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Peripheral arterial disease (PAD) is associated with cerebral and coronary artery disease. Symptomatic PAD affects about 5% of people over 55 years; many more have asymptomatic PAD. Early detection enables modification of arterial disease risk factors. Diagnostically, assessment of symptoms or signs can be unreliable; ankle brachial pressure index (ABPI) testing is time-consuming and few healthcare professionals are properly trained. This study assessed the diagnostic accuracy of multi-site photoplethysmography (MPPG), an alternative non-invasive test for PAD, in primary care. PAD patients identified from general practice registers were age- and sex-matched with controls. Participants were assessed using MPPG, ABPI and duplex ultrasound (DUS). Outcome measures were sensitivity and specificity of MPPG and ABPI (relative to DUS) and concordance. MPPG test results were available in 249 of 298 eligible participants from 16 practices between May 2015 and November 2016. DUS detected PAD in 101/249 (40.6%). MPPG sensitivity was 79.8% (95% confidence interval [CI] 69.9-87.6%), with specificity 71.9% (95% CI 63.7-79.2%). ABPI sensitivity was 80.2% (95% CI 70.8-87.6%), with specificity 88.6% (95% CI 82-93.5%). With comparable sensitivity to ABPI, MPPG is quick, automated and simpler to do than ABPI; it offers the potential for rapid and accessible PAD assessments in primary care.

Objectives: To evaluate the impact of introducing CT fractional flow reserve (FFR CT ) on stable chest pain pathways, concordance with National Institute for Health and Care Excellence (NICE) chest pain guidelines, resource usage and revascularisation of patients from a tertiary UK cardiac centre rapid access chest pain clinic (RACPC)., Methods: Single-centre before and after study comparing data from electronic records and Strategic Tracing Service of all RACPC patients attending between 1 July 2017 and 31 December 2017, and 1 August 2018 and 31 January 2019., Results: Two hundred and sixty-eight and 287 patients (overall mean age 62 years, range 26-89 years, 48.3% male), were eligible for first-line CT coronary angiography (CTCA) pre-FFR CT and post-FFR CT , respectively. First-line CTCA use per NICE Guideline CG95 increased (50.6% pre-FFR CT vs 75.7% post-FFR CT , p<0.001). More patients reached pathway endpoint (revascularisation or assumed medical management) after one investigation (74.9% pre-FFR CT vs 84.9% post-FFR CT , p=0.005). There were fewer stress (22.8% pre-FFR CT vs 7.7% post-FFR CT , p<0.001) and rest (10.4% pre-FFR CT vs 4.2% post-FFR CT , p=0.007) myocardial perfusion scans and diagnostic-only angiograms (25.5% vs 13.7%, p<0.001). Despite fewer invasive procedures (29.3% pre-FFR CT vs 17.6% post-FFR CT , p=0.002), revascularisation rates remained similar (10.4% pre-FFR CT vs 8.8% post-FFR CT , p=0.561). Avoiding invasive investigations reduced inpatient admissions (39.0% pre-FFR CT vs 24.3% post-FFR CT , p<0.001). Time to revascularisation was unchanged (153.5 days pre-FFR CT vs 142.0 post-FFR CT , p=0.925). Unplanned hospital attendances, emergency admissions and adverse events were similar., Conclusions: FFR CT adoption was associated with greater compliance with NICE guidelines, reduced invasive diagnostic angiography, planned admissions and needing more than one test to reach a pathway endpoint., Competing Interests: Competing interests: ABe has received honoraria for travel and speaker engagements from HeartFlow. ABa is UK chief investigator of the P4 trial that is part-funded by HeartFlow., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Duplex ultrasound (DUS), a non-invasive means of arterial mapping, allows for the reliable diagnosis of peripheral arterial disease (PAD). One of the authors (C.P.O.), developed a standardised DUS based scoring system, devised for rapid detection and reporting of PAD. The purpose of this study was to validate this system, and to determine the diagnostic performance both overall and per disease severity., Methods: In total, 250 participants were recruited, based on diagnosis of (n = 125) or absence of PAD (n = 125) from general practice registers. Right and left legs per subject were handled as independent readings, determining actual PAD status via ankle brachial pressure index (ABPI) < 0.9, and then further grading disease severity using suggested ABPI ranges. Data were excluded if no corresponding ABPI value was obtained per DUS determination or if the ABPI reading was > 1.4, owing to the risk of false negatives due to incompressible vessels. Diagnostic sensitivity and specificity were obtained overall, and per severity classification. Furthermore, inter-rater agreement between ABPI and DUS determined PAD severity was determined by linear weighted Cohen's kappa., Results: The sensitivity and specificity in the detection of disease overall was 81.0% (95% confidence interval [CI] 73.4 - 87.2) and 86.3% (95% CI 82.3 - 89.8), respectively. From mild to severe PAD, sensitivity increased from 71.1% (95% CI 55.7 - 83.6) to 89.3% (95% CI 71.8 - 97.7). Furthermore, a Cohen's kappa value of 0.63 (95% CI 0.57 - 0.69) was obtained, indicating moderate agreement between the two diagnostic methods., Conclusion: The findings of this study validate the diagnostic performance of the standardised DUS scoring system, as well as its capacity to grade severity of disease, offering a potential tool for the identification of PAD in community/research settings following initial screening methods. Confirmatory work could include a comparison of DUS determined disease with gold standard methods of non-invasive angiography, and novel tools such as toe flex near infrared spectroscopy and multisite photoplethysmography., (Copyright © 2022 The Author(s). Published by Elsevier B.V. All rights reserved.)

