Procedural pain and oxidative stress in premature neonates

Energy Utilization in Premature Neonates Undergoing Screening for Retinopathy of Prematurity

BACKGROUND/OBJECTIVES

Premature neonates are at risk for retinopathy of prematurity (ROP) and routinely undergo screening exams that involve substantial physical manipulation, often causing significant signs of pain, despite pain-relieving interventions. It remains unclear whether these exams affect energy utilization, cellular hypoxia, and clinically significant events, and whether receiving supplemental oxygen affects these relationships. This work examines the effects of ROP screening on (1) urinary uric acid-to-creatinine concentration ratios ([UA]/[Cr]), a known marker of ATP degradation, hypoxia, and oxidative stress; and (2) clinically significant events (apnea, bradycardia, gastric residuals, and oxygen desaturations) in premature neonates on room air or oxygen support.

METHODS

This prospective pilot study included premature neonates requiring ROP screening examinations at Loma Linda University's NICU. Urinary [UA]/[Cr], measured by high-performance liquid chromatography, and clinical events, documented by prospective medical chart review, were analyzed pre- and post-exam in subjects on room air (n = 18) or on oxygen support (n = 20). Statistical analyses included a generalized linear mixed model for urinary [UA]/[Cr] and Wilcoxon signed rank tests for clinical events.

RESULTS

A significant time effect (p = 0.010) was observed for urinary [UA]/[Cr], with higher levels at 0-12 (p = 0.023) and 12-24 (p = 0.023) hours post-exam. Subjects receiving oxygen support had more total (p = 0.028) and more severe (p = 0.026) oxygen desaturations.

CONCLUSIONS

ROP examinations may increase energy utilization in premature neonates, with those receiving oxygen support being particularly susceptible to oxygen desaturations post-exam. Further research is needed to clarify the full impact of the procedure and to identify strategies to minimize stress associated with these screening examinations.

Neonatal amygdala volumes, procedural pain and the association with social-emotional development in children born very preterm

Very preterm birth (< 32 weeks' gestational age) is associated with later social and emotional impairments, which may result from enhanced vulnerability of the limbic system during this period of heightened vulnerability. Evidence suggests that early procedural pain may be a key moderator of early brain networks. In a prospective cohort study, neonates born very preterm (< 30 weeks' gestation) underwent MRI scanning at term-equivalent age (TEA) and clinical data were collected (mechanical ventilation, analgesics, sedatives). Procedural pain was operationalized as the number of skin breaking procedures. Amygdala volumes were automatically extracted. The Strengths and Difficulties questionnaire was used to assess social-emotional outcomes at 5 years of age (mean age 67.5 months). General linear models were employed to examine the association between neonatal amygdala volumes and social-emotional outcomes and the timing and amount of procedural pain exposure (early within the first weeks of life to TEA) as a moderator, adjusting for biological sex, gestational age, 5-year assessment age, days of mechanical ventilation and total cerebral volumes. A total of 42 preterm infants participated. Right amygdala volumes at TEA were associated with prosocial behaviour at age 5 (B = -0.010, p = 0.005). Procedural pain was found to moderate the relationship between right amygdala volumes in the neonatal period and conduct problems at 5 years, such that early skin breaking procedures experienced within the first few weeks of life strengthened the association between right amygdala volumes and conduct problems (B = 0.005, p = 0.047). Late skin breaking procedures, experienced near TEA, also strengthened the association between right amygdala volumes and conduct problems (B = 0.004, p = 0.048).

Lower plasma melatonin levels in non-hypoxic premature newborns associated with neonatal pain

We analyzed plasma melatonin levels in different groups of preterm newborns without hypoxia and their relationship with several perinatal variables like gestational age or neonatal pain. Prospective cohort study of preterm newborns (PTNB) without perinatal hypoxia, Apgar > 6 at 5 min, and oxygen needs on the third day of life. We compared melatonin levels at day 3 of life in different groups of non-hypoxic preterm infants (Student's t-tests, Mann-Whitney U, and chi2) and analyzed the relationship of melatonin with GA, birth weight, neonatal pain (Premature Infant Pain Profile (PIPP) scale), caffeine treatment, parenteral nutrition, or the development of free radical diseases (correlation study, linear regression) and factors associated with moderate/intense pain and free radical diseases (logistic regression analysis). Sixty-one preterm infants with gestational age (GA) of 30.7 ± 2.0 weeks with no oxygen requirements at day 3 of life were studied with plasma melatonin levels of 33.8 ± 12.01 pg/ml. Preterm infants weighing < 1250 g at birth had lower plasma melatonin levels (p = 0.05). Preterm infants with moderate or severe pain (PPIPP > 5) have lower melatonin levels (p = 0.01), and being preterm with PIPP > 5 is associated with lower plasma melatonin levels (p = 0.03). Being very preterm (GA < 32 GS), having low weight for gestational age (LWGA), receiving caffeine treatment, or requiring parenteral nutrition did not modify melatonin levels in non-hypoxic preterm infants (p = NS). Melatonin on day 3 of life in non-hypoxic preterm infants is not associated with later development of free radical diseases (BPD, sepsis, ROP, HIV, NEC).

