Oxford University Hospitals NHS Trust Research Articles

Copeptin and the syndrome of inappropriate antidiuresis (SIAD) after pituitary transsphenoidal surgery.

This study evaluates the predictive value of copeptin for syndrome of inappropriate antidiuresis (SIAD) postpituitary transsphenoidal surgery (TSS). Data from 133 consecutive patients undergoing TSS (November 2017-October 2022) at Oxford University Hospitals NHS trust are presented in this retrospective study. Logistic regression (LR) and receiver operating characteristic (ROC) curves were performed to evaluate the diagnostic utility of copeptin. The Mann-Whitney U test was used to compare copeptin levels between the SIAD and no SIAD groups. Fourteen patients (10.8%) developed SIAD. Copeptin was available in 121, 53 and 87 patients for Days 1, 241 and 8 post-TSS, respectively. LR for Day 1 copeptin to predict SIAD gave an odds ratio (OR) of 1.0 (95%CI 42 0.84-1.20, p = .99), area under-ROC curve (AUC) was 0.49; Day 2 copeptin OR was 0.65 (95%CI 0.39-1.19, 43 p = .77), AUC was 0.57 LR for Day 1 sodium to predict SIAD gave an odds ratio (OR) of 1.0 (95%CI 0.85-1.21, p = .99), AUC was 0.50. In conclusion, our data provide no evidence for copeptin as a predictive marker for post-TSS SIAD.

Evidence-based Medical Leadership Development: A Systematic Review

1Alexander Mafi, 2Oscar Lyons, 3Robynne George, 4Joao Galante, 5Thomas Fordwoh, 6Jan Frich,7Jaason Geerts
 1University of Oxford, UK, 2University of Oxford, UK, 3Royal United Hospital Bath NHS Trust,4Oxford University Hospitals NHS Trust, UK, 5University of Oxford, UK, 6University of Oslo,Norway, 7Canadian College of Health Leaders, Ottawa, Canada
 
 Health systems invest significant resources in leadership development for physicians and other health professionals. Competent leadership is considered vital for maintaining and improving quality and patient safety. We carried out this systematic review to synthesise new empirical evidence regarding medical leadership development programme factors which are associated with outcomes at the clinical and organisational levels.
 117 studies were included in this systematic review. 28 studies met criteria for higher reliability studies. The median critical appraisal score according to the Medical Education Research Study Quality Instrument for quantitative studies was 8.5/18 and the median critical appraisal score according to the Jonna Briggs Institute checklist for qualitative studies was 3/10. There were recurring causes of low study quality scores related to study design, data analysis and reporting. There was considerable heterogeneity in intervention design and evaluation design. Programmes with internal or mixed faculty were significantly more likely to report organisational outcomes than programmes with external faculty only (p=0.049). Project work and mentoring increased the likelihood of organisational outcomes. No leadership development content area was particularly associated with organisational outcomes.
 In leadership development programmes in healthcare, external faculty should be used to supplement in-house faculty and not be a replacement for in-house expertise. To facilitate organisational outcomes, interventions should include project work and mentoring. Educational methods appear to be more important for organisational outcomes than specific curriculum content. Improving evaluation design will allow educators and evaluators to more effectively understand factors which are reliably associated with organisational outcomes of leadership development.

Relative benefits of extracorporeal shockwave lithotripsy (ESWL) compared to observation in acute renal colic

Miss Catherine Lovegrove1,2Mandy Spencer1Prof Ben Turney1,2Ms Naomi Neal1
 1 Department of Urology, Oxford University Hospitals NHS Trust, Oxford, Oxfordshire, UK2 University of Oxford Nuffield Department of Surgical Sciences, Oxford, Oxfordshire, UK
 
