who received water. As has been previously reported, sucrose markedly reduced both crying and grimacing, and attenuated the rise in heart rate that normally accompanies blood collection (p < .002). Water, via syringe or on a pacifier, did not prevent the increase in heart rate, nor did colostrum via syringe. In contrast, colostrum delivered on a pacifier prevented the increase in heart rate despite pain reactivity and extreme crying. The implications of this dissociation are discussed.

The ontogeny of face recognition: eye contact and sweet taste induce face preference in 9- and 12-week-old human infants

Nine and 12-week-old infants (N = 140) who were either calm or crying sat facing a researcher for 3.5 min. The researcher gazed into the infant's eyes with a smiling face or looked above the infant's forehead. She delivered a 12% sucrose solution via a syringe or a pacifier, or she did not deliver anything. After the exposure period, the mother held her infant over her shoulder. Infant gaze direction was recorded while the infant faced the same researcher and a stranger. The confluence of sweet taste and eye contact was necessary and sufficient for calm 9- and 12-week-olds to form a preference for the researcher. Crying infants never did so, even though eye contact and sweet taste arrested crying. Different visual-gustatory combinations induced unanticipated affective states and are discussed within the contexts of cognitive mechanisms that mediate face learning and preference, the proximate mechanisms involved, and the evolutionary significance of face recognition.

Analgesia of newborn lambs before castration and tail docking with rubber rings

This study assessed the effects of suckled sucrose and parenteral carprofen treatment on behavioural measurements of discomfort and serum haptoglobin concentration in lambs following rubber ring castration and/or tail docking. Twenty-eight male and 20 ewe lambs were allocated to either a male or ewe lamb control group (n=4) or to one of three male and two ewe lamb treatment groups (n=8). Male lambs in one treatment group received carprofen subcutaneously (0.5 mg/kg) 30 minutes before castration and docking. Lambs in all other treatment groups suckled sucrose or colostrum immediately before castration and/or tail docking. Behavioural measurements of discomfort were made following castration or tail docking in treatment groups and also in control animals which were not castrated or tail docked. Blood sampling of animals in treatment groups for analysis of serum haptoglobin, an acute phase protein used as an indicator of an acute inflammatory response, was performed before castration or docking and at 24 and 48 hours after castration or docking. Control lambs were blood sampled at 0, 24 and 48 hours following behavioural assessment Neither suckled sucrose nor carprofen treatment altered discomfort behaviour associated with castration or tail docking. Haptoglobin levels following castration or tail docking remained close to the detection limits of the assay and were similar to those recorded in control animals.

Sensorial saturation: an effective analgesic tool for heel-prick in preterm infants: a prospective randomized trial

Pain is traumatic for preterm infants and can damage their CNS. We wanted to assess whether multisensorial stimulation can be analgesic and whether this effect is only due to oral glucose or sucking. We performed a randomized prospective study, using a validated acute pain rating scale to assess pain during heel-prick combined with five different procedures: (A) control, (B) 10% oral glucose plus sucking, (C) sensorial saturation (SS), (D) oral water, and (E) 10% oral glucose. SS is a multisensorial stimulation consisting of delicate tactile, vestibular, gustative, olfactory, auditory and visual stimuli. Controls did not receive any analgesia. We studied 85 heel-pricks (5 per baby) performed for routine blood samples in 17 preterm infants (28-35 weeks of gestational age). We applied in random order in each patient the five procedures described above and scored pain. SS and sucking plus oral glucose have the greater analgesic effect with respect to no intervention (p < 0.001). The effect of SS is statistically better than that of glucose plus sucking (p < 0.01). SS promotes interaction between nurse and infant and is a simple effective form of analgesia for the NICU.