Mechanisms of Injury Leading to Concussions in Collegiate Soccer Players: A CARE Consortium Study

BACKGROUND

Few previous studies have investigated how different injury mechanisms leading to sport-related concussion (SRC) in soccer may affect outcomes.

PURPOSE

To describe injury mechanisms and evaluate injury mechanisms as predictors of symptom severity, return to play (RTP) initiation, and unrestricted RTP (URTP) in a cohort of collegiate soccer players.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

The Concussion Assessment, Research and Education (CARE) Consortium database was used. The mechanism of injury was categorized into head-to-ball, head-to-head, head-to-body, and head-to-ground/equipment. Baseline/acute injury characteristics-including Sports Concussion Assessment Tool-3 total symptom severity (TSS), loss of consciousness (LOC), and altered mental status (AMS); descriptive data; and recovery (RTP and URTP)-were compared. Multivariable regression and Weibull models were used to assess the predictive value of the mechanism of injury on TSS and RTP/URTP, respectively.

RESULTS

Among 391 soccer SRCs, 32.7% were attributed to a head-to-ball mechanism, 27.9% to a head-to-body mechanism, 21.7% to a head-to-head mechanism, and 17.6% to a head-to-ground/equipment mechanism. Event type was significantly associated with injury mechanism [χ2(3) = 63; P < .001), such that more head-to-ball concussions occurred in practice sessions (n = 92 [51.1%] vs n = 36 [17.1%]) and more head-to-head (n = 65 [30.8%] vs n = 20 [11.1]) and head-to-body (n = 76 [36%] vs n = 33 [18.3%]) concussions occurred in competition. The primary position was significantly associated with injury mechanism [χ2(3) = 24; P < .004], with goalkeepers having no SRCs from the head-to-head mechanism (n = 0 [0%]) and forward players having the least head-to-body mechanism (n = 15 [19.2%]). LOC was also associated with injury mechanism (P = .034), with LOC being most prevalent in head-to-ground/equipment. Finally, AMS was most prevalent in head-to-ball (n = 54 [34.2%]) and head-to-body (n = 48 [30.4%]) mechanisms [χ2(3) = 9; P = .029]. In our multivariable models, the mechanism was not a predictor of TSS or RTP; however, it was associated with URTP (P = .044), with head-to-equipment/ground injuries resulting in the shortest mean number of days (14 ± 9.1 days) to URTP and the head-to-ball mechanism the longest (18.6 ± 21.6 days).

CONCLUSION

The mechanism of injury differed by event type and primary position, and LOC and AMS were different across mechanisms. Even though the mechanism of injury was not a significant predictor of acute symptom burden or time until RTP initiation, those with head-to-equipment/ground injuries spent the shortest time until URTP, and those with head-to-ball injuries had the longest time until URTP.

Gene Expression Alterations in Peripheral Blood Following Sport-Related Concussion in a Prospective Cohort of Collegiate Athletes: A Concussion Assessment, Research and Education (CARE) Consortium Study

BACKGROUND

Molecular-based approaches to understanding concussion pathophysiology provide complex biological information that can advance concussion research and identify potential diagnostic and/or prognostic biomarkers of injury.

OBJECTIVE

The aim of this study was to identify gene expression changes in peripheral blood that are initiated following concussion and are relevant to concussion response and recovery.

METHODS

We analyzed whole blood transcriptomes in a large cohort of concussed and control collegiate athletes who were participating in the multicenter prospective cohort Concussion Assessment, Research, and Education (CARE) Consortium study. Blood samples were collected from collegiate athletes at preseason (baseline), within 6 h of concussion injury, and at four additional prescribed time points spanning 24 h to 6 months post-injury. RNA sequencing was performed on samples from 230 concussed, 130 contact control, and 102 non-contact control athletes. Differential gene expression and deconvolution analysis were performed at each time point relative to baseline.

RESULTS

Cytokine and immune response signaling pathways were activated immediately after concussion, but at later time points these pathways appeared to be suppressed relative to the contact control group. We also found that the proportion of neutrophils increased and natural killer cells decreased in the blood following concussion.

CONCLUSIONS

Transcriptome signatures in the blood reflect the known pathophysiology of concussion and may be useful for defining the immediate biological response and the time course for recovery. In addition, the identified immune response pathways and changes in immune cell type proportions following a concussion may inform future treatment strategies.

Does Increased Physical Activity Explain the Psychosocial Benefits of Sport Participation During COVID-19?

CONTEXT

Although the return to sports during COVID-19 has been associated with improvements in mental health and quality of life (QOL), whether these benefits are primarily due to increases in physical activity (PA) is unknown.

OBJECTIVE

To determine whether PA increases were responsible for the improvements in mental health and QOL among adolescents who returned to sport during the COVID-19 pandemic.

DESIGN

Cross-sectional study.

SETTING

Wisconsin secondary schools.

PATIENTS OR OTHER PARTICIPANTS

A total of 559 adolescent athletes (age = 15.7 + 1.2 years, females = 43.6%) from 44 schools completed a survey in October 2020.

MAIN OUTCOME MEASURE(S)

Demographic information, whether they had returned to sport participation, school instruction type, anxiety (Generalized Anxiety Disorder-7), depression (Patient Health Questionnaire-9), QOL (Pediatric Quality of Life Inventory 4.0), and PA (Hospital for Special Surgery Pediatric Functional Activity Brief Scale). Mediation analysis was used to assess whether the relationships between sport status and anxiety, depression, and QOL were mediated by PA.

RESULTS

At the time of the study, 171 (31%) had returned to play and 388 (69%) had not. Athletes who had returned to play had less anxiety (3.6 ± 0.4 versus 8.2 ± 0.6, P < .001) and depression (4.2 ± 0.4 versus 7.3 ± 0.6, P < .001) and higher QOL (88.1 ± 1.0 versus 80.2 ± 1.4, P < .001) and more PA (24.0 ± 0.5 versus 16.3 ± 0.7, P < .001). Physical activity explained a significant, but small, proportion of the difference in depression (22.1%, P = .02) and QOL (16.0%, P = .048) but not anxiety (6.6%, P = .20) between athletes who had and those who had not returned to play.

CONCLUSIONS

Increased PA was responsible for only a small portion of the improvements in depression and QOL among athletes who returned to sports. This suggests that most of the mental health benefits of sport participation for adolescents during the COVID-19 pandemic were independent of the benefits of increased PA.

Plasma phosphorylated tau181 as a biomarker of mild traumatic brain injury: findings from THINC and NCAA-DoD CARE Consortium prospective cohorts

Objective

The aim of this study was to investigate phosphorylated tau (p-tau181) protein in plasma in a cohort of mild traumatic brain injury (mTBI) patients and a cohort of concussed athletes.

Methods

This pilot study comprised two independent cohorts. The first cohort-part of a Traumatic Head Injury Neuroimaging Classification (THINC) study-with a mean age of 46 years was composed of uninjured controls (UIC, n = 30) and mTBI patients (n = 288) recruited from the emergency department with clinical computed tomography (CT) and research magnetic resonance imaging (MRI) findings. The second cohort-with a mean age of 19 years-comprised 133 collegiate athletes with (n = 112) and without (n = 21) concussions. The participants enrolled in the second cohort were a part of a multicenter, prospective, case-control study conducted by the NCAA-DoD Concussion Assessment, Research and Education (CARE) Consortium at six CARE Advanced Research Core (ARC) sites between 2015 and 2019. Blood was collected within 48 h of injury for both cohorts. Plasma concentration (pg/ml) of p-tau181 was measured using the Single Molecule Array ultrasensitive assay.

