Changes in the term neonatal electroencephalogram with general anesthesia - a systematic review with narrative synthesis.

While effects of general anesthesia on neuronal activity in the human neonatal brain are incompletely understood, electroencephalography (EEG) provides some insight and may identify age-dependent differences. A systematic search (MEDLINE, Embase, PUBMED, Cochrane Library to November 2023) retrieved English language publications reporting EEG during general anesthesia for cardiac or non-cardiac surgery in term neonates (37 to 44 weeks post-menstrual age). Data were extracted and risk of bias (ROBINS-I Cochrane tool) and quality of evidence (GRADE checklist) assessed. From 1155 abstracts, nine publications (157 neonates; 55.7% male) fulfilled eligibility criteria. Data were limited and study quality was very low. The occurrence of discontinuity, a characteristic pattern of alternating higher and lower amplitude EEG segments, was reported with general anesthesia (94 of 119 neonates, six publications) and with hypothermia (23 of 23 neonates, two publications). Decreased power in the delta (0.5-4Hz) frequency range was also reported with increasing anesthetic dose (39 neonates; three publications). While evidence gaps were identified, both increasing sevoflurane concentration and decreasing temperature are associated with increasing discontinuity.

Age and sex Differences in Pediatric Neuropathic Pain and Complex Regional Pain Syndrome: A Scoping Review.

BACKGROUND: Age and sex differences may exist in the frequency (incidence, prevalence) or symptoms of neuropathic pain (NP) and complex regional pain syndrome (CRPS) due to biopsychosocial factors (e.g., neurodevelopment, physiological and hormonal changes, psychosocial differences) that evolve through childhood and adolescence.2 Age and sex differences may have implications for evaluating screening and diagnostic tools and treatment interventions. OBJECTIVE: To map the existing literature on pediatric NP and CRPS with respect to age and sex distributions, and age and sex differences in symptomology and frequency. METHODS: A scoping literature review was conducted. Databases were searched from inception to January 2023. Data were collected on study design, setting, demographics, and age and sex differences in frequency and symptoms. RESULTS: Eighty-seven studies were included. Distribution of participants with CRPS (n=37 studies) was predominantly early adolescence (10-14 years) and female sex, while NP (n=42 studies) was most commonly reported throughout adolescence (10-19 years) in both sexes. Forty-one studies examined age and sex differences in frequency; 6 studies reported higher frequency in adolescence. Very few studies (n=11) examined differences in symptomology. DISCUSSION: Large epidemiological studies are required to further understand age and sex differences in frequency of pediatric NP and CRPS. Age and sex differences must be considered when evaluating screening and diagnostic tools and treatment interventions to ensure relevance and validity to both sexes and across ages. Validated tools will improve understanding of age- and sex-dependent differences in symptoms, pathophysiology, and psychosocial impact of pediatric NP and CRPS.

Sensitivity and Specificity of a Neuropathic Screening Tool (Self-Report Leeds Assessment of Neuropathic Symptoms and Signs, S-LANSS) in Adolescents With Moderate-Severe Chronic Pain.

Neuropathic screening tools improve recognition of neuropathic pain in adults. Although utilized in pediatric populations, the sensitivity, specificity and methodology of screening tool delivery have not been compared in children. We evaluated the Self-Report Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) in adolescents (10-18 years) referred to a tertiary pediatric pain clinic. History and examination by specialist clinicians and multidisciplinary assessment informed classification of the primary pain type. In a prospective cohort, scores were obtained at interview (S-LANSS interview; n = 161, 70% female), and following substitution of self-reported signs with examination findings in the primary pain region (Leeds Assessment of Neuropathic Symptoms and Signs, LANSS examination). Secondly, we retrospectively retrieved questionnaires self-completed by adolescents at their initial clinic appointment (S-LANSS self-completed; n = 456, 73% female). Thirdly, we explored relationships between patient-reported outcomes and S-LANSS scores. S-LANSS interview scores varied with pain classification, and S-LANSS self-completed scores were similarly highest with neuropathic pain (median [interquartile range]: 18 [11, 21]) and complex regional pain syndrome (21 [14, 24]), variable with musculoskeletal pain (13 [7, 19]) and lowest with visceral pain (6.5 [2, 11.5]) and headache (8.5 [4, 14]). As in adults, the cutpoint score of 12/24 was optimal. Sensitivity was highest with inclusion of examination findings and lowest with self-completion (LANSS examination vs S-LANSS interview vs S-LANSS self-completed: 86.3% vs 80.8% vs 74.7%), but specificity was relatively low (37.8% vs 36.7% vs 48%). High S-LANSS scores in non-neuropathic groups were associated with female sex and high pain catastrophizing. The S-LANSS is a sensitive screening tool for pain with neuropathic features in adolescents, but needs to be interpreted in the context of clinical evaluation (clinicaltrials.gov NCT03312881). PERSPECTIVE: This article reports high sensitivity of the S-LANSS screening tool for identifying pain with neuropathic features in adolescents with moderate-severe chronic pain. However, as sensitivity is lower than in adult populations, further interdisciplinary evaluation is necessary to inform diagnosis and management.

