Oral sucrose as an analgesic drug for procedural pain in newborn infants: a randomised controlled trial

Non-pharmacological management of infant and young child procedural pain

BACKGROUND

Infant acute pain and distress is commonplace. Infancy is a period of exponential development. Unrelieved pain and distress can have implications across the lifespan. 

OBJECTIVES

To assess the efficacy of non-pharmacological interventions for infant and child (up to three years) acute pain, excluding breastmilk, sucrose, and music. Analyses accounted for infant age (preterm, neonate, older) and pain response (pain reactivity, pain-related regulation). 

SEARCH STRATEGY

We searched CENTRAL in The Cochrane Library (2011, Issue 1), MEDLINE (1966 to April 2011), EMBASE (1980 to April 2011), PsycINFO (1967 to April 2011), Cumulative Index to Nursing and Allied Health Literature (1982 to 2011), Dissertation Abstracts International (1980 to 2011) and www.clinicaltrials.gov. We also searched reference lists and contacted researchers via electronic list-serves.

SELECTION CRITERIA

Participants included infants from birth to three years. Only randomized controlled trials (RCTs) or RCT cross-overs that had a no-treatment control comparison were eligible for inclusion in the analyses. We examined studies that met all inclusion criteria except for study design (e.g. had an active control) to qualitatively contextualize results.

DATA COLLECTION AND ANALYSIS

We refined search strategies with three Cochrane-affiliated librarians. At least two review authors extracted and rated 51 articles. Study quality ratings were based on a scale by Yates and colleagues. We analyzed the standardized mean difference (SMD) using the generic inverse variance method. We also provided qualitative descriptions of 20 relevant but excluded studies.

MAIN RESULTS

Fifty-one studies, with 3396 participants, were analyzed. The most commonly studied acute procedures were heel-sticks (29 studies) and needles (n = 10 studies). The largest SMD for treatment improvement over control conditions on pain reactivity were: non-nutritive sucking-related interventions (preterm: SMD -0.42; 95% CI -0.68 to -0.15; neonate: SMD -1.45, 95% CI -2.34 to -0.57), kangaroo care (preterm: SMD -1.12, 95% CI -2.04 to -0.21), and swaddling/facilitated tucking (preterm: SMD -0.97; 95% CI -1.63 to -0.31). For immediate pain-related regulation, the largest SMDs were: non-nutritive sucking-related interventions (preterm: SMD -0.38; 95% CI -0.59 to -0.17; neonate: SMD -0.90, 95% CI -1.54 to -0.25), kangaroo care (SMD -0.77, 95% CI -1.50 to -0.03), swaddling/facilitated tucking (preterm: SMD -0.75; 95% CI -1.14 to -0.36), and rocking/holding (neonate: SMD -0.75; 95% CI -1.20 to -0.30). The presence of significant heterogeneity limited our confidence in the lack of findings for certain analyses.

AUTHORS' CONCLUSIONS

There is evidence that different non-pharmacological interventions can be used with preterms, neonates, and older infants to significantly manage pain behaviors associated with acutely painful procedures.

A shift in sensory processing that enables the developing human brain to discriminate touch from pain

When and how infants begin to discriminate noxious from innocuous stimuli is a fundamental question in neuroscience [1]. However, little is known about the development of the necessary cortical somatosensory functional prerequisites in the intact human brain. Recent studies of developing brain networks have emphasized the importance of transient spontaneous and evoked neuronal bursting activity in the formation of functional circuits [2, 3]. These neuronal bursts are present during development and precede the onset of sensory functions [4, 5]. Their disappearance and the emergence of more adult-like activity are therefore thought to signal the maturation of functional brain circuitry [2, 4]. Here we show the changing patterns of neuronal activity that underlie the onset of nociception and touch discrimination in the preterm infant. We have conducted noninvasive electroencephalogram (EEG) recording of the brain neuronal activity in response to time-locked touches and clinically essential noxious lances of the heel in infants aged 28–45 weeks gestation. We show a transition in brain response following tactile and noxious stimulation from nonspecific, evenly dispersed neuronal bursts to modality-specific, localized, evoked potentials. The results suggest that specific neural circuits necessary for discrimination between touch and nociception emerge from 35–37 weeks gestation in the human brain.

Sex Differences in Pain Responses at Maturity Following Neonatal Repeated Minor Pain Exposure in Rats

There is mounting evidence of long-lasting changes in pain sensitivity in school-age children who were cared for in a neonatal intensive care unit. Such care involves multiple pain exposures, 70% of which are accounted for by heel lance to monitor physiological well-being. The authors sought to model the repeated brief pain resulting from heel lance by administering repeated paw needle stick to neonatal rat pups. Repeated needle stick during the first 8 days of life was sex-specific in altering responses to mechanical and inflammatory stimuli, but not to a thermal stimulus, at maturity. Specifically, neonatal paw needle stick males exhibited significantly greater mechanical sensitivity in response to von Frey hair testing, whereas neonatal paw needle stick females exhibited significantly greater pain behavior scores following hindpaw formalin injection. This is the first study to show such sex-dependent changes in pain responsiveness at maturity in animals having experienced repeated neonatal needle stick pain. These findings support existing evidence that there are long-term sensory sequelae following neonatal pain experiences in rats and further suggest that there are sex-linked differences in the nature of the consequences. If these relationships hold in humans, these findings suggest that even mild painful insults early in life are not without sensory consequences.