Results

Concentrations of plasma p-tau181 in both cohorts were significantly elevated compared to controls within 48 h of injury, with the highest concentrations of p-tau181 within 18 h of injury, with an area under the curve (AUC) of 0.690-0.748, respectively, in distinguishing mTBI patients and concussed athletes from controls. Among the mTBI patients, the levels of plasma p-tau181 were significantly higher in patients with positive neuroimaging (either CT+/MRI+, n = 74 or CT-/MRI+, n = 89) compared to mTBI patients with negative neuroimaging (CT-/MRI-, n = 111) findings and UIC (P-values < 0.05).

Conclusion

These findings indicate that plasma p-tau181 concentrations likely relate to brain injury, with the highest levels in patients with neuroimaging evidence of injury. Future research is needed to replicate and validate this protein assay's performance as a possible early diagnostic biomarker for mTBI/concussions.

Are EPB41 and alpha-synuclein diagnostic biomarkers of sport-related concussion? Findings from the NCAA and Department of Defense CARE Consortium

BACKGROUND

Current protein biomarkers are only moderately predictive at identifying individuals with mild traumatic brain injury or concussion. Therefore, more accurate diagnostic markers are needed for sport-related concussion.

METHODS

This was a multicenter, prospective, case-control study of athletes who provided blood samples and were diagnosed with a concussion or were a matched non-concussed control within the National Collegiate Athletic Association-Department of Defense Concussion Assessment, Research, and Education Consortium conducted between 2015 and 2019. The blood was collected within 48 h of injury to identify protein abnormalities at the acute and subacute timepoints. Athletes with concussion were divided into 6 h post-injury (0-6 h post-injury) and after 6 h post-injury (7-48 h post-injury) groups. We applied a highly multiplexed proteomic technique that used a DNA aptamers assay to target 1305 proteins in plasma samples from athletes with and without sport-related concussion.

RESULTS

A total of 140 athletes with concussion (79.3% males; aged 18.71 ± 1.10 years, mean ± SD) and 21 non-concussed athletes (76.2% males; 19.14 ± 1.10 years) were included in this study. We identified 338 plasma proteins that significantly differed in abundance (319 upregulated and 19 downregulated) in concussed athletes compared to non-concussed athletes. The top 20 most differentially abundant proteins discriminated concussed athletes from non-concussed athletes with an area under the curve (AUC) of 0.954 (95% confidence interval: 0.922‒0.986). Specifically, after 6 h of injury, the individual AUC of plasma erythrocyte membrane protein band 4.1 (EPB41) and alpha-synuclein (SNCA) were 0.956 and 0.875, respectively. The combination of EPB41 and SNCA provided the best AUC (1.000), which suggests this combination of candidate plasma biomarkers is the best for diagnosing concussion in athletes after 6 h of injury.

CONCLUSION

Our data suggest that proteomic profiling may provide novel diagnostic protein markers and that a combination of EPB41 and SNCA is the most predictive biomarker of concussion after 6 h of injury.

A Multiyear Assessment of the Effect of Sport Participation on the Health of Adolescent Athletes During the COVID-19 Pandemic

CONTEXT

Sport cancellations early in the COVID-19 pandemic had a significant negative effect on the health of US adolescents. The effect of restarting sports during the pandemic has not been described.

OBJECTIVE

To identify the effect of sport participation on the health of adolescents before and during the COVID-19 pandemic.

DESIGN

Cross-sectional study.

SETTING

Sample recruited via social media.

PATIENTS OR OTHER PARTICIPANTS

Wisconsin adolescent athletes.

MAIN OUTCOME MEASURE(S)

Participants provided information regarding their age, sex, and sport(s) involvement and completed the Patient Health Questionnaire-9 Item to assess depression symptoms, the Hospital for Special Surgery Pediatric Functional Activity Brief Scale to measure physical activity, and the Pediatric Quality of Life Inventory 4.0 to measure quality of life (QoL). Data were collected in spring 2021 (Spring21; n = 1906, age = 16.0 ± 1.2 years, females = 48.8%), when interscholastic sports had fully resumed, and were compared with similar cohorts of adolescent athletes at 2 time points: (1) spring 2020 (Spring20; n = 3243, age = 16.2 ± 1.2 years, females = 57.9%) when sports were cancelled and (2) 2016-2018 (PreCOVID-19) before the pandemic (n = 5231, age = 15.7 ± 1.1 years, females = 65.0%). Comparisons were conducted via analysis-of-variance models and ordinal regressions with age and sex as covariates.

RESULTS

The prevalence of moderate to severe depression was lower in Spring21 than in Spring20 but higher than in PreCOVID-19 (PreCOVID-19 = 5.3%, Spring20 = 37.8%, Spring21 = 22.8%; P < .001). Physical activity scores (mean [95% CI]) were higher in Spring21 than in Spring20 but lower than in PreCOVID-19 (PreCOVID-19 = 23.1 [22.7, 23.5], Spring20 = 13.5 [13.3, 13.7], Spring21 = 21.9 [21.6, 22.2]). Similarly, QoL scores were higher in Spring21 than in Spring20 but lower than in PreCOVID-19 (PreCOVID-19 = 92.8 [92.5, 93.1], Spring20 = 80.7 [80.3, 81.1], Spring21 = 84.3 [83.8, 84.8]).

CONCLUSIONS

Although sports have restarted, clinicians should be aware that physical activity, mental health, and QoL are still significantly affected in adolescent athletes by the ongoing pandemic.

EGS P01 The diurnal and seasonal relationships of pedestrian injuries secondary to motor vehicles in young people

Background

There remains a significant morbidity and mortality in young pedestrians hit by motor vehicles, even in the era of pedestrian crossings and speed limits. The aim of this study was to compare incidence and injury severity of motor vehicle-related pedestrian trauma according to time of day and season in a young population, based on the supposition that injuries would be more prevalent during dusk and dawn and during autumn and winter.

Methods

Data was retrieved for patients between 10–25 years old from the national Trauma Audit and Research Network (TARN) database, who had been involved as pedestrians in motor vehicle accidents between 2015–2020. The incidence of injuries, their severity (using the Injury Severity Score [ISS]), hospital transfer time and mortality were analysed according to the hours of daylight, darkness and season.

Results

The study identified a seasonal pattern, showing that autumn was the predominant season and lead to 34.9% of injuries, with a further 25.4% in winter in comparison to spring and summer, with 21.4% and 18.3% of injuries respectively. However, visibility alone was not a sufficient factor as 49.5% of injuries occurred during time of darkness, while 50.5% occurred during daylight. Importantly, the greatest injury rate (number of injuries/hour) occurred between 1500–1630 correlating to school pick up times. A further significant relationship between injury severity score (ISS) and daylight was demonstrated (p-value= 0.0124) with moderate injuries (ISS 9–14) occurring most commonly during the day (72.7%) and more severe injuries (ISS&gt;15) occurred during the night (55.8%).

Conclusions

We have identified a relationship between time of day and the frequency and severity of pedestrian trauma in young people. In addition, particular time groupings correspond to the greatest injury rate, suggesting that reduced visibility coupled with school pick up times may play a significant role . This could be addressed through a targeted public health approach to implement change. We recommend targeted public health measures to improve road safety that focus on these times and that increase the visibility of children combined with education for drivers.