Pharmacokinetic pharmacodynamic modeling of analgesics and sedatives in children.

Pharmacokinetic pharmacodynamic modeling is an important tool which uses statistical methodology to provide a better understanding of the relationship between concentration and effect of drugs such as analgesics and sedatives. Pharmacokinetic pharmacodynamic models also describe between-subject variability that allows identification of subgroups and dose adjustment for optimal pain management in individual patients. This approach is particularly useful in the pediatric population, where most drugs have received limited evaluation and dosing is extrapolated from adult practice. In children, the covariates of weight and age are used to describe size- and maturation-related changes in pharmacokinetics. It is important to consider both size and maturation in order to develop an accurate model and determine the optimal dose for different age groups. An adequate assessment of analgesic and sedative effect using pain scales or brain activity measures is essential to build reliable pharmacokinetic pharmacodynamic models. This is often challenging in children due to the multidimensional nature of pain and the limited sensitivity and specificity of some measurement tools. This review provides a summary of the pharmacokinetic and pharmacodynamic methodology used to describe the dose-concentration-effect relationship of analgesics and sedation in children, with a focus on the different pharmacodynamic endpoints and the challenges of pharmacodynamic modeling.

Investigating genotype-phenotype relationship of extreme neuropathic pain disorders in a UK national cohort.

The aims of our study were to use whole genome sequencing in a cross-sectional cohort of patients to identify new variants in genes implicated in neuropathic pain, to determine the prevalence of known pathogenic variants and to understand the relationship between pathogenic variants and clinical presentation. Patients with extreme neuropathic pain phenotypes (both sensory loss and gain) were recruited from secondary care clinics in the UK and underwent whole genome sequencing as part of the National Institute for Health and Care Research Bioresource Rare Diseases project. A multidisciplinary team assessed the pathogenicity of rare variants in genes previously known to cause neuropathic pain disorders and exploratory analysis of research candidate genes was completed. Association testing for genes carrying rare variants was completed using the gene-wise approach of the combined burden and variance-component test SKAT-O. Patch clamp analysis was performed on transfected HEK293T cells for research candidate variants of genes encoding ion channels. The results include the following: (i) Medically actionable variants were found in 12% of study participants (205 recruited), including known pathogenic variants: SCN9A(ENST00000409672.1): c.2544T>C, p.Ile848Thr that causes inherited erythromelalgia, and SPTLC1(ENST00000262554.2):c.340T>G, p.Cys133Tr variant that causes hereditary sensory neuropathy type-1. (ii) Clinically relevant variants were most common in voltage-gated sodium channels (Nav). (iii) SCN9A(ENST00000409672.1):c.554G>A, pArg185His variant was more common in non-freezing cold injury participants than controls and causes a gain of function of NaV1.7 after cooling (the environmental trigger for non-freezing cold injury). (iv) Rare variant association testing showed a significant difference in distribution for genes NGF, KIF1A, SCN8A, TRPM8, KIF1A, TRPA1 and the regulatory regions of genes SCN11A, FLVCR1, KIF1A and SCN9A between European participants with neuropathic pain and controls. (v) The TRPA1(ENST00000262209.4):c.515C>T, p.Ala172Val variant identified in participants with episodic somatic pain disorder demonstrated gain-of-channel function to agonist stimulation. Whole genome sequencing identified clinically relevant variants in over 10% of participants with extreme neuropathic pain phenotypes. The majority of these variants were found in ion channels. Combining genetic analysis with functional validation can lead to a better understanding as to how rare variants in ion channels lead to sensory neuron hyper-excitability, and how cold, as an environmental trigger, interacts with the gain-of-function NaV1.7 p.Arg185His variant. Our findings highlight the role of ion channel variants in the pathogenesis of extreme neuropathic pain disorders, likely mediated through changes in sensory neuron excitability and interaction with environmental triggers.

