Factors that influence the behavioral pain responses of premature infants

Sex differences in facial expressions of pain: results from a combined sample

ABSTRACT

Facial expressions of pain play an important role in pain diagnostics and social interactions. Given the prominent impact of sex on various aspects of pain, it is not surprising that sex differences have also been explored regarding facial expressions of pain; however, with inconclusive findings. We aim to further investigate sex differences in facial expressions of pain by using a large, combined sample to maximize statistical power. Data from 7 previous studies of our group were merged, combining in total the data of 392 participants (male: 192, female: 200). All participants received phasic heat pain, with intensities being tailored to the individual pain threshold. Pain intensity ratings were assessed, and facial responses were manually analyzed using the Facial Action Coding. To compare facial and subjective responses between sexes, linear mixed-effects models were used, with study ID as a random effect. We found significant sex differences in facial responses, with females showing elevated facial responses to pain, although they received lower physical heat intensities (women had lower pain thresholds). In contrast, pain intensity ratings did not differ between sexes. Additionally, facial and subjective responses to pain were significantly associated across sexes, with females showing slightly stronger associations. Although variations in facial expressions of pain are very large even within each sex, our findings demonstrate that women facially communicate pain more intensively and with a better match to their subjective experience compared with men. This indicates that women might be better in using facial communication of pain in an intensity-discriminative manner.

Behavioral and physiological pain structures of PIPP-R and parental stress: structural equation modeling approach

BACKGROUND

Although most non-acute pain assessment tools are multi-dimensional (behavioral and physiological measures) in their approach, the outputs of such tools are considered unidimensional. This study aimed to explore and determine the behavioral and physiological pain structures of Premature Infant Pain Profile-Revised (PIPP-R) for neonates and its association with parental stress.

METHODS

This cross-sectional study was conducted in 2022-2023 in Isfahan, Iran. We recruited 400 pre-term infants, i.e. with gestational age (GA) of less than 37weeks who were admitted to the NICU of educational hospitals. PIPP-R and Parental Stressor Scale: Neonatal Intensive Care Unit (PSS: NICU) were used for data gathering. The latent structures of pain and its association with parental stress were explored using latent variable modeling approach.

RESULTS

A two-factor model, i.e. behavioral and physiological pain factors, was extracted, explaining 65% of the total variance. The results of confirmatory factor analysis showed that the identified structures in the exploratory factor analysis could be nearly replicated (CFI = 0.99، TLI = 0.98, RMSEA = 0.001). Behavioral pain structure, independent from gestational age had a significant direct association with parental stress score (β = 0.005, SE = 0.002, p = 0.026).

CONCLUSIONS

The PIPP-R assesses both behavioral and physiological pain factors. We also found that behavioral pain factor was associated with parental stress.

IMPACT

These results may provide a potential clue for physicians, nurses, and parents to manage the pain in preterm infant. The PIPP-R scores in preterm infants consist of "Behavioral and Physiological" pain factors. Single dependence on behavioral indicators (such as facial expression) has some limitations. Multidimensional tools may be the optimal method in detecting pain in preterm infants. Parental stress can affect behavioral pain structure in preterm infants. Intensive care nurses play an effective role in reducing the parental stress and pain severity of these preterm infants by including the help of mothers in procedures and providing them with psychological support.

Sucrose analgesia for heel-lance procedures in neonates

BACKGROUND

Sucrose has been examined for calming and pain-relieving effects in neonates for invasive procedures such as heel lance.

OBJECTIVES

To assess the effectiveness of sucrose for relieving pain from heel lance in neonates in terms of immediate and long-term outcomes SEARCH METHODS: We searched (February 2022): CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, Web of Science, and three trial registries.

SELECTION CRITERIA

We included randomised controlled trials where term and/or preterm neonates received sucrose for heel lances. Comparison treatments included water/placebo/no intervention, non-nutritive sucking (NNS), glucose, breastfeeding, breast milk, music, acupuncture, facilitated tucking, and skin-to-skin care.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. We reported mean differences (MD) with 95% confidence intervals (CI) using the fixed-effect model for continuous outcome measures. We assessed heterogeneity by the I2 test. We used GRADE to assess certainty of evidence.

MAIN RESULTS

We included 55 trials (6273 infants): 29 included term neonates, 22 included preterm neonates, and four included both. Heel lance was investigated in 50 trials; 15 investigated other minor painful procedures in addition to lancing. Sucrose vs control The evidence suggests that sucrose probably results in a reduction in PIPP scores compared to the control group at 30 seconds (MD -1.74 (95% CI -2.11 to -1.37); I2 = 62%; moderate-certainty evidence) and 60 seconds after lancing (MD -2.14, 95% CI -3.34 to -0.94; I2 = 0%; moderate-certainty evidence). The evidence is very uncertain about the effects of sucrose on DAN scores compared to water at 30 seconds after lancing (MD -1.90, 95% CI -8.58 to 4.78; heterogeneity not applicable (N/A); very low-certainty evidence). The evidence suggests that sucrose probably results in a reduction in NIPS scores compared to water immediately after lancing (MD -2.00, 95% CI -2.42 to -1.58; heterogeneity N/A; moderate-certainty evidence). Sucrose vs NNS The evidence is very uncertain about the effect of sucrose on PIPP scores compared to NNS during the recovery period after lancing (MD 0.60, 95% CI -0.30 to 1.50; heterogeneity not applicable; very low-certainty evidence) and on DAN scores at 30 seconds after lancing (MD -1.20, 95% CI -7.87 to 5.47; heterogeneity N/A; very low-certainty evidence). Sucrose + NNS vs NNS The evidence is very uncertain about the effect of sucrose + NNS on PIPP scores compared to NNS during lancing (MD -4.90, 95% CI -5.73 to -4.07; heterogeneity not applicable; very low-certainty evidence) and during recovery after lancing (MD -3.80, 95% CI -4.47 to -3.13; heterogeneity N/A; very low-certainty evidence). The evidence is very uncertain about the effects of sucrose + NNS on NFCS scores compared to water + NNS during lancing (MD -0.60, 95% CI -1.47 to 0.27; heterogeneity N/A; very low-certainty evidence). Sucrose vs glucose The evidence suggests that sucrose results in little to no difference in PIPP scores compared to glucose at 30 seconds (MD 0.26, 95% CI -0.70 to 1.22; heterogeneity not applicable; low-certainty evidence) and 60 seconds after lancing (MD -0.02, 95% CI -0.79 to 0.75; heterogeneity N/A; low-certainty evidence). Sucrose vs breastfeeding The evidence is very uncertain about the effect of sucrose on PIPP scores compared to breastfeeding at 30 seconds after lancing (MD -0.70, 95% CI -0.49 to 1.88; I2 = 94%; very low-certainty evidence). The evidence is very uncertain about the effect of sucrose on COMFORTneo scores compared to breastfeeding after lancing (MD -2.60, 95% CI -3.06 to -2.14; heterogeneity N/A; very low-certainty evidence). Sucrose vs expressed breast milk The evidence suggests that sucrose may result in little to no difference in PIPP-R scores compared to expressed breast milk during (MD 0.3, 95% CI -0.24 to 0.84; heterogeneity not applicable; low-certainty evidence) and at 30 seconds after lancing (MD 0.3, 95% CI -0.11 to 0.71; heterogeneity N/A; low-certainty evidence). The evidence suggests that sucrose probably may result in slightly increased PIPP-R scores compared to expressed breast milk 60 seconds after lancing (MD 1.10, 95% CI 0.34 to 1.86; heterogeneity N/A; low-certainty evidence). The evidence is very uncertain about the effect of sucrose on DAN scores compared to expressed breast milk 30 seconds after lancing (MD -1.80, 95% CI -8.47 to 4.87; heterogeneity N/A; very low-certainty evidence). Sucrose vs laser acupuncture There was no difference in PIPP-R scores between sucrose and music groups; however, data were reported as medians and IQRs. The evidence is very uncertain about the effect of sucrose on NIPS scores compared to laser acupuncture during lancing (MD -0.86, 95% CI -1.43 to -0.29; heterogeneity N/A; very low-certainty evidence). Sucrose vs facilitated tucking The evidence is very uncertain about the effect of sucrose on total BPSN scores compared to facilitated tucking during lancing (MD -2.27, 95% CI -4.66 to 0.12; heterogeneity N/A; very low-certainty evidence) and during recovery after lancing (MD -0.31, 95% CI -1.72 to 1.10; heterogeneity N/A; very low-certainty evidence). Sucrose vs skin-to-skin + water (repeated lancing) The evidence suggests that sucrose results in little to no difference in PIPP scores compared to skin-to-skin + water at 30 seconds after 1st (MD 0.13, 95% CI -0.70 to 0.96); 2nd (MD -0.56, 95% CI -1.57 to 0.45); or 3rd lancing (MD-0.15, 95% CI -1.26 to 0.96); heterogeneity N/A, low-certainty evidence for all comparisons. The evidence suggests that sucrose results in little to no difference in PIPP scores compared to skin-to-skin + water at 60 seconds after 1st (MD -0.61, 95% CI -1.55 to 0.33); 2nd (MD -0.12, 95% CI -0.99 to 0.75); or 3rd lancing (MD-0.40, 95% CI -1.48 to 0.68); heterogeneity N/A, low-certainty evidence for all comparisons. Minor adverse events required no intervention.