Sustainable financing for Immunization Agenda 2030

Sustainable financing for immunization refers to the sufficient and predictable allocation and use of resources to support the achievement of immunization goals within the framework of overall health financing. The Immunization Agenda 2030 (IA2030) agenda spells out four important focus areas needed for sustainable financing: (1) ensuring sufficient and predictable resources, (2) making optimal use of resources, (3) aligning partnerships, and (4) supporting sustainable transitions from external assistance. This paper summarizes the evidence and proposes interventions under each area. While immunization is one of the best investments and justifies public financing, the COVID-19 pandemic has led to the worst economic recession since the Great Depression and threatens countries' ability to mobilize funding to ensure continuity and access to essential services, including immunization. Strategies for ensuring adequate resources differ by income group but include raising more revenues, reprioritizing the budget towards health, and ensuring that health resources favor Primary Health Care (PHC) and immunization. In low- and lower-middle income countries, support from Gavi, the Vaccine Alliance, which channels the largest amount of external financing, will remain important, but some lower-middle income countries will need to prepare for transition. Countries benefitting from the Global Polio Eradication Initiative (GPEI) are also experiencing a transition from GPEI financing to domestic and other external financing. This paper outlines ways in which countries can improve the use of domestic and external resources to better incentivize high-quality PHC and immunization services and align immunization programs with health sector reforms. While governments must lead, collective action from development partners, the private sector, and civil society is needed to promote health system financing systems that ensure that the world is better prepared for future outbreaks and pandemics, while reinforcing the IA2030 vision and making progress towards universal health coverage and the Sustainable Development Goals.

Time Delta Head Impact Frequency: An Analysis on Head Impact Exposure in the Lead Up to a Concussion: Findings from the NCAA-DOD Care Consortium

Sport-related concussions can result from a single high magnitude impact that generates concussive symptoms, repeated subconcussive head impacts aggregating to generate concussive symptoms, or a combined effect from the two mechanisms. The array of symptoms produced by these mechanisms may be clinically interpreted as a sport-related concussion. It was hypothesized that head impact exposure resulting in concussion is influenced by severity, total number, and frequency of subconcussive head impacts. The influence of total number and magnitude of impacts was previously explored, but frequency was investigated to a lesser degree. In this analysis, head impact frequency was investigated over a new metric called ‘time delta’, the time difference from the first recorded head impact of the day until the concussive impact. Four exposure metrics were analyzed over the time delta to determine whether frequency of head impact exposure was greater for athletes on their concussion date relative to other dates of contact participation. Those metrics included head impact frequency, head impact accrual rate, risk weighted exposure (RWE), and RWE accrual rate. Athletes experienced an elevated median number of impacts, RWE, and RWE accrual rate over the time delta on their concussion date compared to non-injury sessions. This finding suggests elevated frequency of head impact exposure on the concussion date compared to other dates that may precipitate the onset of concussion.

Proteomic Profiling of Plasma Biomarkers Associated With Return to Sport Following Concussion: Findings From the NCAA and Department of Defense CARE Consortium

Objective

To investigate the plasma proteomic profiling in identifying biomarkers related to return to sport (RTS) following a sport-related concussion (SRC).

Methods

This multicenter, prospective, case-control study was part of a larger cohort study conducted by the NCAA-DoD Concussion Assessment, Research, and Education (CARE) Consortium, athletes (n = 140) with blood collected within 48 h of injury and reported day to asymptomatic were included in this study, divided into two groups: (1) recovery <14-days (n = 99) and (2) recovery ≥14-days (n = 41). We applied a highly multiplexed proteomic technique that uses DNA aptamers assay to target 1,305 proteins in plasma samples from concussed athletes with <14-days and ≥14-days.

Results

We identified 87 plasma proteins significantly dysregulated (32 upregulated and 55 downregulated) in concussed athletes with recovery ≥14-days relative to recovery <14-days groups. The significantly dysregulated proteins were uploaded to Ingenuity Pathway Analysis (IPA) software for analysis. Pathway analysis showed that significantly dysregulated proteins were associated with STAT3 pathway, regulation of the epithelial mesenchymal transition by growth factors pathway, and acute phase response signaling.

Conclusion

Our data showed the feasibility of large-scale plasma proteomic profiling in concussed athletes with a <14-days and ≥ 14-days recovery. These findings provide a possible understanding of the pathophysiological mechanism in neurobiological recovery. Further study is required to determine whether these proteins can aid clinicians in RTS decisions.

Better Understanding of the Metamorphosis of Pregnancy (BUMP): protocol for a digital feasibility study in women from preconception to postpartum

The Better Understanding the Metamorphosis of Pregnancy (BUMP) study is a longitudinal feasibility study aimed to gain a deeper understanding of the pre-pregnancy and pregnancy symptom experience using digital tools. The present paper describes the protocol for the BUMP study. Over 1000 participants are being recruited through a patient provider-platform and through other channels in the United States (US). Participants in a preconception cohort (BUMP-C) are followed for 6 months, or until conception, while participants in a pregnancy cohort (BUMP) are followed into their fourth trimester. Participants are provided with a smart ring, a smartwatch (BUMP only), and a smart scale (BUMP only) alongside cohort-specific study apps. Participant centric engagement strategies are used that aim to co-design the digital approach with participants while providing knowledge and support. The BUMP study is intended to lay the foundational work for a larger study to determine whether participant co-designed digital tools can be used to detect, track and return multimodal symptoms during the perinatal window to inform individual level symptom trajectories.

Impact of enhanced personal protective equipment on surgeon workload and intraoperative patient outcomes

This work shows the need for targeted improvement to mitigate communication challenges associated with use of enhanced personal protective equipment. The data provide reassurance to surgeons and patients that there is no negative impact on surgeon workload or patient outcomes from use of enhanced personal protective equipment in the operating theatre.

O35 The impact of COVID-19 on access and availability of radiological imaging and surgical intervention at the east Midlands major trauma centre: an icon trauma study

Introduction

During the COVID-19 pandemic, Major Trauma services were subject to significant challenges including reduced access to Computed Tomography (CT) scanning and restrictions on operative intervention due to limited intensive care beds. This study evaluated the pandemic’s impact on access and timeliness of imaging and surgical intervention.

Method

This observational study compared 2 cohorts of patients admitted in a 10-week period during the COVID-19 pandemic and a similar time period in 2019. Variables included demographics, time to CT scan and to surgery and operative characteristics. Statistical comparisons were undertaken using Mann Whitney U, Fisher’s exact and Chi-squared tests.

Result

Of 642 patients, 405 were admitted in 2019 and 237 in 2020 representing a 41.5% absolute reduction in trauma admissions during the pandemic. There were no statistical differences (P = 0.2585) between arrival to the Emergency Department and time to CT scan across both years (median 42 minutes) or between operative approach (P = 0.728) and level of post-operative care (P = 0.788). However, there were statistical differences in time to surgery (P = 0.0193) and operative length (P = 0.0141) with a 2-fold increase in overnight operating, 31.2% increase in patients operated on &lt; 24 hours from admission, and 42.9% reduction in surgery lasting &gt;120 minutes during the COVID-19 pandemic.

Conclusion

Early robust restructuring of trauma services during the COVID-19 pandemic ensured timely access to appropriate imaging and surgery for major trauma injured patients. The higher rates of overnight surgery and shorter duration of procedure were likely explained by the increased onsite availability of suitably trained trauma surgical teams.

Take-home Message

COVID-19 had the potential to significantly impact Major Trauma services, however excellence in patient care was maintained by quick restructuring to staff, space and services Improvements to the Major Trauma pathway have become ingrained into daily practice and optimised for future outbreaks.

Discriminative Validity of Vestibular Ocular Motor Screening in Identifying Concussion Among Collegiate Athletes: A National Collegiate Athletic Association-Department of Defense Concussion Assessment, Research, and Education Consortium Study

BACKGROUND

Vestibular and ocular motor screening tools, such as the Vestibular/Ocular Motor Screening (VOMS), are recognized as important components of a multifaceted evaluation of sport-related concussion. Previous research has supported the predictive utility of the VOMS in identifying concussion, but researchers have yet to examine the predictive utility of the VOMS among collegiate athletes in the first few days after injury.