CONCLUSION

We observed that preterm infants with moderate to severe pain have lower melatonin levels. These findings are relevant because they reinforce the findings of other authors that melatonin supplementation decreases pain and oxidative stress in painful procedures in premature infants. Further studies are needed to evaluate whether melatonin could be used as an analgesic in painful procedures in preterm infants.

TRIAL REGISTRATION

Trial registration was not required since this was an observational study.

WHAT IS KNOWN

• Melatonin is a potent antioxidant and free radical scavenger in newborns under stress conditions: hypoxia, acidosis, hypotension, painful procedures, or parenteral nutrition. • Pain stimulates the production of melatonin. • Various studies conclude that melatonin administration decreases pain during the neonatal period.

WHAT IS NEW

• Non-hypoxic preterm infants with moderate to severe pain (PIPP>5) have lower levels of melatonin. • Administration of caffeine and treatment with parenteral nutrition do not modify melatonin levels in non-hypoxic preterm infants.

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.

Biomarkers for assessing pain and pain relief in the neonatal intensive care unit

Newborns admitted to the neonatal intensive care unit (NICU) regularly undergo painful procedures and may face various painful conditions such as postoperative pain. Optimal management of pain in these vulnerable preterm and term born neonates is crucial to ensure their comfort and prevent negative consequences of neonatal pain. This entails accurate and timely identification of pain, non-pharmacological pain treatment and if needed administration of analgesic therapy, evaluation of treatment effectiveness, and monitoring of adverse effects. Despite the widely recognized importance of pain management, pain assessment in neonates has thus far proven to be a challenge. As self-report, the gold standard for pain assessment, is not possible in neonates, other methods are needed. Several observational pain scales have been developed, but these often rely on snapshot and largely subjective observations and may fail to capture pain in certain conditions. Incorporation of biomarkers alongside observational pain scores holds promise in enhancing pain assessment and, by extension, optimizing pain treatment and neonatal outcomes. This review explores the possibilities of integrating biomarkers in pain assessment in the NICU.

Video-Based versus On-Site Neonatal Pain Assessment in Neonatal Intensive Care Units: The Impact of Video-Based Neonatal Pain Assessment in Real-World Scenario on Pain Diagnosis and Its Artificial Intelligence Application

BACKGROUND

Neonatal pain assessment (NPA) represents a huge global problem of essential importance, as a timely and accurate assessment of neonatal pain is indispensable for implementing pain management.

PURPOSE

To investigate the consistency of pain scores derived through video-based NPA (VB-NPA) and on-site NPA (OS-NPA), providing the scientific foundation and feasibility of adopting VB-NPA results in a real-world scenario as the gold standard for neonatal pain in clinical studies and labels for artificial intelligence (AI)-based NPA (AI-NPA) applications.

SETTING

A total of 598 neonates were recruited from a pediatric hospital in China.

METHODS

This observational study recorded 598 neonates who underwent one of 10 painful procedures, including arterial blood sampling, heel blood sampling, fingertip blood sampling, intravenous injection, subcutaneous injection, peripheral intravenous cannulation, nasopharyngeal suctioning, retention enema, adhesive removal, and wound dressing. Two experienced nurses performed OS-NPA and VB-NPA at a 10-day interval through double-blind scoring using the Neonatal Infant Pain Scale to evaluate the pain level of the neonates. Intra-rater and inter-rater reliability were calculated and analyzed, and a paired samples t-test was used to explore the bias and consistency of the assessors' pain scores derived through OS-NPA and VB-NPA. The impact of different label sources was evaluated using three state-of-the-art AI methods trained with labels given by OS-NPA and VB-NPA, respectively.

RESULTS

The intra-rater reliability of the same assessor was 0.976-0.983 across different times, as measured by the intraclass correlation coefficient. The inter-rater reliability was 0.983 for single measures and 0.992 for average measures. No significant differences were observed between the OS-NPA scores and the assessment of an independent VB-NPA assessor. The different label sources only caused a limited accuracy loss of 0.022-0.044 for the three AI methods.

CONCLUSION

VB-NPA in a real-world scenario is an effective way to assess neonatal pain due to its high intra-rater and inter-rater reliability compared to OS-NPA and could be used for the labeling of large-scale NPA video databases for clinical studies and AI training.

Melatonin in Newborn Infants Undergoing Surgery: A Pilot Study on Its Effects on Postoperative Oxidative Stress