AUTHORS' CONCLUSIONS

Sucrose compared to control probably results in a reduction of PIPP scores 30 and 60 seconds after single heel lances (moderate-certainty evidence). Evidence is very uncertain about the effect of sucrose compared to NNS, breastfeeding, laser acupuncture, facilitated tucking, and the effect of sucrose + NNS compared to NNS in reducing pain. Sucrose compared to glucose, expressed breast milk, and skin-to-skin care shows little to no difference in pain scores. Sucrose combined with other nonpharmacologic interventions should be used with caution, given the uncertainty of evidence.

Diagnosing Pain in Individuals with Intellectual and Developmental Disabilities: Current State and Novel Technological Solutions

Pain assessment poses a challenge in several groups of clients, yet specific barriers arise when it comes to pain assessment of individuals with intellectual and developmental disabilities (IDD), due mostly to communication challenges preventing valid and reliable self-reports. Despite increased interest in pain assessment of those diagnosed with IDD within recent years, little is known about pain behavior in this group. The present article overviews the current state of pain diagnosis for individuals with IDD, focusing on existing pain assessment scales. In addition, it suggests technological developments offering new ways to diagnose existence of pain in this population, such as a Smartphone App for caregivers based on unique acoustic characteristics of pain-related vocal responses, or the use of smart wearable shirts that enable continuous surveillance of vital physiological signs. Such novel technological solutions may improve diagnosis of pain in the IDD population, as well as in other individuals with complex communication needs, to provide better pain treatment and enhance overall quality of life.

Assessment of neonatal pain: uni- and multidimensional evaluation scales

Neonatal pain is a problem that is easily overlooked. According to the status quo of neonatal pain management, commonly 9 scales are used for evaluation of neonatal pain; details of the specific indicators, such as the applicable neonatal gestational age range, score, and the type of pain, for the domestic references are provided so as to provide reference for the proper evaluation and standardized management of neonatal pain, as well as to promote the management level of neonatal pain.

The influence of skin-to-skin contact on Cortical Activity during Painful procedures in preterm infants in the neonatal intensive care unit (iCAP mini): study protocol for a randomized control trial

BACKGROUND

Strong evidence suggests that maternal-infant skin-to-skin contact (SSC) is effective in reducing behavioural responses to pain. Given the multi-sensory benefits of SSC, it is highly likely that SSC provided during pain in early life may reduce pain-induced brain activity. The aim of this study is to examine the effect of SSC compared to 24% sucrose on pain-induced activity in the preterm infant brain during a medically required heel lance. Secondary objectives include determining (a) differences between behavioural pain response and noxious-related brain activity during heel lance and (b) rate of adverse events across groups.

METHODS

We will randomly assign 126 babies (32 to 36 completed weeks gestational age) admitted to the neonatal intensive care unit, and their mothers within the first seven days of age to receive (i) SSC plus sterile water and (ii) 24% oral sucrose. Each baby will receive a medically indicated heel lance, following a no treatment baseline period. The primary outcome is noxious-related brain activity measured using an electroencephalogram (EEG) pain-specific event-related potential. Secondary outcomes include pain intensity measured using a bio-behavioural infant pain assessment tool (Premature Infant Pain Profile-Revised) and rate of adverse events.

DISCUSSION

This will be the first clinical trial to compare the effect of SSC and 24% sucrose on pain-induced brain activity in the preterm infant brain during a clinical noxious stimulus, measured using EEG. Given the negative neurodevelopmental outcomes associated with unmanaged pain, it is imperative that preterm babies receive the most effective pain-reducing treatments to improve their health outcomes. Our findings will have important implications in informing optimal pain assessment and management in preterm infants.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03745963 . Registered on November 19, 2018.

Evaluation of the Premature Infant Pain Profile-Revised (PIPP-R) e-Learning Module: Immediate and Sustained Competency

BACKGROUND

Electronic health (e-health) learning is a potential avenue to educate health professionals about accurately using infant pain assessment tools, although little is known about the impact of e-health interventions on clinical competence.

PURPOSE

To evaluate whether an e-health learning module for teaching the accurate use of the Premature Infant Pain Profile-Revised (PIPP-R) pain assessment tool results in immediate and sustained competency to assess infant pain.

METHODS

Neonatal intensive care unit (NICU) nurses who participated in a larger study across 2 tertiary NICUs in Canada examining the implementation and clinical utility of the PIPP-R e-learning module completed 2 follow-up evaluations at 1 week and 3 months. Participants were asked to view a video recording of an infant undergoing a painful procedure and to assess the infant's pain intensity response using the PIPP-R measure. Immediate and sustained competency was assessed via interrater consensus of participant-reported PIPP-R scores compared with those of an experienced trained coder.

RESULTS

Of the 25 eligible nurses, 22 completed 1-week and 3-month follow-up evaluations. At the 1-week follow-up, 84% of nurses scored the video accurately compared with 50% at 3 months. Behavioral pain indicators were more likely to be scored incorrectly than physiological indicators.

IMPLICATIONS FOR PRACTICE

Follow-up training after completion of the initial e-learning module training may improve competency related to the clinical use of the PIPP-R tool to assess infant pain over time.

IMPLICATIONS FOR RESEARCH

Additional study regarding the need and timing of e-health training to optimize sustained competency in infant pain assessment is warranted.

