Neonatal pain: What's age got to do with it?

Prolonged pain in premature neonates hospitalised in neonatal intensive care units: A scoping review

BACKGROUND

Exposure to repetitive pain during the neonatal period has been shown to have important short and long-term effects on the neurodevelopment of the premature neonate and can contribute to experienced prolonged pain. A uniform taxonomy of neonatal prolonged pain is still lacking to this day which contributes to suboptimal prolonged pain management in neonatal intensive care units. Accordingly, a scoping review exploring the state of knowledge about prolonged pain in preterm neonates hospitalised in the neonatal intensive care unit will contribute to the developing field of neonatal prolonged pain and provide recommendations for clinical prolonged pain management.

OBJECTIVE

To determine the scope, extent, and nature of the available literature on prolonged pain in premature neonates hospitalised in neonatal intensive care units.

DESIGN

Scoping review.

METHODS

An electronic search was conducted from inception to November 2023 in the databases of CINAHL, PubMed, Medline, Web of Science, GeryLit.org and Grey Source Index. Included studies discussed concepts related to neonatal prolonged pain such as definitions of prolonged pain, indicators of prolonged pain, contexts that result in prolonged pain, prolonged pain evaluation tools, consequences of prolonged pain and interventions for prolonged pain management.

RESULTS

Key concepts of neonatal prolonged pain were identified in the 86 included articles of this scoping review such as definitions (n = 26), indicators (n = 39), contexts (n = 49), scales (n = 56), consequences of prolonged pain (n = 30) and possible interventions for prolonged pain management (n = 22). Whilst a consensus on a definition has yet to be achieved, no proximate event was shown to cause prolonged pain and a time criterion was identified by authors as being relevant in defining prolonged pain. Interestingly, the context of hospitalisation was identified as being the most indicative of prolonged pain in premature neonates and should guide its evaluation and management, whilst only limited pain management interventions and consequences were discussed.

CONCLUSION

The findings of this scoping review contribute to the foundation of growing knowledge in neonatal prolonged pain and shed light on the ambiguity that currently exists on this topic in the scientific literature. This review summarises knowledge of key concepts necessary for a better understanding of prolonged pain and stresses the importance of considering contexts of hospitalisation for prolonged pain evaluation and management in neonatal intensive care units, with the objective of improving developmental outcomes of premature neonates.

TWEETABLE ABSTRACT

A scoping review reveals that the contexts of prolonged pain in premature neonates hospitalised in the neonatal intensive care unit are essential in guiding its evaluation and management.

Age-related changes in intraoperative mean values of nociceptive response in patients undergoing non-cardiac surgery under general anesthesia: A retrospective cohort study

Intraoperative nociception is affected by preoperative factors, surgical invasiveness, and anesthesia. Although age-related changes in nociception in conscious humans have been well examined, those in intraoperative nociception in unconscious patients under general anesthesia are unknown. To clarify associations between age and intraoperative nociception under general anesthesia, we performed a retrospective cohort study in consecutive patients of all ages undergoing non-cardiac surgery under general anesthesia from January 2019 to July 2023. The intraoperative nociception value in each surgery was assessed by the averaged value of nociceptive response (mean NR) index during surgery. Patient characteristics, including age, sex, body mass index (BMI), emergent surgery, preoperative serum C-reactive protein (CRP) level, and comorbidities were also collected. After excluding patients with missing data of CRP and mean NR index, 22,061 patients were enrolled, and were divided into low, intermediate, and high surgical risk groups. Multivariable regression analysis showed a significant association between age and mean NR index in all three surgical procedure risk groups. The preoperative variables of CRP levels, BMI, emergent surgery, atrial fibrillation, renal failure, and long-term steroid use also showed significant associations with mean NR index in all three groups. Sensitivity analysis showed that intraoperative mean NR index was higher in younger children than that in both older children and younger adults, and it gradually increased again in older adults to the same level as in younger children. In conclusion, there is likely an association between age and intraoperative mean NR index in patients under general anesthesia.

The relationship between neonatal stress in preterm infants and developmental outcomes at the corrected age of 24-30 months

Aim

The aim of research was to study the relationship between the stress experienced by preterm infants in the neonatal intensive care unit (NICU) and developmental status in the follow up, and to establish factors, associated with their neurodevelopment.

Methods

The first stage of research involved measuring stress markers (cortisol, melatonin) in infants (n = 56) during their NICU stay; the second phase assessed the developmental status at the corrected age of 24-30 months.

Results

The total ASQ-3 score, communication, problem solving, and personal-social skills scores at the corrected age of 24-30 months were positively correlated with melatonin level determined in the neonatal period (r = 0.31, p = 0.026; r = 0.36, p = 0.009; r = 0.30, p = 0.033, and r = 0.32; p = 0.022 respectively). In the same time, ASQ-3 communication and personal-social scores were negatively correlated with cortisol level (r = -0.31, p = 0.043; r = -0.35, p = 0.022). The ROC-curve analysis revealed that a decrease of melatonin below 3.44 ng/mL and 3.71 ng/mL during the neonatal period could predict communication and problem-solving delay, respectively. An increase in cortisol above 0.64 mcg/dl is predictive in personal-social delay. Negative correlation was identified between the NICU and total hospital stay duration and ASQ-3 communication scores in the follow-up (r = -0.27; p = 0.049 and r = -0.41; p = 0.002, respectively). The duration of mechanical ventilation was negatively correlated with gross motor scores (r = -0.46; p = 0.043). Apgar score was positively correlated with ASQ-3 communication (r = 0.29; p = 0.032) and personal-social scores (r = 0.28; p = 0.034); maternal age-with ASQ-3 total (r = 0.29; p = 0.034), communication (r = 0.37; p = 0.006), and personal-social scores (r = 0.29; p = 0.041). Positive correlations were observed between gestational age and communication scores (r = 0.28; p = 0.033). Infants who suffered neonatal sepsis had significantly often delay of communication (p = 0.014) and gross motor skills (p = 0.016). Children who required mechanical ventilation were more likely to have communication delay (p = 0.034).

Conclusion

Developmental outcomes in preterm infants at the corrected age of 24-30 months were associated with neonatal stress. Correlations between the communication, problem-solving and personal-social development in the follow up and cortisol and melatonin levels determined in the neonatal period supported this evidence. Factors as low gestational age, duration of hospital and NICU stay, mechanical ventilation, and sepsis were associated with more frequent delays in communication, gross motor and problems-solving skills.

Effect of pacifier and pacifier with dextrose in reducing pain during orogastric tube insertion in newborns: a randomized controlled trial

OBJECTIVE

This study aimed to assess the efficacy of pacifier use, with and without 25% dextrose, in reducing pain during orogastric tube insertion in newborns.

STUDY DESIGN

In a randomized controlled trial involving 60 newborns at a public hospital from April to December 2019, participants were divided into three groups: pacifier (n = 20), pacifier with 25% dextrose (n = 20), and control (n = 20). A pacifier, with and without dextrose, was used for the experimental groups, while the control group performed a routine procedure. Neonatal infant pain scale, crying duration, heart rate (HR), and oxygen saturation (SpO2) were evaluated.

RESULTS

Results indicated that the control group experienced significantly higher pain levels, elevated HRs, decreased SpO2, and prolonged crying. Conversely, the pacifier with 25% dextrose group showed a notable reduction in crying duration.

CONCLUSION

A pacifier, with and without 25% dextrose, effectively reduces pain and improves physiological and behavioral parameters during orogastric tube insertion.

CLINICAL TRIAL NUMBER

NCT05462964 CLINICAL TRIAL REGISTRATION: The protocol for this randomized controlled experimental trial is registered on ClinicalTrials.gov. The clinical trial registration number is https://clinicaltrials.gov ; NCT05462964.