 Background NICE guidance recommends patients with renal colic be offered surgical treatment, including extracorporeal shockwave lithotripsy (ESWL), within 48 hours if pain is uncontrolled or stones unlikely to pass. We compared outcomes for ureteric stone passage after ESWL with those of observation to ascertain the relative benefits of ESWL.
 Methods We collected data on stone location, size and number of ESWL treatments required prospectively over 18 months. Stone passage was confirmed radiologically. Data were compared with MIMIC, a multi-centre collaborative study examining spontaneous stone passage after observation alone.
 Results 166 patients had ESWL for ureteric stones. Median size was 6.5mm (IQR 5.0-8.0mm). 57.2% (N=95) were proximal stones. Smaller stones required fewer treatments (P=0.003). Patients with a ureteric stone <5mm required median 1.0 ESWL treatments (IQR 1.0-2.0). Ureteric stones 5-7mm had median 1.0 treatments (IQR 1.0-2.0) and stones >7mm median 2.0 treatments (IQR 1.0-2.0). Compared to MIMIC, patients with ESWL for stones <5mm were 11% more likely to achieve stone clearance (100.0% vs 89.0%, P=0.001). ESWL for 5-7mm stones had 28.1% greater clearance compared to observation (77.1% vs. 49.0%, P<0.001) and ESWL for stones >7mm 21% greater likelihood of clearance (50.0% vs. 29.0%, P<0.001). Proximal ureteric stones were 16.4% more likely to pass with ESWL than observation (68.4% vs 52%, P=0.02). Distal stones showed similar passage with ESWL (77.5%) and observation (83.0%), P=0.43.
 Conclusions Proximal ureteric stones and those >5mm stones benefit most from ESWL. Results aid identification of patients whose stones are less likely to pass and warrant urgent review to consider ESWL.

Association of Increased Body Mass Index and Waist to Hip Ratio with Kidney Stone Disease: a prospective analysis of 493,410 UK Biobank participants

Catherine E Lovegrove1,2 – catherine.lovegrove@nds.ox.ac.ukThomas Littlejohns3- thomas.littlejohns@ndph.ox.ac.ukNaomi Allen3- naomi.allen@ndph.ox.ac.ukSarah A Howles1,4- sarah.bounds@doctors.org.ukBenjamin W Turney 1,2- ben.turney@nds.ox.ac.uk
 1 Department of Urology, Oxford University Hospitals NHS Trust, Oxford, Oxfordshire, UK2 University of Oxford Nuffield Department of Surgical Sciences, Oxford, Oxfordshire, UK3 University of Oxford Nuffield Department of Public Health, Oxford, Oxfordshire, UK4 Academic Endocrine Unit, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
 
 Objectives To investigate the relationship between measures of adiposity and risk of incident kidney stone disease.
 Patients and methods The UK Biobank is a prospective cohort study of ~500,000 participants whose height, weight, BMI, waist circumference, hip circumference, waist:hip ratio (WHR), total fat mass, fat-free mass, body-fat percentage and percentage truncal fat were measured at enrolment with linkage to medical records. ICD-10 and OPCS codes were used to identify individuals with a new diagnosis of nephrolithiasis from 2006-2010. Individuals with a history of kidney stones or incomplete data were excluded. Multivariate Cox-proportional hazard models were used to assess associations between anthropometric measures and incident kidney stones.
 Results From the UK Biobank, 493,410 individuals were identified for inclusion; 3,466 developed a kidney stone during the study period. Increasing weight, BMI, waist and hip circumferences, WHR, and body and truncal fat were associated with increased risk of incident kidney stone disease. However, after adjustment for BMI, only waist circumference and WHR remained significantly associated with risk of nephrolithiasis. In overweight patients, high (men 94-102cm, women 80-88cm) waist circumference or WHR (men >0.9, women >0.85) conferred >40% increased risk of stone formation.
 Conclusion This study indicates that android fat distribution is independently associated with increased risk of developing nephrolithiasis. Kidney stone disease is known to be associated with hypertension, cardiovascular disease, and diabetes, all of which are linked to android body shape. Our findings provide insight into anthropometric risk factors for stone disease, will facilitate identification of patients at greatest risk of stone recurrence, and will inform prevention strategies.