Developmental mechanisms of CPSP: Clinical observations and translational laboratory evaluations.

Understanding mechanisms that underly the transition from acute to chronic pain and identifying potential targets for preventing or minimizing this progression have specific relevance for chronic postsurgical pain (CPSP). Though it is clear that multiple psychosocial, family, and environmental factors may influence CPSP, this review will focus on parallels between clinical observations and translational laboratory studies investigating the acute and long-term effects of surgical injury on nociceptive pathways. This includes data related to alterations in sensitivity at different points along nociceptive pathways from the periphery to the brain; age- and sex-dependent mechanisms underlying the transition from acute to persistent pain; potential targets for preventive interventions; and the impact of prior surgical injury. Ongoing preclinical studies evaluating age- and sex-dependent mechanisms will also inform comparative efficacy and preclinical safety assessments of potential preventive pharmacological interventions aimed at reducing the risk of CPSP. In future clinical studies, more detailed and longitudinal peri-operative phenotyping with patient- and parent-reported chronic pain core outcomes, alongside more specialized evaluations of somatosensory function, modulation, and circuitry, may enhance understanding of individual variability in postsurgical pain trajectories and improve recognition and management of CPSP.

La compréhension des mécanismes qui sous-tendent la transition de la douleur aiguë à la douleur chronique et la détermination de cibles potentielles pour prévenir ou minimiser cette progression ont une pertinence particulière pour la douleur chronique. La détermination de cibles potentielles pour prévenir ou minimiser cette progression sont particulièrement pertinentes pour la douleur postopératoire chronique (DPOC). Bien qu'il soit clair que de multiples facteurs psychosociaux, familiaux et environnementaux peuvent influencer la DPOC, cette revue se concentrera sur les parallèles entre les observations cliniques et les études translationnelles en laboratoire qui étudient les effets aigus et à long terme d'une blessure chirurgicale sur les voies nociceptives. Cela inclut les données relatives aux altérations de la sensibilité à différents points le long des nociceptives, de la périphérie au cerveau; les mécanismes dépendant de l'âge et du sexe qui sous-tendent la transition de la douleur aiguë à la douleur persistante; les cibles potentielles des interventions préventives et l'impact d'une blessure chirurgicale antérieure. Les études précliniques en cours, qui évaluent les mécanismes dépendant de l'âge et du sexe, permettront également d'évaluer l'efficacité comparative et la sécurité préclinique d'éventuelles interventions pharmacologiques préventives potentielles visant à réduire le risque de DPOC. Dans les futures études cliniques, un phénotypage péri-opératoire plus détaillé et longitudinal avec des résultats rapportés par les patients - et les parents- ainsi que des évaluations plus spécialisées de la fonction de la modulation et des circuits somatosensoriels, pourrait améliorer la compréhension de la variabilité individuelle des trajectoires de la douleur postopératoire et améliorer la reconnaissance et la gestion de la DPOC.

Amygdalar Functional Connectivity Differences Associated With Reduced Pain Intensity in Pediatric Peripheral Neuropathic Pain.