Intertemporal Improvement in Physicians' Perceptions of the Short-Term Adverse Outcomes of Neonatal Pain: Results of a Two-Time-Point National Survey

Pain in early life may seriously impact neonatal outcomes. This study aimed to evaluate whether the perceptions of physicians working in neonatal intensive care units (NICUs) of the short-term adverse outcomes associated with neonatal pain have changed over a 20-year period. Self-administered questionnaires were distributed to 117 and 145 neonatologists, pediatricians, and fellows working in level III NICUs in 2000 (T1) and 2019 (T2), respectively. The questionnaire consisted of four domains, including the central nervous, cardiovascular, and respiratory systems, as well as "other systems" (metabolic/endocrine system, growth, and general condition), with 21 total items overall. Although the proportion of positive (correct) responses to the total and system-specific domain scores was significantly higher at T2 than T1, the knowledge of certain short-term adverse outcomes was suboptimal even at T2. Adjustment for cofactors confirmed the independent association of the survey time-point with the total and system-specific domain scores. Moreover, NICU type was an independent significant factor associated with the adjusted total and central nervous system scores, while young doctors had a better knowledge of adverse cardiovascular effects. Conclusions: The perceptions of NICU physicians concerning the short-term outcomes associated with neonatal pain have significantly improved over the past 20 years, although remaining knowledge gaps mandate ongoing efforts to achieve an improvement in neonatal care.

Non-pharmacological interventions for the prevention of pain during endotracheal suctioning in ventilated neonates

BACKGROUND

Pain, when treated inadequately, puts preterm infants at a greater risk of developing clinical and behavioural sequelae because of their immature pain system. Preterm infants in need of intensive care are repeatedly and persistently exposed to noxious stimuli, and this happens during a critical window of their brain development with peak rates of brain growth, exuberant synaptogenesis and the developmental regulation of specific receptor populations. Nearly two-thirds of infants born at less than 29 weeks' gestation require mechanical ventilation for some duration during the newborn period. These neonates are endotracheally intubated and require repeated endotracheal suctioning. Endotracheal suctioning is identified as one of the most frequent and most painful procedures in premature infants, causing moderate to severe pain. Even with improved nursing performance and standard procedures based on neonatal needs, endotracheal suctioning remains associated with mild pain.

OBJECTIVES

To evaluate the benefits and harms of non-pharmacological interventions for the prevention of pain during endotracheal suctioning in mechanically ventilated neonates. Non-pharmacological interventions were compared to no intervention, standard care or another non-pharmacological intervention.

SEARCH METHODS

We conducted searches in June 2023 in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE via PubMed, Embase, CINAHL and three trial registries. We searched the reference lists of related systematic reviews, and of studies selected for inclusion.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), quasi-RCTs and cluster-RCTs that included term and preterm neonates who were mechanically ventilated via endotracheal tube or via tracheostomy tube and required endotracheal suctioning performed by doctors, nurses, physiotherapists or other healthcare professionals.

DATA COLLECTION AND ANALYSIS

Our main outcome measures were validated composite pain scores (including a combination of behavioural, physiological and contextual indicators). Secondary outcomes included separate physiological and behavioural pain indicators. We used standard methodological procedures expected by Cochrane. For continuous outcome measures, we used a fixed-effect model and reported mean differences (MDs) with 95% confidence intervals (CIs). For categorical outcomes, we reported the typical risk ratio (RR) and risk difference (RD) and 95% CIs. We assessed risk of bias using the Cochrane RoB 1 tool, and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included eight RCTs (nine reports), which enroled 386 infants, in our review. Five of the eight studies were included in a meta-analysis. All studies enrolled preterm neonates. Facilitated tucking versus standard care (four studies) Facilitated tucking probably reduces Premature Infant Pain Profile (PIPP) score during endotracheal suctioning (MD -2.76, 95% CI 3.57 to 1.96; I² = 82%; 4 studies, 148 infants; moderate-certainty evidence). Facilitated tucking probably has little or no effect during endotracheal suctioning on: heart rate (MD -3.06 beats per minute (bpm), 95% CI -9.33 to 3.21; I² = 0%; 2 studies, 80 infants; low-certainty evidence); oxygen saturation (MD 0.87, 95% CI -1.33 to 3.08; I² = 0%; 2 studies, 80 infants; low-certainty evidence); or stress and defensive behaviours (SDB) (MD -1.20, 95% CI -3.47 to 1.07; 1 study, 20 infants; low-certainty evidence). Facilitated tucking may result in a slight increase in self-regulatory behaviours (SRB) during endotracheal suctioning (MD 0.90, 95% CI 0.20 to 1.60; 1 study, 20 infants; low-certainty evidence). No studies reported intraventricular haemorrhage (IVH). Familiar odour versus standard care (one study) Familiar odour during endotracheal suctioning probably has little or no effect on: PIPP score (MD -0.30, 95% CI -2.15 to 1.55; 1 study, 40 infants; low-certainty evidence); heart rate (MD -6.30 bpm, 95% CI -16.04 to 3.44; 1 study, 40 infants; low-certainty evidence); or oxygen saturation during endotracheal suctioning (MD -0.80, 95% CI -4.82 to 3.22; 1 study, 40 infants; low-certainty evidence). No studies reported SRB, SDB or IVH. White noise (one study) White noise during endotracheal suctioning probably has little or no effect on PIPP (MD -0.65, 95% CI -2.51 to 1.21; 1 study, 40 infants; low-certainty evidence); heart rate (MD -1.85 bpm, 95% CI -11.46 to 7.76; 1 study, 40 infants; low-certainty evidence); or oxygen saturation (MD 2.25, 95% CI -2.03 to 6.53; 1 study, 40 infants; low-certainty evidence). No studies reported SRB, SDB or IVH.

AUTHORS' CONCLUSIONS

Facilitated tucking / four-handed care / gentle human touch probably reduces PIPP score. The evidence of a single study suggests that facilitated tucking / four-handed care / gentle human touch slightly increases self-regulatory and approach behaviours during endotracheal suctioning. Based on a single study, familiar odour and white noise have little or no effect on any of the outcomes compared to no intervention. The use of expressed breast milk or oral sucrose suggests that there is no discernible advantage of one method over the other for reducing pain during endotracheal suctioning. None of the studies reported on any of the prespecified secondary outcomes of adverse events.

Cortisol levels are related to neonatal pain exposure in children born very preterm at age 18 months in two independent cohorts

Exposure to pain-related stress from frequent invasive procedures in the neonatal intensive care unit (NICU) has been associated with altered physiological stress regulation, neurodevelopment, and behavior in children born very preterm (≤32 weeks gestation). Previously, in a cohort born 2003-2006 (Cohort 1), we found that, at 18 months corrected age (CA), children born extremely low gestational age (ELGA; 24-28 weeks) and very low gestational age (VLGA; 29-32 weeks), had higher pre-test cortisol levels and a different pattern of cortisol output across a developmental assessment involving cognitive challenge compared to children born full-term (FT; 39-41 weeks). Also, greater neonatal pain-related stress exposure among the preterm children was related to higher pre-test cortisol levels. Given the adverse long-term effects of neonatal pain in preterm infants and the ensuing rise in clinical concerns to appropriately manage pain in the NICU in recent years, we aimed to examine whether our findings from Cohort 1 would still be evident in an independent cohort (Cohort 2) born 2006-2011 and recruited from the same tertiary NICU in Vancouver, Canada. We also compared the cortisol patterns, clinical and socio-demographic factors, and their interrelationships between the two cohorts. In Cohort 2, our findings using multi-level modeling support and extend our earlier findings in Cohort 1, demonstrating that children born ELGA display higher pre-test cortisol levels than FT. As well, greater cortisol output across assessment was related to more anxiety/depressive behaviors in children born VLGA. Importantly, children born ELGA were exposed to less neonatal pain/stress, mechanical ventilation, and morphine in Cohort 2 than Cohort 1. In both cohorts, however, cortisol levels and patterns were related to neonatal pain/stress and clinical factors (days on mechanical ventilation, overall morphine exposure). Despite less exposure to pain/stress and adverse clinical factors in Cohort 2 compared to Cohort 1, cortisol levels and patterns across cognitive challenge in preterm children at 18-month CA were consistent across the two independent cohorts. These findings highlight that, despite improvements to neonatal care, children born extremely preterm continue to display altered HPA axis activity, which is associated with their poorer neurodevelopmental and behavioral outcomes.

A Randomized Comparative Effectiveness Study of Reflexology, Sucrose, and Other Treatments for Needle Procedures in Newborns

BACKGROUND

Approximately 10 to 14 painful procedures per day are performed in infants during the hospital stay. We aimed to determine the effect of reflexology applied to the sole during painful procedures on pain perception in newborns compared with other nonpharmacologic methods.