PURPOSE

To determine the discriminative validity of individual VOMS item scores and an overall VOMS score for identifying collegiate athletes with an acute sport-related concussion (≤72 hours) from healthy controls matched by age, sex, and concussion history.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Participants (N = 570) aged 17 to 25 years were included from 8 institutions of the National Collegiate Athletic Association-Department of Defense CARE Consortium (Concussion Assessment, Research, and Education): 285 athletes who were concussed (per current consensus guidelines) and 285 healthy controls matched by age, sex, and concussion history. Participants completed the VOMS within 3 days of injury (concussion) or during preseason (ie, baseline; control). Symptoms are totaled for each VOMS item for an item score (maximum, 40) and totaled across items for an overall score (maximum, 280), and distance (centimeters) for near point of convergence (NPC) is averaged across 3 trials. Receiver operating characteristic analysis of the area under the curve (AUC) was performed on cutoff scores using Youden index (J) for each VOMS item, overall VOMS score, and NPC distance average. A logistic regression was conducted to identify which VOMS scores identified concussed status.

RESULTS

A symptom score ≥1 on each VOMS item and horizontal vestibular/ocular reflex ≥2 significantly discriminated concussion from control (AUC, 0.89-0.90). NPC distance did not significantly identify concussion from control (AUC, 0.51). The VOMS overall score had the highest accuracy (AUC, 0.91) for identifying sport-related concussion from control. Among the individual items, vertical saccades ≥1 and horizontal vestibular/ocular reflex ≥2 best discriminated concussion from control.

CONCLUSION

The findings indicate that individual VOMS items and overall VOMS scores are useful in identifying concussion in collegiate athletes within 3 days of injury. Clinicians can use the cutoffs from this study to help identify concussion in collegiate athletes.

617 Does Wearing Enhanced Personal Protective Equipment (PPE) In Theatre Increase Surgeon Workload and Patient Morbidity?

Introduction

Delivery of surgical services during the Covid-19 pandemic has required the use of enhanced PPE in the operating theatre. We sought to evaluate the impact of this change on surgeon workload and intraoperative patient outcomes.

Method

Surgeons performing as primary operator completed an online procedure-specific questionnaire on workload ratings for each operative case, using an extension of the validated Surgeon Task Load Index (SURG-TLX) tool (reported on a 20-point scale), together with operative details. Local approval was obtained at individual sites. Data was analysed in Stata SE v16.

Results

118 responses (17 surgeons, 7 specialties) were collected from June to September 2020. 77.1% used enhanced PPE. There was no association between enhanced PPE use and overall workload (p = 0.151) as measured with SURG-TLX, although surgeons wearing enhanced PPE commonly reported finding individual procedures harder than expected (37% vs 0%, p < 0.001). Communication was rated worse when using enhanced PPE use (MD -4.38, 95%CI -6.74 to 02.03; p < 0.001). There was no association between enhanced PPE use and intraoperative complications (p = 0.745).

Conclusions

The use of enhanced PPE is not associated with complications or increased surgeon workload assessed by SURG-TLX. It is, however, associated with difficulty in communicating, and subjectively experiencing more procedural challenge than anticipated.

664 The ICON Trauma Study: The Impact of the COVID-19 Lockdown on Major Trauma Workload in the UK

Introduction

Anecdotal evidence suggest a direct impact of the SARS-COV-2-pandemic on presentation and severity of major trauma.

Method

This observational study from a UK Major Trauma Centre matched a cohort of patients admitted during a 10-week period of the SARS-CoV-2-pandemic (09/03/2020 to 18/05/2020) to a historical cohort admitted during a similar time period in 2019 (11/03/2019 to 20/05/2019). Demographic differences, injury method and severity were compared using Fisher’s and Chi-squared tests. Multivariable logistic regression examined the associated factors predicting 30-day mortality.

Results

Of 642 patients, 405 and 237 were in the 2019 and 2020 cohorts respectively. 1.69%(4/237) of the 2020 cohort tested SARS-CoV-2 positive. There was a 41.5% decrease in trauma admissions in 2020. The 2020 cohort was older (median 46 vs.40 years), more comorbid and frailer (p < 0.0015). There was a significant difference in injury method with a decrease in vehicle related trauma, but an increase in falls. There was a 2-fold increased risk of mortality in the 2020 cohort that in adjusted models, was explained by higher injury severity and frailty. Positive SARS-CoV-2 status was not associated with increased mortality on multivariable analysis.

Conclusions

Patients admitted during the SARS-CoV-2-pandemic were older, frailer, more co-morbid and had an increased risk of mortality.

1002 Calcium administration in Major haemorrhage Protocol

Introduction

Calcium gluconate is an essential part of the major haemorrhage protocol (MHP). It minimizes the exacerbation of transfusion coagulopathies due to the citrate preservative. As fifty percent of trauma patients present with hypocalcaemia prior to transfusion, the risk is pertinent. Given the importance of the issue, surprisingly current guidelines remain sparse. We analysed the percentage of patients who received calcium and their hypocalcaemia incidence.

Method

A Retrospective review of red traumas during June to August 2019. The frequency of MHP and the patient’s ionised plasma calcium levels on VBG (1.15-1.26mmol/L) were identified. Our standard stated 100% of MHP should receive calcium. A massive transfusion was defined as 10 red blood cells units in 24 hours or 4 blood products within 30mins.

Results

27 red traumas were accepted to audit, MHP was activated in 85%. Out of these 75% received calcium and on average after 6.4 units of blood products. The incidence of ionised hypocalcaemia in all MHP patients was 67%.

Conclusions

We identified a standard that supplementary calcium should be supplemented in all MHPs. Hypocalcaemia was more frequency than our research stipulated. Improvement needs to be made to meet standards. We recommend incorporation of Calcium gluconate into major haemorrhage pack and transfusion guidelines.

Proceedings From the Ice Hockey Summit III: Action on Concussion

OBJECTIVES

The Ice Hockey Summit III provided updated scientific evidence on concussions in hockey to inform these 5 objectives: (1) describe sport related concussion (SRC) epidemiology; (2) classify prevention strategies; (3) define objective, diagnostic tests; (4) identify treatment; and (5) integrate science and clinical care into prioritized action plans and policy.

METHODS

Our action plan evolved from 40 scientific presentations. The 155 attendees (physicians, athletic trainers, physical therapists, nurses, neuropsychologists, scientists, engineers, coaches, and officials) voted to prioritize these action items in the final Summit session.

RESULTS

To (1) establish a national and international hockey database for SRCs at all levels; (2) eliminate body checking in Bantam youth hockey games; (3) expand a behavior modification program (Fair Play) to all youth hockey levels; (4) enforce game ejection penalties for fighting in Junior A and professional hockey leagues; (5) establish objective tests to diagnose concussion at point of care; and (6) mandate baseline testing to improve concussion diagnosis for all age groups.

CONCLUSIONS

Expedient implementation of the Summit III prioritized action items is necessary to reduce the risk, severity, and consequences of concussion in the sport of ice hockey.