Background: There is evidence of altered corticolimbic circuitry in adults with chronic pain, but relatively little is known of functional brain mechanisms in adolescents with neuropathic pain (NeuP). Pediatric NeuP is etiologically and phenotypically different from NeuP in adults, highlighting the need for pediatric-focused research. The amygdala is a key limbic region with important roles in the emotional-affective dimension of pain and in pain modulation. Objective: To investigate amygdalar resting state functional connectivity (rsFC) in adolescents with NeuP. Methods: This cross-sectional observational cohort study compared resting state functional MRI scans in adolescents aged 11-18 years with clinical features of chronic peripheral NeuP (n = 17), recruited from a tertiary clinic, relative to healthy adolescents (n = 17). We performed seed-to-voxel whole-brain rsFC analysis of the bilateral amygdalae. Next, we performed post hoc exploratory correlations with clinical variables to further explain rsFC differences. Results: Adolescents with NeuP had stronger negative rsFC between right amygdala and right dorsolateral prefrontal cortex (dlPFC) and stronger positive rsFC between right amygdala and left angular gyrus (AG), compared to controls (P FDR <0.025). Furthermore, lower pain intensity correlated with stronger negative amygdala-dlPFC rsFC in males (r = 0.67, P = 0.034, n = 10), and with stronger positive amygdala-AG rsFC in females (r = -0.90, P = 0.006, n = 7). These amygdalar rsFC differences may thus be pain inhibitory. Conclusions: Consistent with the considerable affective and cognitive factors reported in a larger cohort, there are rsFC differences in limbic pain modulatory circuits in adolescents with NeuP. Findings also highlight the need for assessing sex-dependent brain mechanisms in future studies, where possible.

Perioperative critical events and morbidity associated with anesthesia in early life: Subgroup analysis of United Kingdom participation in the NEonate and Children audiT of Anaesthesia pRactice IN Europe (NECTARINE) prospective multicenter observational study.

BACKGROUND: The NEonate and Children audiT of Anaesthesia pRactice IN Europe (NECTARINE) prospective observational study reported critical events requiring intervention during 35.2% of 6542 anesthetic episodes in 5609 infants up to 60 weeks postmenstrual age. The United Kingdom (UK) was one of 31 participating countries. METHODS: Subgroup analysis of UK NECTARINE cases (12.8% of cohort) to identify perioperative critical events that triggered medical interventions. Secondary aims were to describe UK practice, identify factors more commonly associated with critical events, and compare 30-day morbidity and mortality between participating UK and nonUK centers. RESULTS: Seventeen UK centers recruited 722 patients (68.7% male, 36.1% born preterm, and 48.1% congenital anomalies) undergoing anesthesia for 876 surgical or diagnostic procedures at 25-60 weeks postmenstrual age. Repeat anesthesia/surgery was common: 17.6% patients prior to and 14.4% during the recruitment period. Perioperative critical events triggered interventions in 300/876 (34.3%) cases. Cardiovascular instability (16.9% of cases) and/or reduced oxygenation (11.4%) were more common in younger patients and those with co-morbidities or requiring preoperative intensive support. A higher proportion of UK than nonUK cases were graded as ASA-Physical Status scores >2 or requiring urgent or emergency procedures, and 39% required postoperative intensive care. Thirty-day morbidity (complications in 17.2%) and mortality (8/715, 1.1%) did not differ from nonUK participants. CONCLUSIONS: Perioperative critical events and co-morbidities are common in neonates and young infants. Thirty-day morbidity and mortality data did not demonstrate national differences in outcome. Identifying factors associated with increased risk informs preoperative assessment, resource allocation, and discussions between clinicians and families.

Evaluation of neurotoxicity and long-term function and behavior following intrathecal 1 % 2-chloroprocaine in juvenile rats.