METHODS

Our study was planned as a randomized controlled trial in term infants being followed up in the neonatal intensive care unit and maternity ward. To reduce pain during collection of venous blood or heel lance reflexology on the soles of the foot, 24% sucrose solution, kangaroo care, and classical music listening were applied to the infants. The Neonatal Infant Pain Scale (NIPS) was used to assess newborns during acute pain.

RESULTS

A total of 300 patients were enrolled in the study. Higher pain scores and crying times were observed during heel blood collection. All analgesic methods significantly reduced NIPS scores during heel blood collection. Sucrose was the most effective method, followed by reflexology. The best method that significantly shortened the crying time was again sucrose solution followed by reflexology, kangaroo care, and classical music, during heel blood collection. However, none of the nonpharmacologic methods was effective during venous blood collection.

CONCLUSIONS

Although sucrose was the most effective method, reflexology has significant positive effects, especially on average heartbeat, reducing pain, and shortening crying times during heel blood sampling. Reflexology might be considered among the nonpharmacologic methods to be applied before routine interventions, but still, there is a need for further studies to investigate the efficiency.

Skin-to-skin contact-An effective intervention on pain and stress reduction in preterm infants

Introduction

The outcomes of pain and stress in preterm infants in the neonatal intensive care units (NICUs) compel the continued search for pain- and stress-reducing interventions.

The objective of the study

To investigate how skin-to-skin contact (SSC) influences chronic pain and stress in preterm infants in the NICU.

Materials and methods

The study included 140 preterm infants in the NICU with gestational age less than 34 weeks. The overall design was a baseline-response design. Urine and saliva were collected before (baseline) and after SSC to measure pain and stress markers by enzyme immunoassay method. The behavioral indicators of chronic pain were assessed using the EDIN (Échelle Douleur Inconfort Nouveau-Né-neonatal pain and discomfort).

Results

There was a significant decrease in the dopamine level in preterm infants after SSC in comparison with baseline values (85.99 [69.35; 112.20] pg/ml vs. 132.20 [104.80; 183.70] pg/ml), p < 0.001. The β-endorphin and serotonin levels increased after SSC (40.09 [26.81; 70.63] pg/ml vs. 29.87 [20.61; 46.94] pg/ml, p = 0.009 and 25.49 [20.45; 40.08] ng/ml vs. 22.30 [15.13; 31.65] ng/ml, p = 0.011, respectively). A significant decrease in cortisol levels in saliva and urine after SSC in comparison with baseline values (0.125 [0.079; 0.225] μg/dl vs. 0.371 [0.188; 1.002] μg/dl, p = 0.000 and 27.06 [14.59; 35.35] ng/ml vs. 35.25 [19.78; 61.94] ng/ml, p = 0.001, with a simultaneous increase of oxytocin level (57.00 [36.55; 88.49] pg/ml vs. 38.20 [28.78; 56.04] pg/ml, p = 0.009 were revealed. The total pain EDIN score in infants after SSC was below 6 points, significantly decreasing compared to the baseline (p < 0.05).

Conclusion

Preterm infants in the NICU experience stress and pain, which were confirmed by the EDIN pain scale and laboratory markers. The level of dopamine and cortisol as pain and stress hormones were reliably high, and normalized after regular SSC. Simultaneously, pain-relieving and anti-stress markers of oxytocin, β-endorphin and serotonin reliably increased in preterm infants in response to the SSC.

The fetal pain paradox

Controversy exists as to when conscious pain perception in the fetus may begin. According to the hypothesis of cortical necessity, thalamocortical connections, which do not form until after 24-28 weeks gestation, are necessary for conscious pain perception. However, anesthesiologists and neonatologists treat age-matched neonates as both conscious and pain-capable due to observable and measurable behavioral, hormonal, and physiologic indicators of pain. In preterm infants, these multimodal indicators of pain are uncontroversial, and their presence, despite occurring prior to functional thalamocortical connections, has guided the use of analgesics in neonatology and fetal surgery for decades. However, some medical groups state that below 24 weeks gestation, there is no pain capacity. Thus, a paradox exists in the disparate acknowledgment of pain capability in overlapping patient populations. Brain networks vary by age. During the first and second trimesters, the cortical subplate, a unique structure that is present only during fetal and early neonatal development, forms the first cortical network. In the third trimester, the cortical plate assumes this function. According to the subplate modulation hypothesis, a network of connections to the subplate and subcortical structures is sufficient to facilitate conscious pain perception in the fetus and the preterm neonate prior to 24 weeks gestation. Therefore, similar to other fetal and neonatal systems that have a transitional phase (i.e., circulatory system), there is now strong evidence for transitional developmental phases of fetal and neonatal pain circuitry.

Procedural Analgesia in the Neonatal Intensive Care Unit: A Quality Improvement Initiative

OBJECTIVE

Neonates perceive pain which also has adverse long-term consequences. Newborns experience several painful procedures a day. Various methods of analgesia may be used but are underutilized. The SMART aim of this project was to increase the use of procedural analgesia from 11.5 to 75% in 6 months by using quality improvement principles.

STUDY DESIGN

After a baseline audit, a root cause analysis was done. Based on this, a series of interventions were done as Plan-Do-Study-Act (PDSA) cycles. These included posters on analgesia, display of the pain protocol, orders for analgesia, a written test, small power point presentations on the importance of analgesia, and reminders on the trays used for procedures. At the end of each PDSA cycle, an audit was done to determine the proportion of times analgesia was used. Process indicators were also used when possible. Analysis was done by using the Chi-square test and the paired t-test.

RESULTS

At baseline 11% of procedures were done after giving analgesia. This significantly improved to 40% at the end of the first PDSA, and 81% after third PDSA. This was sustained at 75% over the next 2 months.

CONCLUSION

Procedural analgesia can improve and be sustained by using simple interventions.

KEY POINTS

· Procedural pain in neonates can be decreased by the use of analgesia.. · However, most units do not utilize analgesia appropriately.. · This QI showed that simple interventions can optimize use of procedural analgesia..

Association of Neonatal Pain-Related Stress and Parent Interaction With Internalizing Behaviors Across 1.5, 3.0, 4.5, and 8.0 Years in Children Born Very Preterm

IMPORTANCE

Internalizing (anxiety and/or depressive) behaviors are prevalent in children born very preterm (24-32 weeks' gestation). Procedural pain-related stress in the neonatal intensive care unit (NICU) is associated with long-term internalizing problems in this population; however, whether positive parenting during toddlerhood attenuates development of internalizing behaviors across childhood is unknown.

OBJECTIVE

To investigate whether neonatal pain-related stress is associated with trajectories of internalizing behaviors across 1.5, 3.0, 4.5, and 8.0 years, and whether supportive parenting behaviors and lower parenting stress at 1.5 and 3.0 years attenuate this association.

DESIGN, SETTING, AND PARTICIPANTS

In this prospective longitudinal cohort study, preterm neonates (born at 24-32 weeks' gestation) were recruited from August 16, 2006, to September 9, 2013, with follow-up visits at ages 1.5, 3.0, 4.5, and 8.0 years. The study was conducted at BC Women's Hospital, Vancouver, Canada, with recruitment from a level III neonatal intensive care unit and sequential developmental assessments performed in a Neonatal Follow-up Program. Data analysis was performed from August to December 2021.

MAIN OUTCOMES AND MEASURES

Parental report of child internalizing behaviors on the Child Behavior Checklist at 1.5, 3.0, 4.5, and 8.0 years.

RESULTS

A total of 234 neonates were recruited, and 186 children (101 boys [54%]) were included in the current study across ages 1.5 (159 children), 3.0 (169 children), 4.5 (162 children), and 8.0 (153 children) years. After accounting for clinical factors associated with prematurity, greater neonatal pain-related stress was associated with more internalizing behaviors across ages (B = 4.95; 95% CI, 0.76 to 9.14). Higher parenting stress at age 1.5 years (B = 0.17; 95% CI, 0.11 to 0.23) and a less supportive parent environment (less sensitivity, structure, nonintrusiveness, nonhostility, and higher parenting stress; B = -5.47; 95% CI, -9.44 to -1.51) at 3.0 years were associated with greater internalizing problems across development to age 8.0 years.