88 - Survival outcomes following concomitant chemoradiation (CRT) for stage III non-small cell lung cancer (NSCLC) at Oxford University Hospitals (OUH) NHS Trust

88 - Survival outcomes following concomitant chemoradiation (CRT) for stage III non-small cell lung cancer (NSCLC) at Oxford University Hospitals (OUH) NHS Trust

180 Management of Open Fractures at Oxford University Hospitals NHS Trust Major Trauma Centre

Abstract Introduction This audit was developed after noticing patients with open fractures had poor neurovascular assessment documentation (non-specific, none post-manipulation), and to check these patients received appropriate antibiotics. Review of open fracture management guidelines identified areas to be improved. Method Pre-operative hospital management of open fractures was audited using the NICE (NG37) and joint BOAST/BAPRAS guidelines on open fracture management. Interventions were awareness and education of junior doctors and editing the Trauma Clerking Form to prompt appropriate management and documentation, followed by re-audit. Results 30 patients were assessed pre- and post-intervention. Correct antibiotic administration rate (93%vs97%) and speed (50% <2 hours where not given pre-hospital - in both groups) were similar. The initial neurovascular assessment frequency was identical (93%), however documentation of assessment of specific arteries (86%vs30%) and nerves (60%vs23%) and assessing all appropriate arteries (60%vs13%) and nerves (60%vs20%) improved. There were increased frequencies of documenting manipulation in A&E (90%vs47%) and neurovascular assessment post-manipulation (90%vs16%). Tetanus cover (87%vs77%), photo availability (70%vs40%), and appropriate dressing use (47%vs27%) improved. Conclusions Antibiotic management was consistent and appropriate. There were improvements in frequency and quality of neurovascular assessment, tetanus cover, availability of photographs of injuries and appropriate dressings used. Overall, pre-operative hospital management of open fractures improved.

An increase in accident and emergency presentations for adverse events following immunisation after introduction of the group B meningococcal vaccine: an observational study

ObjectivesTo determine whether the introduction of the capsular group B meningococcal vaccine (4CMenB) in the UK has increased presentations of infants to emergency departments with adverse events following immunisation (AEFI).Participants,...

Effects of digital Cognitive Behavioural Therapy for Insomnia on cognitive function: study protocol for a randomised controlled trial

BackgroundThe daytime effects of insomnia pose a significant burden to patients and drive treatment seeking. In addition to subjective deficits, meta-analytic data show that patients experience reliable objective impairments across several cognitive domains. While Cognitive Behavioural Therapy for Insomnia (CBT-I) is an effective and scalable treatment, we know little about its impact upon cognitive function. Trials of CBT-I have typically used proxy measures for cognitive functioning, such as fatigue or work performance scales, and no study has assessed self-reported impairment in cognitive function as a primary outcome. Moreover, only a small number of studies have assessed objective cognitive performance, pre-to-post CBT-I, with mixed results. This study specifically aims to (1) investigate the impact of CBT-I on cognitive functioning, assessed through both self-reported impairment and objective performance measures, and (2) examine whether change in sleep mediates this impact.Methods/designWe propose a randomised controlled trial of 404 community participants meeting criteria for Insomnia Disorder. In the DISCO trial (Defining the Impact of improved Sleep on COgnitive function (DISCO)) participants will be randomised to digital automated CBT-I delivered by a web and/or mobile platform (in addition to treatment as usual (TAU)) or to a wait-list control (in addition to TAU). Online assessments will take place at 0 (baseline), 10 (post-treatment), and 24 (follow-up) weeks. At week 25, all participants allocated to the wait-list group will be offered digital CBT-I, at which point the controlled element of the trial will be complete. The primary outcome is self-reported cognitive impairment at post-treatment (10 weeks). Secondary outcomes include objective cognitive performance, insomnia severity, sleepiness, fatigue, and self-reported cognitive failures and emotional distress. All main analyses will be carried out on completion of follow-up assessments and will be based on the intention-to-treat principle. Further analyses will determine to what extent observed changes in self-reported cognitive impairment and objective cognitive performance are mediated by changes in sleep. The trial is supported by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre (BRC) based at Oxford University Hospitals NHS Trust and University of Oxford, and by the NIHR Oxford Health BRC.DiscussionThis study will be the first large-scale examination of the impact of digital CBT-I on self-reported cognitive impairment and objective cognitive performance.Trial registrationISRCTN, ID: ISRCTN89237370. Registered on 17 October 2016.

Benchmarking of methods for identification of antimicrobial resistance genes in bacterial whole genome data.