Neonatal pain: A journey spanning three decades

From 1980 into present day, 2020, the evolution of neonatal pain research is told as a journey by one researcher, Celeste Johnston. At the beginning of her work, there was essentially no interest or work in the area. She was fortunate to be led into the area by a clinical problem: how to determine the amount of pain babies in the NICU were experiencing. That question resulted in over three decades of work with neonates. Measuring pain was the first challenge and is one that remains a focus of current research. Initially, the only choices for treating pain in neonates were either opioids or anesthetics, each with problems. Research on sweet taste and more recently on skin‐to‐skin contact has offered effective and safe options for procedural pain. Although progress has been made in the incidence of pain management in infants, it still is far less than it could be. Steps along the way of measurement, treatment, and knowledge utilization are chronicled by this researcher.

Acute pain measured with the modified Bernese Pain Scale for Neonates is influenced by individual contextual factors

BACKGROUND

Individual contextual factors like gestational age (GA) or previous painful experiences have an influence on neonates' pain responses and may lead to inaccurate pain assessment when not appropriately considered.

OBJECTIVES

We set out to determine the influence of individual contextual factors on variability in pain response in neonates, measured with the modified Bernese Pain Scale for Neonates (BPSN), and, if necessary, to incorporate relevant individual factors into a revised version of the BPSN.

METHODS

We videotaped 154 full-term and preterm neonates of different GAs during 1-5 capillary heel sticks in their first 14 days of life. For each heel stick, we produced three video sequences: baseline, heel stick, and recovery. The randomized sequences were rated on the BPSN by five blinded nurses. Individual contextual factors were retrospectively extracted from patient charts and from the video recordings. We analysed the data in single and multiple linear mixed models.

RESULTS

Premature birth (b = -0.721), caffeine (b = -0.302), and the behavioural states quiet and awake (b = -0.283), active and asleep (b = -0.158), and quiet and asleep (b = -0.498) were associated with changes in behavioural pain scores. Premature birth (b = -0.232), mechanical ventilation (b = -0.196), and duration of the heel stick procedure (b = 0.0004) were associated with changes in physiological pain scores. Premature birth (b = -0.907), Caffeine (b = -0.402), the behavioural states quiet and awake (b = -0.274), and quiet and asleep (b = -0.459), and duration of the heel stick procedure (b = 0.001) were associated with changes in the modified BPSN total scores.

CONCLUSIONS

Postmenstrual age, behavioural state, caffeine, and ventilation status have an influence on neonates' pain response and should be incorporated in the revised BPSN to enhance clinical pain assessment in neonates with different GAs.

SIGNIFICANCE

We identified individual contextual factors associated with dampened pain response in neonates and will incorporate them into a revised version of the Bernese Pain Scale for Neonates to provide clinicians with a tool they can use to more accurately assess and manage pain in this vulnerable population.

Nociception and the neonatal brain

Measuring brain activity in infants provides an objective surrogate approach with which to infer pain perception following noxious events. Here we discuss different approaches which can be used to measure noxious-evoked brain activity, and discuss how these measures can be used to assess the analgesic efficacy of pharmacological and non-pharmacological interventions. We review factors that can modulate noxious-evoked brain activity, which may impact infant pain experience, including gestational age, sex, prior pain, stress, and illness.

Video and audio processing in paediatrics: a review

OBJECTIVE

Video and sound acquisition and processing technologies have seen great improvements in recent decades, with many applications in the biomedical area. The aim of this paper is to review the overall state of the art of advances within these topics in paediatrics and to evaluate their potential application for monitoring in the neonatal intensive care unit (NICU).

APPROACH

For this purpose, more than 150 papers dealing with video and audio processing were reviewed. For both topics, clinical applications are described according to the considered cohorts-full-term newborns, infants and toddlers or preterm newborns. Then, processing methods are presented, in terms of data acquisition, feature extraction and characterization.

MAIN RESULTS

The paper first focuses on the exploitation of video recordings; these began to be automatically processed in the 2000s and we show that they have mainly been used to characterize infant motion. Other applications, including respiration and heart rate estimation and facial analysis, are also presented. Audio processing is then reviewed, with a focus on the analysis of crying. The first studies in this field focused on induced-pain cries and the newest ones deal with spontaneous cries; the analyses are mainly based on frequency features. Then, some papers dealing with non-cry signals are also discussed.

SIGNIFICANCE

Finally, we show that even if recent improvements in digital video and signal processing allow for increased automation of processing, the context of the NICU makes a fully automated analysis of long recordings problematic. A few proposals for overcoming some of the limitations are given.

The human newborn's umwelt: Unexplored pathways and perspectives

Historically, newborns, and especially premature newborns, were thought to "feel nothing." However, over the past decades, a growing body of evidence has shown that newborns are aware of their environment, but the extent and the onset of some sensory capacities remain largely unknown. The goal of this review is to update our current knowledge concerning newborns' perceptual world and how ready they are to cope with an entirely different sensory environment following birth. We aim to establish not only how and when each sensory ability arises during the pre-/postbirth period but also discuss how senses are studied. We conclude that although many studies converge to show that newborns are clearly sentient beings, much is still unknown. Further, we identify a series of internal and external factors that could explain discrepancies between studies, and we propose perspectives for future studies. Finally, through examples from animal studies, we illustrate the importance of this detailed knowledge to pursue the enhancement of newborns' daily living conditions. Indeed, this is a prerequisite for assessing the effects of the physical environment and routine procedures on newborns' welfare.

EEG, behavioural and physiological recordings following a painful procedure in human neonates

We present a dataset of cortical, behavioural, and physiological responses following a single, clinically required noxious stimulus in a neonatal sample. Cortical activity was recorded from 112 neonates (29–47 weeks gestational age at study) using a 20-channel electroencephalogram (EEG), which was time-locked to a heel lance. This data is linked to pain-related behaviour (facial expression), physiology (heart rate, oxygenation) and a composite clinical score (Premature Infant Pain Profile, PIPP). The dataset includes responses to non-noxious sham and auditory controls. The infants’ relevant medical and pain history was collected up to the day of the study and recorded in an extensive database of variables including clinical condition at birth, diagnoses, medications, previous painful procedures, injuries, and selected maternal information. This dataset can be used to investigate the cortical, physiological, and behavioural pain-related processing in human infants and to evaluate the impact of medical conditions and experiences upon the infant response to noxious stimuli. Furthermore, it provides information on the formation of individual pain phenotypes.

The distribution of pain activity across the human neonatal brain is sex dependent

In adults, there are differences between male and female structural and functional brain connectivity, specifically for those regions involved in pain processing. This may partly explain the observed sex differences in pain sensitivity, tolerance, and inhibitory control, and in the development of chronic pain. However, it is not known if these differences exist from birth. Cortical activity in response to a painful stimulus can be observed in the human neonatal brain, but this nociceptive activity continues to develop in the postnatal period and is qualitatively different from that of adults, partly due to the considerable cortical maturation during this time. This research aimed to investigate the effects of sex and prematurity on the magnitude and spatial distribution pattern of the long-latency nociceptive event-related potential (nERP) using electroencephalography (EEG). We measured the cortical response time-locked to a clinically required heel lance in 81 neonates born between 29 and 42 weeks gestational age (median postnatal age 4 days). The results show that heel lance results in a spatially widespread nERP response in the majority of newborns. Importantly, a widespread pattern is significantly more likely to occur in females, irrespective of gestational age at birth. This effect is not observed for the short latency somatosensory waveform in the same infants, indicating that it is selective for the nociceptive component of the response. These results suggest the early onset of a greater anatomical and functional connectivity reported in the adult female brain, and indicate the presence of pain-related sex differences from birth.