CONCLUSIONS AND RELEVANCE

In this cohort study of children born very preterm, exposure to repetitive neonatal pain-related stress was associated with persistent internalizing behavior problems across toddlerhood to age 8.0 years. Supportive parenting behaviors during early childhood were associated with better long-term behavioral outcomes, whereas elevated parenting stress was associated with more child anxiety and/or depressive behaviors in this population. These findings reinforce the need to prevent pain in preterm neonates and inform future development of targeted parent-led behavioral interventions.

Long-Lasting Analgesia With Transdermal Fentanyl: A New Approach in Rat Neonatal Research

Background: With advances in neonatal care, management of prolonged pain in newborns is a daily concern. In addition to ethical considerations, pain in early life would have long-term effects and consequences. However, its treatment remains inadequate. It was therefore important to develop an experimental model of long-lasting analgesia for neonatal research.

Materials and Methods: Experiments were performed in six groups of rats with transdermal fentanyl 0, 3, 12, 50, 100, or 200 μg/kg/h from second postnatal day (P2) until weaning. Assessment of analgesia was carried out at P21, with behavioral scores (ranging from 0 to 3) using a 4% formalin test. Plasma levels of fentanyl were determined by UPLC/TQD at P22. Growth rate was investigated.

Results: Fentanyl 100 and 200 μg/kg/h reduced scores of formalin-evoked behavioral pain. They increased time spent in pain score 0 (8 min 55 s and 6 min 34 s versus 23 s in controls) as in low pain scores 1 and 2, and decreased time in the most severe pain score 3 (19 min 56 s and 17 min 39 s versus 44 min 15 s). Fentanylemia increased in a dose-dependent manner from 50 μg/kg/h (2.36 ± 0.64 ng/ml) to 200 μg/kg/h (8.66 ± 1.80 ng/ml). Concerning growth, no difference was observed except weaker growth from P17 to P22 with 200 μg/kg/h. Clinically, we noticed no visible side effect from 3 to 100 μg/kg/h. Concomitantly, 200 μg/kg/h was responsible for ophthalmological side effects with appearance of corneal bilateral clouding in 90% pups. No difference was observed between male and female rats.

Conclusion: Altogether, results indicate that transdermal fentanyl 100 μg/kg/h is an efficient therapeutic for long-lasting analgesia in lactating pups. This new model provides a useful tool for protection and welfare, and future opportunity for studying long-term health consequences of sustainable neonatal analgesia.

Neonatal Nurse and Midwife Competence Regarding Pain Management in Neonates: A Systematic Review

BACKGROUND

Neonates in need of intensive care are often subjected to numerous painful procedures. Despite the growing scientific research, hospitalized neonates continue to experience unrelieved pain. Enhancing the competence of neonatal intensive care nurses is an integral component of effective pain management.

PURPOSE

The purpose of this article is to identify and synthesize the existing evidence on nurses' and midwives' competence regarding neonatal pain management internationally.

METHODS/SEARCH STRATEGY

The review was guided by Whittemore and Knafl's 5-stage framework, with 8 databases searched in June 2020 including PubMed, CINAHL Complete (via EBSCOhost), MEDLINE (via EBSCOhost), PsycINFO (via Ovid), EMBASE, Scopus, Cochrane Library, and Google Scholar. Reference lists of selected articles were also hand-searched. Studies were reviewed independently for methodology and inclusion and exclusion criteria. The initial search yielded 3037 articles; 19 met the inclusion criteria and were included for analysis: qualitative (n = 5) and quantitative (n = 14).

FINDINGS/RESULTS

Nurses' and midwives' competence regarding neonatal pain management in the neonatal intensive care unit is discussed in relation to knowledge, attitudes, behaviors, and perceptions of competence by most studies. The barriers to effective neonatal pain management were found to relate to nurses' and midwives' factors, underutilized pain assessment tools, and organizational factors. Potential facilitators to effective neonatal pain management included clear evidence-based guidelines/protocols, adequate training, and the use of appropriate and accurate pain assessment tools. Parent involvement and a team approach to neonatal pain management were also identified.

IMPLICATIONS FOR PRACTICE AND RESEARCH

These findings suggest that further research is necessary to address the barriers and promote facilitators to improve neonatal pain management.

Rescue Paracetamol in Postoperative Pain Management in Extremely Low Birth Weight Neonates Following Abdominal Surgery: A Single Unit Retrospective Study

BACKGROUND

Intravenous paracetamol added to morphine reduces postoperative morphine consumption in (near)term neonates. However, there are only sparse data on intravenous paracetamol as multimodal strategy in extremely low birth weight (ELBW) neonates.

OBJECTIVES

This study aims to assess the effects of rescue intravenous paracetamol on postoperative pain management (≤48 h postoperatively) in relation to both analgesic efficacy (validated pain assessment, drug consumption, adequate rescue medication) and safety (hypotension and bradycardia). This rescue practice was part of a standardized pain management approach in a single neonatal intensive care unit (NICU).

METHODS

A single-center retrospective observational study included 20 ELBW neonates, who underwent major abdominal surgery. The primary endpoints of the postoperative study period were pain intensity, over-sedation, time to first rescue analgesic dose, and the effect of paracetamol on opiate consumption. Secondary endpoints were safety parameters (hypotension, bradycardia). And as tertiary endpoints, the determinants of long-term outcome were evaluated (i.e., duration of mechanical ventilation, intraventricular hemorrhage - IVH, periventricular leukomalacia - PVL, postnatal growth restriction, stage of chronic lung disease - CLD or neurodevelopmental outcome according to Bayley-II Scales of Infant Development at 18-24 months).

RESULTS

All neonates received continuous opioids (sufentanil or morphine) and 13/20 also intravenous paracetamol as rescue pain medication during a 48-h postoperative period. Although opioid consumption was equal in the non-paracetamol and the paracetamol group over 48 h, the non-paracetamol group was characterized by oversedation (COMFORTneo < 9), a higher incidence of severe hypotension, and younger postnatal age (p < 0.05). All long-term outcome findings were similar between both groups.

CONCLUSIONS

Our study focused on postoperative pain management in ELBW neonates, and showed that intravenous paracetamol seems to be safe. Prospective validation of dosage regimens of analgesic drugs is needed to achieve efficacy goals.

Premature Infants Display Discriminable Behavioral, Physiological, and Brain Responses to Noxious and Nonnoxious Stimuli

Pain assessment in preterm infants is challenging as behavioral, autonomic, and neurophysiological measures of pain are reported to be less sensitive and specific than in term infants. Understanding the pattern of preterm infants’ noxious-evoked responses is vital to improve pain assessment in this group. This study investigated the discriminability and development of multimodal noxious-evoked responses in infants aged 28–40 weeks postmenstrual age. A classifier was trained to discriminate responses to a noxious heel lance from a nonnoxious control in 47 infants, using measures of facial expression, brain activity, heart rate, and limb withdrawal, and tested in two independent cohorts with a total of 97 infants. The model discriminates responses to the noxious from the nonnoxious procedure with an overall accuracy of 0.76–0.84 and an accuracy of 0.78–0.79 in the 28–31-week group. Noxious-evoked responses have distinct developmental patterns. Heart rate responses increase in magnitude with age, while noxious-evoked brain activity undergoes three distinct developmental stages, including a previously unreported transitory stage consisting of a negative event-related potential between 30 and 33 weeks postmenstrual age. These findings demonstrate that while noxious-evoked responses change across early development, infant responses to noxious and nonnoxious stimuli are discriminable in prematurity.