Next generation sequencing (NGS) may be an alternative to phenotypic susceptibility testing for surveillance and clinical diagnosis. However, current bioinformatics methods may be associated with false positives and negatives. In this study, a novel mapping method was developed and benchmarked to two different methods in current use for identification of antibiotic resistance genes in bacterial WGS data. A novel method, KmerResistance, which examines the co-occurrence of k-mers between the WGS data and a database of resistance genes, was developed. The performance of this method was compared with two previously described methods; ResFinder and SRST2, which use an assembly/BLAST method and BWA, respectively, using two datasets with a total of 339 isolates, covering five species, originating from the Oxford University Hospitals NHS Trust and Danish pig farms. The predicted resistance was compared with the observed phenotypes for all isolates. To challenge further the sensitivity of the in silico methods, the datasets were also down-sampled to 1% of the reads and reanalysed. The best results were obtained by identification of resistance genes by mapping directly against the raw reads. This indicates that information might be lost during assembly. KmerResistance performed significantly better than the other methods, when data were contaminated or only contained few sequence reads. Read mapping is superior to assembly-based methods and the new KmerResistance seemingly outperforms currently available methods particularly when including datasets with few reads.

PTU-076 Bile Sampling to Ensure Appropriate Antibiotic Treatment of Infection in Patients Undergoing Percutaneous Transhepatic Cholangiography and Biliary Drainage

Introduction Biliary sepsis and cholangitis are frequent complications of percutaneous transhepatic cholangiography and biliary drainage (PTCBD). Due to bacterial resistance, biliary infection is often difficult to eradicate. The aims of this audit were to evaluate the frequency of bile sample collection during PTCBD for culture and antibiotic sensitivity tests. Further, whether antibiotic management of biliary infections post-procedure are appropriate. Methods A retrospective review of electronic patient records were conducted for 138 patients that underwent PTCBD for management of malignant biliary obstruction from 2012–2015 in the Interventional Radiology departments of the Oxford University Hospitals NHS Trust. Due to limitations of the electronic system, drug histories were only accessible from the 45 patients that underwent PTCBD in 2015. Results Of the 138 patients, 36% had samples cultured during the procedure. Of the positive bile samples, 61% had antibiotic sensitivities reported. Organisms identified included mixed faecal flora (33%), anaerobes (12%), aerobic gram-positive cocci (23%), aerobic gram-negative (14%), Pseudomonas (7%) and Candida (7%). In 2015, 53% that underwent PTCBD received antibiotics for biliary infection, of these, 46% had bile cultures and of the positive samples, 33% were tested for antibiotic sensitivity. Antibiotics administered included: amoxicillin/clavulanic acid (30%), metronidazole (33%), gentamycin (14%), piperacillin/tazobactam (9%), ceftriaxone (9%), ciprofloxacin (5%). Conclusion Thus, antibiotics to treat biliary infection following PTCBD are often prescribed without knowledge of the infective organism or its resistance and therefore may not be appropriate. Additionally, many of the treatments administered do not provide complete coverage of organisms identified in bile, notably Pseudomonas and Candida. Bile sample collection during PTCBD should become a standard procedure to delineate infective organisms and drug susceptibilities, hence driving a more targeted treatment in the event of biliary infection post-procedure, which may reduce mortality and costs associated with bacterial resistance. Disclosure of Interest None Declared

P-404: Macrolide co-prescription with statins: an Oxford University Hospitals (OUH) NHS Trust audit

P-404: Macrolide co-prescription with statins: an Oxford University Hospitals (OUH) NHS Trust audit

Regional Anaesthesia for Carotid Endarterectomy

Nuffield Division of Anaesthetics, Level 2, Oxford University Hospitals NHS Trust, Oxford, United Kingdom.

