Highlighting extended-spectrum beta-lactamase-producing Klebsiella pneumoniae outbreak by routine genomic typing

Whole genome sequencing has become the gold standard for any microbiological investigations. Taking the opportunity to doing it prospectively and routinely allowed to detect undeclared outbreaks. Thanks to that, we investigated and ended a rare epidemic extended-spectrum beta-lactamase-producing Klebsiella pneumoniae ST584 strain on two intensive care units over a 4-month period.

Comprehensive pediatric reference intervals for 79 hematology markers in the CALIPER cohort of healthy children and adolescents using the Mindray BC-6800Plus system

BACKGROUND

Hematological parameters vary significantly throughout growth and development due to physiological processes such as fetal-to-adult erythropoiesis and puberty. Pediatric age- and sex-specific reference intervals (RIs) are thus essential for appropriate clinical decision-making. The current study aimed to establish RIs for both common and novel hematology parameters on the Mindray BC-6800Plus system.

METHODS

Six hundred and eighty-seven healthy children and adolescents (30 days to 18 years) were enrolled. Participants were recruited as part of the Canadian Laboratory Initiative on Pediatric Reference Intervals Program upon informed consent or identified from apparently healthy outpatient clinics. Whole blood was collected and assayed for 79 hematology parameters on the BC-6800Plus system (Mindray). Age- and sex-specific RIs were established as per Clinical and Laboratory Standards Institute EP28-A3c guidelines.

RESULTS

Dynamic reference value distributions were observed for several hematology parameters, including erythrocytes, leukocytes, platelets, reticulocytes, and research-use-only markers. Age partitioning was required for 52 parameters, demonstrating changes in infancy and puberty. Sex partitioning was required for 11 erythrocyte parameters (i.e., red blood cell (RBC), hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin concentration, RBC distribution width coefficient of variation, hemoglobin distribution width, macrocyte count, macrocyte percentage, RBC (optical), and reticulocyte production index). Few parameters had undetectable levels in our healthy cohort (i.e., nucleated RBC count and immature granulocyte count).

CONCLUSIONS

The current study completed hematological profiling for 79 parameters on the BC-6800Plus system in a healthy cohort of Canadian children and adolescents. These data emphasize the complex biological patterns of hematology parameters in childhood, particularly at the onset of puberty, and support the need for age- and sex-specific RIs for clinical interpretation.

A192 EFFICACY OF USTEKINUMAB IN SMALL BOWEL STRICTURES OF FIBROSTENOTIC CROHN'S DISEASE AS ASSESSED BY INTESTINAL ULTRASOUND

Background

Small bowel Crohn’s disease (CD) strictures can lead to debilitating obstructive symptoms and the deterioration of quality of life. Imaging modalities such as intestinal ultrasound (IUS) are invaluable in the diagnosis of strictures. The use of IUS in CD is rapidly growing, is cost-effective, easily repeatable, and similar in accuracy to magnetic resonance enterography. Evidence for medical management of fibrostenotic CD has been limited to anti-tumor necrosis factor biologics. Studies on the efficacy of other biologic therapies for strictures such as ustekinumab, a p40/interleukin 12 and 23 inhibitor, are lacking.

Purpose

The objective of this study was to evaluate the efficacy of ustekinumab in the treatment of small bowel strictures on IUS.

Method

This retrospective cohort study evaluated the IUS changes of terminal ileal (TI) CD strictures at baseline and 12 months following ustekinumab initiation from 2016 to 2020 at a single tertiary care center. Strictures identified were defined as 1) increased bowel wall thickness (BWT) > 3mm, 2) narrowed luminal apposition, and 3) presence of pre-stenotic dilation (PSD) or the inability to pass the colonoscope through the narrowed area. Changes in sonographic parameters (BWT, luminal size, PSD, length, hyperemia, inflammatory fat, dysfunctional peristalsis) were recorded at baseline prior to initiation of ustekinumab and compared 12 months after treatment. Differences from baseline to 12 months were paired within-person and statistical analysis was performed using paired T-tests for continuous variables and McNemar’s test for categorical variables.

Result(s)

Of the 18 patients identified, 55% (n = 10) were male, median age was 49 years (Q1-Q3: 33-63 years) at initial scan, with median CD duration of 10 years (Q1-Q3: 8-20 years). The majority of TI strictures were surgically naïve (67%, n = 12). Between pre- and 12-month post ustekinumab therapy scans, there was significant improvement in BWT [8.2 mm vs 7.2 mm, p = 0.048], however there was no significant difference in the presence of peri-enteric inflammatory fat (p = 0.10), mean stricture length (17.7 vs 21.7 cm, p = 0.18), and mean stricture lumen diameter (3.3 mm vs 2.7 mm, p = 0.44) (Table 1). There was also no significant difference in the presence of stricture-associated peri-enteric fat (89% vs 67%, p = 0.10), stricture-associated hyperemia (83% vs 89%, p = 0.65) or dysfunctional peristalsis (50% vs 61%, p = 0.41) (Table 1).

Image

Conclusion(s)

Our study is the first to report the efficacy of ustekinumab in small bowel CD strictures using IUS at baseline and 12 months. This study shows that although ustekinumab leads to improvement in overall sonographic appearance of bowel thickness, it does not improve luminal narrowing nor PSD, two hallmark criteria of fibrostenosis. More extensive studies with larger sample sizes evaluating ustekinumab, or combination therapies, are required to identify their role in stricturing CD.

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Disclosure of Interest

None Declared

Pediatric reference interval verification for 17 specialized immunoassays and cancer markers on the Abbott Alinity i system in the CALIPER cohort of healthy children and adolescents

OBJECTIVES

Clinical laboratory investigation of autoimmune, metabolic, and oncologic disorders in children and adolescents relies on appropriateness of reference intervals (RIs). The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) previously established comprehensive pediatric RIs for specialized immunoassays on the Abbott ARCHITECT system. Herein, we aim to verify performance on new Alinity i assays by evaluating sera collected from healthy children as per Clinical and Laboratory Standards Institute (CLSI) EP-28A3C guidelines.