Fetal Pain in the First Trimester

Fetal pain perception has important implications for fetal surgery, as well as for abortion. Current neuroscientific evidence indicates the possibility of fetal pain perception during the first trimester (<14 weeks gestation). Evidence for this conclusion is based on the following findings: (1) the neural pathways for pain perception via the cortical subplate are present as early as 12 weeks gestation, and via the thalamus as early as 7–8 weeks gestation; (2) the cortex is not necessary for pain to be experienced; (3) consciousness is mediated by subcortical structures, such as the thalamus and brainstem, which begin to develop during the first trimester; (4) the neurochemicals in utero do not cause fetal unconsciousness; and (5) the use of fetal analgesia suppresses the hormonal, physiologic, and behavioral responses to pain, avoiding the potential for both short- and long-term sequelae. As the medical evidence has shifted in acknowledging fetal pain perception prior to viability, there has been a gradual change in the fetal pain debate, from disputing the existence of fetal pain to debating the significance of fetal pain. The presence of fetal pain creates tension in the practice of medicine with respect to beneficence and nonmaleficence.

Cross-sectional study of pediatric pain prevalence, assessment, and treatment at a Canadian tertiary hospital

Background

Painful experiences are common among hospitalized children. Long-term negative biopsychosocial consequences of undertreated pain are recognized.

Aims

The study benchmarks pain prevalence, assessment, and treatment as first steps to improve pain care in a Canadian tertiary hospital.

Methods

Single-day audits were undertaken on the pediatric ward (PW), pediatric emergency department (ED), and maternal services (MS). Participants (child or caregiver proxy) reported hospital pain experiences in the preceding 24 h; medical records were reviewed for assessment and treatment.

Results

Among 84 participants, pain prevalence ranged from 75% to 88%; mean pain intensity ranged from 5.7 to 6.5/10. Prevalence of moderate to severe pain was 78% on PW, 65% in ED, and 55% on MS; needle pokes were the most frequent cause of worst pain. Documentation of pain assessment varied by setting (PW, 93%; ED, 13%; MS, 0%). Documented maximum pain scores were significantly lower compared to participant report (mean difference 4.5/10, SD 3.1, P < 0.0001). A total 29% (6/21) of infants with heel lance or injection received breastfeeding or sucrose, and 29% (7/24) of participants receiving other needle procedures had documented or reported topical lidocaine use. All participants on MS underwent needle procedures.

Conclusions

Pain is experienced commonly by infants and children in PW, ED, and MS. Pain assessment documentation is not routine and underestimates participant report. Evidence-based pain management strategies are underutilized. An institution-wide quality improvement approach is required to address pain care. Pain assessment and needle pain prevention and treatment should be prioritized in these pediatric acute care and newborn care settings.

Pain in Preterm Infants: Different Perspectives

In the last decades, there has been a tremendous change in approaching and managing neonates' pain. These changes began with rebutting the previous misconception about neonates' , particularly preterm infants' , pain. The development in neuroimaging has revealed that by 24 weeks of gestation the peripheral nervous system is mature and function fully. Researchers now know that neonates experience pain and premature infants have even lower pain thresholds. Since that time, a mounting amount of literature has addressed the issue of neonatal pain. Many pharmacological and non pharmacological pain reduction strategies have been investigated for their safety and analgesic effectiveness. Many interventions such as nonnutritive sucking (NNS), skin-to-skin contact (SSC), and facilitated tucking are effective in controlling neonates pain.

Effects of Sucrose and Nonnutritive Sucking on Pain Behavior in Neonates and Infants undergoing Wound Dressing after Surgery: A Randomized Controlled Trial

INTRODUCTION

 Wound dressing, a procedure that pediatric patients are commonly exposed to postoperatively, can cause strong physiological and pain behavioral responses despite being brief. This study evaluated the effects of using 24% sucrose plus a pacifier versus a pacifier alone to reduce the pain response from dressing wounds in neonates and infants.

MATERIALS AND METHODS

 Thirty-two neonates and infants who underwent surgery and required postoperative wound dressing were randomized to a pacifier group (n = 16) and a 24% sucrose plus pacifier group ("sucrose group"; n = 16). Demographic data, crying time, and pain behaviors were recorded using a video recorder. The pain behaviors were assessed independently using the neonatal infant pain scale (NIPS) by three assessors, who were expert in pediatric pain assessment and blinded to the subject allocations.

RESULTS

 Participants in the sucrose group were older than those in the pacifier group (6.19 ± 2.95 vs. 3.88 ± 3.2 months). While there were no differences in the NIPS scores of the two groups at 30, 120, and 240 seconds, the incidence of moderate-to-severe pain was lower in the sucrose group than the pacifier group at 120 seconds (37.5 vs. 50%). The crying time was lower in the sucrose group, but without statistical significance.

CONCLUSION

 The 24% sucrose plus pacifier was not superior to the pacifier alone in decreasing pain behavioral responses. Dressing wound pain produced a high-intensity pain behavioral response. A pain management strategy should be developed to lessen the postoperative procedural pain in pediatric patients.

New perspective for pain control in neonates: a comparative effectiveness research

OBJECTIVE

To compare sucrose 24% oral gel formulation to liquid formula and breastfeeding during a heel prick in neonates.

STUDY DESIGN

In this comparative effectiveness research 195 neonates >36 weeks' gestation were randomised to three groups, receiving during heel stick: (i) breastfeeding, (ii) sucrose 24% liquid with non-nutritive sucking and (iii) sucrose 24% gel with non-nutritive sucking. The pain was assessed through the Neonatal Infant Pain Scale.

RESULTS

All the methods analysed has shown to be effective in reducing pain. There was an increase in odds of pain following liquid sucrose compared to breastfeeding (OR = 1.60; 95% CI: 0.82-3.3; p = 0.17). A reduction of odds of pain was showed comparing sucrose to breastfeeding (OR = 0.78; 0.38-1.6; 0.48), and comparing sucrose gel to liquid formula (OR = 0.48; 0.23-0.96; p = 0.04).

CONCLUSION

Sucrose 24% gel with non-nutritive sucking seems to be a valid alternative when breastfeeding is not possible. Further research is needed.

Evaluation of pain and physiological stress during targeted neonatal echocardiography

BACKGROUND

Targeted neonatal echocardiography (Tn-Echo) is a non-invasive examination which may cause pain/discomfort and physiological instability in neonates, but there is little evidence for the same. We conducted this study to evaluate whether targeted neonatal echocardiography causes pain or physiological stress to newborn infants.

METHODS

This cross-sectional study was conducted in a tertiary level NICU. Neonates undergoing targeted neonatal echocardiography were enrolled in this study. Pain was assessed using Premature Infant Pain Profile-Revised (PIPP-R) score before, during and after targeted neonatal echocardiography examination. Heart rate, oxygen saturation, perfusion index and blood pressure were also recorded at the same time points.

RESULTS

A total of 88 neonates were enrolled. Mean (SD) PIPP-R score during Tn-Echo was 8.18 (2.6) versus 3.60 (1.8) and 4.24 (2.0) before and after respectively (p value <  0.001). Heart rate and respiratory rate were significantly higher during targeted neonatal echocardiography; oxygen saturation and perfusion index were significantly lower during targeted neonatal echocardiography. Preterm infants had higher PIPP-R score compared to term neonates before, during and after the Tn-Echo [8.76 (2.4) versus 6.81 (2.4); p value <  0.001].

CONCLUSION

Targeted neonatal echocardiography causes significant pain/discomfort and physiological instability in neonates.

Effects of Kangaroo Mother Care on Repeated Procedural Pain and Cerebral Oxygenation in Preterm Infants

OBJECTIVE

 The study aimed to investigate the effects of kangaroo mother care (KMC) on repeated procedural pain and cerebral oxygenation in preterm infants.

STUDY DESIGN

 Preterm infants of 31 to 33 weeks of gestational age were randomly divided into an intervention group (n = 36) and a control group (n = 37). Premature infant pain profile (PIPP) scores, heart rate, oxygen saturation, regional cerebral tissue oxygenation saturation (rcSO₂), and cerebral fractional tissue oxygen extraction (cFTOE) were evaluated during repeated heel stick procedures. Each heel stick procedure included three phases: baseline, blood collection, and recovery. KMC was given to the intervention group 30 minutes before baseline until the end of the recovery phase.

RESULTS

 Compared with the control group, the intervention group showed lower PIPP scores and heart rates, higher oxygen saturation, and rcSO₂ from the blood collection to recovery phases during repeated heel sticks. Moreover, there were significant changes in cFTOE for the control group, but not the intervention group associated with repeated heel stick procedures.