Sediment and nutrient sources and sinks in a wet-dry tropical catchment draining to the Great Barrier Reef

Many tropical river systems have altered water quality due to human land use, impacting the biodiversity of freshwater and coastal ecosystems. Long-term, catchment-scale monitoring is needed to understand pollutant sources, controls, and trends. This 12-year study monitored baseflow and flood event nutrient and sediment concentrations, and estimated sediment loads across the Normanby Basin in northern Australia. Suspended sediment concentrations and yields were highest in upper catchment areas where cattle grazing occurred on erosion-prone sodic soils. Mid- and lower catchment rivers and floodplains were a sink for sediments and nutrients, trapping around 75% of suspended sediments during events. Clays (<4 μm) were preferentially transported to the estuary, with an estimated 46% sediment delivery ratio. In the estuary, suspended sediment concentrations were influenced by tidal resuspension processes and there were significant sources of DIN. These findings can help prioritise land management investments for the protection of Great Barrier Reef and freshwater ecosystems.

Assessment of Blood Biomarker Profile After Acute Concussion During Combative Training Among US Military Cadets: A Prospective Study From the NCAA and US Department of Defense CARE Consortium

IMPORTANCE

Validation of protein biomarkers for concussion diagnosis and management in military combative training is important, as these injuries occur outside of traditional health care settings and are generally difficult to diagnose.

OBJECTIVE

To investigate acute blood protein levels in military cadets after combative training-associated concussions.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective case-control study was part of a larger cohort study conducted by the National Collegiate Athletic Association and the US Department of Defense Concussion Assessment Research and Education (CARE) Consortium from February 20, 2015, to May 31, 2018. The study was performed among cadets from 2 CARE Consortium Advanced Research Core sites: the US Military Academy at West Point and the US Air Force Academy. Cadets who incurred concussions during combative training (concussion group) were compared with cadets who participated in the same combative training exercises but did not incur concussions (contact-control group). Clinical measures and blood sample collection occurred at baseline, the acute postinjury point (<6 hours), the 24- to 48-hour postinjury point, the asymptomatic postinjury point (defined as the point at which the cadet reported being asymptomatic and began the return-to-activity protocol), and 7 days after return to activity. Biomarker levels and estimated mean differences in biomarker levels were natural log (ln) transformed to decrease the skewness of their distributions. Data were collected from August 1, 2016, to May 31, 2018, and analyses were conducted from March 1, 2019, to January 14, 2020.

EXPOSURE

Concussion incurred during combative training.

MAIN OUTCOMES AND MEASURES

Proteins examined included glial fibrillary acidic protein, ubiquitin C-terminal hydrolase-L1, neurofilament light chain, and tau. Quantification was conducted using a multiplex assay (Simoa; Quanterix Corp). Clinical measures included the Sport Concussion Assessment Tool-Third Edition symptom severity evaluation, the Standardized Assessment of Concussion, the Balance Error Scoring System, and the 18-item Brief Symptom Inventory.

RESULTS

Among 103 military service academy cadets, 67 cadets incurred concussions during combative training, and 36 matched cadets who engaged in the same training exercises did not incur concussions. The mean (SD) age of cadets in the concussion group was 18.6 (1.3) years, and 40 cadets (59.7%) were male. The mean (SD) age of matched cadets in the contact-control group was 19.5 (1.3) years, and 25 cadets (69.4%) were male. Compared with cadets in the contact-control group, those in the concussion group had significant increases in glial fibrillary acidic protein (mean difference in ln values, 0.34; 95% CI, 0.18-0.50; P < .001) and ubiquitin C-terminal hydrolase-L1 (mean difference in ln values, 0.97; 95% CI, 0.44-1.50; P < .001) levels at the acute postinjury point. The glial fibrillary acidic protein level remained high in the concussion group compared with the contact-control group at the 24- to 48-hour postinjury point (mean difference in ln values, 0.22; 95% CI, 0.06-0.38; P = .007) and the asymptomatic postinjury point (mean difference in ln values, 0.21; 95% CI, 0.05-0.36; P = .01). The area under the curve for all biomarkers combined, which was used to differentiate cadets in the concussion and contact-control groups, was 0.80 (95% CI, 0.68-0.93; P < .001) at the acute postinjury point.

CONCLUSIONS AND RELEVANCE

This study's findings indicate that blood biomarkers have potential for use as research tools to better understand the pathobiological changes associated with concussion and to assist with injury identification and recovery from combative training-associated concussions among military service academy cadets. These results extend the previous findings of studies of collegiate athletes with sport-associated concussions.

Maxillofacial injury related to an exploding e-cigarette

Electronic cigarettes (also known as e-cigarettes or electronic nicotine delivery systems) were invented in China in 2003 then introduced to the British market in 2007. They remain popular among the public and are deemed to be effective in reducing tobacco smoking (the UK being one of the first countries to embrace them in a harm reduction policy). However, reports in the media of e-cigarettes exploding are of concern, considering the potential functional and psychological impairment that lifelong disfigurement will cause, especially given their uptake among people of any age. We present a case of this rare, but dramatic, effect of e-cigarette use as a warning to the public.

Viscoelastic haemostatic assay augmented protocols for major trauma haemorrhage (ITACTIC): a randomized, controlled trial

PURPOSE

Contemporary trauma resuscitation prioritizes control of bleeding and uses major haemorrhage protocols (MHPs) to prevent and treat coagulopathy. We aimed to determine whether augmenting MHPs with Viscoelastic Haemostatic Assays (VHA) would improve outcomes compared to Conventional Coagulation Tests (CCTs).

METHODS

This was a multi-centre, randomized controlled trial comparing outcomes in trauma patients who received empiric MHPs, augmented by either VHA or CCT-guided interventions. Primary outcome was the proportion of subjects who, at 24 h after injury, were alive and free of massive transfusion (10 or more red cell transfusions). Secondary outcomes included 28-day mortality. Pre-specified subgroups included patients with severe traumatic brain injury (TBI).

RESULTS

Of 396 patients in the intention to treat analysis, 201 were allocated to VHA and 195 to CCT-guided therapy. At 24 h, there was no difference in the proportion of patients who were alive and free of massive transfusion (VHA: 67%, CCT: 64%, OR 1.15, 95% CI 0.76-1.73). 28-day mortality was not different overall (VHA: 25%, CCT: 28%, OR 0.84, 95% CI 0.54-1.31), nor were there differences in other secondary outcomes or serious adverse events. In pre-specified subgroups, there were no differences in primary outcomes. In the pre-specified subgroup of 74 patients with TBI, 64% were alive and free of massive transfusion at 24 h compared to 46% in the CCT arm (OR 2.12, 95% CI 0.84-5.34).

CONCLUSION

There was no difference in overall outcomes between VHA- and CCT-augmented-major haemorrhage protocols.

Mental Health, Physical Activity, and Quality of Life of US Adolescent Athletes During COVID-19-Related School Closures and Sport Cancellations: A Study of 13 000 Athletes

CONTEXT

In the spring of 2020, US schools closed to in-person teaching and sports were cancelled to control the transmission of coronavirus disease 2019 (COVID-19). It is critical to understand the mental and physical health of adolescent athletes during this time.

OBJECTIVE

To describe the health of athletes during COVID-19-related school closures and sport cancellations.

DESIGN

Cross-sectional study.

SETTING

A national sample recruited via social media.

PATIENTS OR OTHER PARTICIPANTS

A total of 13 002 US adolescent athletes (age = 16.3 ± 1.2 years, females = 52.9%, males = 47.0%) completed an anonymous online survey.

MAIN OUTCOME MEASURE(S)

Demographic information collected was sex, grade, sport(s) played, and zip code. Assessments used were the General Anxiety Disorder 7-Item for anxiety, Patient Health Questionnaire 9-Item for depression, the Pediatric Functional Activity Brief Scale for physical activity, and the Pediatric Quality of Life Inventory 4.0 for quality of life. Mental health, physical activity, and health-related quality-of-life variables were compared among sex, grade, sport(s) played, and poverty level using means and 95% confidence intervals (CIs) from the survey-weighted analysis of variance.