METHODS

Precision, linearity, and method comparison experiments were completed for 17 specialized Alinity immunoassays, including cancer antigens, autoimmune peptides, and hormones. Sera collected from healthy children and adolescents (birth-18 years, n=100) were evaluated. CLSI-based verification was completed using previously established CALIPER RIs for ARCHITECT assays as the reference.

RESULTS

Of 17 specialized immunoassays assays, only anti-cyclic citrullinated peptides (anti-CCP) did not meet acceptable verification criterion (i.e., ≥90% of results within ARCHITECT reference CI). Anti-thyroglobulin, anti-thyroid peroxidase, and carcinoembryonic antigen did not require age-specific consideration beyond one year of age, with 63, 91, and 80% of samples equalling the limit of detection, respectively. Estimates were separated by sex for relevant assays (e.g., sex hormone binding globulin, total and free prostate specific antigen).

CONCLUSIONS

Findings support transferability of pediatric RIs on ARCHITECT system to the Alinity system for 16 specialized immunoassays in the CALIPER cohort and will be a useful resource for pediatric clinical laboratories using Alinity assays. Further work is needed to establish evidence-based interpretative recommendations for anti-CCP and continue to evaluate pediatric RI acceptability for newly available assay technologies.

Comparative efficacy of tannin-free grain sorghum varieties for the control of necrotic enteritis caused by Clostridium perfringens in broiler chickens

A 28-day battery cage study was conducted to test the efficacy of tannin-free grain sorghum varieties fed to Cobb 500 male broiler chickens (n = 512) and challenged with Eimeria maxima (EM) and Clostridium perfringens (CP). Birds were fed 1 of 8 treatments (corn, red/bronze, white/tan, or U.S. No. 2 sorghum) and were grouped by challenge method (challenged with EM/CP or unchallenged). On d 14, birds in the challenge group were orally inoculated with ∼5,000 oocysts of EM, and on d 19, 20, and 21, birds were given a broth culture of CP with ∼10⁸ CFU/mL once daily. On d 21, three birds were scored for the degree/presence of necrotic enteritis (NE) lesions. Birds and feed were group weighed (d 0, 14, 21, and 28) to calculate average feed intake (FI), body weight gain (BWG), and adjusted feed conversion ratio (AdjFCR). Intestinal integrity was assessed through histological analysis of intestinal tissues, and change in transcriptome was determined using mRNA-sequencing on intestinal mucosa. Relative concentrations of secondary metabolites in grain sorghum were determined by LC-MS/MS analysis. Data were analyzed as a 2-way ANOVA with factors of treatment, challenge and their interaction. Regardless of challenge from 14 to 21 d, birds on the corn, white/tan, and U.S. No. 2 treatments were more efficient than those fed red/bronze treatment (P = 0.0026). From 14 to 28 d, BWG was significantly higher for the white/tan treatment (P = 0.024) compared to the red/bronze treatment. At 21 d, a significant interaction was observed for lesion score (P = 0.0001) in which, challenged birds fed red/bronze and white/tan treatments had reduced intestinal lesions compared to U.S. No. 2 and corn treatments. No differences among treatments were observed in jejunum morphology, but differential expression analysis showed an upregulation in defense response to bacteria and biotic stress in the challenged red/bronze treatment compared to the challenged corn. This study demonstrated improved gut health and minimal impact on growth and efficiency of broilers fed select grain sorghum varieties when challenged with EM/CP.

Participation in paid and unpaid work one year after injury and the impact of subsequent injuries for Māori: Results from a longitudinal cohort study in New Zealand

INTRODUCTION

Indigenous populations experience greater injury burdens than non-indigenous groups. This paper investigated, for injured Māori (New Zealand's indigenous population): 1) participation in paid and unpaid work 12 months after injury, 2) whether subsequent injuries are predictive of reduced participation, and 3) if particular characteristics of subsequent injuries predict reduced participation.

METHODS

The Subsequent Injury Study utilised data from the earlier Prospective Outcomes of Injury Study, a study of 2856 injured New Zealanders (including 566 Māori; 20%) who had an Accident Compensation Corporation (ACC; New Zealand's no-fault injury insurer) entitlement claim (sentinel injury). Data about subsequent injuries reported to ACC and hospital discharge data for injuries resulting in hospitalisation were also utilised. Multivariable models were used to examine if certain aspects of subsequent injury predicted either of two outcomes - reduced participation in paid, and unpaid work 12 months after a sentinel injury.

RESULTS

Eligible participants were identified from the 405 Māori participants interviewed at 12 months. Thirty-two percent sustained at least one ACC subsequent injury, and 16% reported reduced participation in unpaid work. Of the eligible participants working for pay at the time of their sentinel injury, 35% reported reduced participation in paid work. Although the relationship between sustaining a subsequent injury (or not) and reduced participation in paid work was unclear (aRR 1.4, 95%CI 0.9,2.3), particular subsequent injury characteristics were identified as being independently predictive: subsequent injury resulting from an assault (aRR 2.4, 95%CI 1.2,4.9), a subsequent injury involving an entitlement claim (aRR 2.0, 95%CI 1.1,3.4), sustaining more than one subsequent injury (aRR 2.0, 95%CI 1.1,3.6), and only non-work-related subsequent injuries (aRR 1.6, 95%CI 1.0,2.7).

CONCLUSIONS

Reduced participation in paid work is prevalent for Māori after an ACC entitlement claim injury. Particular characteristics of subsequent injuries after such an event impacts on participation in paid work 12 months after the sentinel injury, but the picture is less clear for unpaid work. Understanding the changes in paid and unpaid work, and the predictive characteristics of subsequent injuries for injured Māori, is important for future injury prevention strategies and supporting return to work rehabilitation programmes, specifically for Māori.