Objectives: To identify paediatric intracapsular Coblation tonsillectomy procedures from routine administrative data in England, and determine their safety., Design: Retrospective observational cohort study of four ENT centres using routine data from Hospital Episode Statistics (HES)., Setting: Acute NHS trusts in England conducting exclusively intracapsular Coblation tonsillectomy., Participants: Children (≤16 years old) undergoing bilateral intracapsular Coblation tonsillectomy., Main Outcome Measures: Number of procedures, readmissions for pain, readmissions for bleeding and requirement for additional surgery for regrowth., Results: A total of 5525 procedures were identified. The median patient age was 4 (IQR 2-5). In-hospital complications occurred in 1%, with 0.1% returning to theatre for arrest of primary tonsil bleeding. Almost half of the procedures were conducted as a day-case (44%), with only a small proportion staying in hospital more than one night (7%). Within 28 days, 1.2% of patients were readmitted with bleeding, 0.7% with infection and 0.3% with pain; 0.2% of patients required return to theatre for control of secondary haemorrhage. Longitudinal follow-up has found that revision tonsil surgery is 0.3% at 1 year (n = 4498), 1.1% at 2 years (n = 2938), 1.7% at 3 years (n = 1781), 1.9% at 4 years (n = 905) and 2.2% at 5 years (n = 305)., Conclusions: Intracapsular coblation tonsillectomy safety outcomes in this study show primary and secondary bleeding rates and emergency return to theatre rates are lower than all tonsillectomy techniques reported in the National Prospective Tonsillectomy Audit and also lower than previously published Hospital Episode Statistics analysis of tonsillectomy procedures., (© 2022 The Authors. Clinical Otolaryngology published by John Wiley & Sons Ltd.)

Aims: Non-valvular atrial fibrillation (AF) greatly increases the risk of ischaemic stroke. For people with contraindications to oral anticoagulation, left atrial appendage occlusion (LAAO) provides a non-pharmacological management alternative. The aim of this study was to measure the procedural safety and longer-term effectiveness of LAAO for AF in a UK setting., Methods and Results: This was a prospective, single-armed registry of patients with AF for whom anticoagulation was unsuitable. Registry data were collected between October 2014 and April 2018 and linked to routine data sources for follow-up. Data from 583 LAAO procedures were entered into the registry, of which 537 (from 525 patients) were eligible for inclusion (median CHA2DS2-VASc score 4). A closure device was successfully implanted in 93.4% of cases, with a procedural success rate (device implanted without major complication) of 88.9%. Five patients (1.0%) died in hospital. During follow-up [median 729 (Q1:Q3, 523:913) days] 45 patients experienced neurological events; 33 of which were ischaemic. The ischaemic neurological event rate was 3.3 (1.6-5.0)% at 1 year (n = 387) and 7.0 (4.3-9.6)% at 2 years (n = 196). There were significant improvements in overall patient health (via Visual Analogue Scale) measured at 6 weeks and 6 months, but no significant improvements observed in patient utility over time., Conclusion: The findings of our study suggest that LAAO is not without procedural risk, but that this risk may be justified in high-risk patients with AF who cannot take an anticoagulant. Moreover, the data do not provide support for more widespread use of LAAO as the complication rate was relatively high and would be difficult to justify in many patients with AF who tolerate anticoagulation., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

A premise of stream restoration theory and practice is that it is often futile to attempt to restore a stream at the reach scale (101-103 metres) until catchment scale problems have been addressed. This study considers reach scale restoration actions undertaken in Bryan Creek, a sand bed river in south east Australia impacted by a sediment pulse, after catchment sediment sources have been addressed. Local scale interventions, which were in-stream sand extraction, fencing to exclude stock and riparian revegetation, were evaluated by quantifying cross-section and thalweg variability, mapping in-stream and riparian vegetation and by classifying the morphology that emerged following each intervention. Following intervention channel reaches moved to one of three distinct states: simple clay bed, eroding reaches dominated by Juncus acutus, and reaches with deep pools and Phragmites australis. Boundaries between the intervention reaches were sharp, suggesting local scale interventions dominate over catchment scale processes. The magnitude and spread of variability metrics were similar between all reaches and differences in variability bore no relation to intervention type, despite the stark difference in post-intervention morphology. These findings suggest that cross-section and thalweg variability metrics are an inadequate proxy for the effectiveness of local scale interventions in accelerating the recovery of sand bed reaches from a bedload pulse. The most important implications for river managers is that local scale interventions can lead to substantial and rapid improvements in condition, and the change in condition of these reaches is almost independent of other reaches. In this case, the key to the pattern of reach scale geomorphic recovery is excluding stock from waterways so that a specific macrophyte can establish, trap sediment and develop pools., Competing Interests: The authors have declared that no competing interests exist.