Spinally-administered local anesthetics provide effective perioperative anesthesia and/or analgesia for children of all ages. New preparations and drugs require preclinical safety testing in developmental models. We evaluated age-dependent efficacy and safety following 1 % preservative-free 2-chloroprocaine (2-CP) in juvenile Sprague-Dawley rats. Percutaneous lumbar intrathecal 2-CP was administered at postnatal day (P)7, 14 or 21. Mechanical withdrawal threshold pre- and post-injection evaluated the degree and duration of sensory block, compared to intrathecal saline and naive controls. Tissue analyses one- or seven-days following injection included histopathology of spinal cord, cauda equina and brain sections, and quantification of neuronal apoptosis and glial reactivity in lumbar spinal cord. Following intrathecal 2-CP or saline at P7, outcomes assessed between P30 and P72 included: spinal reflex sensitivity (hindlimb thermal latency, mechanical threshold); social approach (novel rat versus object); locomotor activity and anxiety (open field with brightly-lit center); exploratory behavior (rearings, holepoking); sensorimotor gating (acoustic startle, prepulse inhibition); and learning (Morris Water Maze). Maximum tolerated doses of intrathecal 2-CP varied with age (1.0 µL/g at P7, 0.75 µL/g at P14, 0.5 µL/g at P21) and produced motor and sensory block for 10-15 min. Tissue analyses found no significant differences across intrathecal 2-CP, saline or naïve groups. Adult behavioral measures showed expected sex-dependent differences, that did not differ between 2-CP and saline groups. Single maximum tolerated in vivo doses of intrathecal 2-CP produced reversible spinal anesthesia in juvenile rodents without detectable evidence of developmental neurotoxicity. Current results cannot be extrapolated to repeated dosing or prolonged infusion.

Intravenous opioids for chemotherapy-induced severe mucositis pain in children: Systematic review and single-center case series of management with patient- or nurse-controlled analgesia (PCA/NCA).

BACKGROUND: Chemotherapy-induced oral mucositis can result in severe pain. Intravenous (IV) opioids are recommended, but management protocols vary. We systematically reviewed studies reporting IV opioid use for pain related to chemotherapy-induced severe oral mucositis in children and conducted a large single-center case series. METHODS: Ovid MEDLINE, PubMed, and Cochrane databases were searched for studies reporting IV opioid duration and/or dose requirements for severe mucositis. Secondly, our pain service database was interrogated to describe episodes of opioid administration by patient- or nurse-controlled analgesia (PCA/NCA) for children with mucositis and cancer treatment-related pain. RESULTS: Seventeen studies (six randomized trials, two prospective observational, three retrospective cohort, six retrospective case series) included IV opioid in 618 patients (age 0.3-22.3 years), but reported parameters varied. Mucositis severity and chemotherapy indication influenced IV opioid requirements, with duration ranging from 3 to 68 days and variable dose trajectories (hourly morphine or equivalent 0-97 mcg/kg/h). Our 7-year series included PCA/NCA for 364 episodes of severe mucositis (302 patients; age 0.12-17.2 years). Duration ranged from 1 to 107 days and dose requirements in the first 3 days from 1 to 110 mcg/kg/h morphine. Longer PCA/NCA duration was associated with: higher initial morphine requirements (ρ = 0.46 [95% CI 0.35, 0.57]); subsequent increased pain and need for ketamine co-analgesia (118/364 episodes with opioid/ketamine 13.9 [9.8-22.2] days vs opioid alone 6.0 [3.9-10.8] days; median [IQR]); but not with age or sex. CONCLUSIONS: Management of severe mucositis pain can require prolonged IV opioid therapy. Individual and treatment-related variability in analgesic requirements highlight the need for regular review, titration, and management by specialist services.

Morbidity and mortality after anaesthesia in early life: results of the European prospective multicentre observational study, neonate and children audit of anaesthesia practice in Europe (NECTARINE).

BACKGROUND: Neonates and infants requiring anaesthesia are at risk of physiological instability and complications, but triggers for peri-anaesthetic interventions and associations with subsequent outcome are unknown. METHODS: This prospective, observational study recruited patients up to 60 weeks' postmenstrual age undergoing anaesthesia for surgical or diagnostic procedures from 165 centres in 31 European countries between March 2016 and January 2017. The primary aim was to identify thresholds of pre-determined physiological variables that triggered a medical intervention. The secondary aims were to evaluate morbidities, mortality at 30 and 90 days, or both, and associations with critical events. RESULTS: Infants (n=5609) born at mean (standard deviation [sd]) 36.2 (4.4) weeks postmenstrual age (35.7% preterm) underwent 6542 procedures within 63 (48) days of birth. Critical event(s) requiring intervention occurred in 35.2% of cases, mainly hypotension (>30% decrease in blood pressure) or reduced oxygenation (SpO2 <85%). Postmenstrual age influenced the incidence and thresholds for intervention. Risk of critical events was increased by prior neonatal medical conditions, congenital anomalies, or both (relative risk [RR]=1.16; 95% confidence interval [CI], 1.04-1.28) and in those requiring preoperative intensive support (RR=1.27; 95% CI, 1.15-1.41). Additional complications occurred in 16.3% of patients by 30 days, and overall 90-day mortality was 3.2% (95% CI, 2.7-3.7%). Co-occurrence of intraoperative hypotension, hypoxaemia, and anaemia was associated with increased risk of morbidity (RR=3.56; 95% CI, 1.64-7.71) and mortality (RR=19.80; 95% CI, 5.87-66.7). CONCLUSIONS: Variability in physiological thresholds that triggered an intervention, and the impact of poor tissue oxygenation on patient's outcome, highlight the need for more standardised perioperative management guidelines for neonates and infants. CLINICAL TRIAL REGISTRATION: NCT02350348.