Perspective: Challenges in the Aerospace Marketplace and Growth Opportunities for Thermal Spray

The market needs for increased engine efficiency and environmentally friendly solutions remain the key drivers for the aerospace industry. These efficiency gains will be achieved by meeting the challenges of higher engine operating temperatures, weight reduction, and novel surface solutions for increased component longevity. A critical question to address is if the thermal spray (TS) industry can continue to meet the challenges and demands seen by the airlines and the engine manufacturers. In addition to non-aerospace influences, the COVID-19 pandemic has dramatically affected the landscape of industry growth, not only directly on airlines but also on the associated supply chain. This article reviews this market, its suppliers, and identifies the challenges and opportunities for future growth. Primary focus is on technology and what will be required to bring about reliable, robust, and cost-effective TS solutions into the marketplace. Several issues affecting the global landscape of the aerospace industry are discussed including (1) sustainability, (2) technology, (3) cost of ownership, (4) evolving marketplace, (5) workforce and behavior, and (6) supply chain vitality. An important question to address is if the TS industry can accelerate development with its supply chain and have the ability to commercialize technology more efficiently. Despite the market setbacks from the pandemic and previous issues with the Boeing 737 MAX fleet, the aerospace industry is poised to make significant advancements. These will create new opportunities for thermal spray technology in materials, equipment, and processes. To deliver on them, the implementation of Industry 4.0 along with the investment in human resources is more critical than ever. Based on the findings, the authors project a bright long-term future for both the aerospace and thermal spray industries.

384 Local Closed Loop Audit: COVID-19 Screening Before Endoscopic Ultrasound

Aim

Endoscopic Ultrasound (EUS) is one of the important diagnostic tests in patients with probable hepatobiliary or lung diseases. As it is an airborne procedure and due to the current COVID-19 pandemic, British Society of Gastroenterology and NICE guidelines have stated that patients who are undergoing EUS must be tested for COVID-19 within 3 days before the procedure. EUS must be considered deferring if the patient tests positive. The aim of this audit is to increase the proportion of patients being swabbed within 3 days/72 hours of the procedure to > 90% by the end of 2021.

Method

A list of patients who underwent elective EUS in January (initial audit) and mid-May to mid-June (re-audit) were collected using Endosoft software. Afterwards, electronic patient record system was checked for the date of the COVID-19 swab and its results. This data was then recorded in a password-protected Excel spreadsheet and the proportion of the patients meeting the standard was calculated.

Results

The results of the initial audit indicated that although 95.7% of swabs were done within 3 days of the procedure, only 40.9% were done within 72 hours. These results were discussed at a mortality and morbidity meeting, and recommendations were. Hence, in the re-audit, 98.4% of the swabs were done within 3 days of the procedure and the percentage of swabs being done within 72 hours increased to 95.2%.

Conclusions

The target of increasing the proportion of patients being swabbed within 3 days/72 hours of the EUS procedure to > 90% was met in mid-2021.

396 Rotator Cuff Assessment Following Traumatic Anterior Shoulder Dislocation

Aim

Glenohumeral joint dislocation is the most common traumatic joint dislocation with a high recurrence rate correlating with age at first dislocation. There is an associated increased incidence in concurrent rotator cuff tears with increasing age affecting 40% aged 40–60. Patient care was assessed against BESS/BOA standard: These patients should have rotator cuff assessment and those aged 40–60 should undergo routine MRI/Ultrasound imaging.

Method

All patients admitted to the emergency departments of the 3 Lanarkshire hospitals undergoing first time traumatic anterior dislocation of the shoulder in February 2021 were included. This was the third cycle of this audit. Previous interventions were presentation at a CPD meeting after cycle one and an NHS Lanarkshire regional meeting after cycle two.

Results

Cycle one (2018)-14 patients. 3/14 underwent rotator cuff assessment. 5/14 aged 40–60. 1/5 underwent rotator cuff imaging.

Cycle two (2020)-11 patients. 0/9 underwent rotator cuff assessment (Two excluded as managed operatively). 4/11 aged 40–60. 0/4 underwent rotator cuff imaging.

Cycle three (2021)-13 patients. 3/11 underwent rotator cuff assessment (Two excluded as managed operatively). 3/13 aged 40–60. 0/3 underwent rotator cuff imaging.

Conclusions

Although a slight improvement has been made over the 3 cycles with rotator cuff assessment the BOA standard is not being met. There has been no improvement in the additional imaging required in traumatic anterior shoulder dislocations in those aged 40–60 over the 3 cycles. These patients may develop pain, reduced function, and rotator cuff arthropathy. There is now an aim to introduce a pathway for these patients across the health board.

Pediatric Reference Intervals for Point-of-Care Random Glucose in Healthy Children and Adolescents

BACKGROUND

Glucose testing at the point-of-care (POC) is routinely used in the diagnosis, prognosis, and monitoring of diabetic states and other clinical conditions. Accurate reference intervals (RIs) are essential in appropriate clinical decision-making. In this study, RIs were established for random glucose (whole blood) in the Canadian Laboratory Initiative on Pediatric Reference (CALIPER) cohort using 2 POC instruments: the Nova Biomedical StatStrip (handheld glucometer) and Radiometer ABL90 FLEX Plus (benchtop instrument). An analytical comparison was also completed between the 2 POC systems and a laboratory-based analyzer (Ortho Vitros 5600).

METHODS

Approximately 400 healthy children and adolescents (birth to 18 years) were recruited with informed consent from community schools or clinics providing care to metabolically stable/healthy children. Random venous samples were collected and run sequentially on the Nova Biomedical StatStrip (whole blood), Radiometer ABL90 FLEX Plus (whole blood), and Ortho Vitros 5600 (serum). RIs and method comparisons between analytical platforms were completed according to CLSI guidelines.