Aims: Percutaneous mitral valve leaflet repair is a treatment option for some people with severe mitral valve regurgitation for whom conventional mitral valve surgery is clinically inappropriate. This study aimed to determine the safety, efficacy, and costs of percutaneous mitral valve leaflet repair, using the MitraClip device in a UK setting., Methods and Results: This was a prospective, single-armed registry with a follow-up of 2 years that reported a range of procedural, clinical and patient-orientated outcomes. Registry data were linked to routine data sources to allow for more comprehensive follow up concerning mortality and healthcare resource use. The registry received data for 199 mainly elective patients with mixed mitral regurgitation aetiology. A MitraClip device was implanted in 187 patients (94%), with a procedural success rate of 86%, with 8% of patients having a serious in-hospital adverse event (including 5% mortality). Percutaneous mitral valve leaflet repair reduced mitral regurgitation from 100% MR grade ≥ 3+ to 7% at discharge. There were corresponding improvements in New York Heart Association functional class, reducing from 92% (class ≥ 3) at baseline to 18% at 6 weeks. There were significant improvements in generic and disease specific quality of life indicators up to 2 years. The all-cause mortality rate was estimated to be 12.7% (95% CI 7.5 to 17.7%) at 1 year. Percutaneous mitral valve leaflet repair was associated with reduced hospital readmissions and potential cost-savings in post-procedural care., Conclusion: This study shows that percutaneous mitral valve leaflet repair using MitraClip is a relatively safe and effective treatment in patients unable to tolerate surgery and has the potential to reduce ongoing healthcare costs in the UK., Competing Interests: AJS reports grants from NIHR and Wellcome Trust and outside the submitted work. KK reports grants from NIHR outside the submitted work. HPa, HPo and LB are employed by NICE and were contracted by NHS England to oversee the Commissioning through Evaluation scheme. JS is employed by NHS Digital. There are no other financial relationships with any organisations that might have an interest in the submitted work in the previous three years and no other relationships or activities that could appear to have influenced the submitted work. In May 2020 HC moved to a new role and is employed by the Northern Health Science Alliance Ltd., who have no past or present interest in the study. This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Objectives: To assess the safety of paediatric tonsillectomy procedures conducted in NHS hospitals in England between 2008 and 2019., Design: Retrospective observational cohort study using Hospital Episode Statistics (HES) data., Setting: Acute NHS trusts in England conducting paediatric tonsillectomy procedures., Participants: Children (≤16 years old) undergoing bilateral tonsillectomy., Main Outcome Measures: Number of tonsillectomies performed per year by procedural method. In-hospital complications including return to theatre for arrest of haemorrhage. Readmission within 28 days, including those for pain, haemorrhage and surgical arrest of haemorrhage. Long-term outcomes: all-cause mortality, revision tonsillectomy., Results: A total of 318 453 paediatric tonsillectomies were performed from 2008 to 2019:278,772 dissection (87.5%) and 39 681 coblation (12.5%). The proportion of tonsillectomy performed using coblation increased from 7% in 2008/9 to 27% in 2018/9. Five patients died in hospital (including 4 due to respiratory complications). In-hospital complications occurred in 4202 children (1.3%), with the most frequent being haemorrhage. Within 28 days of tonsillectomy, 28 170 patients (8.8%) were readmitted and 7 deaths occurred. Readmission rates for haemorrhage and pain have increased since 2008. The proportion of children undergoing revision tonsillectomy procedures within 5 years following coblation tonsillectomy (1.4%) was approximately double that of dissection (0.6%)., Conclusions: Clinical practice of paediatric tonsillectomy has changed in England over the past 11 years. The overall mortality rate associated with the procedure is 0.0037%. Differences in outcomes have been identified for different procedural methods. However, routine administrative data are limited in differentiating procedural detail (eg we are unable to differentiate intra or extra-capsular techniques from current clinical coding of tonsillectomy procedures). Therefore, prospective national data collection or more granular clinical coding is essential to capture relative outcomes of the different tonsillectomy methods and techniques being used in the NHS., (© 2020 The Authors. Clinical Otolaryngology published by John Wiley & Sons Ltd.)