Effects of Covering the Eyes versus Playing Intrauterine Sounds on Premature Infants' Pain and Physiological Parameters during Venipuncture

BACKGROUND

There is a need to assess the impact of initiatives to reduce exposure to environmental light and sound in preterm infants undergoing painful interventions in neonatal intensive care units.

OBJECTIVES

In this study, we aimed to identify the effect of covering the eyes and playing the intrauterine ambient sounds on premature infants' pain and physiological parameters during venipuncture.

METHODS

This was a randomized controlled trial. Ninety-four preterm infants were randomly divided into three groups: intrauterine sounds (n=32), covered eyes (n=32), and control (n=30) groups. Data were collected on the Preterm Infant Information Form, Preterm Infant Follow-up Form, and Neonatal Infant Pain Scale (NIPS), used to assess pain.

RESULTS

A significant difference was found between the intervention and control groups' NIPS score after venipuncture, which was primarily due to covered eyes' group. No significant difference was found between the intervention and control groups' NIPS score during venipuncture. In addition, no significant difference was found between the intervention and control groups of infants physiological parameters before, during, and after venipuncture. The practice of covering preterm infants' eyes during venipuncture positively affected their pain scores after venipuncture.

CLINICAL IMPLICATIONS

The effect of covering the eyes and playing the intrauterine ambient sounds in preterm infants may be recommended as simple, safe, and supportive stimuli that facilitate positive effects during painful procedures.

Sucrose for analgesia in newborn infants undergoing painful procedures

BACKGROUND

Administration of oral sucrose with and without non-nutritive sucking is the most frequently studied non-pharmacological intervention for procedural pain relief in neonates.

OBJECTIVES

To determine the efficacy, effect of dose, method of administration and safety of sucrose for relieving procedural pain in neonates as assessed by validated composite pain scores, physiological pain indicators (heart rate, respiratory rate, saturation of peripheral oxygen in the blood, transcutaneous oxygen and carbon dioxide (gas exchange measured across the skin - TcpO2, TcpCO2), near infrared spectroscopy (NIRS), electroencephalogram (EEG), or behavioural pain indicators (cry duration, proportion of time crying, proportion of time facial actions (e.g. grimace) are present), or a combination of these and long-term neurodevelopmental outcomes.

SEARCH METHODS

We used the standard methods of the Cochrane Neonatal. We performed electronic and manual literature searches in February 2016 for published randomised controlled trials (RCTs) in the Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library, Issue 1, 2016), MEDLINE (1950 to 2016), EMBASE (1980 to 2016), and CINAHL (1982 to 2016). We did not impose language restrictions.

SELECTION CRITERIA

RCTs in which term or preterm neonates (postnatal age maximum of 28 days after reaching 40 weeks' postmenstrual age), or both, received sucrose for procedural pain. Control interventions included no treatment, water, glucose, breast milk, breastfeeding, local anaesthetic, pacifier, positioning/containing or acupuncture.

DATA COLLECTION AND ANALYSIS

Our main outcome measures were composite pain scores (including a combination of behavioural, physiological and contextual indicators). Secondary outcomes included separate physiological and behavioural pain indicators. We reported a mean difference (MD) or weighted MD (WMD) with 95% confidence intervals (CI) using the fixed-effect model for continuous outcome measures. For categorical data we used risk ratio (RR) and risk difference. We assessed heterogeneity by the I(2) test. We assessed the risk of bias of included trials using the Cochrane 'Risk of bias' tool, and assessed the quality of the evidence using the GRADE system.

MAIN RESULTS

Seventy-four studies enrolling 7049 infants were included. Results from only a few studies could be combined in meta-analyses and for most analyses the GRADE assessments indicated low- or moderate-quality evidence. There was high-quality evidence for the beneficial effect of sucrose (24%) with non-nutritive sucking (pacifier dipped in sucrose) or 0.5 mL of sucrose orally in preterm and term infants: Premature Infant Pain Profile (PIPP) 30 s after heel lance WMD -1.70 (95% CI -2.13 to -1.26; I(2) = 0% (no heterogeneity); 3 studies, n = 278); PIPP 60 s after heel lance WMD -2.14 (95% CI -3.34 to -0.94; I(2) = 0% (no heterogeneity; 2 studies, n = 164). There was high-quality evidence for the use of 2 mL 24% sucrose prior to venipuncture: PIPP during venipuncture WMD -2.79 (95% CI -3.76 to -1.83; I(2) = 0% (no heterogeneity; 2 groups in 1 study, n = 213); and intramuscular injections: PIPP during intramuscular injection WMD -1.05 (95% CI -1.98 to -0.12; I(2) = 0% (2 groups in 1 study, n = 232). Evidence from studies that could not be included in RevMan-analyses supported these findings. Reported adverse effects were minor and similar in the sucrose and control groups. Sucrose is not effective in reducing pain from circumcision. The effectiveness of sucrose for reducing pain/stress from other interventions such as arterial puncture, subcutaneous injection, insertion of nasogastric or orogastric tubes, bladder catherization, eye examinations and echocardiography examinations are inconclusive. Most trials indicated some benefit of sucrose use but that the evidence for other painful procedures is of lower quality as it is based on few studies of small sample sizes. The effects of sucrose on long-term neurodevelopmental outcomes are unknown.

AUTHORS' CONCLUSIONS

Sucrose is effective for reducing procedural pain from single events such as heel lance, venipuncture and intramuscular injection in both preterm and term infants. No serious side effects or harms have been documented with this intervention. We could not identify an optimal dose due to inconsistency in effective sucrose dosage among studies. Further investigation of repeated administration of sucrose in neonates is needed. There is some moderate-quality evidence that sucrose in combination with other non-pharmacological interventions such as non-nutritive sucking is more effective than sucrose alone, but more research of this and sucrose in combination with pharmacological interventions is needed. Sucrose use in extremely preterm, unstable, ventilated (or a combination of these) neonates needs to be addressed. Additional research is needed to determine the minimally effective dose of sucrose during a single painful procedure and the effect of repeated sucrose administration on immediate (pain intensity) and long-term (neurodevelopmental) outcomes.

Staff Nurse Utilization of Kangaroo Care as an Intervention for Procedural Pain in Preterm Infants

BACKGROUND

Skin-to-skin contact between mother and infant, commonly referred to as Kangaroo Care (KC), has demonstrated efficacy as a pain-relieving strategy for infants, yet, it remains underutilized in clinical practice.

PURPOSE

To evaluate changes in neonatal intensive care unit staff nurse beliefs, utilization, and challenges related to practice change in implementing KC as an intervention for management of procedural pain in preterm infants between 2 time points.

METHODS

Nurses who participated in a larger clinical trial examining the sustained efficacy of KC were asked to complete a questionnaire at 2 time points: 1- and 6 month(s) following study initiation. Identified benefits, expectations, frequency of use, and challenges related to practice change uptake were described using frequencies and percentages. Data from the 2 different time points were compared using χ analysis.

RESULTS

Of the 40 nurses approached, all completed the questionnaire (19 at the 1-month and 21 at the 6-month time point). Of the sample (n = 40), 97% of participants indicated that they expected KC to provide good pain relief or better. Staff nurses reported significantly improved preconceived ideas (χ = 22.68, P < .01) and significantly fewer concerns (χ = 22.10, P = .01) related to using KC as a pain-relieving intervention between the 2 time points. No significant differences were seen in the frequency of using KC as an intervention between time points.

IMPLICATIONS FOR RESEARCH AND PRACTICE

Despite increasingly positive preconceived ideas and reduced concerns, the frequency of using KC for procedural pain relief remained unchanged. Further research addressing ways to overcome barriers to utilizing KC as an intervention for procedural pain is warranted.