RESULTS

Significantly different glucose concentrations were observed in infancy, requiring age-specific partitioning (0-<1 month, 1-<6 months, 6 months-<19 years) on all platforms. Excellent concordance was observed between POC platforms (Pearson r > 0.90), with a small negative bias. Good comparability was observed between POC and laboratory-based platforms (Pearson r > 0.80).

CONCLUSION

This study established comprehensive pediatric RIs for random glucose (whole blood) on modern POC systems in the CALIPER cohort for the first time. Results demonstrate excellent concordance in glucose values between POC systems and good comparability with a laboratory-based analyzer. These data will assist in more accurate clinical decision-making in pediatric healthcare institutions.

Pediatric Reference Intervals for Critical Point-of-Care Whole Blood Assays in the CALIPER Cohort of Healthy Children and Adolescents

OBJECTIVES

Point-of-care testing (POCT) is being increasingly adopted to support clinical care. Data for critical care parameters in healthy children on POCT instruments are lacking. We established comprehensive reference standards for several whole blood parameters on the Radiometer ABL90 FLEX PLUS blood gas analyzer in the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) cohort.

METHODS

Approximately 300 healthy children and adolescents (age range, birth to <19 years; sex, boys and girls) were recruited with informed consent. Venous whole blood was collected (using heparinized syringes) and rapidly analyzed at the point of collection for pH, Pco2, Po2, carboxyhemoglobin, methemoglobin, lactate, and electrolytes on the ABL90 FLEX PLUS instrument. Reference intervals were established according to Clinical and Laboratory Standards Institute guidelines.

RESULTS

Of the parameters assessed, 6 required age partitioning; none required sex partitioning. Reference value distributions were consistent across the pediatric age range, demonstrating higher variation in the early neonatal period.

CONCLUSIONS

This study established reference standards for 10 critical care analytes in the CALIPER cohort for the first time. These data contribute to our understanding of normative pediatric values for venous electrolytes, metabolites, and blood gases on a modern POCT instrument, facilitating test interpretation in clinical settings that use these assays.

1607 Seeing White: Management of TIVA During Autologous Breast Reconstruction

Background

Free flap surgery has inherent risks, and the venous drainage of the Deep Inferior Epigastric Perforator (DIEP) flap is particularly vulnerable to congestion. In these cases, an algorithm for flap salvage should be followed and one of the final steps in this process is a cephalic vein transposition.

Case Report

We describe two patients undergoing mastectomy and immediate bilateral DIEP breast reconstruction, where cephalic vein transposition was required. As part of the Enhanced Recovery After Surgery (ERAS) pathway, patients are anaesthetised with a continuous propofol infusion (Total Intravenous Anaesthesia; TIVA). When the cephalic vein was identified, the propofol infusion was visible within the vein, which would have interrupted TIVA if harvested. To maintain continuous TIVA infusion, the cannula was resited prior to harvest of the cephalic vein. The cephalic vein was anastomosed to the superficial inferior epigastric vein and resolution of the venous congestion was noted.

Conclusions

These cases although rare highlight the importance of robust preoperative planning and communication between the team and preparation for all eventualities to ensure patient safety and successful outcomes. These cases highlight the potential effects vein harvesting or transposition may have on the safe and effective delivery of anaesthetic agents and other medication. We hope these cases prompt a discussion in the preoperative stage for alternate strategies for monitoring and intravenous access in response to diversions from the standard operating procedure.

Continuous reference curves for common hematology markers in the CALIPER cohort of healthy children and adolescents on the Sysmex XN-3000 system

INTRODUCTION

Clinicians and healthcare professionals rely heavily on health-associated standards, such as reference intervals (RIs), for appropriate laboratory test result interpretation. RIs are commonly partitioned into discrete age/sex bins based on statistical and/or clinical significance. In pediatric hematology, such partitioning does not adequately represent complex variation in analyte concentrations throughout maturation. The objective of this study was to establish continuous RIs for common hematological parameters in the healthy pediatric Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort.

METHODS

Data from healthy CALIPER children and adolescents (6 months-<19 years) were used to generate continuous RIs (ie, 2.5th and 97.5th quantiles) for 19 hematological parameters. Continuous curves were statistically established with nonparametric quantile regressions. Flagging rate analysis was completed for the established continuous upper and lower reference limits and subsequently compared to previously published discrete CALIPER reference intervals for all parameters.

RESULTS

Continuous RIs were established for 19 hematology parameters, where seven required sex-specific reference curves. Based on flagging rate assessment, continuous RIs appear to more accurately estimate hematological reference limits over the pediatric age range, especially for analytes with complex age- and sex-specific reference value patterns.

CONCLUSIONS

This is the first study to generate continuous RIs for a breadth of hematological markers in a healthy pediatric Canadian population. The increased power of continuous reference intervals to accurately estimate the complex relationship between hematological analyte concentration and age during a time of extensive growth and development is expected to improve laboratory test result interpretation and, subsequently, pediatric clinical decision-making.

Pediatric reference interval verification for endocrine and fertility hormone assays on the Abbott Alinity system

OBJECTIVES

The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) has developed an extensive database of reference intervals (RIs) for several biomarkers on various analytical systems. In this study, pediatric RIs were verified for key immunoassays on the Abbott Alinity system based on the analysis of healthy children samples and comparison to comprehensive RIs previously established for Abbott ARCHITECT assays.

METHODS

Analytical performance of Alinity immunoassays was first assessed. Subsequently, 100 serum samples from healthy children recruited with informed consent were analyzed for 16 Alinity immunoassays. The percentage of test results falling within published CALIPER ARCHITECT reference and confidence limits was determined. If ≥ 90% of test results fell within the confidence limits, they were considered verified based on CLSI guidelines. If <90% of test results fell within the confidence limits, additional samples were analyzed and new Alinity RIs were established.

RESULTS

Of the 16 immunoassays assessed, 13 met the criteria for verification with test results from ≥ 90% of healthy serum samples falling within the published ARCHITECT confidence limits. New CALIPER RIs were established for free thyroxine and prolactin on the Alinity system. Estradiol required special considerations in early life.