Phenotyping peripheral neuropathic pain in male and female adolescents: pain descriptors, somatosensory profiles, conditioned pain modulation, and child-parent reported disability.

ABSTRACT: Neuropathic pain (NeuP) can be difficult to diagnose and manage in children. Data regarding prevalence and sex-dependent differences are limited, and more detailed phenotyping is needed. This observational cohort study recruited adolescents (10-17 years) with NeuP or complex regional pain syndrome (CRPS). After pain history and NeuP questionnaires, quantitative sensory testing was performed. Individual z-score plots were calculated with body-region control measures and matched to mechanism-related sensory profiles (sensory loss, thermal hyperalgesia, and mechanical hyperalgesia). Conditioned pain modulation was assessed with pressure pain threshold and a contralateral cold conditioning stimulus, and meaningful conditioned pain modulation defined as twice the standard error of measurement. Patients and parents completed validated questionnaires for child quality of life (QoL), pain catastrophizing, and self-reported anxiety/depression. Males (n = 23) and females (n = 43) with NeuP (n = 52) or CRPS (n = 14) reported moderate-severe pain with neuropathic sensory descriptors. Mixed patterns of sensory gain/loss at pain sites were not sex-dependent. Thermal hyperalgesia was common in both NeuP and CRPS, whereas sensory loss occurred only with NeuP and in a smaller proportion than adult cohorts. Conditioned pain modulation was inhibitory in 54%, facilitatory in 14%, and nonresponders had variable cold conditioning sensitivity. Males and females reported marked impairment of QoL, increased emotional distress, and pain catastrophising. Child-parent QoL scores correlated, but catastrophizing scores were discordant when parents or adolescents reported higher anxiety/depression. NeuP in adolescents is associated with significant pain, physical impairment, and psychosocial impairment. Quantifying alterations in somatosensory profiles, descending modulation, child and parent psychological function will inform individualized therapy and stratification for future clinical trials.

Neuropathic pain in children: Steps towards improved recognition and management.

Neuropathic pain in children can be severe and persistent, difficult to recognise and manage, and associated with significant pain-related disability. Recognition based on clinical history and sensory descriptors is challenging in young children, and screening tools require further validation at older ages. Confirmatory tests can identify the disease or lesion of the somatosensory nervous system resulting in neuropathic pain, but feasibility and interpretation may be influenced by age- and sex-dependent changes throughout development. Quantitative sensory testing identifies specific mechanism-related sensory profiles; brain imaging is a potential biomarker of alterations in central processing and modulation of both sensory and affective components of pain; and genetic analysis can reveal known and new causes of neuropathic pain. Alongside existing patient- and parent-reported outcome measures, somatosensory system research methodologies and validation of mechanism-based standardised end-points may inform individualised therapy and stratification for clinical trials that will improve evidence-based management of neuropathic pain in children.

A systematic review of outcomes reported inpediatric perioperative research: A report from the Pediatric Perioperative Outcomes Group.