Procedural Pain Management in Neonates, Infants and Children

Neonates, infants and children all feel pain and require analgesia for painful procedures.Many painful procedures are associated with medical interventions, including immunisation, heel lance, venesection, IV cannulation and dressing change.Untreated pain can have short and long term effects, including sensitisation to pain episodes in later life.A range of non-pharmacological and pharmacological interventions have been shown to be effective for procedural pain management in infants and children, and are most effective when used in combination.Developmental changes in pain responses, analgesic response and drug pharmacokinetics need to be taken into account when planning procedural pain management for neonates.Comprehensive evidence based guidelines are available to guide effective procedural pain management in neonates, infants and older children.

Pain relief for premature infants during ophthalmology assessment

BACKGROUND

The ophthalmological examination of premature infants, which is essential for the detection of retinopathy of prematurity (ROP), can be painful and distressing for the infant. Various researchers have investigated the benefits of topical anesthesia, oral sucrose, and non pharmacological intervention for pain relief. The purpose of this study is to review the current state of knowledge on the effectiveness of these approaches.

METHODS

A literature search was performed with MEDLINE (January 1980 to January 2011) and the Cochrane Central Register of Controlled Trials, Issue 1 of 4 (January 2011), to determine the currently available evidence on methods of pain relief for premature infants undergoing ROP examination.

RESULTS

Most studies supported the use of topical proparacaine, which marginally decreased pain without any side effects. Oral sucrose did not significantly reduce pain scores during ROP examinations, and withholding feeding before the examination was not beneficial. Infants given pacifiers had lower pain scores than those without pacifiers, and infants who were nested experienced less distress during and after the procedure. Conflicting data existed on the benefits of different examination techniques, but the insertion of a lid speculum appeared to be the most uncomfortable aspect of the screening examination.

CONCLUSIONS

Topical anesthetics marginally reduce pain during eye examination in premature infants. Contrary to standard practice, it appears that patients are more comfortable if they are fed before the examination, and there is no benefit of oral sucrose. Nonpharmacological interventions, including sucking on a pacifier and nesting, may also be beneficial.

Newborn Analgesia Mediated by Oxytocin during Delivery

The mechanisms controlling pain in newborns during delivery are poorly understood. We explored the hypothesis that oxytocin, an essential hormone for labor and a powerful neuromodulator, exerts analgesic actions on newborns during delivery. Using a thermal tail-flick assay, we report that pain sensitivity is two-fold lower in rat pups immediately after birth than 2 days later. Oxytocin receptor antagonists strongly enhanced pain sensitivity in newborn, but not in 2-day-old rats, whereas oxytocin reduced pain at both ages suggesting an endogenous analgesia by oxytocin during delivery. Similar analgesic effects of oxytocin, measured as attenuation of pain-vocalization induced by electrical whisker pad stimulation, were also observed in decerebrated newborns. Oxytocin reduced GABA-evoked calcium responses and depolarizing GABA driving force in isolated neonatal trigeminal neurons suggesting that oxytocin effects are mediated by alterations of intracellular chloride. Unlike GABA signaling, oxytocin did not affect responses mediated by P2X3 and TRPV1 receptors. In keeping with a GABAergic mechanism, reduction of intracellular chloride by the diuretic NKCC1 chloride co-transporter antagonist bumetanide mimicked the analgesic actions of oxytocin and its effects on GABA responses in nociceptive neurons. Therefore, endogenous oxytocin exerts an analgesic action in newborn pups that involves a reduction of the depolarizing action of GABA on nociceptive neurons. Therefore, the same hormone that triggers delivery also acts as a natural pain killer revealing a novel facet of the protective actions of oxytocin in the fetus at birth.

Assessing pain in preterm infants in the neonatal intensive care unit: moving to a 'brain-oriented' approach

Preterm infants in the neonatal intensive care unit undergo repeated exposure to procedural and ongoing pain. Early and long-term changes in pain processing, stress-response systems and development may result from cumulative early pain exposure. So that appropriate treatment can be given, accurate assessment of pain is vital, but is also complex because these infants' responses may differ from those of full-term infants. A variety of uni- and multidimensional assessment tools are available; however, many have incomplete psychometric testing and may not incorporate developmentally important cues. Near-infrared spectroscopy and/or EEG techniques that measure neonatal pain responses at a cortical level offer new opportunities to validate neonatal pain assessment tools.

Pain in neonates is different

Pain processing and management in neonates, especially preterm neonates, differs from older populations. In this review, a brief background on pain processing in neonatal life, pain exposure in Neonatal Intensive Care Units (NICU), the consequences of untreated pain, and the difficulties in treating procedural pain pharmacologically will be presented. A more detailed review of non-pharmacological interventions for procedural pain in neonates will include sensory stimulation approaches, oral sweet solutions, and maternal interventions. Some possible mechanisms for the effectiveness of non-pharmacological interventions are offered. Finally, avenues of research into similar interventions as adjuvant therapies or drug-sparing effects in older populations are suggested.