CONCLUSIONS

Our data demonstrate excellent concordance between ARCHITECT and Alinity immunoassays, as well as the robustness of previously established CALIPER RIs for most immunoassays, eliminating the need for de novo RI studies for most parameters. Availability of pediatric RIs for immunoassays on the Alinity system will assist clinical laboratories using this new platform and contribute to improved clinical decision-making.

POCT: An Inherently Ideal Tool in Pediatric Laboratory Medicine

Point of care testing (POCT) is important in the provision of timely laboratory test results and continues to gain specific appreciation in the setting of pediatric healthcare. POCT platforms offer several advantages compared to central laboratory testing, including improved clinical outcomes, reduced time to diagnosis, length of stay, and blood volume requirements, as well as increased accessibility. These advantages are most pronounced in acute care settings such as pediatric emergency departments, intensive care units, and in remote settings, wherein rapid patient assessment and prognostication is essential to patient outcomes. The current review provides an overview and critical discussion of the evidence supporting clinical implementation of POCT systems in pediatric clinical decision-making, including but not limited to the diagnosis of viral and bacterial infection, identification of critical glucose and electrolyte dysregulation, and prognostication of post-operative inpatients. Important considerations for test result reporting and interpretation are also discussed, including analytical concordance between POCT systems and central laboratory analyzers as well as availability of pediatric reference intervals for key analytes on POCT systems. Notably, a paucity of evidence-based pediatric reference intervals for test interpretation for critical care parameters on POCT platforms is highlighted, warranting further study and unique consideration prior to clinical implementation.

Pediatric reference interval verification for common biochemical assays on the Abbott Alinity system

OBJECTIVES

The quality of clinical laboratory service depends on quality laboratory operations and accurate test result interpretation based on reference intervals (RIs). As new analytical systems continue to be developed and improved, previously established RIs must be verified. The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) has established comprehensive RIs for many biomarkers on several analytical systems. Here, published CALIPER RIs for 28 chemistry assays on the Abbott ARCHITECT were assessed for verification on the newer Alinity system.

METHODS

An analytical validation was first completed to assess assay performance. CALIPER serum samples (100) were analyzed for 28 chemistry assays on the Alinity system. The percentage of results falling within published pediatric ARCHITECT reference and confidence limits was determined for each analyte. Based on Clinical and Laboratory Standards Institute (CLSI) guidelines, if ≥90% of test results fell within confidence limits of ARCHITECT assay RIs, they were considered verified.

RESULTS

Of the 28 assays assessed, 26 met the criteria for verification. Reference values for calcium and magnesium did not meet the criteria for verification with 87% and 35% falling within previously established ARCHITECT confidence limits, respectively. However, both assays could be verified using pediatric RIs provided in the Abbott Alinity package insert.

CONCLUSIONS

In this study, CALIPER ARCHITECT RIs were verified on the Alinity system for several chemistry assays. These data demonstrate excellent concordance for most assays between the Abbott ARCHITECT and Alinity systems and will assist in the implementation of the Alinity system in pediatric healthcare institutions.

Continuous reference intervals for 19 endocrine, fertility, and immunochemical markers in the CALIPER cohort of healthy children and adolescents

BACKGROUND

Reference intervals are traditionally partitioned into discrete ranges by major covariates such as age and sex. However, discrete reference intervals often oversimplify the complex relationship between analyte concentration and age. Continuous reference intervals have been suggested to more accurately represent this complex relationship, particularly in pediatrics. The objective of this study was to establish continuous reference intervals for endocrine, fertility, and additional immunochemical parameters in the CALIPER cohort of healthy children and adolescents.

METHODS

Continuous reference intervals from 1 to 18.5 years of age were established using retrospective CALIPER data collected from healthy Canadian children and adolescents. Continuous reference intervals (2.5th and 97.5th percentiles) were determined for 19 parameters by nonparametric quantile regression. Total and yearly flagging rates were calculated for the upper and lower continuous reference limits and compared to previously published partitioned reference limits.

RESULTS

Continuous reference intervals were established for 19 endocrine, fertility, and additional immunochemical parameters, with 11 requiring sex-specific reference curves. Continuous reference intervals assessed both visually and by flagging rate analysis more accurately represented the relationship between analyte concentration and age, particularly for parameters with complex reference value patterns.

CONCLUSION

This is the first comprehensive report to establish continuous reference intervals for several immunochemical parameters including endocrine and fertility markers in a healthy paediatric Canadian cohort. The ability of continuous reference intervals to provide a better estimate of age-related changes in reference values suggest their potential to improve paediatric laboratory test result interpretation and clinical decision-making.

A123 DEFINING CROHN’S DISEASE STRICTURES USING INTESTINAL ULTRASOUND COMPARED TO HISTOPATHOLOGY

Background

Fibrostenotic Crohn’s Disease (CD) is a challenging phenotype often leading to surgical resection. Diagnostic imaging is an invaluable tool to diagnose CD strictures. MRE (Magnetic Resonance Enterography) is the most widely used modality for evaluating strictures, but is limited by access and cost. The current definition of strictures is based only on MRE or CT (computed tomography). Strictures are defined as increased bowel wall thickness (BWT), narrowed luminal apposition, and pre-stenotic dilation &gt; 3cm according to CONSTRICT MR/CT expert consensus criteria. However, this definition has not been studied in intestinal US (IUS). IUS is a cost-effective, easily repeatable, and well-tolerated tool shown to have equal accuracy to MRE in diagnosing and monitoring CD.

Aims

The objective of this study was to assess the utility of identifying strictures with IUS using CONSTRICT definition.