The Pediatric Perioperative Outcomes Group (PPOG) is an international collaborative of clinical investigators and clinicians within the subspecialty of pediatric anesthesiology and perioperative care which aims to use COMET (Core Outcomes Measures in Effectiveness Trials) methodology to develop core outcome setsfor infants, children and young people that are tailored to the priorities of the pediatric surgical population.Focusing on four age-dependent patient subpopulations determined a priori for core outcome set development: i) neonates and former preterm infants (up to 60 weeks postmenstrual age); ii) infants (>60 weeks postmenstrual age - <1 year); iii) toddlers and school age children (>1-<13 years); and iv) adolescents (>13-<18 years), we conducted a systematic review of outcomes reported in perioperative studies that include participants within age-dependent pediatric subpopulations. Our review of pediatric perioperative controlled trials published from 2008 to 2018 identified 724 articles reporting 3192 outcome measures. The proportion of published trials and the most frequently reported outcomes varied across pre-determined age groups. Outcomes related to patient comfort, particularly pain and analgesic requirement, were the most frequent domain for infants, children and adolescents. Clinical indicators, particularly cardiorespiratory or medication-related adverse events, were the most common outcomes for neonates and infants < 60 weeks and were the second most frequent domain at all other ages. Neonates and infants <60 weeks of age were significantly under-represented in perioperative trials. Patient-centered outcomes, heath care utilization, and bleeding/transfusion related outcomes were less often reported. In most studies, outcomes were measured in the immediate perioperative period, with the duration often restricted to the post-anesthesia care unit or the first 24 postoperative hours. The outcomes identified with this systematic review will be combined with patient centered outcomes identified through a subsequent stakeholder engagement study to arrive at a core outcome set for each age-specific group.

The feasibility and acceptability of research magnetic resonance imaging in adolescents with moderate-severe neuropathic pain.

INTRODUCTION: Multimodal characterisation with questionnaires, Quantitative Sensory Testing (QST), and neuroimaging will improve understanding of neuropathic pain (NeuP) in adolescents. Magnetic resonance imaging (MRI) data in adolescents with NeuP are limited, and the perceived practical or ethical burden of scanning may represent a barrier to research. OBJECTIVE: To determine the feasibility of MRI scanning in adolescents with moderate-severe NeuP, with respect to consent rate, postscan acceptability, and data quality. METHODS: This prospective cohort study evaluating questionnaires and QST recruited adolescents aged 10 to 18 years with clinically diagnosed NeuP from a tertiary clinic. Eligible adolescents aged 11 years and older could additionally agree/decline an MRI scan. After the scan, families rated discomfort, perceived risk, and acceptability of current and future MRI scans (0-10 numerical rating scales). Head motion during scanning was compared with healthy controls to assess data quality. RESULTS: Thirty-four families agreed to MRI (72% recruitment), and 21 adolescents with moderate-severe pain (average last week 6.7 ± 1.7; mean ± SD) and with neuropathic QST profiles were scanned. Three adolescents reported positional or noise-related discomfort during scanning. Perceived risk was low, and acceptability of the current scan was high for parents (range [median]: 7 to 10/10 [10]) and adolescents (8-10/10 [10]). Willingness to undergo a future research scan was high for parents (7-10/10 [10]) and adolescents (5-10/10 [10]) and did not differ from future scans for clinical purposes. Mean head motion during resting state functional MRI did not differ from control adolescents. CONCLUSION: Research MRI is feasible and acceptable for many adolescents with moderate-severe NeuP.

Pediatric perioperative outcomes: Protocol for a systematic literature review and identification of a core outcome set for infants, children, and young people requiring anesthesia and surgery.