21. Assessing technical skills in oncoplastic breast surgery: Procedure specific global rating scales for wide local excision are construct valid

21. Assessing technical skills in oncoplastic breast surgery: Procedure specific global rating scales for wide local excision are construct valid

130: Stereotactic ablative radiotherapy (SABR) for early stage, medically inoperable non-small cell lung cancer (NSCLC): initial outcomes from 2 years' experience at the Oxford Cancer Centre, Oxford University Hospitals NHS Trust

130: Stereotactic ablative radiotherapy (SABR) for early stage, medically inoperable non-small cell lung cancer (NSCLC): initial outcomes from 2 years' experience at the Oxford Cancer Centre, Oxford University Hospitals NHS Trust

High Proportions of Regulatory T Cells in Peripheral Blood Stem Cell Grafts Are Associated with Improved Total Lymphocyte, CD8+ T Cell and CD19+ Cell Recovery Following Allogeneic Haematopoietic Stem Cell Transplantation

Co-infusion of donor regulatory T-cells (Tregs) with conventional T-cells (Tcons) in allogeneic haematopoietic stem cell transplantation (HSCT) may improve immune reconstitution and suppress graft-versus-host disease (GvHD) without inhibiting the graft-versus-tumour (GvT) response. While phase I/II studies have focused on co-infusion of ex-vivo isolated Tregs, few have examined the impact of Tregs within peripheral blood stem cell (PBSC) grafts. In previous work, we observed that high proportions of Tregs (CD4+CD25+FOXP3+CD127-/dim T-cells; expressed as percentage of CD4+ T-cells) in PBSC grafts were associated with improved myeloid and platelet recovery and decreased non-relapse mortality (NRM). In this current study, we therefore hypothesised that patients transplanted with high proportions of Tregs within allogeneic PBSC grafts will also have improved lymphocyte recovery.Ninety-four allogeneic HSCT transplants were recruited from Oxford University Hospitals NHS Trust. The median age of the recipients was 48 years (range, 18-74). Forty-seven (50%) of the transplants were performed for acute leukaemia and 80 (85%) were performed using a reduced intensity conditioning regimen. Thirty-eight (40%) PBSC grafts were obtained from sibling donors (37 HLA-matched; 1 single HLA-mismatch (9/10)) and 56 (60%) from unrelated donors (39 HLA-matched (10/10); 17 single HLA-mismatch (9/10)). The cellular contents of the grafts were analysed using multi-colour flow cytometry. The median total nucleated cell (TNC), CD34+, CD3+, CD19+ and CD3-CD56+ cell dose per kg recipient body weight was 10.1 x 108/kg (range, 2.7-37.6), 6.3 x 106/kg (range, 1.1-19.8), 280 x106/kg (range, 87-801), 62 x 106/kg (range, 13-245) and 35 x106/kg (range, 8-101) respectively. Tregs accounted for a median of 2.96% of CD4+ T-cells (range, 0.81-8.56%) within the grafts with a median Treg dose of 4.7 x 106/kg (range, 0.8-20.6). There were no significant correlations between the proportion of Tregs in the grafts and the TNC, CD34+, CD3+, CD19+ or CD3-CD56+ cell dose.The cumulative incidence of total lymphocyte (>1.0 x 109/l), CD3+ (>0.7 x 109/l), CD19+ (>0.1 x 109/l) and CD3-CD56+ (>0.1 x 109/l) cell recovery by 6 months was 71.3% (95% CI, 60.8-79.4%), 51.2% (95% CI, 40.6-62.3%), 62.4% (95% CI, 50.8-72.0%) and 91.0% (95% CI, 82.0-95.7%) respectively. The median time to total lymphocyte, CD3+, CD19+ and CD3-CD56+ recovery was 47 days (range, 11-455), 40 days (range, 33-265), 62 days (range, 27-262) and 34 days (range, 27-173) respectively. Patients transplanted with PBSC grafts containing higher proportions of Tregs (>2.96% CD4+ T-cells (median)) had improved lymphocyte recovery (P<0.001), with a cumulative incidence at 6 months of 83.0% (95% CI, 68.1-91.3%) compared to 59.6% (95% CI, 43.9-72.2%) for those receiving less. In multivariate analysis, high proportions of Tregs in the graft (%CD4+ T-cells) (HR 1.95 (95% CI, 1.24-3.06), P=0.004), use of Alemtuzumab during conditioning (HR 0.31 (95% CI, 0.17-0.56), P<0.001) and use of female donors (HR 1.65 (95% CI, 1.01-2.56), P=0.03) were independent predictors of total lymphocyte recovery. When analysing the major lymphocyte populations, high proportions of Tregs in the grafts were significantly associated with improved recovery of CD8+ T-cells (HR 1.98 (95% CI, 1.12-3.50), P=0.02) and CD19+ cells (HR 2.02 (95% CI, 1.23-3.06), P=0.004). In relation to clinical markers of immune recovery, there was no significant difference in the rates of CMV reactivation (P=0.89) between the two groups. However, less acute GvHD (grade II-IV) was observed in those patients receiving higher proportions of Tregs in the graft (23.4% (95% CI, 12.5-36.3%) vs 38.3% (95% CI, 24.5-51.9%) at 100 days), although this did not reach statistical significance (P=0.11). NRM at 3-years was lower (P=0.02) in patients receiving high proportions of Tregs in the grafts (12.8% (95% CI, 5.1-24.0%) [GvHD (n=1), infection (n=2), other (n=3)] vs 34.7% (95% CI, 21.2-48.5%) [GvHD (n=9), infection (n=4), other (n=3)]). The proportion of Tregs in the graft (HR 0.30 (0.11-0.85), P=0.02) was an independent predictor of NRM.These data support the hypothesis that higher proportions of donor Tregs in PBSC grafts may also enhance lymphoid reconstitution following allogeneic HSCT. However, larger studies will be required to understand the potential mechanisms involved and to confirm our findings. DisclosuresNo relevant conflicts of interest to declare.