Neonatal pain and reduced maternal care: Early-life stressors interacting to impact brain and behavioral development

Advances in neonatal intensive care units (NICUs) have drastically increased the survival chances of preterm infants. However, preterm infants are still exposed to a wide range of stressors during their stay in the NICU, which include painful procedures and reduced maternal contact. The activation of the hypothalamic-pituitary-adrenal (HPA) axis, in response to these stressors during this critical period of brain development, has been associated with many acute and long-term adverse biobehavioral outcomes. Recent research has shown that Kangaroo care, a non-pharmacological analgesic based on increased skin-to-skin contact between the neonate and the mother, negates the adverse outcomes associated with neonatal pain and reduced maternal care, however the biological mechanism remains widely unknown. This review summarizes findings from both human and rodent literature investigating neonatal pain and reduced maternal care independently, primarily focusing on the role of the HPA axis and biobehavioral outcomes. The physiological and positive outcomes of Kangaroo care will also be discussed in terms of how dampening of the HPA axis response to neonatal pain and increased maternal care may account for positive outcomes associated with Kangaroo care.

Self-regulation (recovery) from pain: association between time-based measures of infant pain behavior and prenatal exposure to maternal depression and anxiety

OBJECTIVES

Capacities for self-regulation that influence infant adaptation to noxious stimulation require investigation of changes in behavior over time. Prenatal exposure to maternal depression and anxiety (MDA) has been linked to altered infant pain reactivity; however, findings are inconclusive about MDA dynamic impacts on recovery. This study quantified the temporal profile of behavioral response and recovery to routine heel lance (HL) of infants with and without prenatal-MDA exposure. Aims were to examine whether MDA were associated with alterations in time-based measures of infant behavior and sequential patterning in pain expression.

MATERIALS AND METHODS

Videotaped facial, body, and cry behaviors of 21 full-term newborns were coded second-by-second for the duration of HL (baseline, HL, Post-HL) using validated behavioral coding systems. Mean heart rate and proportion of time infants spent exhibiting behavioral measures were compared between infant groups and over subphases of HL. Simple regressions, latency, and Yule-Q measures of effect size examined which behaviors were predicted by prenatal-MDA and magnitude of sequential association between first and subsequent behavior.

RESULTS

During HL, all infants reacted immediately and substantially on heart rate, facial, body, and cry measures. Facial reactivity was followed within 2 seconds by body and cry behavior. There were no group differences in magnitude of initial behavioral reactions, but during Post-HL, MDA-exposed infants spent more time crying in a weak/exhausted manner and displayed strained and erratic limb movement and immobility.

CONCLUSIONS

Temporal measures can further help in understanding of infant complex behavioral responses to pain. Delayed recovery in MDA-exposed infants suggested diminished capacities for self-regulation of noxious distress.

Oral glucose solution to alleviate pain induced by intramuscular injections in preterm infants

PURPOSE

The purpose was to assess the effectiveness of 5% oral glucose solution in reducing pain in preterm infants during intramuscular injection.

DESIGN AND METHODS

We conducted a prospective, randomized, controlled, unblinded trial to investigate the effect of glucose solution on the pain of intramuscular injection in preterm infants (N = 80).

RESULTS

Infants who received oral glucose had significantly lower pain scores (p < .001), less crying time (p < .001), higher oxygen saturation (p < .001), and lower heart rate after compared with during the procedure (p = .02).

PRACTICE IMPLICATIONS

Our results suggest that oral glucose, even if used in the lowest dose, may have a pain-relieving effect in preterm infants if administered pre-procedure.

The effects of olfactory stimulation and gender differences on pain responses in full-term infants

AIM

Studies have reported conflicting findings on whether different smells can reduce distress when infants undergo painful procedures. Our study assessed the impact of vanilla on infants' responses to a painful toe lance, including possible gender differences.

METHODS

We measured the pain responses of 69 full-term infants - 34 girls and 35 boys - during toe lance, using two multidimensional scales - the Neonatal Facial Coding System and Behavioural Indicators of Infant Pain - together with crying duration and hand movements. Three sets of data were collected during baseline, toe lance and recovery, while the babies were exposed to the odour of vanilla (n = 39) or odourless water (n = 30).

RESULTS

Pain responses increased significantly during toe lance, then declined during recovery. Crying duration correlated significantly with finger splaying/fisting and both pain scale scores, with boys displaying higher pain scores than girls. Vanilla had no impact on pain levels.

CONCLUSION

Crying and finger splaying/fisting were observable responses that may be useful for screening pain or distress in healthy neonates. Increased pain reactions by boys may reflect higher irritability. Exposure to an unfamiliar odour did not have a calming effect on full-term neonates.

The premature infant pain profile-revised (PIPP-R): initial validation and feasibility

OBJECTIVES

To describe revisions to the Premature Infant Pain Profile (PIPP) and initial construct validation and feasibility of the Premature Infant Pain Profile-Revised (PIPP-R).

METHODS

The PIPP was revised to enhance validity and feasibility. To validate the PIPP-R, data from 2 randomized cross-over studies were utilized to: (1) calculate and compare PIPP and PIPP-R scores in extremely low gestational age infants undergoing a painful and nonpainful event (N=52; dataset #1) and (2) calculate and compare PIPP and PIPP-R scores in assessing the effectiveness of (a) sucrose, (b) non-nutritive sucking (NNS)+sucrose, and (c) facilitated tucking+NNS+sucrose during heel lance (N = 85; dataset #2). Pearson correlations between PIPP and PIPP-R scores were calculated, and Student t tests and 1-way analysis of variance were used to determine construct validity during painful and nonpainful events. To establish feasibility, a survey of 31 Neonatal Intensive Care Unit nurses was conducted.

RESULTS

PIPP-R scores were significantly lower during nonpainful (mean, 8.3; SD = 2.9) compared with painful (mean, 9.9; SD=3.1; t95 = 4.51, P = 0.036) events in extremely low gestational age infants in dataset #1. In dataset #2, PIPP-R scores were significantly lower in infants 25 to 41 weeks gestation in the group receiving NNS+sucrose compared with the other 2 groups (F2,79 = 2.9, P<0.05). Overall, nurses rated the PIPP-R as feasible.

DISCUSSION

Initial construct validation and feasibility of the PIPP-R was demonstrated. Further testing with infants of varying gestational ages, diagnoses, and pain conditions is required; as is exploration of PIPP-R in relation to other types of physiological and cognitive responses.

Pain assessment and measurement in neonates: an updated review

Pain assessment and measurement are the cornerstones of pain management. Pain assessment connotes a comprehensive multidimensional description. Conversely, pain measurement provides a numeric quantitative description of each factor illustrating pain qualities. Pain scales provide a composite score used to guide practice and research. The type of infant pain instrument chosen is a significant factor in guiding pain management practice. The purpose of this review was to summarize current infant pain measures by introducing a conceptual framework for pain measurement. Although more than 40 infant pain instruments exist, many were devised solely for research purposes; several of the newly developed instruments largely overlap with existing instruments. Integration of pain management into daily practice remains problematic. Understanding how each instrument measures infant pain allows clinicians to make better decisions about what instrument to use with which infant and in what circumstances. In addition, novel new measurement techniques need further testing.

Physiological parameters after nonpharmacological analgesia in preterm infants: a randomized trial

AIM

To compare the influence of three different nonpharmacological interventions on cortical activation, heart rate and peripheral oxygen saturation (SaO2 ) after heelstick in preterm infants.