Surgery is frequently associated with excessive oxidative stress. Melatonin acts as an antioxidant and transient melatonin deficiency has been described in neonatal surgical patients. This randomized, blinded, prospective pilot study tested the hypothesis that oral melatonin supplementation in newborn infants undergoing surgery is effective in reducing perioperative oxidative stress. A total of twenty-three newborn infants requiring surgery were enrolled: 10 received a single dose of oral melatonin 0.5 mg/kg in the morning, before surgery (MEL group), and 13 newborns served as the control group (untreated group). Plasma concentrations of melatonin, Non-Protein-Bound Iron (NPBI), Advanced Oxidation Protein Products (AOPP), and F2-Isoprostanes (F2-IsoPs) were measured. Both in the pre- and postoperative period, melatonin concentrations were significantly higher in the MEL group than in the untreated group (preoperative: 1265.50 ± 717.03 vs. 23.23 ± 17.71 pg/mL, p < 0.0001; postoperative: 1465.20 ± 538.38 vs. 56.47 ± 37.18 pg/mL, p < 0.0001). Melatonin significantly increased from the pre- to postoperative period in the untreated group (23.23 ± 17.71 vs. 56.47 ± 37.18 pg/mL; pg/mL p = 0.006). In the MEL group, the mean blood concentrations of NPBI, F2-IsoPs, and AOPP significantly decreased from the pre- to the postoperative period (4.69 ± 3.85 vs. 1.65 ± 1.18 micromol/dL, p = 0.049; 128.40 ± 92.30 vs. 50.25 ± 47.47 pg/mL, p = 0.037 and 65.18 ± 15.50 vs. 43.98 ± 17.92 micromol/dL, p = 0.022, respectively). Melatonin concentration increases physiologically from the pre- to the postoperative period, suggesting a defensive physiologic response to counteract oxidative stress. The administration of exogenous melatonin in newborn infants undergoing surgery reduces lipid and protein peroxidation in the postoperative period, showing a potential role in protecting babies from the deleterious consequences of oxidative stress.

Physiological Effects of Handling in Moderate to Late Preterm Infants Receiving Neonatal Intensive Care

BACKGROUND

Of all preterm births, approximately 82% are moderate to late preterm. Moderate to late preterm infants are often treated like full-term infants despite their physiological and metabolic immaturity, increasing their risk for mortality and morbidity.

PURPOSE

To describe the relationship between routine caregiving methods and physiological markers of stress and hypoxemia in infants born between 32 and 36 weeks' gestation.

METHODS

This descriptive study used a prospective observational design to examine the relationship between routine caregiving patterns (single procedure vs clustered care) and physiological markers of stress and hypoxemia such as regional oxygen saturation, quantified as renal and cerebral regional oxygen saturation (StO2), systemic oxygen saturation (Spo2), and heart rate (HR) in moderate to late preterm infants. Renal and cerebral StO2 was measured using near-infrared spectroscopy during a 6-hour study period. Spo2 and HR were measured using pulse oximetry.

RESULTS

A total of 231 procedures were captured in 37 participants. We found greater alterations in cerebral StO2, renal StO2, Spo2, and HR when routine procedures were performed consecutively in clusters than when procedures were performed singly or separately.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Our results suggest that the oxygen saturation and HR of moderate to late preterm infants were significantly altered when exposed to routine procedures that were performed consecutively, in clusters, compared with when exposed to procedures that were performed singly or separately. Adequately powered randomized controlled trials are needed to determine the type of caregiving patterns that will optimize the health outcomes of this vulnerable population.

Neonatal diseases and oxidative stress in premature infants: an integrative review

OBJECTIVE

To describe the relationship of oxidative stress and antioxidant biomarkers in cord blood of premature newborns and the prognosis of diseases in the neonatal period.

SOURCES

This study consists of an integrative review. Searches were conducted in electronic databases Scopus, PubMed, Web of Science, and Medline/Lilacs through the Virtual Library on Health Issues, using the descriptors: "premature infants", "preterm infants", "preterm birth", "preterm", "oxidative stress", "antioxidants", "infant, premature, diseases" and "cord blood". Original articles published between 2016 and 2021 in Portuguese, English, or Spanish, which analyzed oxidative stress and/or antioxidant levels through cord blood of premature newborns and evaluated clinical outcomes, were included.

SUMMARY OF THE FINDINGS

Of the 1,003 studies reviewed, after exclusion of duplicate articles, analysis of titles, abstracts, and full texts, 18 articles were included. 72.2% (n = 13) of analyzed studies reported a positive association between oxidative stress and the development of prematurity-related diseases; 27.7% (n = 5) showed no significant relation. Outcomes that showed a positive association were: intrauterine growth restriction, necrotizing enterocolitis, bronchopulmonary dysplasia, intraventricular hemorrhage, fetal inflammatory response syndrome, early-onset neonatal sepsis, retinopathy of prematurity, morbidity, and mortality.

CONCLUSION

The analysis of oxidative stress and antioxidants in cord blood of premature newborns may be useful in the prognosis of some pathologies. The consequences of oxidative damage are known to be associated with increased morbidity in the short and long term. Further investigation is needed in this population in order to define normality parameters of biomarkers, clinical manifestations, diagnosis and treatment of these conditions.

Associations of Mitochondrial Function, Stress, and Neurodevelopmental Outcomes in Early Life: A Systematic Review

Early life stress is commonly experienced by infants, especially preterm infants, and may impact their neurodevelopmental outcomes in their early and later lives. Mitochondrial function/dysfunction may play an important role underlying the linkage of prenatal and postnatal stress and neurodevelopmental outcomes in infants. This review aimed to provide insights on the relationship between early life stress and neurodevelopment and the mechanisms of mitochondrial function/dysfunction that contribute to the neuropathology of stress. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was used to develop this systematic review. PubMed, Scopus, PsycINFO, and Biosis databases were searched for primary research articles published between 2010 and 2021 that examined the relationships among mitochondrial function/dysfunction, infant stress, and neurodevelopment. Thirty studies were identified. There is evidence to support that mitochondrial function/dysfunction mediates the relationship between prenatal and postnatal stress and neurodevelopmental outcomes in infants. Maternal transgenerational transmission of mitochondrial bioenergetic patterns influenced prenatal stress induced neurodevelopmental outcomes and behavioral changes in infants. Multiple functionally relevant mitochondrial proteins, genes, and polymorphisms were associated with stress exposure. This is the first review of the role that mitochondrial function/dysfunction plays in the association between stress and neurodevelopmental outcomes in full-term and preterm infants. Although multiple limitations were found based on the lack of data on the influence of biological sex, and due to invasive sampling, and lack of longitudinal data, many genes and proteins associated with mitochondrial function/dysfunction were found to influence neurodevelopmental outcomes in the early life of infants.