Is temporal artery biopsy (TAB) always necessary in suspected giant cell arteritis (GCA)?

s / International Journal of Surgery 12 (2014) S13eS117 S114 Department of Surgery, University of Queensland, Queensland, Australia; Imperial College NHS Healthcare Trust, London, UK; Department of Vascular Surgery, Norfolk and Norwich, Norfolk and Norwich, UK. Introduction: Aortic aneurysms represent a significant burden of disease worldwide. Whilst some risk factors for rupture are well established, such as hypertension, smoking and female gender, the impact of season and meteorological variables is less clear. We systematically reviewed the literature in order to conclusively determine whether these variables are associated with aortic aneurysm rupture. Methods: Reviewmethodswereaccording to thePreferredReporting Items for Systematic Reviews and Meta-Analysis guidelines. Data was extracted from all identified studies with regard to study design, geographical location, aortic lesion, sample size, and meteorological variables including season, atmospheric pressure, temperature and daylight hours. Results: 27 studies representing 46,580 patients were investigated. Whilst there is no consensus within the literature, several large studies suggest a statistically significant seasonal variation in the incidence of aortic aneurysm rupture, with winter months broadly conferring a greater degree of risk. There is also some evidence for an association with atmospheric pressure. Associations with temperature and daylight hours, however, remain more controversial. Conclusions: Meteorological and seasonal variables may affect the haemodynamic stability of aortic aneurysms. This may have implications on the epidemiology of aneurysm rupture, and thus influence the provision of vascular services and timing of surgical intervention. 0803: IS TEMPORAL ARTERY BIOPSY (TAB) ALWAYS NECESSARY IN SUSPECTED GIANT CELL ARTERITIS (GCA)? Eva Andreotti, Nicholas Farkas *, Emma Rose McGlone, Aziz Anjum. Epsom and St Helier University Hospitals NHS Trust, Surrey, UK. Introduction: In the diagnosis of GCA, an American College of Rheumatology (ACR) criteria score of three or more has very high sensitivity and specificity. Current guidelines recommend early TAB of sufficient length in all cases of suspected GCA, however recent studies suggest that TAB does not change management in the majority of cases. This retrospective audit aimed to investigate the safety of restricting TAB to only those with indeterminate pre-biopsy ACR score. Methods: We identified 45 consecutive patients undergoing TAB from April 2012 onwards. Notes were analysed for indications for, timing, length and results of TAB, and subsequent patient management. Results: Of those started immediately on steroids, 8/40 (20%) underwent TAB within one week. 21/45 specimens (48%) were one centimetre or longer. Seven patients (16%) had their management changed following biopsy result; of these, 2/17 (11.7%) had pre-biopsy ACR score of 2, 4/19 (21%) of 3, and 1/9 (11%) of 4. Conclusions: In our trust, TAB changes management in patients with prebiopsy ACR score of 2, 3 or 4. Guidelines for specimen length and timing are poorly adhered to, which may influence interpretation of results. At present, TAB cannot be restricted to those with indeterminate pre-biopsy ACR score. 0830: LENGTH OF THE EXTRACRANIAL INTERNAL CAROTID ARTERY AND DEGREE OF STENOSIS: ARE THEY RELATED? Emma Wilton , Naomi Warner *, Patrick Lintott . Oxford University Hospitals NHS Trust, Oxford, UK; Buckinghamshire Healthcare NHS Trust, High Wycombe, Buckinghamshire, UK. Introduction: To determine if the degree of stenosis within the internal carotid artery (ICA) is related to the length of the extracranial ICA. Methods: Retrospective analysis of patients that underwent carotid endarterectomy between September 2009 and August 2013, in one institution, was carried out. Magnetic resonance angiography time-of-flight images were reviewed and the distance between the carotid bifurcation and the base of the skull was recorded bilaterally. The degree of internal carotid artery stenosis measured on preoperative carotid artery duplex scanning, according to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria, was also recorded. The results were analysed using Pearson's product-moment correlation. Results: A total of 369 patients underwent carotid endarterectomy within the study period. 175 patients were excluded due to insufficient imaging. 194 patients were included (mean age ± SEM 1⁄4 73±1 year; 125 male, 69 female) and their images andcarotidduplex scan resultswere reviewed. 361 pairs of data were analysed using Pearson's correlation (r1⁄40.06, p1⁄40.23). Conclusions: We showed no significant correlation between the length of the extracranial ICA and the degree of stenosis that may develop within it. 0832: MORTALITY FOLLOWING ACUTE NATIVE ARTERY EMBOLECOTMY FOR ARTERIAL EMBOLISM UNRELATED TO PERIPHERAL ARTERIAL DISEASE (PAD): 18 YEAR REVIEW Joel Lambert *, Sobath Premaratne, Anthony Jaipersad, Andy Houghton, Anthony Fox, Kate Merriman. Shrewsbury & Telford NHS Trust, Shrewsbury,