CONCLUSION

 The analgesic effect of KMC is sustained over repeated painful procedures in preterm infants, and it is conducive to stabilizing cerebral oxygenation, which may protect the development of brain function.

KEY POINTS

· KMC stabilizes cerebral oxygenation during repeated heel sticks in preterm infants.. · The analgesic effect of KMC is sustained over repeated painful procedures in preterm infants.. · KMC may protect the development of brain function..

The efficacy of administrating a sweet-tasting solution for reducing the pain related to dental injections in children: A randomized controlled trial

BACKGROUND

Anaesthetic injections are an unpleasant experience for children in the dental office. Oral intake of sweet substances by newborns has been shown to be effective in reducing pain.

AIM

The purpose of this study was to determine whether a prior administration of a sweet-tasting solution has an effect on dental injection pain.

DESIGN

A total of 56 healthy children needing bilateral maxillary primary canine extraction were included in this split-mouth randomized clinical trial. In the test side, dental injection (local infiltration) was applied after the patient received a sweet-tasting solution, while in the control side sterile water was administered. The patients' demographic characteristics, body mass index (BMI), and sweet taste preference were recorded. Pain perception during injection was measured using visual analogue scale (VAS) and sound, eye, body movement (SEM).

RESULTS

Mean VAS (28.30 ± 6.43) and SEM (2.14 ± 0.78) in the test side were lower than the control side (45.80 ± 7.17 and 2.95 ± 1.00). It was shown that higher BMI was associated with reduction in the analgesic effect, while the individual's tendency to sweetness increased pain reduction.

CONCLUSIONS

Sweet taste administration before dental injections in children helps to control the associated pain. This effect is influenced by the individual's sweet taste tendency and BMI.

Can Event-Related Potentials Evoked by Heel Lance Assess Pain Processing in Neonates? A Systematic Review

To clarify the possibility of event-related potential (ERP) evoked by heel lance in neonates as an index of pain assessment, knowledge acquired by and problems of the methods used in studies on ERP evoked by heel lance in neonates were systematically reviewed, including knowledge about Aδ and C fibers responding to noxious stimuli and Aβ fibers responding to non-noxious stimuli. Of the 863 reports searched, 19 were selected for the final analysis. The following points were identified as problems for ERP evoked by heel lance in neonates to serve as a pain assessment index: (1) It is possible that the ERP evoked by heel lance reflected the activation of Aβ fibers responding to non-noxious stimuli and not the activation of Aδ or C fibers responding to noxious stimulation; (2) Sample size calculation was presented in few studies, and the number of stimulation trials to obtain an averaged ERP was small. Accordingly, to establish ERP evoked by heel lance as a pain assessment in neonates, it is necessary to perform a study to clarify ERP evoked by Aδ- and C-fiber stimulations accompanied by heel lance in neonates.

Premature Birth and Developmental Programming: Mechanisms of Resilience and Vulnerability

The third trimester of pregnancy represents a sensitive phase for infant brain plasticity when a series of fast-developing cellular events (synaptogenesis, neuronal migration, and myelination) regulates the development of neural circuits. Throughout this dynamic period of growth and development, the human brain is susceptible to stress. Preterm infants are born with an immature brain and are, while admitted to the neonatal intensive care unit, precociously exposed to stressful procedures. Postnatal stress may contribute to altered programming of the brain, including key systems such as the hypothalamic-pituitary-adrenal axis and the autonomic nervous system. These neurobiological systems are promising markers for the etiology of several affective and social psychopathologies. As preterm birth interferes with early development of stress-regulatory systems, early interventions might strengthen resilience factors and might help reduce the detrimental effects of chronic stress exposure. Here we will review the impact of stress following premature birth on the programming of neurobiological systems and discuss possible stress-related neural circuits and pathways involved in resilience and vulnerability. Finally, we discuss opportunities for early intervention and future studies.

Optimal Methods of Documenting Analgesic Efficacy in Neonatal Piglets Undergoing Castration

Analgesic products for piglet castration are critically needed. This requires extensive animal experimentation such as to meet regulatory-required proof of efficacy. At present, there are no validated methods of assessing pain in neonatal piglets. This poses challenges for investigators to optimize trial design and to meet ethical obligations to minimize the number of animals needed. Pain in neonatal piglets may be subtle, transient, and/or variably expressed and, in the absence of validated methods, investigators must rely on using a range of biochemical, physiological and behavioural variables, many of which appear to have very low (or unknown) sensitivity or specificity for documenting pain, or pain-relieving effects. A previous systematic review of this subject was hampered by the high degree of variability in the literature base both in terms of methods used to assess pain and pain mitigation, as well as in outcomes reported. In this setting we provide a narrative review to assist in determining the optimal methods currently available to detect piglet pain during castration and methods to mitigate castration-induced pain. In overview, the optimal outcome variables identified are nociceptive motor and vocal response scores during castration and quantitative sensory-threshold response testing and pain-associated behaviour scores following castration.

Early Neonatal Pain-A Review of Clinical and Experimental Implications on Painful Conditions Later in Life

Modern health care has brought our society innumerable benefits but has also introduced the experience of pain very early in life. For example, it is now routine care for newborns to receive various injections or have blood drawn within 24 h of life. For infants who are sick or premature, the pain experiences inherent in the required medical care are frequent and often severe, with neonates requiring intensive care admission encountering approximately fourteen painful procedures daily in the hospital. Given that much of the world has seen a steady increase in preterm births for the last several decades, an ever-growing number of babies experience multiple painful events before even leaving the hospital. These noxious events occur during a critical period of neurodevelopment when the nervous system is very vulnerable due to immaturity and neuroplasticity. Here, we provide a narrative review of the literature pertaining to the idea that early life pain has significant long-term effects on neurosensory, cognition, behavior, pain processing, and health outcomes that persist into childhood and even adulthood. We refer to clinical and pre-clinical studies investigating how early life pain impacts acute pain later in life, focusing on animal model correlates that have been used to better understand this relationship. Current knowledge around the proposed underlying mechanisms responsible for the long-lasting consequences of neonatal pain, its neurobiological and behavioral effects, and its influence on later pain states are discussed. We conclude by highlighting that another important consequence of early life pain may be the impact it has on later chronic pain states-an area of research that has received little attention.

Pain in Neonates: A Concept Analysis

Context

The term pain in neonates is emerged in recent decades. However, studies on pain in neonates are still limited and have various indicators. In addition, the term pain still often overlaps with stress in various studies and clinical circumstances. The concepts of pain and stress in the neonates need to be clarified to be better understood and then applied to improve neonates’ quality of life. Therefore, the current study aimed at clarifying the concept of pain in neonates.

Evidence Acquisition

The current study employed the concept analysis approach developed by Walker and Avant. The authors reviewed articles from JSTOR, ScienceDirect, Proquest, Sage, Cochrane, and Springer databases from 1980 to 2016 using keywords pain, stress, neonatal, neonates, and quality of life.

Results

Pain had attributes such as tissue damage, physiological changes, metabolic changes, and behavioral changes. Stress had attributes such as physiological changes, metabolic changes, and behavioral changes.

Conclusions

Attributes of pain and stress have similarities and differences. The main difference is the stimulus that induces a response. Pain has an attribute of tissue damage, whereas stress is not always due to tissue damage. The attributes of physical, metabolic, and behavioral changes between pain and stress are similar.

Early Pain Exposure Influences Functional Brain Connectivity in Very Preterm Neonates

Background

Early exposure to nociceptive events may cause brain structural alterations in preterm neonates, with long-lasting consequences on neurodevelopmental outcome. Little is known on the extent to which early pain may affect brain connectivity. We aim to evaluate brain functional connectivity changes in preterm neonate that underwent multiple invasive procedures during the postnatal period, and to correlate them with the neurodevelopmental outcome at 24 months.

Methods

In this prospective case-control study, we collected information about exposure to painful events during the early postnatal period and resting-state BOLD-fMRI data at term equivalent age from two groups of preterm neonate: 33 subjected to painful procedures during the neonatal intensive care (mean gestational age 27.9 ± 1.8 weeks) and 13 who did not require invasive procedures (average gestational age 31.2 ± 2.1 weeks). A data-driven principal-component-based multivariate pattern analysis (MVPA) was used to investigate the effect of early pain exposure on brain functional connectivity, and the relationship between connectivity changes and neurodevelopmental outcome at 24 months, assessed with Griffiths, Developmental Scale-Revised: 0-2.