Objectives: Use data from the UK Severe Asthma Registry (UKSAR) to assess the efficacy and safety of bronchial thermoplasty (BT) in routine UK clinical practice and to identify characteristics of 'responders'., Design: Prospective, longitudinal, cohort, multicentre registry study., Setting: All (11) UK centres performing BT., Participants and Intervention: Patients receiving BT in the UK between 01/06/2011 and 30/09/2016 who had consented to data entry into UKSAR (n=133). Efficacy data were available for 86 patients with a BT baseline and at least one follow-up record. Safety data were available for 131 patients with at least one BT procedure record., Primary and Secondary Outcome Measures: Efficacy: AQLQ, ACQ, EuroQol, HADS anxiety and HADS depression scores, FEV 1 (% predicted), rescue steroid courses, unscheduled healthcare visits (A&E/Asthma clinic/GP), hospital admissions and days lost from work/school., Safety: peri-procedural events, device problems and any other safety-related findings. Responder analysis: differences in baseline characteristics of 'responders' (≥0.5 increase in AQLQ at 12 months) and 'non-responders'., Results: Following Bonferroni correction for paired comparisons, mean improvement in AQLQ at 12 months follow-up compared with BT baseline was statistically and clinically significant (0.75, n=28, p=0.0003). Median reduction in hospital admissions/year after 24 months follow-up was also significant (-1.0, n=26, p<0.0001). No deterioration in FEV 1 was observed. From 28 patients with AQLQ data at BTBL and 12-month follow-up, there was some evidence that lower age may predict AQLQ improvement. 18.9% (70/370) of procedures and 44.5% (57/128) of patients were affected by an adverse event; only a minority were considered serious., Conclusions: Improvement in AQLQ is consistent with similar findings from clinical trials. Other efficacy outcomes demonstrated improving trends without reaching statistical significance. Missing follow-up data impacted this study but multiple imputation confirmed observed AQLQ improvement. The safety review suggested BT is being performed safely in the UK., Competing Interests: Competing interests: LGH has received grant funding from Medimmune, Novartis UK, Roche/Genentech Inc, Astra Zeneca and Glaxo Smith Kline, have taken part in Advisory Boards and given lectures at meetings supported by Glaxo Smith Kline, Respivert, Merck Sharpe & Dohme, Nycomed, Boehringer Ingelheim, Novartis and Astra Zeneca. LGH has received support funding to attend International Respiratory meetings (Astra Zeneca, Chiesi, Novartis, Boehringer Ingelheim and Glaxo Smith Kline) and has taken part in asthma clinical trials (GSK, Schering Plough, Synairgen and Roche/Genentech) for which his Institution was remunerated. LGH is Academic Lead for the Medical Research Council Stratified Medicine UK Consortium in Severe Asthma which involves Industrial Partnerships with Amgen, Johnson & Johnson, Genentech / Roche, Astra Zeneca / Medimmune, Aerocrine and Vitalograph. RN was PI on several of the thermoplasty trials, and has received honoraria for lecturing & attending advisory boards from Boston Scientific., (© Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY. Published by BMJ.)

Objective: I-123-2β-Carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl)nortropane (FP-CIT) imaging is an established biomarker used in the diagnosis of Lewy body disease. Images are often reported with the aid of striatal binding ratios (SBRs), comparing uptake to a normal database via Z scores. It is well known that SBRs are age dependent. However, previous studies cover wide age ranges between 20 and 80 years, rather than focusing on older adults. Typically a linear relationship is reported, but some authors have suggested that SBRs do not decline as rapidly in old age. Commercial software packages usually adjust the SBR Z score to attempt to compensate for age-related decline, but the model used varies. Ensuring age correction is appropriate for older adults is important, given that the majority of patients referred for FP-CIT scans are aged over 60 years. We examined the relationship of SBR with age in older adults and the effect of age correction using research scans from 123 adults over 60 years of age., Methods: Twenty-nine healthy older adults and twenty-three with MCI due to Alzheimer's disease were included as controls, i.e. individuals with no evidence of Lewy body disease. Their ages ranged from 60 to 92 years (mean 76; SD 7.9). SBRs and Z scores were calculated using BRASS (Hermes Medical) and DaTQUANT (GE Healthcare). SBRs were plotted against age and linear mixed effect models applied. We tested the effect of removing age correction in BRASS using an independent dataset of 71 older adults with dementia or mild cognitive impairment., Results: The slopes of the linear fits between SBR and age per year were - 0.007 (p = 0.30) with BRASS and - 0.004 (p = 0.35) with DaTQUANT. The slopes are smaller than reported in the literature and show no statistically significant difference from zero. Switching age correction off in BRASS in the test subjects reduced Z scores by approximately 1 standard deviation at 80 years of age., Conclusion: We found no statistically significant age-related decline in SBR in adults over 60 years of age without Lewy body disease. Commercial software packages that apply a fixed rate of age correction may be overcorrecting for age in older adults, which could contribute to misdiagnosis.