Longitudinally extensive spinal cord infarction in CADASIL

Department of Neurology, Oxford University Hospitals NHS Trust, Oxford, UK Stroke and Dementia Research Centre, St George’s University of London, London, UK NEUROFARBA Department, Neuroscience Section, University of Florence, Florence,...

Can rapid integrated polymerase chain reaction-based diagnostics for gastrointestinal pathogens improve routine hospital infection control practice? A diagnostic study.

Every year approximately 5000-9000 patients are admitted to a hospital with diarrhoea, which in up to 90% of cases has a non-infectious cause. As a result, single rooms are 'blocked' by patients with non-infectious diarrhoea, while patients with infectious diarrhoea are still in open bays because of a lack of free side rooms. A rapid test for differentiating infectious from non-infectious diarrhoea could be very beneficial for patients. To evaluate MassCode multiplex polymerase chain reaction (PCR) for the simultaneous diagnosis of multiple enteropathogens directly from stool, in terms of sensitivity/specificity to detect four common important enteropathogens: Clostridium difficile, Campylobacter spp., Salmonella spp. and norovirus. A retrospective study of fixed numbers of samples positive for C. difficile (n = 200), Campylobacter spp. (n = 200), Salmonella spp. (n = 100) and norovirus (n = 200) plus samples negative for all these pathogens (n = 300). Samples were sourced from NHS microbiology laboratories in Oxford and Leeds where initial diagnostic testing was performed according to Public Health England methodology. Researchers carrying out MassCode assays were blind to this information. A questionnaire survey, examining current practice for infection control teams and microbiology laboratories managing infectious diarrhoea, was also carried out. MassCode assays were carried out at Oxford University Hospitals NHS Trust. Further multiplex assays, carried out using Luminex, were run on the same set of samples at Leeds Teaching Hospitals NHS Trust. The questionnaire was completed by various NHS trusts. Sensitivity and specificity to detect C. difficile, Campylobacter spp., Salmonella spp., and norovirus. Nucleic acids were extracted from 948 clinical samples using an optimised protocol (200 Campylobacter spp., 199 C. difficile, 60 S. enterica, 199 norovirus and 295 negative samples; some samples contained more than one pathogen). Using the MassCode assay, sensitivities for each organism compared with standard microbiological testing ranged from 43% to 94% and specificities from 95% to 98%, with particularly poor performance for S. enterica. Relatively large numbers of unexpected positives not confirmed with quantitative PCR were also observed, particularly for S. enterica, Giardia lamblia and Cryptosporidium spp. As the results indicated that S. enterica detection might provide generic challenges to other multiplex assays for gastrointestinal pathogens, the Luminex xTag(®) gastrointestinal assay was also run blinded on the same extracts (937/948 remaining) and on re-extracted samples (839/948 with sufficient material). For Campylobacter spp., C. difficile and norovirus, high sensitivities (> 92%) and specificities (> 96%) were observed. For S. enterica, on the original MassCode/Oxford extracts, Luminex sensitivity compared with standard microbiological testing was 84% [95% confidence interval (CI) 73% to 93%], but this dropped to 46% on a fresh extract, very similar to MassCode, with a corresponding increase in specificity from 92% to 99%. Overall agreement on the per-sample diagnosis compared with combined microbiology plus PCR for the main four/all pathogens was 85.6%/64.7%, 87.0%/82.9% and 89.8%/86.8% for the MassCode assay, Luminex assay/MassCode extract and