Methods

In this retrospective pilot study, 30 of 80 CD patients who underwent small bowel resection (gold standard for stricture diagnosis) between 2015–2019 with IUS within 6 months prior to surgery were randomly identified for chart review. IUS was performed in a fasted state without oral contrast. Data extracted included confirmed stricture on resection specimens defined as having fibrosis and prestenotic dilation. Fistulizing disease was excluded. Student’s t-tests, sensitivities, specificities, positive (PNV) and negative predictive values (NPV) were calculated for IUS in detecting strictures.

Results

Of the 30 CD patients evaluated, 20 patients had fibrostenosis on pathology and IUS reports. Only 40% (8/20) met CONSTRICT criteria for stricture diagnosis on IUS, despite having a stricture on pathology. All patients had elevated BWT and luminal narrowing, but 60% (12/20) did not have prestenotic dilation &gt; 3cm. Mean dilation was 2.9 cm (SD 1.38) and was significantly different from the mean stricture diameter of 1.3cm (SD 0.59 cm, p=0.0001, 95% CI: 0.9–2.2). Mean BWT was 8.7 mm (SD: 2.5, range 5–15) where normal is &lt; 3mm, and mean luminal apposition was 2.3 mm (SD 1.2, range 0.2–5.8mm). IUS has a sensitivity of 95.2% (95% CI: 76.2 - 99.9%), specificity of 66.7% (95% CI: 29.9 - 92.5%), PPV of 87.0% (95% CI: 72.5–94.4), and NPV of 85.7% (95% CI 45.6–97.7%) in detecting strictures when compared to gold standard.

Conclusions

CONSTRICT criteria for diagnosing fibrostenotic CD on CT/MR may not be applicable to IUS. In this study, only 40% of patients met criteria despite having histologic confirmed strictures. Thus, perhaps additional criteria of stricture diameter &lt; 50% of prestenotic dilation size is most appropriate for IUS. This pilot study provides the initial data to delineate an IUS stricture definition for future validation and to inform both clinical practice and trial design.

Funding Agencies

None

Drill design using the 'control-chaos continuum': Blending science and art during return to sport following knee injury in elite football

Establishing the level of risk, planning and adapting the return to sport (RTS) process following a complex knee injury involves drawing on a combination of relevant high-quality evidence and practitioner experience. On-pitch rehabilitation is a critical element of this process, providing an effective transition from rehabilitation to team training. The 'control-chaos continuum' (CCC) is an adaptable framework for on-pitch rehabilitation moving from high control to high chaos, progressively increasing running load demands and incorporating greater perceptual and neurocognitive challenges within sport-specific drills. Drills are a key element of the CCC, and are designed to ensure specificity, ecological validity and maintaining player interest. We showcase drill progression through the phases of the CCC, highlighting the use of constraints to create drills that incorporate the physical, technical, tactical and injury-specific needs of the player. We also provide recommendations to help practitioners create training session content using the CCC to help replicate the demands of team training within their own environment.

Investigating Wilms' Tumours Worldwide: A Report of the OxPLORE Collaboration-A Cross-Sectional Observational Study

BACKGROUND

Childhood cancer is neglected within global health. Oxford Pediatrics Linking Oncology Research with Electives describes early outcomes following collaboration between low- and high-income paediatric surgery and oncology centres. The aim of this paper is twofold: to describe the development of a medical student-led research collaboration; and to report on the experience of Wilms' tumour (WT).

METHODS

This cross-sectional observational study is reported as per STROBE guidelines. Collaborating centres included three tertiary hospitals in Tanzania, Rwanda and the UK. Data were submitted by medical students following retrospective patient note review of 2 years using a standardised data collection tool. Primary outcome was survival (point of discharge/death).

RESULTS

There were 104 patients with WT reported across all centres over the study period (Tanzania n = 71, Rwanda n = 26, UK n = 7). Survival was higher in the high-income institution [87% in Tanzania, 92% in Rwanda, 100% in the UK (X² 36.19, p < 0.0001)]. Given the short-term follow-up and retrospective study design, this likely underestimates the true discrepancy. Age at presentation was comparable at the two African sites but lower in the UK (one-way ANOVA, F = 0.2997, p = 0.74). Disease was more advanced in Tanzania at presentation (84% stage III-IV cf. 60% and 57% in Rwanda and UK, respectively, X² 7.57, p = 0.02). All patients had pre-operative chemotherapy, and a majority had nephrectomy. Post-operative morbidity was higher in lower resourced settings (X² 33.72, p < 0.0001). Methodology involving medical students and junior doctors proved time- and cost-effective. This collaboration was a valuable learning experience for students about global research networks.

CONCLUSIONS

This study demonstrates novel research methodology involving medical students collaborating across the global south and global north. The comparison of outcomes advocates, on an institutional level, for development in access to services and multidisciplinary treatment of WT.

Microplastics and other anthropogenic particles in the surface waters of the Chesapeake Bay

Microplastics are a ubiquitous environmental contaminant whose distributions have been correlated with land-use and population density. Although there are numerous studies quantifying microplastics in the environment, local studies help inform sources, pathways, and policy. Here, we measure the concentration of microplastics in the surface waters across the Chesapeake Bay - the largest estuary in the USA. Thirty surface water samples from throughout the Chesapeake Bay were collected with a manta trawl. Samples were manually processed for microplastics and other anthropogenic particles. Fourier-transform infrared spectroscopy (FTIR) was used to determine the chemical composition of the particles. Higher concentrations were found near major cities and where larger rivers or tributaries met the Chesapeake Bay. Fragments, films, and fibres were the most common morphologies found, and polyethylene and polypropylene were the most common plastic types. These results can be used to inform mitigation strategies for microplastic pollution in the Chesapeake Bay region.

Comparison of two Meglumine-Diatrizoate based bowel preparations for computed tomography colonography: Comparison of patient symptoms and bowel preparation quality

INTRODUCTION

To investigate the impact of two Meglumine-Diatrizoate based bowel preparation regimes for computed tomography colonography (CTC) on the patient experience and image quality.