METHODS

Twenty five preterm infants between 24 0/7 and 32 0/7 weeks of gestational age were randomized to either oral sucrose (S), facilitated tucking (FT) or a combination of the two interventions (SFT) prior to five heelsticks each within the first 14 days of life. SaO2 , heart rate and oxygenation of the somatosensory cortex, measured by near infrared spectroscopy (NIRS), were analysed.

RESULTS

Hundred and twenty five heelsticks were performed. The heart rate increased significantly after heelstick in all three intervention groups (p < 0.004 in all groups). The increase was higher in the FT group compared with the other groups (S: p = 0.007; SFT: p = 0.004). There was no difference among the two groups receiving sucrose (S and SFT; p = 0.87). SaO2 did not change significantly after heelstick in all intervention groups. Near infrared spectroscopy measurements did not show a significant change in the curve but patients in the FT group showed a trend towards higher average oxygenation of the contralateral somatosensory cortex.

CONCLUSION

Oral sucrose seems to be more effective in reducing reaction to pain than FT. Application of both interventions did not show an additive effect.

Role of sucrose in reducing painful response to orogastric tube insertion in preterm neonates

OBJECTIVES

To study whether orogastric tube (OGT) insertion elicits a painful response in preterm neonates, and the role of oral sucrose in reducing this pain.

METHODS

This double blinded, randomized control trial was conducted in the neonatal intensive care units of Kalawati Saran Children's Hospital. Clinically stable preterms within the first 7 postnatal days, who had not received painful stimulus 30 min prior to intervention, and who required routine OGT insertion were included. Lingual 24 % sucrose or distilled water (1 ml) was administered 2 min before OGT insertion. The primary outcome was painful response assessed by Premature Infant Pain Profile scale (PIPP), while the secondary outcomes were heart rate and SpO2 changes. The trial is registered with ClinicalTrials.gov (

REGISTRATION NUMBER

NCT 00949104) RESULTS: Sixty preterms were randomized in each group. Final analysis was carried out on 52 subjects in the placebo group and 53 in the sucrose group. The mean intra-procedure PIPP scores were significantly higher than the mean pre-procedure PIPP scores, in the gestational age groups of more than 34 wk, and 32 wk to 33 wk, 6 d, in both the placebo (7.25 vs. 3, and 8.14 vs. 3.14, respectively) and sucrose arm (8.06 vs. 3.21, and 7.18 vs. 4.18, respectively). The mean PIPP scores assessed at 30 s post procedure in the sucrose group were significantly lower than the placebo group (4.32 vs. 5.6, p = 0.014). No significant adverse events were seen.

CONCLUSIONS

OGT insertion causes pain in preterms and single dose lingual 24 % sucrose may alleviate this pain.

Brain development in infants born preterm: looking beyond injury

Infants born very preterm are high risk for acquired brain injury and disturbances in brain maturation. Although survival rates for preterm infants have increased in the last decades owing to improved neonatal intensive care, motor disabilities including cerebral palsy persist, and impairments in cognitive, language, social, and executive functions have not decreased. Evidence from neuroimaging studies exploring brain structure, function, and metabolism has indicated abnormalities in the brain development trajectory of very preterm-born infants that persist through to adulthood. In this chapter, we review neuroimaging approaches for the identification of brain injury in the preterm neonate. Advances in medical imaging and availability of specialized equipment necessary to scan infants have facilitated the feasibility of conducting longitudinal studies to provide greater understanding of early brain injury and atypical brain development and their effects on neurodevelopmental outcome. Improved understanding of the risk factors for acquired brain injury and associated factors that affect brain development in this population is setting the stage for improving the brain health of children born preterm.

Sucrose for analgesia in newborn infants undergoing painful procedures

BACKGROUND

Administration of oral sucrose with and without non-nutritive sucking is the most frequently studied non-pharmacological intervention for procedural pain relief in neonates.

OBJECTIVES

To determine the efficacy, effect of dose and safety of oral sucrose for relieving procedural pain in neonates.

SEARCH METHODS

We used the standard methods of the Cochrane Neonatal Review Group. Electronic and manual searches were performed in November 2011 for published randomised controlled trials (RCTs) in MEDLINE (1950 to November 2011), EMBASE (1980 to 2011), CINAHL (1982 to November 2011) and the Cochrane Central Register of Controlled Trials (The Cochrane Library). We did not impose language restrictions.

SELECTION CRITERIA

RCTs in which term, preterm, or both term and preterm neonates (postnatal age maximum of 28 days after reaching 40 weeks' postmenstrual age) received sucrose for procedural pain. Control conditions included no treatment, water, pacifier, positioning/containing or breastfeeding.

DATA COLLECTION AND ANALYSIS

Main outcome measures were physiological, behavioural, or both pain indicators with or without composite pain scores. A mean difference (MD) with 95% confidence intervals (CI) using the fixed-effect model was reported for continuous outcome measures. Trial quality was assessed as per The Cochrane Collaboration

MAIN RESULTS

Fifty-seven studies enrolling 4730 infants were included. Results from only a few studies could be combined in meta-analyses. When Premature Infant Pain Profile (PIPP) scores were pooled, sucrose groups had significantly lower scores at 30 seconds (weighted mean difference (WMD) -1.76; 95% CI -2.54 to - 0.97; 4 trials; 264 neonates] and 60 seconds (WMD -2.05; 95% CI -3.08 to -1.02; 3 trials' 195 neonates) post-heel lance. For retinopathy of prematurity (ROP) examinations, sucrose did not significantly reduce PIPP scores (WMD -0.65; 95% CI -1.88 to 0.59; 3 trials; 82 neonates). There were no differences in adverse effects between sucrose and control groups. Sucrose significantly reduced duration of total crying time (WMD -39 seconds; 95% CI -44 to -34; 2 trials; 88 neonates), but did not reduce duration of first cry during heel lance (WMD -9 seconds; 95% CI -20 to 2; 3 trials; 192 neonates). Oxygen saturation (%) was significantly lower in infants given sucrose during ROP examination compared to controls (WMD -2.6; 95% CI -4.9 to - 0.2; 2 trials; 62 neonates). Results of individual trials that could not be incorporated in meta-analyses supported these findings. The effects of sucrose on long-term neurodevelopmental outcomes are unknown.

AUTHORS' CONCLUSIONS

Sucrose is safe and effective for reducing procedural pain from single events. An optimal dose could not be identified due to inconsistency in effective sucrose dosage among studies. Further investigation on repeated administration of sucrose in neonates and the use of sucrose in combination with other non-pharmacological and pharmacological interventions is needed. Sucrose use in extremely preterm, unstable, ventilated (or a combination of these) neonates needs to be addressed. Additional research is needed to determine the minimally effective dose of sucrose during a single painful procedure and the effect of repeated sucrose administration on immediate (pain intensity) and long-term (neurodevelopmental) outcomes.

Expressed breast milk for procedural pain in preterm neonates: a randomized, double-blind, placebo-controlled trial

AIM

To determine whether expressed breast milk (milk) reduces procedural pain associated with heel lancing in preterm neonates.

METHODS

In this placebo-controlled trial, preterm neonates received 5 mL of distilled water as placebo (water, n = 44), 25% glucose water (glucose, n = 39) or milk (n = 40). Heel lancing was performed 2 min later. The primary outcome was the duration of first cry after lancing.