Results

Early pain was associated with decreased functional connectivity between thalami and bilateral somatosensory cortex, and between the right insular cortex and ipsilateral amygdala and hippocampal regions, with a more evident effect in preterm neonate undergoing more invasive procedures. Functional connectivity of the right thalamocortical pathway was related to neuromotor outcome at 24 months (P = 0.003).

Conclusion

Early exposure to pain is associated with abnormal functional connectivity of developing networks involved in the modulation of noxious stimuli in preterm neonate, contributing to the neurodevelopmental consequence of preterm birth.

Associations between preterm infant stress, epigenetic alteration, telomere length and neurodevelopmental outcomes: A systematic review

BACKGROUND

Every year, an estimated 15 million babies are born preterm (<37 weeks' gestational age [GA]) globally. These preterm infants are exposed to repeated stressful and often painful procedures as part of routine life-saving care within the neonatal intensive care unit (NICU). Preterm birth continues to be a major health issue associated with increased risk of neurodevelopmental and behavioral disorders such as cerebral palsy, cognitive impairment, autism spectrum disorders and psychiatric disease.

OBJECTIVE

This paper identifies epigenetic alterations and incidence of telomere erosion that have been studied in preterm infants while in the NICU and as a long-term outcome measure. Better understanding of epigenetic alterations and telomere erosion might aid in early detection and prevention/alleviation of the negative effects of cumulative painful/stressful experiences in this population.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards were used to guide this review. Systematic searches of databases included PubMed, CINAHL, SCOPUS and PsychInfo.

RESULTS

Twenty-one studies were included, appraised and then synthesized into a narrative summary.

DISCUSSION

Several putative epigenetic markers were identified although there was a paucity of studies related to telomere length. The interaction of disease entity combined with therapeutic interventions intended to treat may inadvertently increase infant allostatic load or ability to adapt to stress. Future research should include not only human studies but leverage newly available large data sets to conduct additional analysis.

Neonatal Pain: Perceptions and Current Practice

Neonates may experience more than 300 painful procedures throughout their hospitalizations. Prior to 1980, there was a longstanding misconception that neonates do not experience pain. Current studies demonstrate that not only do neonates experience pain but also, due to their immature nervous systems, they are hypersensitive to painful stimuli. Poorly treated pain may lead to negative long-term consequences. Proper assessment of neonate pain is vital. The use of nonpharmacologic treatments may be beneficial in alleviating neonate pain. Pharmacologic treatments in the neonate have been well established. Pharmacologic and nonpharmacologic interventions can be used in conjunction to increase the efficacy of analgesia.

Repeated neonatal needle-prick stimulation increases inflammatory mechanical hypersensitivity in adult rats

BACKGROUND AND AIMS

Newborn infants are vulnerable to procedural stress and pain exposure on the first weeks of life that represents a critical period for the development of nociceptive, sensory, emotional, and social functions. We evaluated the nociceptive behavior of adult male and female rats that were submitted to nociceptive experience in the neonatal period and the maternal behavior in the postnatal period.

METHODS

The animals were submitted to repetitive needle pricking from the second to the fifteenth postnatal day (PND 2-15). Maternal behavior and litter weight were evaluated during this period. Mechanical sensitivity to pain was assessed in offsprings during the adulthood by exposing them to inflammatory stimuli, including formalin test or the Freund's complete adjuvant (CFA) injection followed by the electronic von Frey test at 0, 3, 6 and 24 h later.

RESULTS

Maternal behavior and litter weight were not altered by pinprick stimuli during PND 2-15. Additionally, pinprick stimulation reduced the paw withdrawal threshold in CFA-injected animals compared to control. In the formalin test, there was a difference between the genders. Female rats are statically more sensitive to formalin stimulation and showed an increased licking time in both the first and second phases and increased number of flinches in second phase.

CONCLUSIONS

Experiencing early life repetitive pain exposure increased inflammatory pain sensitivity in adult offspring rats and female rats are more sensitive to chemical stimulation.

IMPLICATIONS

Future investigations of the mechanisms involved in this effect may contribute to the improvement of the understanding of inflammatory pain sensitivity differences.

A Systematic Review of Behavioral and Environmental Interventions for Procedural Pain Management in Preterm Infants

PROBLEM

Current research suggests behavioral and environmental interventions to prevent neonatal pain prior to an invasive procedure are rarely administered and seldom documented. The aim of this study was to systematically review findings from published randomized controlled trials that tested the effects of behavioral and environmental procedural pain management interventions on behavioral pain response in preterm infants.

ELIGIBILITY CRITERIA

Randomized controlled trials examining the effects of behavioral and environmental pain management interventions on behavioral pain response in preterm infants were identified. Articles accepted for inclusion met the following criteria: English language, original, peer refereed, randomized controlled clinical trials published within the past 5 years, study sample: preterm infants, setting: neonatal intensive care units, study intervention behavioral and environmental, outcome pain measurement score from valid and reliable pain scale.

SAMPLE

Fourteen randomized controlled trials from a literature search of PubMed and Medline databases were included in this review.

RESULTS

Across all age groups, facilitated tucking, oral sucrose, and kangaroo care decreased behavioral and physiologic pain response alone and in combination with other behavioral and environmental interventions.

CONCLUSION

Among preterm infants, facilitated tucking, oral sucrose, and kangaroo care significantly mitigates biobehavioral pain response associated with acutely painful procedures.

IMPLICATIONS

Evidence suggests that behavioral and environmental interventions can decrease biobehavioral pain response associated with acutely painful procedures in preterm infants. This review highlights the need for rigorous studies to help healthcare providers to build a tailored pain treatment plan for preterm infants.

Epigenetic Modifications Following Noxious Stimuli in Infants

Purpose:

To recruit healthy full- and preterm infants into genetic research and determine the effectiveness of a noninvasive DNA sampling technique for comparing epigenetic modifications.

Background:

Noxious stimuli during a vulnerable period of infant neuronal plasticity may trigger long-term epigenetic changes affecting neurodevelopment, pain modulation, and reactivity. Recognizing epigenetic pain findings is problematic because parents are reluctant to enroll newborns into genetic research.

Methods:

Design: Within-subject change over time candidate-gene DNA methylation association study. Setting/ sample: Urban teaching hospital’s neonatal intensive care unit and newborn nursery. Convenience sample of healthy full- (>37 weeks, n = 6) and preterm (<37 weeks, n = 6) infants. Procedure: Parents participated in a genetic presentation prior to informed consent. Infant buccal saliva was collected after admission to the unit and prior to discharge. Analysis: The methylation pattern at the 5′ end of µ-opioid receptor gene ( OPRM1) was examined. DNA was treated with bisulfite to convert all cytosines to uracil residues, leaving methylated cytosines unchanged. Sequencing of untreated and bisulfite-converted DNA was carried out. The sequences of unconverted and bisulfite-converted DNA were aligned with ClustalW, fidelity of the polymerase chain reaction and the sequencing reaction evaluated, and the methylation pattern identified.

Results:

Recruitment and assessment of a noninvasive DNA sampling technique for comparing epigenetic modifications were successful; however, infant stress did not produce a change in OPRM1 methylation expression.

Relevance:

This study established the feasibility of recruiting healthy full-term infants into genetic research and the effectiveness of noninvasive DNA sampling for comparing epigenetic modification in infants.