METHODS

100 patients consumed Meglumine-Diatrizoate at 24 h and 12 h prior to the CTC examination. 50 patients followed regime 1 (50:50), 50 ml of Meglumine-Diatrizoate at both 24 and 12 h prior to the examination. 50 patients followed regime 2 (75:25), 75 ml of Meglumine-Diatrizoate at 24 h prior to the examination and 25 ml of Meglumine-Diatrizoate at 12 h prior to the examination. All patients completed a questionnaire to indicate the time of onset of adverse effects and when they were most severe. Five advanced practitioners assessed the image quality in a visual grading study. Visual grading characteristic (VGC) analysis was applied with regime 1 as the reference condition and regime 2 and test condition; test alpha was set at 0.05.

RESULTS

Image quality was assessed with successful bowel cleansing as the scoring criteria for the visual grading study. The bowel cleansing as provided by the two Meglumine-Diatrizoate regimes was revealed not to be statistically different, with the area under the VGC curve and 95% confidence intervals 0.487 (0.287, 0.701), p = 0.887. Patients taking the 75:25 bowel preparation experienced a shorter median time to the onset of adverse effects.

CONCLUSION

There was no observed difference in Image quality criteria score for the two Meglumine-Diatrizoate based bowel preparation with more predictable adverse effects of Meglumine-Diatrizoate with the 75:25 preparation.

IMPLICATIONS FOR PRACTICE

Providing patients with a higher contrast burden 24 h prior to CTC may have a positive impact on the patient experience without compromising image quality.

Patient deprivation and perceived scan burden negatively impact the quality of whole-body MRI

AIM

To evaluate the association between the image quality of cancer staging whole-body magnetic resonance imaging (WB-MRI) and patient demographics, distress, and perceived scan burden.

MATERIALS AND METHODS

A sample of patients recruited prospectively to multicentre trials comparing WB-MRI with standard scans for staging lung and colorectal cancer were invited to complete two questionnaires. The baseline questionnaire, administered at recruitment, collated data on demographics, distress and co-morbidity. The follow-up questionnaire, completed after staging investigations, measured perceived WB-MRI scan burden (scored 1 low to 7 high). WB-MRI anatomical coverage, and technical quality was graded by a radiographic technician and grading combined to categorise the scan as "optimal", "sub-optimal" or "degraded". A radiologist categorised 30 scans to test interobserver agreement. Data were analysed using the chi-square, Fisher's exact, t-tests, and multinomial regression.

RESULTS

One hundred and fourteen patients were included in the study (53 lung, 61 colorectal; average age 65.3 years, SD=11.8; 66 men [57.9%]). Overall, 45.6% (n=52), scans were classified as "optimal" quality, 39.5% (n=45) "sub-optimal", and 14.9% (n=17) as "degraded". In adjusted analyses, greater deprivation level and higher patient-reported scan burden were both associated with a higher likelihood of having a sub-optimal versus an optimal scan (odds ratio [OR]: 4.465, 95% confidence interval [CI]: 1.454 to 13.709, p=0.009; OR: 1.987, CI: 1.153 to 3.425, p=0.013, respectively). None of the variables predicted the likelihood of having a degraded scan.

CONCLUSIONS

Deprivation and patients' perceived experience of the WB-MRI are related to image quality. Tailored protocols and individualised patient management before and during WB-MRI may improve image quality.

Primary paediatric chest wall tumours necessitating surgical management

INTRODUCTION

Limited literature exists on oncological chest wall reconstruction in the paediatric population, with the field still largely undecided on the best surgical reconstructive techniques to employ. The use of biological grafts/meshes is gaining popularity in certain adult surgical procedures but their use in paediatric procedures is rarely reported in the literature. We present the outcomes of our institution's multidisciplinary approach to managing paediatric chest wall tumours as well as our experience with the use of biological grafts for chest wall reconstruction following oncological resections.

METHODS

Data were analysed retrospectively from eight paediatric patients who were treated for primary chest wall tumours between 2010 and 2018.

RESULTS

The tumours comprised two lipoblastomas, three Ewing's sarcomas, an undifferentiated sarcoma with osteosarcomatous differentiation, a high grade undifferentiated sarcoma and a myofibroma. Seven of the eight patients underwent chest wall reconstruction with a biological graft. There were no postoperative mortalities and no evidence of recurrence in any of the patients in the series. No further chest wall operations were required and there were no postoperative infection related complications.

CONCLUSIONS

We support the use of biological grafts for chest wall reconstruction after oncological resections and maintain that a multidisciplinary approach is essential for the management of paediatric chest wall tumours.

Evaluating the use of whole genome sequencing for the investigation of a large mumps outbreak in Ontario, Canada

In 2017 Ontario experienced the largest mumps outbreak in the province in 8 years, at a time when multiple outbreaks were occurring across North America. Of 259 reported cases, 143 occurred in Toronto, primarily among young adults. Routine genotyping of the small hydrophobic gene indicated that the outbreak was due to mumps virus genotype G. We performed a retrospective study of whole genome sequencing of 26 mumps virus isolates from early in the outbreak, using a tiling amplicon method. Results indicated that two of the cases were genetically divergent, with the remaining 24 cases belonging to two major clades and one minor clade. Phylogeographic analysis confirmed circulation of virus from each clade between Toronto and other regions in Ontario. Comparison with other genotype G strains from North America suggested that the presence of co-circulating major clades may have been due to separate importation events from outbreaks in the United States. A transmission network analysis performed with the software program TransPhylo was compared with previously collected epidemiological data. The transmission tree correlated with known epidemiological links between nine patients and identified new potential clusters with no known epidemiological links.