Luminex assay/fresh extract, respectively. Luminex assay results from fresh extracts implied that 5% of samples did not represent infectious diarrhoea, even though enteropathogens were genuinely present. Managing infectious diarrhoea was a significant burden for infection control teams (taking 21% of their time) and better diagnostics were identified as having major potential benefits for patients. Overall, the Luminex xTag gastrointestinal panel showed similar or superior sensitivity and specificity to the MassCode assay. However, on fresh extracts, this test had low sensitivity to detect a key enteric pathogen, S. enterica; making it an unrealistic option for most microbiology laboratories. Extraction efficiency appears to be a major obstacle for nucleic acid-based tests for this organism, and possibly the whole Enterobacteriaceae family. To improve workflows in service microbiology laboratories, to reduce workload for infection control practitioners, and to improve outcomes for NHS patients, further research on deoxyribonucleic acid-based multiplex gastrointestinal diagnostics is urgently needed. The Health Technology Assessment programme of the National Institute for Health Research.

Predictive monitoring of mobile patients by combining clinical observations with data from wearable sensors.

The majority of patients in the hospital are ambulatory and would benefit significantly from predictive and personalized monitoring systems. Such patients are well suited to having their physiological condition monitored using low-power, minimally intrusive wearable sensors. Despite data-collection systems now being manufactured commercially, allowing physiological data to be acquired from mobile patients, little work has been undertaken on the use of the resultant data in a principled manner for robust patient care, including predictive monitoring. Most current devices generate so many false-positive alerts that devices cannot be used for routine clinical practice. This paper explores principled machine learning approaches to interpreting large quantities of continuously acquired, multivariate physiological data, using wearable patient monitors, where the goal is to provide early warning of serious physiological determination, such that a degree of predictive care may be provided. We adopt a one-class support vector machine formulation, proposing a formulation for determining the free parameters of the model using partial area under the ROC curve, a method arising from the unique requirements of performing online analysis with data from patient-worn sensors. There are few clinical evaluations of machine learning techniques in the literature, so we present results from a study at the Oxford University Hospitals NHS Trust devised to investigate the large-scale clinical use of patient-worn sensors for predictive monitoring in a ward with a high incidence of patient mortality. We show that our system can combine routine manual observations made by clinical staff with the continuous data acquired from wearable sensors. Practical considerations and recommendations based on our experiences of this clinical study are discussed, in the context of a framework for personalized monitoring.

PARV4: an emerging tetraparvovirus.

1 Nuffield Department of Medicine, Peter Medawar Building for Pathogen Research, Oxford, United Kingdom, 2 Department of Infectious Diseases and Microbiology, Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Oxford, United Kingdom, 3 Department of Paediatrics, Peter Medawar Building for Pathogen Research, Oxford, United Kingdom, 4 The Roslin Institute, The University of Edinburgh, Easter Bush, Midlothian, Scotland, United Kingdom, 5 NIHR Biomedical Research Centre, John Radcliffe Hospital, Headington, Oxford, United Kingdom