Biomarker of Urinary Malondialdehyde and Tumor Necrosis Factor-Alpha with Pain Progress in a Patient with Low Back Pain

Introduction: This study aims to determine the urine concentrations of MDA, and TNF-α biomarkers with pain intensity in a patient with low back pain (LBP) compared to healthy controls. Also, the correlation between these biomarkers and clinical findings of pain intensity was determined during 25 weeks to find a molecular diagnostic factor of disease progression. Case Presentation: Participants in this case study are students at Shahed University, Iran. A 22‑year‑old man patient with a three-month history of progressive LBH and gait instability and an age, sex, and body mass index (BMI) matched healthy man was enrolled for 25 weeks. Spinal MRI (Siemens 1.5 T) revealed disc degeneration and displacement. LBP symptoms were diagnosed by a neurologist using ICD-9 diagnostic codes. Other diseases that affect the urine levels of MDA and TNF-α in the patient, such as allergic or infectious diseases, have been ruled out. After collecting demographic information, the facial pain scale (FPS) and numerical rating scale (NRS) for pain and 24-hour urine samples of a healthy person and a patient were collected weekly for 25 weeks. Samples were analyzed for malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α). Conclusions: During the experiment, urinary MDA levels were significantly elevated while TNF-α levels were not changed in LBP patients compared to control individuals (P ≤ 0.001). Furthermore, the assessment of LBP by the facial pain scale (FPS) and numerical rating scale (NRS) pain scores was only correlated with urinary MDA levels, and urinary TNF-α levels did not change during the experiment. Pearson correlation analysis revealed a positive correlation between pain scores during 25 weeks and urine concentrations of MDA (r = 0.60, P-value < 0.001). According to the present study, chronic LBP patients had higher levels of MDA in their urine than those who did not have chronic LBP. There was a significant positive association between urine MDA level and pain intensity progression.

A pilot study on the biochemical effects of repeated administration of 24% oral sucrose vs. 30% oral dextrose on urinary markers of adenosine triphosphate degradation

OBJECTIVES

Premature neonates often receive oral sucrose or dextrose before tissue-damaging procedures (TDPs). Previous work showed that a single dose of sucrose, but not dextrose, increased cellular energy utilization and ATP degradation. This pilot study probes the effects of repeated administration of sucrose or dextrose on energy metabolism.

METHODS

Urinary markers of ATP metabolism (hypoxanthine, xanthine, uric acid) are measured in premature neonates randomized to receive: (a) standard of care, (b) 0.2 ml 24% oral sucrose, or (c) 0.2 ml 30% oral dextrose, before every painful procedure on days-of-life 3-7.

RESULTS

Standard of care is associated with highest xanthine/creatinine and uric acid/creatinine, likely because of fewer pain treatments. Benefits of repeated oral sucrose are unclear. Neonates receiving oral dextrose had lower xanthine/creatinine and uric acid/creatinine.

CONCLUSIONS

Repeated treatments of neonatal procedural pain with 30% oral dextrose are less energetically demanding. Larger clinical studies are needed for comparison with sucrose treatments.

Oxidative Stress in Preterm Newborns

Preterm babies are highly susceptible to oxidative stress (OS) due to an imbalance between the oxidant and antioxidant systems. The generation of free radicals (FR) induces oxidative damage to multiple body organs and systems. OS is the main factor responsible for the development of typical premature infant diseases, such as bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis, intraventricular hemorrhage, periventricular leukomalacia, kidney damage, eryptosis, and also respiratory distress syndrome and patent ductus arteriosus. Many biomarkers have been detected to early identify newborns at risk of developing a free radical-mediated disease and to investigate new antioxidant strategies. This review reports the current knowledge on OS in the preterm newborns and the newest findings concerning the use of OS biomarkers as diagnostic tools, as well as in implementing antioxidant therapeutic strategies for the prevention and treatment of these diseases and their sequelae.

Functional thalamocortical connectivity at term equivalent age and outcome at 2 years in infants born preterm

Infants born preterm are at high risk of long-term motor and neurocognitive deficits. In the majority of these infants structural MRI at the time of normal birth does not predict motor or cognitive outcomes accurately, and many infants without apparent brain lesions later develop motor and cognitive deficits. Thalamocortical connections are known to be necessary for normal brain function; they develop during late fetal life and are vulnerable to perinatal adversity. This study addressed the hypothesis that abnormalities in the functional connectivity between cortex and thalamus underlie neurocognitive impairments seen after preterm birth. Using resting state functional connectivity magnetic resonance imaging (fMRI) in a group of 102 very preterm infants without major focal brain lesions, we used partial correlations between thalamus and functionally-derived cortical areas to determine significant connectivity between cortical areas and thalamus, and correlated the parameter estimates of these connections with standardised neurocognitive assessments in each infant at 20 months of age. Pre-motor association cortex connectivity to thalamus correlates with motor function, while connectivity between primary sensory-motor cortex and thalamus correlates with cognitive scores. These results demonstrate the importance and vulnerability of functional thalamocortical connectivity development in the perinatal period for later neurocognitive functioning.