Memokath-051 is a thermo-expandable, nickel-titanium alloy spiral stent used to treat ureteric obstruction resulting from malignant or benign strictures. The National Institute for Health and Care Excellence (NICE) selected Memokath-051 for evaluation. The company, PNN Medical, claimed Memokath-051 has clinical superiority and cost savings compared with double-J stents. It identified five studies reporting clinical evidence on Memokath-051 and constructed a de novo cost model comparing Memokath-051 to double-J stents. Results indicated that Memokath-051 generated cost savings of £4156 per patient over 2.5 years. The External Assessment Centre (EAC) critiqued the company's submission and completed substantial additional work. Sixteen studies were identified assessing Memokath-051 and all listed comparators in the scope (double-J stents, reconstructive surgery and metallic and alloy stents) except nephrostomy. Similar success rates were reported for Memokath-051 compared with double-J and Resonance stents and worse outcomes compared with other options with evidence available. The EAC updated the company's cost model structure and modified several inputs. The EAC's model estimated that Memokath-051 generated savings of at least £1619 per patient over 5 years compared with double-J stents, was cost neutral compared with other metallic stents and was cost saving compared with surgery up to month 55. Overall, Memokath-051 is likely to be cost saving in patients not indicated for reconstructive surgery and those expected to require a ureteral stent for at least 30 months. The Medical Technologies Advisory Committee (MTAC) reviewed the evidence and supported the case for adoption, issuing partially supportive recommendations published after public consultation as Medical Technologies Guidance 35.

Physiological signals can often become contaminated by noise from a variety of origins. In this paper, an algorithm is described for the reduction of sporadic noise from a continuous periodic signal. The design can be used where a sample of a periodic signal is required, for example, when an average pulse is needed for pulse wave analysis and characterization. The algorithm is based on cluster analysis for selecting similar repetitions or pulses from a periodic single. This method selects individual pulses without noise, returns a clean pulse signal, and terminates when a sufficiently clean and representative signal is received. The algorithm is designed to be sufficiently compact to be implemented on a microcontroller embedded within a medical device. It has been validated through the removal of noise from an exemplar photoplethysmography (PPG) signal, showing increasing benefit as the noise contamination of the signal increases. The algorithm design is generalised to be applicable for a wide range of physiological (physical) signals.

Objective: Bronchial thermoplasty (BT) is a novel treatment for severe asthma. Its mode of action and ideal target patient group remain poorly defined, though clinical trials provided some evidence on efficacy and safety. This study presents procedural and short-term safety evidence from routine UK clinical practice., Methods: Patient characteristics and safety outcomes (procedural complications, 30-day readmission and accident and emergency (A&E) attendance, length of stay) were assessed using two independent data sources, the British Thoracic Society UK Difficult Asthma Registry (DAR) and Hospital Episodes Statistics (HES) database. A matched cohort (with records in both) was used to estimate safety outcome event rates and compare them with clinical trials., Results: Between June 2011 and January 2015, 215 procedure records (83 patients; 68 treated in England) were available from DAR and 203 (85 patients) from HES. 152 procedures matched (59 patients; 6 centres), and of these, 11.2% reported a procedural complication, 11.8% resulted in emergency respiratory readmission, 0.7% in respiratory A&E attendance within 30 days (20.4% had at least one event) and 46.1% involved a post-procedure stay. Compared with published clinical trials which found lower hospitalisation rates, BT patients in routine clinical practice were, on average, older, had worse baseline lung function and asthma quality of life., Conclusions: A higher proportion of patients experienced adverse events compared with clinical trials. The greater severity of disease amongst patients treated in clinical practice may explain the observed rate of post-procedural stay and readmission. Study of long-term safety and efficacy requires continuing data collection.

Complications of surgical mesh procedures have led to legal cases against manufacturers worldwide and to national inquiries about their safety. The aim of this study was to investigate the rate of adverse events of these procedures for stress urinary incontinence in England over 8 years. This was a retrospective cohort study of first-time tension-free vaginal tape (TVT), trans-obturator tape (TOT) or suprapubic sling (SS) surgical mesh procedures between April 2007 and March 2015. Cases were identified from the Hospital Episode Statistics database. Outcomes included number and type of procedures, including those potentially confounded by concomitant procedures, and frequency, nature and timing of complications. 92,246 first-time surgical mesh procedures (56,648 TVT, 34,704 TOT, 834 SS and 60 combinations) were identified, including 68,002 unconfounded procedures. Peri-procedural and 30-day complication rates in the unconfounded cohort were 2.4 [2.3-2.5]% and 1.7 [1.6-1.8]% respectively; 5.9 [5.7-6.1]% were readmitted at least once within 5 years for further mesh intervention or symptoms of complications, the highest risk being within the first 2 years. Complication rates were higher in the potentially confounded cohort. The complication rate within 5 years of the mesh procedure was 9.8 [9.6:10.0]% This evidence can inform future decision-making on this procedure.