RESULTS

Females reported a higher prevalence of moderate to severe anxiety symptoms (females = 43.7% versus males = 28.2%). The Pediatric Functional Activity Brief Scale score was highest (best) for grade 9 (mean = 14.5, 95% CI = 14.0, 15.0) and lowest for grade 11 (mean = 10.9, 95% CI = 10.5, 11.3). The prevalence of depression symptoms was highest in team sport (74.1%) and lowest in individual sport (64.9%) participants. The total Pediatric Quality of Life Inventory score was lowest (worst) for athletes from counties with the highest poverty levels (high: mean = 74.5, 95% CI = 73.7, 75.3; middle: mean = 78.9, 95% CI = 78.0, 79.8; and low: mean = 78.3, 95% CI = 77.4, 79.1).

CONCLUSIONS

The health of US adolescents during the COVID-19-related school closures and sport cancellations varied to differing degrees depending on sex, grade level, type of sport participation, and level of poverty. Health policy experts should consider these findings in the future when creating and implementing policies to improve the health of adolescents in the United States.

The Health Of Us Adolescent Athletes During Covid-19 Related School Closures And Sport Cancellations

CONTEXT

In the spring of 2020, US schools closed to in-person teaching and sports were cancelled to control the transmission of COVID-19. It is critical to understand the mental and physical health of adolescent athletes during this time.

OBJECTIVE

Describe the health of athletes during COVID-19 related school closures and sport cancellations.

DESIGN

Cross sectional.

SETTING

A national sample recruited via social media.

PATIENTS OR OTHER PARTICIPANTS

13,002 US adolescent athletes (age=16.3+1.2 yrs., female=53.1%) completed an anonymous online survey.

MAIN OUTCOME MEASURE(S)

Demographic information included: sex, grade, sports played and zip code. Assessments included the: General Anxiety Disorder-7 Item (GAD-7) for anxiety, Patient Health Questionnaire-9 Item (PHQ-9) for depression, the Pediatric Functional Activity Brief Scale (PFABS) for physical activity, and the Pediatric Quality of Life Inventory 4.0 (PedsQL) for quality of life. Mental health, physical activity and quality of life variables were compared between sex, grade, sports played and poverty level using means and 95%CI from the survey weighted ANOVA.

RESULTS

Females reported a higher prevalence of moderate to severe anxiety symptoms (females=43.7% vs. males=28.2%). The PFABS score (mean [95%CI] was highest (best) for grade 9 (14.5 [14.0,15.0]) and lowest for grade 11 (10.9 [10.5,11.3]. The prevalence of depression symptoms was highest in team sport (74.1%) and lowest for individual sport participants (64.9%). The total PedsQL score was lowest (worst) for athletes from counties with the highest poverty levels (high=74.5[73.7,75.3], middle=78.9[78.0,79.8], low=78.3 [77.4,79.1]).

CONCLUSIONS

The health of US adolescents during the COVID-19 related school closures and sport cancellations varied to differing degrees depending on sex, grade level, type of sport participation and level of poverty. Health policy experts should consider these findings when creating and implementing policies to improve the health of adolescents in the US in the future.

The Incidence and Risk Factors for Injuries in Girls Volleyball: A Prospective Study of 2072 Players

CONTEXT

Girls high school volleyball is very popular across the United States. There is limited prospective data regarding the incidence and risk factors of time loss (TL) and non-time loss (NTL) injuries sustained in this population.

OBJECTIVES

To estimate the incidence and describe the characteristics of injuries (TL and NTL) sustained in a girls' high school volleyball season.

DESIGN

Descriptive epidemiology study.

SETTING

Convenience sample of 78 high school interscholastic volleyball programs.

PATIENTS OR OTHER PARTICIPANTS

High school volleyball players participating during the 2018 interscholastic season.

MAIN OUTCOME MEASURES

TL and NTL injury rates, proportions, rate ratios, and with 95%CI.

RESULTS

A total of 2,072 girls enrolled in the study with 468 subjects (22.5%) sustaining 549 injuries (NTL=28.4%, TL=71.6%) for an overall injury rate of 5.31 [4.89, 5.79] per 1000 AEs. The competition injury rate was greater than the practice injury rate for all injuries (IRR: 1.19, [1.00, 1.41]) and TL injuries (IRR: 1.31, [1.07, 1.60]). Players with a previous musculoskeletal injury had a higher rate of TL than NTL injuries (IRR; 1.36 [1.12, 1.65]). Ankle injuries accounted for the greatest proportion of TL injuries (n=110, 28%), while the greatest proportion of NTL injuries occurred in the hand/fingers (n=34, 22%). Moreover, ligament sprains accounted for 40% of TL injuries (n=156), whereas muscle/tendon strains (n=79, 51%) accounted for over half of all NTL injuries.

CONCLUSIONS

While the majority of injuries sustained by adolescent girls' volleyball athletes were TL in nature, nearly a third of all injuries were NTL injuries. Injury characteristics differed widely between TL and NTL injuries. Understanding the most common types and characteristics of injury among high school volleyball players is critical for the development of effective injury prevention programs.

Concussion Risk Between Individual Football Players: Survival Analysis of Recurrent Events and Non-events

Concussion tolerance and head impact exposure are highly variable among football players. Recent findings highlight that head impact data analyses need to be performed at the subject level. In this paper, we describe a method of characterizing concussion risk between individuals using a new survival analysis technique developed with real-world head impact data in mind. Our approach addresses the limitations and challenges seen in previous risk analyses of football head impact data. Specifically, this demonstrative analysis appropriately models risk for a combination of left-censored recurrent events (concussions) and right-censored recurrent non-events (head impacts without concussion). Furthermore, the analysis accounts for uneven impact sampling between players. In brief, we propose using the Consistent Threshold method to develop subject-specific risk curves and then determine average risk point estimates between subjects at injurious magnitude values. We describe an approach for selecting an optimal cumulative distribution function to model risk between subjects by minimizing injury prediction error. We illustrate that small differences in distribution fit can result in large predictive errors. Given the vast amounts of on-field data researchers are collecting across sports, this approach can be applied to develop population-specific risk curves that can ultimately inform interventions that reduce concussion incidence.

Estimated age of first exposure to American football and outcome from concussion

OBJECTIVE

To examine the association between estimated age at first exposure (eAFE) to American football and clinical measures throughout recovery following concussion.

METHODS

Participants were recruited across 30 colleges and universities as part of the National Collegiate Athletic Association (NCAA)-Department of Defense Concussion Assessment, Research and Education Consortium. There were 294 NCAA American football players (age 19 ± 1 years) evaluated 24-48 hours following concussion with valid baseline data and 327 (age 19 ± 1 years) evaluated at the time they were asymptomatic with valid baseline data. Participants sustained a medically diagnosed concussion between baseline testing and postconcussion assessments. Outcome measures included the number of days until asymptomatic, Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) composite scores, Balance Error Scoring System (BESS) total score, and Brief Symptom Inventory 18 (BSI-18) subscores. The eAFE was defined as participant's age at the time of assessment minus self-reported number of years playing football.

RESULTS

In unadjusted regression models, younger eAFE was associated with lower (worse) ImPACT Visual Motor Speed (R ² = 0.031, p = 0.012) at 24-48 hours following injury and lower (better) BSI-18 Somatization subscores (R ² = 0.014, p = 0.038) when the athletes were asymptomatic. The effect sizes were very small. The eAFE was not associated with the number of days until asymptomatic, other ImPACT composite scores, BESS total score, or other BSI-18 subscores.