RESULTS

Participants had similar baseline demographic and clinical characteristics. There was a significant difference in the median duration of first cry among the groups: water = 70.5 sec [interquartile range (IQR) = 5.5-104.5]; glucose = 2.0 sec (IQR = 0.0-45.0); milk = 29.5 sec (IQR = 0.0-65.0). Specifically, the duration of first cry was significantly shorter in the glucose group compared with the water group (Bonferroni adjustment, p = 0.011). Pain scores were significantly lower in the glucose and milk groups compared with the water group 1, 2 and 3 min after heel lancing (p < 0.05).

CONCLUSIONS

Although milk did not significantly reduce crying time, our finding that pain scores were significantly lower in the milk group suggests that milk may reduce pain associated with heel lancing in preterm neonates.

Contextual factors associated with pain response of preterm infants to heel-stick procedures

BACKGROUND

Evidence indicates that medical and demographic contextual factors (cFs) impact pain responses in preterm neonates, but the existing evidence is very heterogeneous.

AIM

To explore the effect of cFs on pain responses to heel-stick procedures of preterm infants.

METHODS

This study was a secondary analysis of data collected during a randomized controlled trial examining pain response to non-pharmacological interventions across repeated heel sticks. Five heel sticks across the first 14 days of life were videotaped. Pain response was rated with the Bernese Pain Scale for Neonates (BPSN) by four raters blinded to the heel-stick phases (baseline, heel stick, recovery). Demographic and medical cFs were extracted from medical charts. Mixed single and multiple regression analyses were performed controlling for the intervention group, site and heel-stick phase.

RESULTS

Apgar scores at 1 min were negatively associated with behavioural (p = 0.002) BPSN scores, while Apgar scores at 5 min after birth were positively associated with behavioural (p = 0.006) scores. Accumulated number of painful procedures (p = 0.002) and gender (p = 0.02) were positively associated with physiological scores while continuous positive airway pressure CPAP (p = 0.009) and mechanical ventilation (p = 0.005) were negatively associated.

CONCLUSION

Higher exposure to painful procedures, male infants and having CPAP or mechanical ventilation were cFs associated with physiological response. The only variables significantly associated with behavioural BPSN scores were Apgar scores but these relationships were inconsistent.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

AIM

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

METHOD

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

RESULTS

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

CONCLUSION

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

Sucrose for analgesia in newborn infants undergoing painful procedures

BACKGROUND

Administration of oral sucrose with and without non-nutritive sucking is frequently used as a non-pharmacological intervention for procedural pain relief in neonates.

OBJECTIVES

To determine the efficacy, effect of dose and safety of oral sucrose for relieving procedural pain in neonates.

SEARCH STRATEGY

The standard methods of the Cochrane Neonatal Collaborative Review Group were used.

SELECTION CRITERIA

Randomized controlled trials in which term and/or preterm neonates (postnatal age maximum of 28 days corrected for postmenstrual age) received sucrose for procedural pain. Control conditions included water, pacifier, positioning/containing or breastfeeding.

DATA COLLECTION AND ANALYSIS

The main outcome measures were physiological and/or behavioural pain indicators and/or composite pain scores. 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 enrolling 3,496 infants were included. Results from only a few studies could be combined in meta-analyses. Sucrose significantly reduced duration of total crying time (seconds) [WMD -39.26 (95% CI -44.29, -34.24), 88 neonates], but did not reduce duration of first cry (seconds) during heel lance [WMD -8.99 (95% CI -20.07, 2.10), 192 neonates]. No significant differences were found for percent change in heart rate from baseline at one minute [WMD 0.90 (95% CI -5.81, 7.61), 86 neonates] and three minutes [WMD -6.20 (95% CI -15.27, 2.88), 86 neonates] post-heel lance, or for mean heart rate at three minutes post-heel lance [WMD -0.98 (95% CI -8.29, 6.32), 154 neonates]. Oxygen saturation (%) was significantly lower in infants given sucrose during ROP examination compared to controls [WMD -2.58 (95% CI -4.94, - 0.23), 62 neonates]. Infants given sucrose post-heel lance had significantly lower PIPP scores at 30 seconds [WMD -1.64 (95% CI -2.47, - 0.81), 220 neonates] and 60 seconds [WMD -2.05 (95% CI -3.08, -1.02), 195 neonates]. For ROP exams, sucrose did not significantly reduce PIPP scores [WMD -0.65 (95% CI -1.88, 0.59), 82 neonates]. There were no differences in adverse effects between sucrose and control groups.

AUTHORS' CONCLUSIONS

Sucrose is safe and effective for reducing procedural pain from single events. An optimal dose could not be identified due to inconsistency in effective sucrose dosage among studies.Further investigation on repeated administration of sucrose in neonates and the use of sucrose in combination with other non-pharmacological (e.g. behavioural, physical) and pharmacologic interventions is needed. Sucrose use in extremely low birth-weight and unstable and/or ventilated neonates needs to be addressed.

[The use of sucrose for the prevention of pain during venipuncture in neonates]

OBJECTIVE

To evaluate the effectiveness of sucrose use in the prevention of pain during venipuncture in neonates.

METHOD

Double blind randomized control trial. The population consisted of hospitalized neonates subjected to venipuncture. Sample size was calculated with a 95% confidence level, 80% power, minimum proportion of neonates with pain 40% in the study group and 70% in the control group. The minimum sample size was 49 newborns per group. Five minutes before venipuncture, the neonates received 1cc of oral solution of 12% sucrose (study group) or distilled water (control group). During the procedure the pain level was evaluated with NIPS (Neonatal Infant Pain Scale). A data base was created, and the information processed and analysed using the SPSS program.

RESULTS

A total of 111 neonates were analysed, (55 in study group and 56 in control group). Bivariate analysis showed a smaller NIPS score in the group that received sucrose. Linear regression model explained that the significant variables for pain during the procedure were: hours since birth and the absence of non-nutritious suction, not being related to the sucrose administration.

CONCLUSION

Neonates that received the oral solution of sucrose before venipuncture had an average pain score lower than the placebo controlled group.

The behavioral pain response to heelstick in preterm neonates studied longitudinally: description, development, determinants, and components

OBJECTIVES

Preterm infants often experience multiple painful procedures during their stay in neonatal intensive care units (NICUs). The objectives of this study were to evaluate behavioral responses to heelstick in preterm newborns, characterize developmental changes and the effects of other demographic and clinical variables on the pain response, and estimate the contributions of individual Neonatal Infant Pain Scale (NIPS) behaviors to the summary pain score.

METHODS

A longitudinal study was conducted to evaluate the behavioral responses of 35 preterm newborns to multiple heelstick procedures during their stay in the NICU. Sixty-one video recordings of blood collection by heel lance were evaluated for behavioral pain response using the NIPS. Generalized linear mixed models were calculated to address the study objectives.

RESULTS

The increases in NIPS scores from the baseline to the blood draw were highly significant (mean baseline score=3.34, mean blood draw score=5.45, p<0.001). The newborns' pain responses increased an average of 0.23 points on the NIPS scale each week (p=0.002). Lower NIPS scores during the heelstick procedure were associated with four clinical variables: younger post-menstrual age at birth, lower birthweight, mechanical ventilation, and longer length of stay in the NICU. Crying, arousal state, and facial grimace contributed more than 85% of the increase in NIPS scores during the heelstick procedure.

DISCUSSION

While behavioral responses to pain are attenuated in young, severely ill preterm newborns, they can be reliably detected. The most robust pain behaviors are crying, changes in arousal state, and facial grimacing.