Objectives: To estimate the number of patients with recurrent respiratory papillomatosis currently managed in secondary and tertiary health care in the UK and the frequency of its treatment with radiofrequency cold ablation (Coblation ™ )., Design: Cross-sectional survey of ENT consultants in the UK with validation using Hospital Episode Statistics (HES) inpatient data., Setting: Online survey., Participants: ENT consultants in the UK., Main Outcome Measures: Number of recurrent respiratory papillomatosis patients currently managed in acute care in the UK and frequency of use of Coblation., Results: A total of 283 ENT consultants from 128 UK NHS healthcare trusts and health boards completed the online survey. Responses were received from 86% of surveyed organisations, and an estimated 45% of all ENT consultants in UK. The estimated number of recurrent respiratory papillomatosis patients from the cross-sectional survey was 918 (at August 2015) which included 730 patients in England. The number of recurrent respiratory papillomatosis patients in England estimated from Hospital Episode Statistics (2014/15 financial year) was up to 741. A total of 42 Coblation procedures conducted in the UK were identified from the cross-sectional survey; 36 were conducted in England compared with 34 identified from Hospital Episode Statistics., Conclusions: The numbers of recurrent respiratory papillomatosis patients and Coblation procedures identified in England from a cross-sectional survey and Hospital Episode Statistics were in broad agreement. Our study estimated 1.42 recurrent respiratory papillomatosis patients per 100 000 in the general UK population. We also estimated that Coblation procedures accounted for 3% of interventional treatments conducted in the UK recurrent respiratory papillomatosis population., (© 2016 The Authors. Clinical Otolaryngology Published by John Wiley & Sons Ltd.)

Blood pressure (BP) monitors rely on pulse detection. Some blood pressure monitors use pulse timings to analyse pulse interval variability for arrhythmia screening, but this assumes that the pulse interval timings detected from BP cuffs are accurate compared with RR intervals derived from ECG. In this study we compared the accuracy of pulse intervals detected using an ambulatory blood pressure monitor (ABPM) with single lead ECG. Twenty participants wore an ABPM for three hours and a data logger which synchronously measured cuff pressure and ECG. RR intervals were compared with corresponding intervals derived from the cuff pressure tracings using three different pulse landmarks. Linear mixed effects models were used to assess differences between ECG and cuff pressure timings and to investigate the effect of potential covariates. In addition, the maximum number of successive oscillometric beats detectable in a measurement was assessed. From 243 BP measurements, the landmark at the foot of the oscillometric pulse was found to be associated with fewest covariates and had a random error of 9.5 ms. 99% of the cuff pressure recordings had more than 10 successive detectable oscillometric beats. RR intervals can be accurately estimated using an ABPM.

Background: Atrial fibrillation (AF) affects around 2% of the population and early detection is beneficial, allowing patients to begin potentially life-saving anticoagulant therapies. Blood pressure (BP) monitors may offer an opportunity to screen for AF., Aim: To identify and appraise studies which report the diagnostic accuracy of automated BP monitors used for opportunistic AF detection., Methods: A systematic search was performed of the MEDLINE, MEDLINE In-Process and EMBASE literature databases. Papers were eligible if they described primary studies of the evaluation of a BP device for AF detection, were published in a peer-reviewed journal and reported values for the sensitivity and specificity. Included studies were appraised using the QUADAS-2 tool to assess their risk of bias and applicability to opportunistic AF detection. Values for the sensitivity and specificity of AF detection were extracted from each paper and compared., Results and Conclusions: We identified seven papers evaluating six devices from two manufacturers. Only one study scored low risk in all of the QUADAS-2 domains. All studies reported specificity >85% and 6 reported sensitivity >90%. The studies showed that BP devices with embedded algorithms for detecting arrhythmias show promise as screening tools for AF, comparing favourably with manual pulse palpation. But the studies used different methodologies and many were subject to potential bias. More studies are needed to more precisely define the sensitivity and specificity of opportunistic screening for AF during BP measurement before its clinical utility in the population of interest can be assessed fully.

Background: Although the efficacy of computerized clinical decision support (CCDS) for acute kidney injury (AKI) remains unclear, the wider literature includes examples of limited acceptability and equivocal benefit. Our single-centre study aimed to identify factors promoting or inhibiting use of in-patient AKI CCDS., Methods: Targeting medical users, CCDS triggered with a serum creatinine rise of ≥25 μmol/L/day and linked to guidance and test ordering. User experience was evaluated through retrospective interviews, conducted and analysed according to Normalization Process Theory. Initial pilot ward experience allowed tool refinement. Assessments continued following CCDS activation across all adult, non-critical care wards., Results: Thematic saturation was achieved with 24 interviews. The alert was accepted as a potentially useful prompt to early clinical re-assessment by many trainees. Senior staff were more sceptical, tending to view it as a hindrance. 'Pop-ups' and mandated engagement before alert dismissal were universally unpopular due to workflow disruption. Users were driven to close out of the alert as soon as possible to review historical creatinines and to continue with the intended workflow., Conclusions: Our study revealed themes similar to those previously described in non-AKI settings. Systems intruding on workflow, particularly involving complex interactions, may be unsustainable even if there has been a positive impact on care. The optimal balance between intrusion and clinical benefit of AKI CCDS requires further evaluation.