Substance P in Dorsal Root Ganglion Neurons in Young and Adult Rats, after Nociceptive Stimulation during the Neonatal Period

The nervous system is highly plastic during the neonatal period, being sensitive to noxious stimuli, which may cause short- and long-term pain responsivity changes. Understanding plasticity in peripheral pain pathways is crucial, particularly when the nervous system is still under development and remodeling process. Substance P (SP) is widely used as a marker for peripheral neurons with unmyelinated and small myelinated fibers. We investigated the number of SP immunoreactive neurons in the dorsal root ganglion (DRG) of male and female Wistar rats, 15 and 180 days after nociceptive stimulation during the neonatal period. Right and left 5th lumbar (L5) DRG were incubated in rabbit polyclonal anti-substance P primary followed by biotinylated donkey anti-rabbit secondary antibodies. Reaction was revealed with a nickel-diaminobenzidine solution. Labeled neurons were counted and compared between ages, genders and groups. Gender differences were present in both ages, with the number of SP-positive DRG neurons being larger in 15-days-old males on both sides. After 180 days, males showed a larger number of SP-positive neurons than females only on the nociceptive stimulated side. An increased number of SP-positive neurons in the DRG on the stimulated side was present in females, immediately after nociceptive stimulation, but not after 180 days. In conclusion, neonatal noxious stimulation caused a permanent increase in SP-positive DRG neurons in males that was not observed in females, suggesting that differences in pain processing/responsivity between genders could be related to morphological alterations of the nervous system. Anat Rec, 301:849-861, 2018. © 2017 Wiley Periodicals, Inc.

Five years' follow-up of dental fear and anxiety, experience of dental care and oral health behaviour in Swedish preterm and full-term adolescents

Background

There is rising concern about how preterm birth affects long-term health later in life. The various effects that preterm birth have on developmental outcomes, cognitive profiles and medical health may also affect levels of cooperation in the dental care situation in addition to general oral health and other oral health-related habits. Oral health is an integral part of one’s general health and well-being; however, less is known about how prematurity affects oral health and other related areas such as dental care, and including dental fear and anxiety (DFA) in individuals during adolescence and adulthood. This is considered of special interest to study, as preterm children during the preschool and school period were reported to have behavioural problems during dental treatments and less than favourable oral hygiene.

Methods

A questionnaire was used of self-report design and structured into behavioural aspects relating to dental treatment, oral health-related factors, and medical health. This questionnaire at 17–19 years of age was a follow-up from 12 to 14 years of age and considered a predictor for planning future dental care for this group of patients. The 145 participating adolescents were all preterm, born between 23 and 32 weeks of gestation and 140 full-term controls, born ≥37 weeks of gestation.

Results

Dental fear and anxiety, oral health behaviour, and intake of sweets and sugary drinks of 17–19-year old adolescents born preterm was comparable to that of the full-term control group. Medical health problems as well as the intake of sweets and sugary drinks increased from the time of early adolescence to late adolescence in both groups.

Conclusions

Preterm as well as full-term adolescents between 17 and 19 years of age are satisfied with their dental care and display low prevalence of dental fear and anxiety (DFA). The findings in this study indicate that adolescents born very preterm and extremely preterm are well prepared for transition to dental care in adult life with expectations of being able to take responsibility for their oral health.

Validation of Greek Versions of the Neonatal Infant Pain Scale and Premature Infant Pain Profile in Neonatal Intensive Care Unit

BACKGROUND

The Neonatal Infant Pain Scale and the Premature Infant Pain Profile have been used widely in neonatal intensive care units for pain assessment.

AIM

This study reports the evaluation and validation of these scales in full-term newborns who were hospitalized in two Greek neonatal intensive care units. Evaluation and validation of the Neonatal Infant Pain Scale and the Premature Infant Pain Profile in full-term newborns who were hospitalized in two Greek neonatal intensive care units.

MATERIALS AND METHODS

This is a cross-sectional study. Two neonatal intensive care units at a large General Children's Hospital in Greece. A total of 81 full-term newborns. This cross-sectional study was conducted in two neonatal intensive care units at a large General Children's Hospital in Greece. We studied 81 full-term newborns, who were exposed to various painful routine procedures. A single measurement was taken from each neonate. Two observers were present during each procedure and evaluated pain using both the Neonatal Infant Pain Scale and Premature Infant Pain Profile. Internal consistency coefficient Cronbach's α, internal class agreement coefficient, and κ factor were appropriately measured.

RESULTS

The weighting of the Neonatal Infant Pain Scale and Premature Infant Pain Profile pointed out an excellent coherence between the two scales and agreement among the researchers. The internal consistency coefficient Cronbach's α was >.8 and the internal class agreement coefficient was >.98 for both scales, which indicates an excellent consistency between scales. The κ factor for Neonatal Infant Pain Scale was >.73 and for the Premature Infant Pain Profile it was >.6, which indicates a significant agreement among investigators.

CONCLUSIONS

The Neonatal Infant Pain Scale and Premature Infant Pain Profile were successfully adjusted in Greek standards with reliability between the scales and among the researchers. Moreover, they constitute reliable tools for the evaluation of neonatal procedural pain in full-term newborns in Greece.

A new role of growth hormone and insulin growth factor receptor type 1 in neonatal inflammatory nociception

Neonatal inflammation produces nociception by a local decrease of growth hormone and an increment of the insulin growth factor 1-1R. Systemic growth hormone prevents the development of nociception.

Growth hormone (GH) and insulin growth factor 1 (IGF1) are implicated in nociceptive processing; it has been reported that the latter participates in neonatal inflammatory nociception. In the target article, the authors propose that local inflammation evoked by carrageenan administration in mice produces a decrease in the local GH levels and an increment of IGF1 receptors type 1 expression, this produces behavioral nociception and peripheral sensitization that can be prevented by GH systemic administration pretreatment.

Long-Term Effects of Chronic Buspirone during Adolescence Reduce the Adverse Influences of Neonatal Inflammatory Pain and Stress on Adaptive Behavior in Adult Male Rats

Neonatal pain and stress induce long-term changes in pain sensitivity and behavior. Previously we found alterations in pain sensitivity in adolescent rats exposed to early-life adverse events. We tested whether these alterations have long-lasting effects and if those effects can be improved by the 5-hydroxytryptamine 1A (5-HT1A) receptor agonist buspirone injected chronically during the adolescent period. This study investigates: (1) effects of inflammatory pain (the injection of formalin into the pad of a hind paw) or stress (short maternal deprivation-isolation, MI), or their combination in 1-2-day-old rats on the adult basal pain, formalin-induced pain, anxiety and depression; (2) effects of adolescent buspirone in adult rats that experienced similar early-life insults. Changes in nociceptive thresholds were evaluated using the hot plate (HP) and formalin tests; levels of anxiety and depression were assessed with the elevated plus maze and forced swim tests respectively. Both neonatal painful and stressful treatments induced long-term alterations in the forced swim test. Other changes in adult behavioral responses were dependent on the type of neonatal treatment. There was a notable lack of long-term effects of the combination of early inflammatory pain and stress of MI on the pain responses, anxiety levels or on the effects of adolescent buspirone. This study provides the first evidence that chronic injection of buspirone in adolescent rats alters antinociceptive and anxiolytic effects limited to adult rats that showed behavioral alterations induced by early-life adverse treatments. These data highlight the role of 5-HT1A receptors in long-term effects of neonatal inflammatory pain and stress of short MI on adaptive behavior and possibility of correction of the pain and psychoemotional behavior that were altered by adverse pain/stress intervention using buspirone during critical adolescent period.

Oxidative Stress as a Physiological Pain Response in Full-Term Newborns

This research paper aims to investigate if oxidative stress biomarkers increase after a painful procedure in term newborns and if nonpharmacological approaches, or sex, influence pain degree, and the subsequent OS. 83 healthy term newborns were enrolled to receive 10% oral glucose or sensorial saturation (SS) for analgesia during heel prick (HP). The ABC scale was used to score the pain. Advanced oxidation protein products (AOPP) and total hydroperoxides (TH) as biomarkers of OS were measured at the beginning (early-sample) and at the end (late-sample) of HP. The early-sample/late-sample ratio for AOPP and TH was used to evaluate the increase in OS biomarkers after HP. Higher levels of both AOPP and TH ratio were observed in high degree pain (4–6) compared with low degree pain score (0–3) (AOPP: p = 0.049; TH: p = 0.001). Newborns receiving SS showed a significantly lower pain score (p = 0.000) and AOPP ratio levels (p = 0.021) than those without. Males showed higher TH levels at the end of HP (p = 0.005) compared to females. The current study demonstrates that a relationship between pain degree and OS exists in healthy full-term newborns. The amount of OS is gender related, being higher in males. SS reduces pain score together with pain-related OS in the newborns.