CONCLUSION

Earlier eAFE to American football was not associated with longer symptom recovery, worse balance, worse cognitive performance, or greater psychological distress following concussion. In these NCAA football players, longer duration of exposure to football during childhood and adolescence appears to be unrelated to clinical recovery following concussion.

Plasma Biomarker Concentrations Associated With Return to Sport Following Sport-Related Concussion in Collegiate Athletes-A Concussion Assessment, Research, and Education (CARE) Consortium Study

IMPORTANCE

Identifying plasma biomarkers associated with the amount of time an athlete may need before they return to sport (RTS) following a sport-related concussion (SRC) is important because it may help to improve the health and safety of athletes.

OBJECTIVE

To examine whether plasma biomarkers can differentiate collegiate athletes who RTS in less than 14 days or 14 days or more following SRC.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter prospective diagnostic study, conducted by the National Collegiate Athletics Association-Department of Defense Concussion Assessment, Research, and Education Consortium, included 127 male and female athletes who had sustained an SRC while enrolled at 6 Concussion Assessment, Research, and Education Consortium Advanced Research Core sites as well as 2 partial-Advanced Research Core military service academies. Data were collected between February 2015 and May 2018. Athletes with SRC completed clinical testing and blood collection at preseason (baseline), postinjury (0-21 hours), 24 to 48 hours postinjury, time of symptom resolution, and 7 days after unrestricted RTS.

MAIN OUTCOMES AND MEASURES

A total of 3 plasma biomarkers (ie, total tau protein, glial fibrillary acidic protein [GFAP], and neurofilament light chain protein [Nf-L]) were measured using an ultrasensitive single molecule array technology and were included in the final analysis. RTS was examined between athletes who took less than 14 days vs those who took 14 days or more to RTS following SRC. Linear mixed models were used to identify significant interactions between period by RTS group. Area under the receiver operating characteristic curve analyses were conducted to examine whether these plasma biomarkers could discriminate between RTS groups.

RESULTS

The 127 participants had a mean (SD) age of 18.9 (1.3) years, and 97 (76.4%) were men; 65 (51.2%) took less than 14 days to RTS, and 62 (48.8%) took 14 days or more to RTS. Linear mixed models identified significant associations for both mean (SE) plasma total tau (24-48 hours postinjury, <14 days RTS vs ≥14 days RTS: -0.65 [0.12] pg/mL vs -0.14 [0.14] pg/mL; P = .008) and GFAP (postinjury, 14 days RTS vs ≥14 days RTS: 4.72 [0.12] pg/mL vs 4.39 [0.11] pg/mL; P = .04). Total tau at the time of symptom resolution had acceptable discrimination power (area under the receiver operating characteristic curve, 0.75; 95% CI, 0.63-0.86; P < .001). We also examined a combined plasma biomarker panel that incorporated Nf-L, GFAP, and total tau at each period to discriminate RTS groups. Although the analyses did reach significance at each time period when combined, results indicated that they were poor at distinguishing the groups (area under the receiver operating characteristic curve, <0.7).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that measures of total tau and GFAP may identify athletes who will require more time to RTS. However, further research is needed to improve our ability to determine recovery following an SRC.

A100 ORAL VANCOMYCIN THERAPY FOR CLOSTRIDIOIDES DIFFICILE INFECTION AND RISK OF INFECTION WITH GRAM-NEGATIVE ORGANISMS

Background

Vancomycin is the recommended first-line therapy for mild to severe Clostridioides difficile infection (CDI). However, oral vancomycin is associated with disruption of the indigenous microbiota, predisposing patients to overgrowth of endogenous pathogens such as vancomycin-resistant enterococci.

Aims

The primary objective of the study is to examine the effect of the treatment regimens of CDI on the risk of infection with gram-negative organisms in adult patients treated for CDI.

Methods

A retrospective cohort study of 319 adult patients treated for CDI at Hamilton Health Sciences in the year 2015. A multivariate logistic regression analysis was performed to determine if oral vancomycin-based therapy is associated with an increased risk of infection with gram-negative organisms after adjustment for other factors.

Results

Eighty-one patients were excluded because of recurrent episodes of CDI within the same year or missing information. 238 patients were included in the final analysis. 48 (20.2%) patients had positive culture for gram-negative organisms after onset of CDI. Urine was the most common source for gram-negative organisms (39/48, 81.3%) followed by blood (8/48,16.7%). The most common isolated gram-negative organisms were Escherichia coli (18/48, 37.5%) and Klebsiella pneumonia (9/48, 18.8%).

The most common CDI treatment regimens were metronidazole monotherapy (137/238, 57.6%), vancomycin monotherapy (13/238, 5.5%), and combination therapy (88/238, 37.0%). Among patients who were treated with metronidazole monotherapy, vancomycin monotherapy, and combination therapy, 30(30/137, 21.9%), 3 (3/13,23.1%), and 15 (15/88, 17.1%) had positive culture for gram-negative organisms, respectively (P= 0.6).

Ninety-seven (97/238,40.8%) patients had severe CDI, 40 (40/97, 41.2%) were treated with metronidazole monotherapy, 5(5/97, 5.2%) with vancomycin monotherapy, and 52 (52/97, 53.6%) with combination therapy. 26 (26/141,18.4%) and 22 (22/97, 22.7%) had positive culture for gram-negative organisms among patients with non-severe and severe CDI, receptively (P= 0.7). In the multivariate analysis, neither type of CDI treatment regimen (P=0.2, 95% CI 0.30–1.31) nor CDI severity (P=0.4, 95% CI 0.67–2.69) was associated an increased risk of infection with gram-negative organisms after CDI onset.

Conclusions

Contrary to the reported literature, we did not find that oral vancomycin-based CDI treatment was associated with increased risk of infection with gram-negative organisms.

Funding Agencies

None

Resting-State fMRI Metrics in Acute Sport-Related Concussion and Their Association with Clinical Recovery: A Study from the NCAA-DOD CARE Consortium

There has been a recent call for longitudinal cohort studies to track the physiological recovery of sport-related concussion (SRC) and its relationship with clinical recovery. Resting-state functional magnetic resonance imaging (rs-fMRI) has shown potential for detecting subtle changes in brain function after SRC. We investigated the effects of SRC on rs-fMRI metrics assessing local connectivity (regional homogeneity; REHO), global connectivity (average nodal strength), and the relative amplitude of slow oscillations of rs-fMRI (fractional amplitude of low-frequency fluctuations; fALFF). Athletes diagnosed with SRC (n = 92) completed visits with neuroimaging at 24-48 h post-injury (24 h), after clearance to begin the return-to-play (RTP) progression (asymptomatic), and 7 days following unrestricted RTP (post-RTP). Non-injured athletes (n = 82) completed visits yoked to the schedule of matched injured athletes and served as controls. Concussed athletes had elevated symptoms, worse neurocognitive performance, greater balance deficits, and elevated psychological symptoms at the 24-h visit relative to controls. These deficits were largely recovered by the asymptomatic visit. Concussed athletes still reported elevated psychological symptoms at the asymptomatic visit relative to controls. Concussed athletes also had elevated REHO in the right middle and superior frontal gyri at the 24-h visit that returned to normal levels by the asymptomatic visit. Additionally, REHO in these regions at 24 h predicted psychological symptoms at the asymptomatic visit in concussed athletes. Current results suggest that SRC is associated with an acute alteration in local connectivity that follows a similar time course as clinical recovery. Our results do not indicate strong evidence that concussion-related alterations in rs-fMRI persist beyond clinical recovery.