Whereas the economic evaluation of pharmaceuticals is an established practice within international health technology assessment (HTA) and is often produced with the support of comprehensive methodological guidance, the equivalent procedure for medical devices is less developed. Medical devices, including diagnostic products, are a rapidly growing market in healthcare, with over 10,000 medical technology patent applications filed in Europe in 2012-nearly double the number filed for pharmaceuticals. This increase in the market place, in combination with the limited, or constricting, budgets that healthcare decision makers face, has led to a greater level of examination with respect to the economic evaluation of medical devices. However, methodological questions that arise due to the unique characteristics of medical devices have yet to be addressed fully. This review of journal publications and HTA guidance identified these characteristics and the challenges they may subsequently pose from an economic evaluation perspective. These unique features of devices can be grouped into four categories: (1) data quality issues; (2) learning curve; (3) measuring long-term outcomes from diagnostic devices; and (4) wider impact from organisational change. We review the current evaluation toolbox available to researchers and explore potential future approaches to improve the economic evaluation of medical devices.

Background: Service reorganization to concentrate complex vascular services in hospitals with high caseload volume aims to reduce mortality and complication rates. The present study assessed the relationship between caseload volume and outcome for iliac artery angioplasty and stenting in England using a routinely available national data set (Hospital Episode Statistics, HES)., Methods: Routine administrative data for iliac artery angioplasty and stent procedures performed in England between 2007 and 2011 were analysed. Associations between centre volume and outcomes (death, complications and duration of hospital stay) were tested and compared for two methods of stratification (quartiles and quintiles) and two statistical tests (odds ratios and the Cochran-Armitage test for trend). Multivariable analysis was also performed., Results: There were 23,308 episodes of care recorded in HES with Office of Population Censuses and Surveys Classification of Surgical Operations and Procedures, fourth revision, codes L54.1 or L54.4 corresponding to iliac artery intervention. There was a gradual increase year by year in number of procedures performed. Univariable and multivariable analysis showed no association between centre volume and either death or complications (multivariable odds ratio, OR 1.00, 95 per cent confidence interval 1.00 to 1.00) for elective and non-elective procedures. Age was associated with higher mortality and complication rates in elective procedures, and with mortality in non-elective procedures. The risk of death after elective iliac angioplasty or stenting was significantly higher in women (multivariable OR 4.98, 2.09 to 13.26)., Conclusion: There was no association between the outcomes of endovascular iliac artery intervention and centre volume, but outcomes were significantly worse with increasing age and female sex., (© 2013 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.)

The MIST Therapy wound healing device (Celleration, Eden Prairie, MN, USA), which uses low-frequency ultrasound to deliver an atomized saline spray to acute wounds, was evaluated in a laboratory environment. The output of the MIST device was characterized by its frequency, transmission in the presence and absence of the saline spray and intensity. When measured up to 500 mm away from the transducer tip, the transmission of 39.5 kHz ultrasound was not significantly attenuated by the saline itself. In the absence of the saline spray, the acoustic intensity range of the MIST device was calculated to be 429-188 mW cm(-2) across the manufacturer-specified treatment range (12.5-20 mm). Because of the acoustic impedance mismatch between air and soft tissue, the MIST Therapy device would deliver only 0.1% of this incident intensity into the wound site., (Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Objective: To assess clinical measurement competency by two sequential test formulations [resetting sequential probability ratio test (R-SPRT) and learning curve cumulative summation (LC-CUSUM)]., Design: Numerical simulation and retrospective observational study., Setting: Obstetric ultrasound department., Participants: Cohorts of 10,000 simulated trainees and 62 obstetric sonographers training in nuchal translucency (NT) measurement at the 11-14-week pregnancy scan with limited case availability., Intervention: Application of LC-CUSUM and R-SPRT to clinical measurement training., Main Outcome Measures: Proportions of real trainees achieving competency by LC-CUSUM and R-SPRT, proportions of simulated competent trainees not achieving competency (Type I error), proportions of simulated incompetent trainees achieving competency (Type II error), distribution of case number required to achieve competency (run length) and frequency of resets., Results: For simulated cohorts, significant differences in run-length distribution and true test error rates were found between the R-SPRT and LC-CUSUM tests with equivalent parameters. Increasing the cases available to each trainee reduced the Type I error rate but increased the Type II error rate for both sequential tests for all choices of unacceptable failure rate. Discontinuities in the proportion of trainees expected to be test competent were found at critical values of unacceptable failure rate., Conclusions: With equivalent parameters, the R-SPRT and LC-CUSUM formulations of sequential tests produced different outcomes, demonstrating that the choice of test method, as well as the choice of parameters, is important in designing a training scheme. The R-SPRT detects incompetence as well as competence and may indicate need for further training. Simulations are valuable in estimating the proportions of trainees expected to be assessed as competent.