Cumulative procedural pain and brain development in very preterm infants: A systematic review of clinical and preclinical studies

Very preterm infants may manifest neurodevelopmental impairments, even in the absence of brain lesions. Pathogenesis is complex and multifactorial. Evidence suggests a role of early adversities on neurodevelopmental outcomes, via epigenetic regulation and changes in brain architecture. In this context, we focused on cumulative pain exposure which preterm neonates experience in neonatal intensive care unit (NICU). We systematically searched for: i) evidence linking pain with brain development and exploring the potential pathogenetic role of epigenetics; ii) preclinical research supporting clinical observational studies. Nine clinical neuroimaging studies, during neonatal or school age, mostly from the same research group, revealed volume reduction of white and gray matter structures in association with postnatal pain exposure. Three controlled animal studies mimicking NICU settings found increased cell death or apoptosis; nevertheless, eligible groups were limited in size. Epigenetic modulation (SLC6A4 promoter methylation) was identified in only two clinical trials. We call for additional research and, although knowledge gaps, we also point out the urgent need of minimizing painful procedures in NICUs.

Methodological Issues in the Study of the Development of Pain Responsivity in Preterm Neonates: A Systematic Review

The study of the development of neonatal pain responses is of key importance, both for research and for clinical reasons, with particular regard to the population of preterm neonates, given the amount of painful procedures they are exposed to on a daily basis. The aim of this work was to systematize our knowledge about the development of pain responses in prematurely born neonates by focusing on some key methodological issues. Studies on the impact of age variables, namely gestational age (GA), postmenstrual age (PMA) and chronological age (CH), on pain responsivity in premature neonates were identified using Medline and Scopus. Studies (N = 42) were categorized based on terminological and methodological approaches towards age variables, and according to output variables considered (facial, nonfacial behavioral, physiological). Distinct multidimensional developmental patterns were found for each age-sampling strategy. Overall, each of the three age variables seems to affect pain responsivity, possibly differently across age windows. Targeted as well as integrated approaches, together with a renewed attention for methodological consistency, are needed to further our knowledge on this topic.

Oral dextrose reduced procedural pain without altering cellular ATP metabolism in preterm neonates: a prospective randomized trial

OBJECTIVE

To examine the effects of 30% oral dextrose on biochemical markers of pain, adenosine triphosphate (ATP) degradation, and oxidative stress in preterm neonates experiencing a clinically required heel lance.

STUDY DESIGN

Utilizing a prospective study design, preterm neonates that met study criteria (n = 169) were randomized to receive either (1) 30% oral dextrose, (2) facilitated tucking, or (3) 30% oral dextrose and facilitated tucking 2 min before heel lance. Plasma markers of ATP degradation (hypoxanthine, uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured using the premature infant pain profile-revised (PIPP-R).

RESULTS

Oral dextrose, administered alone or with facilitated tucking, did not alter plasma markers of ATP utilization and oxidative stress.

CONCLUSION

A single dose of 30% oral dextrose, given before a clinically required heel lance, decreased signs of pain without increasing ATP utilization and oxidative stress in premature neonates.

Perioperative Oxidative Stress: The Unseen Enemy

Reactive oxygen species (ROS) are essential for cellular signaling and physiological function. An imbalance between ROS production and antioxidant protection results in a state of oxidative stress (OS), which is associated with perturbations in reduction/oxidation (redox) regulation, cellular dysfunction, organ failure, and disease. The pathophysiology of OS is closely interlinked with inflammation, mitochondrial dysfunction, and, in the case of surgery, ischemia/reperfusion injury (IRI). Perioperative OS is a complex response that involves patient, surgical, and anesthetic factors. The magnitude of tissue injury inflicted by the surgery affects the degree of OS, and both duration and nature of the anesthetic procedure applied can modify this. Moreover, the interindividual susceptibility to the impact of OS is likely to be highly variable and potentially linked to underlying comorbidities. The pathological link between OS and postoperative complications remains unclear, in part due to the complexities of measuring ROS- and OS-mediated damage. Exogenous antioxidant use and exercise have been shown to modulate OS and may have potential as countermeasures to improve postoperative recovery. A better understanding of the underlying mechanisms of OS, redox signaling, and regulation can provide an opportunity for patient-specific phenotyping and development of targeted interventions to reduce the disruption that surgery can cause to our physiology. Anesthesiologists are in a unique position to deliver countermeasures to OS and improve physiological resilience. To shy away from a process so fundamental to the welfare of these patients would be foolhardy and negligent, thus calling for an improved understanding of this complex facet of human biology.