P10.02 Differentiating microglia and tumour associated macrophages in high grade glioma

BACKGROUND

Glioblastoma multiforme (GBM) is the most common primary brain tumour that affects adults. This aggressive tumour is invariably fatal, carrying a rapid progression and a dismal median survival period of only 15 months despite multimodal treatment approaches. Central to GBM pathogenesis is the immunosuppressive profile of these tumours. The two cell types that are highly abundant in these tumours and play critical roles in the immunosuppressive niche are the brain’s resident microglia and their peripheral counterparts - tumour associated macrophages (TAMs). Despite microglia and TAMs being ontogenetically distinct, these cells have largely been grouped together in research owing to the previous lack of cell-specific markers. Recent evidence has suggested that although TAMs may hold a predominantly pro-tumoral role, microglia may adopt a more anti-tumoral phenotype. Therefore, the differentiation of these two cell types is critical in elucidating the potentially characteristic roles of these two cell types in GBM pathogenesis.

MATERIAL AND METHODS

Tissue sections from resected low- and high-grade glioma tumours, along with epilepsy tissue (control), were used for immunohistochemistry (IHC) staining of macrophage pan-makers (Iba1, CD45, PU.1) and microglial-specific markers (TMEM119, P2RY12). Marker co-localisation was then used to differentiate microglia from TAMs. We further investigated a wider subset of cell-specific markers using multicolour flow cytometry and immunocytochemical staining of isolated cells from patient tissue samples.

RESULTS

Immunofluorescent staining of glioma and epilepsy tissue revealed two clear populations of cells; one population displayed long processes and co-labelling for both pan- and microglial-specific markers, whilst the other population displayed an amoeboid phenotype with only pan-maker staining. Preliminary analysis comparing microglia/TAM populations in low-grade, high-grade and epilepsy tissue suggests a clear difference in the proportions of these cells.

CONCLUSION

Our work complements RNA-Seq studies, showing that TMEM119 and P2RY12, alongside other markers, can indeed identify two distinct myeloid cell populations within glioma tissue. This provides a strong basis for further study where we aim to elucidate the respective roles of microglia and TAMs within tumours. Ultimately, this may hold the potential for differential targeting of these cells using immunotherapies.

P10.03 Immunological differences between patient-matched normal-derived and GBM-derived pericytes

BACKGROUND

Glioblastoma Multiforme (GBM) is the most aggressive, fatal, yet most common form of brain malignancy in adults. Despite advances in immune-based treatments for other modes of cancer, GBM remains a challenge due to its ability to dampen immune responses via mechanisms not yet fully understood. With a median survival time of only 15 months following diagnosis, there is a strong push to find new targets for therapy. The microenvironment comprises a mixture of malignant tumour cells, stroma, blood vessels and infiltrating inflammatory cells. Despite advances in understanding the contribution of these cells in establishing an anti-inflammatory microenvironment, the contribution of pericytes, an important neurovascular mural cell that forms the blood-brain barrier, has been inadequately studied. Therefore, we investigated the differences in immune profile between patient-matched non-neoplastic brain- and GBM-derived pericytes under basal and induced conditions.

MATERIAL AND METHODS

Primary patient-matched non-neoplastic brain and GBM tumour derived pericytes were isolated from specimens excised from consenting patients undergoing GBM surgical resection at Auckland City Hospital. Pericytes were treated with inflammatory cytokines including IL-1β, IFN-γ, TNFα and TGFβ for up to 24 hours. Inflammatory profile changes were probed for using fluorescent immunocytochemistry, qRT-PCR and spectral flow cytometry. Media was also collected for secretome analysis via cytometric bead array.

RESULTS

GBM pericytes show decreased expression of CX3CL1, both basally and following IL-1β treatment, via qRT-PCR and CBA. In contrast, increased gene expression and secretion of IL-6 and IL-8 by GBM pericytes were observed. GBM pericytes also basally express CD90 and anti-inflammatory molecule PD-L1 compared to their normal counterparts. In terms of activated pathways, basal SMAD2/3 activation is increased in GBM pericytes, while also showing greater activation following treatment with IL-1β, IFN-γ but not TNFα. C/EBPδ is activated and translocated following inflammatory stimulation; however, shows localised expression within the cytoplasm only observed in GBM pericytes.

CONCLUSION

This immunological screen of GBM pericytes highlights them as key players in the establishment of the tumour microenvironment. With data suggesting the activation of pathways such as the SMAD2/3 pathway in an unconventional manner, it suggests the potential for pericytes to manipulate pathways towards a more immunosuppressive outcome. Further immune characterisation of such cells is required to fully understand how they might contribute to the immunosuppressive nature of GBM.

Accounting for Variance in Concussion Tolerance Between Individuals: Comparing Head Accelerations Between Concussed and Physically Matched Control Subjects

Researchers have been collecting head impact data from instrumented football players to characterize the biomechanics of concussion for the past 15 years, yet the link between biomechanical input and clinical outcome is still not well understood. We have previously shown that even though concussive biomechanics might be unremarkable in large datasets of head impacts, the impacts causing injury are of high magnitude for the concussed individuals relative to their impact history. This finding suggests a need to account for differences in tolerance at the individual level. In this study, we identified control subjects for our concussed subjects who demonstrated traits we believed were correlated to factors thought to affect injury tolerance, including height, mass, age, race, and concussion history. A total of 502 college football players were instrumented with helmet-mounted accelerometer arrays and provided complete baseline assessment data, 44 of which sustained a total of 49 concussion. Biomechanical measures quantifying impact frequency and acceleration magnitude were compared between groups. On average, we found that concussed subjects experienced 93.8 more head impacts (p = 0.0031), 10.2 more high magnitude impacts (p = 0.0157), and 1.9 × greater risk-weighted exposure (p = 0.0175) than their physically matched controls. This finding provides further evidence that head impact data need to be considered at the individual level and that cohort wide assessments may be of little value in the context of concussion.

Prevalence of Potentially Clinically Significant Magnetic Resonance Imaging Findings in Athletes with and without Sport-Related Concussion

Previous studies have shown that mild traumatic brain injury (mTBI) can cause abnormalities in clinically relevant magnetic resonance imaging (MRI) sequences. No large-scale study, however, has prospectively assessed this in athletes with sport-related concussion (SRC). The aim of the current study was to characterize and compare the prevalence of acute, trauma-related MRI findings and clinically significant, non-specific MRI findings in athletes with and without SRC. College and high-school athletes were prospectively enrolled and participated in scanning sessions between January 2015 through August 2017. Concussed contact sport athletes (n = 138; 14 female [F]; 19.5 ± 1.6 years) completed up to four scanning sessions after SRC. Non-concussed contact (n = 135; 15 F; 19.7 ± 1.6) and non-contact athletes (n = 96; 15 F; 20.0 ± 1.7) completed similar scanning sessions and served as controls. Board-certified neuroradiologists, blinded to SRC status, reviewed T₁-weighted and T₂-weighted fluid-attenuated inversion recovery and T₂*-weighted and T₂-weighted images for acute (i.e., injury-related) or non-acute findings that prompted recommendation for clinical follow-up. Concussed athletes were more likely to have MRI findings relative to contact (30.4% vs. 15.6%; odds ratio [OR] = 2.32; p = 0.01) and non-contact control athletes (19.8%; OR = 2.11; p = 0.04). Female athletes were more likely to have MRI findings than males (43.2% vs. 19.4%; OR = 2.62; p = 0.01). One athlete with SRC had an acute, injury-related finding; group differences were largely driven by increased rate of non-specific white matter hyperintensities in concussed athletes. This prospective, large-scale study demonstrates that <1% of SRCs are associated with acute injury findings on qualitative structural MRI, providing empirical support for clinical guidelines that do not recommend use of MRI after SRC.