Clinical outcomes are measurable changes in health, function, or quality of life that are important for evaluating the quality of care and comparing the efficacy of interventions. However, clinical outcomes and related measurement tools need to be well-defined, relevant, and valid. In adults, Core Outcome Measures in Effectiveness Trials (COMET) methodology has been used to develop core outcome sets for perioperative care. Systematic literature reviews identified standardized endpoints (StEP) and valid measurement tools, and consensus across a broader range of relevant stakeholders was achieved via a Delphi process to establish Core Outcome Measures in Perioperative and Anaesthetic Care (COMPAC). Core outcome sets for pediatric perioperative care cannot be directly extrapolated from adult data. The type and weighting of endpoints within particular domains can be influenced by age-dependent differences in the indications for and/or nature of surgery and medical comorbidities, and the validity and utility of many measurement tools vary significantly with developmental stage and age. The involvement of parents/carers is essential as they frequently act as surrogate responders for preverbal and developmentally delayed children, parental response may influence child outcome, and parental and/or child ranking of outcomes may differ from those of health professionals. Here, we describe the formation of the international Pediatric Perioperative Outcomes Group, which aims to identify and create validated, broadly applicable, patient-centered outcome measures for infants, children, and young people. Methodologies parallel that of the StEP and COMPAC projects, and systematic literature searches have been performed within agreed age-dependent subpopulations to identify reported outcomes and measurement tools. This represents the first steps for developing core outcome sets for pediatric perioperative care.

Long-term effects of neonatal pain.

Pain experienced during neonatal intensive care management can influence neurodevelopmental outcome and the somatosensory and/or emotional components of pain response in later life. Alterations in biological factors (e.g. peripheral and central somatosensory function and modulation, brain structure and connectivity) and psychosocial factors (e.g. gender, coping style, mood, parental response) that influence pain have been identified in children and young adults born very preterm or extremely preterm. Earlier gestational age at birth and cumulative pain exposure from tissue-breaking procedures and/or neonatal surgery influence the degree of change. In neonatal rodents, repeated needle insertion or hindpaw incision identify developmentally-regulated and activity-dependent long term alterations in nociceptive processing, and the efficacy of novel or current analgesic interventions can be compared. As prior neonatal experience and sex may influence current pain experience or the risk of persistent pain, these factors should be considered within the biopsychosocial assessment and formulation of pain in later life.

Priming of Adult Incision Response by Early-Life Injury: Neonatal Microglial Inhibition Has Persistent But Sexually Dimorphic Effects in Adult Rats.

Neonatal hindpaw incision primes developing spinal nociceptive circuitry, resulting in enhanced hyperalgesia following reinjury in adulthood. Spinal microglia contribute to this persistent effect, and microglial inhibition at the time of adult reincision blocks the enhanced hyperalgesia. Here, we pharmacologically inhibited microglial function with systemic minocycline or intrathecal SB203580 at the time of neonatal incision and evaluated sex-dependent differences following adult reincision. Incision in adult male and female rats induced equivalent hyperalgesia and spinal dorsal horn expression of genes associated with microglial proliferation (Emr1) and transformation to a reactive phenotype (Irf8). In control adults with prior neonatal incision, the enhanced degree and duration of incision-induced hyperalgesia and spinal microglial responses to reincision were equivalent in males and females. However, microglial inhibition at the time of the neonatal incision revealed sex-dependent effects: the persistent mechanical and thermal hyperalgesia following reincision in adulthood was prevented in males but unaffected in females. Similarly, reincision induced Emr1 and Irf8 gene expression was downregulated in males, but not in females, following neonatal incision with minocycline. To evaluate the distribution of reincision hyperalgesia, prior neonatal incision was performed at different body sites. Hyperalgesia was maximal when the same paw was reincised, and was increased following prior incision at ipsilateral, but not contralateral, sites, supporting a segmentally restricted spinal mechanism. These data highlight the contribution of spinal microglial mechanisms to persistent effects of early-life injury in males, and sex-dependent differences in the ability of microglial inhibition to prevent the transition to a persistent pain state span developmental stages.SIGNIFICANCE STATEMENT Following the same surgery, some patients develop persistent pain. Contributory mechanisms are not fully understood, but early-life experience and sex/gender may influence the transition to chronic pain. Surgery and painful procedural interventions in vulnerable preterm neonates are associated with long-term alterations in somatosensory function and pain that differ in males and females. Surgical injury in neonatal rodents primes the developing nociceptive system and enhances reinjury response in adulthood. Neuroimmune interactions are critical mediators of persistent pain, but sex-dependent differences in spinal neuroglial signaling influence the efficacy of microglial inhibitors following adult injury. Neonatal microglial inhibition has beneficial long-term effects on reinjury response in adult males only, emphasizing the importance of evaluating sex-dependent differences at all ages in preclinical studies.