Comparison of Oxidative Status of Human Milk, Human Milk Fortifiers and Preterm Infant Formulas

Preterm and low birth weight infants require specific nutrition to overcome the accumulated growth deficit, and to prevent morbidities related to postnatal growth failure. In order to guarantee an adequate nutrient-intake, mother’s own milk, when available, or donor human milk, are usually fortified with additional nutrients, in particular proteins. Fortification with processed ingredients may result in additional intake in oxidative compounds, deriving from extensive heat treatments, that are applied during processing. The aim of the present work was to compare the in vitro antioxidant activity and oxidative compound content conveyed by different preterm infant foods and fortifiers, namely raw and pasteurized human milk, two different preterm infant formulas, three bovine milk-based fortifiers and two experimental donkey milk-based fortifiers. Univariate and multivariate statistical analyses revealed significant differences between the different products. The use of human milk minimizes the intake of dietary oxidative compound in comparison to infant formulas, irrespective of pasteurization or fortification, especially as far as malondialdehyde content is concerned. The addition of fortifiers to human milk increases its antioxidant capacity, and the choice of the protein source (hydrolysed vs. whole proteins) differently impacted the resulting total antioxidant capacity of the diet.

Non-invasive assessment of oxidative stress in preterm infants

Preterm newborns have an immature antioxidant defense system and are especially susceptible to oxidative stress. Resuscitation, mechanical ventilation, intermittent hypoxia and apneic episodes require frequently oxygen supplementation which leads to oxidative stress in preterm newborns. The consequences of oxidative damage are increased short and long-term morbidities, neurodevelopmental impairment and increased mortality. Oxidative stress biomarkers are determined in blood samples from preterm children during their stay in neonatal intensive care units especially for research purposes. However, there is a tendency towards reducing invasive and painful techniques in the NICU (Neonatal Intensive Care Unit) and avoiding excessive blood extractions procedures. In this paper, it has been described some studies that employed non-invasive samples to determine oxidative stress biomarkers form preterm infants in order to perform a close monitoring biomarker with a significant greater predictive value. Among these methods we describe a previously developed and validated high-performance liquid chromatography tandem mass spectrometry method that allow to accurately determine the most reliable biomarkers in biofluids, which are non-invasively and painlessly obtained.

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.

Mothers' Perceptions about Pain in Hospitalized Newborn Infants in Kenya

PURPOSE

Explore views of mothers about pain and pain treatment practices in hospitalized newborn infants.

DESIGN AND METHODS

A Qualitative descriptive study using photo-elicitation technique was conducted in a level I and a level II neonatal units in Kenya. Fifteen semi-structured interviews were conducted with mothers of hospitalized infants. The interviews were audio-recorded, transcribed verbatim and analysed using inductive content analysis approach.

RESULTS

Mothers described the experience of witnessing their infants undergo painful procedures as emotionally and psychologically traumatic. Participants felt helpless for not being able to protect their infants from pain a situation which was made worse by health care providers who appeared less concerned about pain relief during procedures. Mothers' views demonstrated a good understanding of pain-relief strategies; they identified strategies that health care providers should routinely use to relief pain in hospitalized infants. Furthermore, participants desired to be involved in comforting their infants during clinical procedures.

CONCLUSION

Repeated and untreated painful procedures continue to define the hospitalisation experience of newborn infants despite the presence of mothers who desire to be involved in comforting their infants during procedures.

PRACTICE IMPLICATION

Minimizing the burden of pain and using pain-relieving interventions could reduce parental stress and optimize parental role attainment following hospitalisation.

The Energy Costs of Prematurity and the Neonatal Intensive Care Unit (NICU) Experience

Premature neonates are in an energy deficient state due to (1) oxygen desaturation and hypoxia events, (2) painful and stressful stimuli, (3) illness, and (4) neurodevelopmental energy requirements. Failure to correct energy deficiency in premature infants may lead to adverse effects such as neurodevelopmental delay and negative long-term metabolic and cardiovascular outcomes. The effects of energy dysregulation and the challenges that clinicians in the Neonatal Intensive Care Unit (NICU) face in meeting the premature infant's metabolic demands are discussed. Specifically, the focus is on the effects of pain and stress on energy homeostasis. Energy deficiency is a complex problem and requires a multi-faceted solution to promote optimum development of premature infants.

The analgesic effect of non-pharmacological interventions to reduce procedural pain in preterm neonates

BACKGROUND

Painful procedures are unavoidable in the medical care of preterm babies. The unpleasant experience during the neonatal period may contribute to hyperalgesia and poor neurodevelopment outcome later. Seeking effective interventions to reduce pain are strongly indicated for these very small premature babies. The aim of this study is to investigate if instilling breast milk (BM) or dextrose water into oral cavity can reduce the procedural pain of heel stick for preterm babies.

METHODS

This is a prospective study; 20 premature neonates are enrolled. Each study case received heel stick 4 times. BM, 10% dextrose water (D10W), distilled water (placebo) and nothing (control group) were given one after the other in random order to the same patient before heel stick. Premature infant pain profile (PIPP) was used to assess the pain scores. The whole process consisted of 4 sections: a baseline period for 1 min, intervention period for 1 min, heel stick period for 20 s, and recovery period for 5 min. The primary outcome is to compare the PIPP scores in the 4 groups.