Rigid-body modeling of knee cartilage and meniscus using experimental pressure-strain curves

Rigid-body knee models have gained popularity thanks to computational speed and ease of setup compared to finite element models-showing exciting potential for clinical patient-specific models in the future. However, Rigid-body studies in general have encountered difficulty in modeling cartilage and especially meniscus material properties, often relying on computationally costly optimization techniques. This paper presents two new methods to alleviate the difficulty-one to define model contact pressure and one to define meniscus internal forces-and is the first to our knowledge to use experimental pressure-strain curves from the literature to simulate cartilage and meniscus behavior in a rigid body model. This paper describes the methodology to derive the proof of concept model and preliminary results from a gait simulation based on ISO 14243-1.

Identical and Nonidentical Twins: Risk and Factors Involved in Development of Islet Autoimmunity and Type 1 Diabetes

OBJECTIVE

There are variable reports of risk of concordance for progression to islet autoantibodies and type 1 diabetes in identical twins after one twin is diagnosed. We examined development of positive autoantibodies and type 1 diabetes and the effects of genetic factors and common environment on autoantibody positivity in identical twins, nonidentical twins, and full siblings.

RESEARCH DESIGN AND METHODS

Subjects from the TrialNet Pathway to Prevention Study (N = 48,026) were screened from 2004 to 2015 for islet autoantibodies (GAD antibody [GADA], insulinoma-associated antigen 2 [IA-2A], and autoantibodies against insulin [IAA]). Of these subjects, 17,226 (157 identical twins, 283 nonidentical twins, and 16,786 full siblings) were followed for autoantibody positivity or type 1 diabetes for a median of 2.1 years.

RESULTS

At screening, identical twins were more likely to have positive GADA, IA-2A, and IAA than nonidentical twins or full siblings (all P < 0.0001). Younger age, male sex, and genetic factors were significant factors for expression of IA-2A, IAA, one or more positive autoantibodies, and two or more positive autoantibodies (all P ≤ 0.03). Initially autoantibody-positive identical twins had a 69% risk of diabetes by 3 years compared with 1.5% for initially autoantibody-negative identical twins. In nonidentical twins, type 1 diabetes risk by 3 years was 72% for initially multiple autoantibody-positive, 13% for single autoantibody-positive, and 0% for initially autoantibody-negative nonidentical twins. Full siblings had a 3-year type 1 diabetes risk of 47% for multiple autoantibody-positive, 12% for single autoantibody-positive, and 0.5% for initially autoantibody-negative subjects.

CONCLUSIONS

Risk of type 1 diabetes at 3 years is high for initially multiple and single autoantibody-positive identical twins and multiple autoantibody-positive nonidentical twins. Genetic predisposition, age, and male sex are significant risk factors for development of positive autoantibodies in twins.

Prolonged-Release vs Immediate-Release Tacrolimus Capsules in Black vs White Kidney Transplant Patients: A Post Hoc Analysis of Phase III Data

BACKGROUND

Black kidney transplant patients experience inferior outcomes compared with other ethnicities. Because scrutiny is required when immunosuppressant drugs are used in such at-risk populations, we report the first large-scale clinical efficacy data assessing prolonged-release tacrolimus (PR-T) in black de novo kidney transplant patients.

METHODS AND MATERIALS

We used logistic regression and proportionate hazards to compare a composite outcome measure (biopsy-proven acute rejection, graft loss, mortality, and loss to follow-up) in black and white patients in treatment groups longer than 24 weeks, from 3 large Phase III randomized controlled trials. Secondary endpoints included tacrolimus trough concentration, dose, and estimated glomerular filtration rate.

RESULTS

The study included 2162 patients whose treatments belonged to two categories (immediate-release tacrolimus: 77 black patients, 721 white patients; and PR-T: 87 black patients, 1277 white patients). Despite demographic factors generally predictive of worse outcomes, efficacy failure among black patients who received PR-T was non-inferior to that among white patients who received either therapy. Compared with immediate-release tacrolimus, black patients who received PR-T achieved stable tacrolimus concentrations 2.5 times faster (21 vs 56 days, P = .04), and more achieved stable target concentrations (76.7% vs 69.3%). Treatment-emergent adverse events were consistent with those reported separately in pivotal trials.

CONCLUSIONS

Overall, black patients who received PR-T achieved non-inferior outcomes compared to white patients, despite higher pretransplant risk among black patients. Moreover, PR-T improved the time to achieve, and the likelihood of reaching, stable therapeutic concentrations among black patients, suggesting that PR-T could improve the consistency of tacrolimus exposure in this patient population.

The Hemisection Approach in Large Animal Models of Spinal Cord Injury: Overview of Methods and Applications

Introduction: Translating basic science research into a safe and effective therapy for spinal cord injury (SCI) requires suitable large animal models for testing both implantable devices and biologic approaches to better approximate human anatomy and function. Hemisection lesions, routinely used for investigational purposes in small animals, are less frequently described in large animals that might be appropriate for translational studies. Size constraints of small animals (mice and rats) limits the predictability of the findings when scaled up. Our goal is to review the status of hemisection SCI in large animals across species and time to prepare for the testing of a novel intradural spinal cord stimulation device for control of spasticity in an ovine model. Methods and Results: We surveyed the literature on hemisection in quadrupeds and nonhuman primates, and catalogued the species, protocols and outcomes of the experimental work in this field. Feline, lapine, canine, simian, porcine, ovine and bovine models were the primary focal points. There is a consistent body of literature reporting use of the hemisection approach in large animals, but with differences in surgical technique depending on the goals and nature of the individual studies. While the injuries are not always consistent, the experimental variability is generally lower than that of the contusion-based approach. In general, as the body size of the animal increases, animal care requirements and the associated costs follow. In most cases, this is inversely correlated with the number of animals used in hemisection models. Conclusions: The hemisection approach to modeling SCI is straightforward compared with other methods such as the contusive impact and enables the transection of isolated ascending and descending tracts and segment specific cell bodies. This has certain advantages in models investigating post-injury axonal regrowth. However, this approach is not generally in line with the patho-physiologies encountered in SCI patients. Even so, the ability to achieve more control over the level of injury makes it a useful adjunct to contusive and ischemic approaches, and suggests a useful role in future translational studies.