Mode of delivery modulates physiological and behavioral responses to neonatal pain

OBJECTIVE

To study whether the mode of delivery alters pain expression.

STUDY DESIGN

Full-term infants born by vaginal delivery or elective caesarean section were observed following high- and low-intensity pain stimuli, with recording of electrocardiogram, facial expression and vocalization.

RESULT

Graded physiological and behavioral responses occurred, with greater responses to higher than lower intensity pain stimuli. Elevation in heart rate following both stimuli increased with time after vaginal delivery. Infants delivered by elective caesarean section showed stronger facial expressions and briefer time in vocalizations response to both interventions.

CONCLUSION

Diminished responses following vaginal delivery suggest that physiological events associated with a normal delivery reduce the physiologic and sympathoadrenal activation by nociceptive mechanisms. Pain and stress reactivity appear to be inhibited during fetal life and sensory inputs during vaginal delivery may reverse this inhibition. To minimize neonatal pain, we recommend that postnatal invasive procedures to be performed shortly after vaginal birth.

Kangaroo Care (skin contact) reduces crying response to pain in preterm neonates: pilot results

Crying commonly occurs in response to heel stick and adversely affects the infant's physiologic stability. Minimal crying in response to pain is desired. "Kangaroo Care," skin contact between mother and infant, reduces pain and may reduce crying in response to pain. The purpose of this pilot study was to test Kangaroo Care's effect on the preterm infant's audible and inaudible crying response to heel stick. Inaudible crying has not been previously studied. A prospective randomized cross-over study with 10 preterm infants 2-9 days old (30-32 weeks' postmenstrual age) was conducted. Infants were randomly assigned to two sequences (sequence A: day 1 heel stick in Kangaroo Care [after 30 min of prone skin contact upright between maternal breasts] and day 2 heel stick in incubator [inclined, nested and prone]; or sequence B: opposite of sequence A) was conducted. Videotapes of baseline, heel warming, heel stick, and recovery phases were scored for audible and inaudible crying times. Audible and inaudible crying times for each subject in each phase were summed and analyzed by repeated-measures analysis of variance. Subject characteristics did not differ between those in the two sequences. Crying time differed between the study phases on both days (p <or= .001). When in Kangaroo Care compared with the incubator, crying time was less during the heel stick (p = .001) and recovery (p = .01) phases, regardless of sequence. Because Kangaroo Care reduced crying in response to heel stick in medically stable preterm infants, a definitive study is merited before making recommendations.

Pain behaviours in Extremely Low Gestational Age infants

BACKGROUND

To date, there are over 40 infant pain measures. Despite this plethora of measures, only 8 have included preterm infants and only 2 have included Extremely Low Gestational Age (ELGA; infants <28 weeks GA) in their development. Without reliable, valid and clinically useful indicators for procedural pain in ELGA infants, clinicians have no means to interpret the responses from an immature infant who may respond differently from infants of older GA.

OBJECTIVE

To examine the physiological, behavioural and biochemical responses to painful and non-painful procedures in ELGA infants and the influence of GA and sex.

DESIGN/METHODS

A prospective crossover design with 50 ELGA infants from one Canadian tertiary level NICU was conducted. Infants were assessed in random order during standardized painful (heel lance) and non-painful (diaper change) procedures. Physiological (heart rate, oxygen saturation) and behavioural (facial and body movement) indicators were continuously collected during 4 phases of the procedures. Biochemical (salivary cortisol) indicators were collected immediately before and 20 min following the procedures.

RESULTS

Four facial actions (brow bulge, eye squeeze, nasolabial furrow, vertical mouth stretch) increased immediately following the heel lance. There were no specific changes in physiological, body movement or cortisol indicators following the heel lance. ELGA infants demonstrated greater body movements during the diaper change, which may reflect immature motor coordination. No differences in pain responses were found for infants born between 23-25 6/7 weeks GA and those between 26-28 weeks GA. Similarly, no gender differences were found.

CONCLUSIONS

Changes in 4 facial actions were the most sensitive indicators of pain in ELGA infants. This finding is consistent with existing measures where facial actions are the most prominent pain indicators. Specific body movements such as those included in NIDCAP, may provide more information about pain in ELGA infants. Movements such as hand-on-face, finger splaying, fisting, arching or yawning need to be examined in future research.

Clinical reliability and validity of the N-PASS: neonatal pain, agitation and sedation scale with prolonged pain

OBJECTIVE

To establish beginning evidence of clinical validity and reliability of the Neonatal Pain, Agitation and Sedation Scale (N-PASS) in neonates with prolonged pain postoperatively and during mechanical ventilation.

STUDY DESIGN

Prospective psychometric evaluation. Two nurses administered the N-PASS simultaneously and independently before and after pharmacologic interventions for pain or sedation. One nurse also administered the premature infant pain profile (PIPP) concurrently with the N-PASS. The setting consisted of 50-bed level III neonatal intensive care unit. Convenience sample of 72 observations of 46 ventilated and/or postoperative infants, 0 to 100 days of age, gestational age 23 to 40 weeks was used. Outcome measures comprised convergent and construct validity, interrater reliability and internal consistency.

RESULT

Interrater reliability measured by intraclass coefficients of 0.85 to 0.95 was high (P<0.001 to 0.0001). Convergent validity was demonstrated by correlation with the PIPP scores (Spearman's rank correlation coefficient of 0.83 at high pain scores, 0.61 at low pain scores). Internal consistency, measured by Cronbach's alpha, was evident with pain scores (0.82), and with sedation scores (0.87). Construct validity was established via the Wilcoxon signed-rank test, comparing the distribution of N-PASS scores before and after pharmacologic intervention showing pain scores of 4.86 (3.38) and 1.81 (1.53) (mean (s.d.), P<0.0001) and sedation scores of 0.85 (1.66) and -2.78 (2.81) (P<0.0001) for pre- and postintervention assessments, respectively.

CONCLUSIONS

This research provides beginning evidence that the N-PASS is a valid and reliable tool for assessing pain/agitation and sedation in ventilated and/or postoperative infants 0 to 100 days of age, and 23 weeks gestation and above.

Analgesia in preterm newborns: the comparative effects of sucrose and glucose

The aim of this study was to evaluate the effectiveness of different oral carbohydrate solutions for alleviation of pain in healthy preterm babies. Thirty-one preterm infants who were having blood drawn by heel prick were given 2 ml of solution A (20% sucrose), solution B (20% glucose) or solution C (placebo, sterile water) into the mouth, 2 min before lancing. Behavioural responses to this painful stimulus were measured by duration of crying and facial expressions (Neonatal Facial Coding System, NFCS) and physiological responses were measured by heart rate (HR), respiratory rate (RR), and oxygen saturation changes (SaO(2)). Infants had a mean birth weight (+/-SD) of 1,401 g (406), gestational age of 30.5 weeks (2.7); at the time of the procedure the postmenstrual age was 32.3 weeks (1.5). There was no significant difference in the time spent squeezing the heel between the three groups (P = 0.669). After the heel prick of both the sucrose and glucose groups the duration of first cry and total crying time was significantly reduced (P = 0.005 and P = 0.007). When the babies received placebo they showed a significantly higher NFCS score at 4 and 5 min after the heel prick (P = 0.009 and 0.046 respectively). Following painful stimulus HR increased significantly in the first 3 min compared with baseline, and at the first minute the mean of the HR was found to be significantly higher in the placebo group than in the sucrose and glucose groups (P = 0.007). We concluded that both sucrose and glucose administered orally before a heel prick reduce the pain response in preterm infants.