RESULTS

Totally 20 babies completed this study. Median gestational age was 32 weeks 2 days (26 weeks 4 days-35 weeks 6 days) and median birth body weight was 1596 g (766-2435 g). The median PIPP scores and interquartile range at each time period were listed in the context. There are significant differences between BM/control group at all time periods, between BM/placebo group at 30-60 s, 1-2 min, and 2-3 min, and between D10W/control group at 0-30 s, 30-60 s, 3-4 min, and 4-5 min. There are no significant differences between BM/D10W, D10W/placebo, and placebo/control groups at any time periods.

CONCLUSION

Giving something with taste such as BM or D10W is safe and effective in reducing the procedural pain of heel stick in preterm neonates; BM is the priority.

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.

Prevention and Management of Procedural Pain in the Neonate: An Update

The prevention of pain in neonates should be the goal of all pediatricians and health care professionals who work with neonates, not only because it is ethical but also because repeated painful exposures have the potential for deleterious consequences. Neonates at greatest risk of neurodevelopmental impairment as a result of preterm birth (ie, the smallest and sickest) are also those most likely to be exposed to the greatest number of painful stimuli in the NICU. Although there are major gaps in knowledge regarding the most effective way to prevent and relieve pain in neonates, proven and safe therapies are currently underused for routine minor, yet painful procedures. Therefore, every health care facility caring for neonates should implement (1) a pain-prevention program that includes strategies for minimizing the number of painful procedures performed and (2) a pain assessment and management plan that includes routine assessment of pain, pharmacologic and nonpharmacologic therapies for the prevention of pain associated with routine minor procedures, and measures for minimizing pain associated with surgery and other major procedures.

Oral sucrose for heel lance enhances adenosine triphosphate use in preterm neonates with respiratory distress

Objective:

To examine the effects of oral sucrose on procedural pain, and on biochemical markers of adenosine triphosphate utilization and oxidative stress in preterm neonates with mild to moderate respiratory distress.

Study design:

Preterm neonates with a clinically required heel lance that met study criteria (n = 49) were randomized into three groups: (1) control (n = 24), (2) heel lance treated with placebo and non-nutritive sucking (n = 15) and (3) heel lance treated with sucrose and non-nutritive sucking (n = 10). Plasma markers of adenosine triphosphate degradation (hypoxanthine, xanthine and uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured using the Premature Infant Pain Profile. Data were analyzed using repeated measures analysis of variance, chi-square and one-way analysis of variance.

Results:

We found that in preterm neonates who were intubated and/or were receiving ⩾30% FiO₂, a single dose of oral sucrose given before a heel lance significantly increased markers of adenosine triphosphate use.

Conclusion:

We found that oral sucrose enhanced adenosine triphosphate use in neonates who were intubated and/or were receiving ⩾30% FiO₂. Although oral sucrose decreased pain scores, our data suggest that it also increased energy use as evidenced by increased plasma markers of adenosine triphosphate utilization. These effects of sucrose, specifically the fructose component, on adenosine triphosphate metabolism warrant further investigation.

Sleep deprivation, pain and prematurity: a review study

The aim was to describe current reports in the scientific literature on sleep in the intensive care environment and sleep deprivation associated with painful experiences in premature infant. A systematic search was conducted for studies on sleep, pain, premature birth and care of the newborn. Web of Knowledge, MEDLINE, LILACS, Cochrane Library, PubMed, EMBASE, Scopus, VHL and SciELO databases were consulted. The association between sleep deprivation and pain generates effects that are observed in the brain and the behavioral and physiological activity of preterm infants. Polysomnography in intensive care units and pain management in neonates allow comparison with the first year of life and term infants. We have found few references and evidence that neonatal care programs can influence sleep development and reduce the negative impact of the environment. This evidence is discussed from the perspective of how hospital intervention can improve the development of premature infants.

Impact of repeated procedural pain-related stress in infants born very preterm

The majority of infants born very preterm (24-32 wk gestational age) now survive; however, long-term neurodevelopmental and behavioral problems remain a concern. As part of their neonatal care, very preterm infants undergo repeated painful procedures during a period of rapid brain development and programming of stress systems. Infants born this early have the nociceptive circuitry required to perceive pain, however, their sensory systems are functionally immature. An imbalance of excitatory vs. inhibitory processes leads to increased nociceptive signaling in the central nervous system. Specific cell populations in the central nervous system of preterm neonates are particularly vulnerable to excitoxicity, oxidative stress, and inflammation. Neonatal rat models have demonstrated that persistent or repeated pain increases apoptosis of neurons, and neonatal pain and stress lead to anxiety-like behaviors during adulthood. In humans, greater exposure to neonatal pain-related stress has been associated with altered brain microstructure and stress hormone levels, as well as with poorer cognitive, motor, and behavioral neurodevelopment in infants and children born very preterm. Therefore, it is important that pain-related stress in preterm neonates is accurately identified, appropriately managed, and that pain management strategies are evaluated for protective or adverse effects in the long term.

Invasive procedures in preterm children: brain and cognitive development at school age

BACKGROUND

Very preterm infants (born 24-32 weeks' gestation) undergo numerous invasive procedures during neonatal care. Repeated skin-breaking procedures in rodents cause neuronal cell death, and in human preterm neonates higher numbers of invasive procedures from birth to term-equivalent age are associated with abnormal brain development, even after controlling for other clinical risk factors. It is unknown whether higher numbers of invasive procedures are associated with long-term alterations in brain microstructure and cognitive outcome at school age in children born very preterm.

METHODS

Fifty children born very preterm underwent MRI and cognitive testing at median age 7.6 years (interquartile range, 7.5-7.7). T1- and T2-weighted images were assessed for the severity of brain injury. Magnetic resonance diffusion tensor sequences were used to measure fractional anisotropy (FA), an index of white matter (WM) maturation, from 7 anatomically defined WM regions. Child cognition was assessed using the Wechsler Intelligence Scale for Children-IV. Multivariate modeling was used to examine relationships between invasive procedures, brain microstructure, and cognition, adjusting for clinical confounders (eg, infection, ventilation, brain injury).

RESULTS

Greater numbers of invasive procedures were associated with lower FA values of the WM at age 7 years (P = .01). The interaction between the number of procedures and FA was associated with IQ (P = .02), such that greater numbers of invasive procedures and lower FA of the superior WM were related to lower IQ.

CONCLUSIONS

Invasive procedures during neonatal care contribute to long-term abnormalities in WM microstructure and lower IQ.

The effect of facilitated tucking position during endotracheal suctioning on physiological responses and coping with stress in premature infants: a randomized controlled crossover study

OBJECTIVE

Premature infants respond more intensively to pain compared with term infants. Facilitated tucking position as a non-pharmacological method of pain in infants has been suggested; however, its effect on acute procedural pain such as endotracheal suctioning remains to be studied. This study examined the effect of facilitated tucking position during suctioning on physiological responses and coping with stress in premature infants.

METHODS

This was a randomized controlled crossover study. Thirty-four premature infants received an order of either suctioning with intervention - suctioning without intervention, or suctioning without intervention - suctioning with intervention. Neonatal Infant Pain Scale (NIPS) was used to collect the data.

RESULTS

No statistical significant difference was seen between intervention and non-intervention cases in terms of the average time duration to reach the pain score to one or zero, and also, in the average of changes in oxygen saturation. However, changes in heart rate were less in intervention cases.

CONCLUSION

The effect of facilitated tucking position on coping with stress was not found in this study. This non-pharmacological strategy can be suggested because of its effect on reducing changes in heart rate during painful procedure. It is suggested to replicate the study with larger number of samples.

Relations between feeding intolerance and stress biomarkers in preterm infants

OBJECTIVES

Feeding intolerance (FI) in preterm infants is common but the etiology remains unclear. This study examined FI as a stress-related disease involving brain-gut interactions and tested the model of allostatic load and complications of prematurity. Specific aims were to describe demographic/medical variables and biomarker levels at each time and over time for the sample; describe/compare variables and biomarker levels at each time for infants with/without FI; and compare biomarker interquartile/interpercentile distributions between infants with/without FI.

METHODS

Preterm infants <32 weeks' gestation were recruited. The primary outcome was FI by day 7 defined as a feeding withheld, discontinued, or decreased because the infant was not tolerating enteral feedings. Allostatic load was operationalized using cortisol and 8-hydroxydeoxyguanosine (8-OHdG) from cord blood and from saliva and urine on days 1, 7, and 14. Descriptive statistics and comparative analyses were performed.

RESULTS

Seven of 31 infants enrolled met criteria for FI. Infants with FI had lower median urinary cortisol on day 1 (P = 0.007) and trended to have lower cortisol in the cord blood (P = 0.056). Interquartile distributions were significantly different between infants with/without FI for urinary cortisol on day 1 (P = 0.034) and trended for differences in 8-OHdG on day 14 (P = 0.087). Interpercentile distributions were significantly different in salivary cortisol on day 14 (P = 0.034) and trended for differences in 8-OHdG on day 1 (P = 0.079).

CONCLUSIONS

Results support further testing of the model in a larger sample; investigation of the cellular mechanisms associated with the stress and the free radical/antioxidant systems; and inclusion of prenatal factors.

Oral sucrose for heel lance increases adenosine triphosphate use and oxidative stress in preterm neonates

OBJECTIVE

To examine the effects of sucrose on pain and biochemical markers of adenosine triphosphate (ATP) degradation and oxidative stress in preterm neonates experiencing a clinically required heel lance.

STUDY DESIGN

Preterm neonates that met study criteria (n = 131) were randomized into 3 groups: (1) control; (2) heel lance treated with placebo and non-nutritive sucking; and (3) heel lance treated with sucrose and non-nutritive sucking. Plasma markers of ATP degradation (hypoxanthine, xanthine, and uric acid) and oxidative stress (allantoin) were measured before and after the heel lance. Pain was measured with the Premature Infant Pain Profile. Data were analyzed by the use of repeated-measures ANOVA and Spearman rho.

RESULTS

We found significant increases in plasma hypoxanthine and uric acid over time in neonates who received sucrose. We also found a significant negative correlation between pain scores and plasma allantoin concentration in a subgroup of neonates who received sucrose.

CONCLUSION

A single dose of oral sucrose, given before heel lance, significantly increased ATP use and oxidative stress in premature neonates. Because neonates are given multiple doses of sucrose per day, randomized trials are needed to examine the effects of repeated sucrose administration on ATP degradation, oxidative stress, and cell injury.