Background: When intubating a child's trachea with an uncuffed tracheal tube (TT), it is current practice in anesthesia and intensive care to use the leak test to assess TT fit. The aim of this study is to compare three measures of assessing leak around uncuffed tracheal tubes in the PICU., Methods: We obtained institutional ethical permission and written informed consent, prior to any clinical investigation, from the parents of 135 children who had surgery for cardiac defects. On admission to the PICU, we measured leak by audible assessment, fractional volume loss, and leak conductance for each patient. Measurements of fractional volume loss and leak conductance were repeated every 4 h thereafter until extubation., Results: On admission to the PICU, calculated values of leak conductance were significantly different between each grade of audible leak (P < 0.001). Values of fractional volume loss were not significantly different between 'no leak' and 'small leak' grades of leak. Throughout the PICU stay, a significant correlation between mean leak conductance and mean fractional volume loss was found (0.86, 95% CI, 0.81-0.90). Significant agreement within time series of leak conductance and fractional volume recorded for each patient occurred in 47/128 cases (37%)., Conclusions: On admission to the PICU, values of leak conductance are more strongly associated with audible assessment than with fractional volume loss. Throughout PICU stay, leak conductance is associated with fractional volume loss. This study demonstrates that leak conductance, calculated from routinely available pressure and flow signals, has the potential to represent the characteristics of the leak interface between a TT and the trachea., (© 2012 Blackwell Publishing Ltd.)

Background: We have developed a technique for measuring a characteristic of the tracheal tube (TT)-trachea interface: the leak conductance (LC). This study aimed to validate the technique in the laboratory and to compare LC with measurements of fractional volume loss (FVL) in neonates undergoing mechanical ventilation., Methods: LC, expressed as leak flow at a lung pressure of 10 cm H(2)O, was derived remotely from ventilator pressure and flow signals. Validation was by simulating breathing circuits for 10 models in which LC was measured directly. LC was compared with FVL for different settings of PEEP, inspired pressure, and time at plateau pressure. Clinically, LC was measured for 135 infants admitted to paediatric intensive care after cardiac surgery and compared with FVL., Results: No significant differences were found between direct and remote laboratory measurements of LC (P>0.05). FVL varied with PEEP, plateau pressure, and time at plateau (P<0.05) but LC did not (P>0.05). The between-patient standard deviation (sd) of LC (0.4 litre min(-1)) exceeded the within-patient sd of lc (0.05 litre min(-1); P<0.05); the between-patient sd of FVL (22.1%) exceeded the within-patient sd of FVL (1.3%; P<0.05). The median LC was 0.38 (inter-quartile range 0.29-0.46) litre min(-1). LC was correlated with FVL (r=0.82; 95% confidence interval 0.76-0.88) but wide ranges of FVL were observed for patients with similar LC., Conclusions: LC can be derived remotely and was correlated with FVL, a conventional proxy for tube fit. It may be a better measure of TT fit than FVL.

Background and Objectives: This study measured the association between the Acute Kidney Injury Network (AKIN) diagnostic and staging criteria and surrogates for baseline serum creatinine (SCr) and body weight, compared urine output (UO) with SCr criteria, and assessed the relationships between use of diuretics and calibration between criteria and prediction of outcomes., Design, Setting, Participants, & Measurements: This was a retrospective cohort study using prospective measurements of SCr, hourly UO, body weight, and drug administration records from 5701 patients admitted, after cardiac surgery, to a cardiac intensive care unit between 1995 and 2006., Results: More patients (n=2424, 42.5%) met SCr diagnostic criteria with calculated SCr assuming a baseline estimated GFR of 75 ml/min per 1.73 m(2) than with known baseline SCr (n=1043, 18.3%). Fewer patients (n=484, 8.5%) met UO diagnostic criteria with assumed body weight (70 kg) than with known weight (n=624, 10.9%). Agreement between SCr and UO criteria was fair (κ=0.28; 95% confidence interval 0.25-0.31). UO diagnostic criteria were specific (0.95; 0.94-0.95) but insensitive (0.36; 0.33-0.39) compared with SCr. Intravenous diuretics were associated with higher probability of falling below the UO diagnostic threshold compared with SCr, higher 30-day mortality (relative risk, 2.27; 1.08-4.76), and the need for renal support (4.35; 1.82-10.4) compared with no diuretics., Conclusions: Common surrogates for baseline estimated GFR and body weight were associated with misclassification of AKIN stage. UO criteria were insensitive compared with SCr. Intravenous diuretic use further reduced agreement and confounded association between AKIN stage and 30-day mortality or need for renal support.

The assessment of circadian blood pressure change by ambulatory blood pressure monitoring has potential as a predictor for cardiovascular events, but its evaluation is problematic due to the difficulty in defining day and night periods for individual subjects. The cumulative sums (cusums) method has the advantage of simplicity over mathematical modelling techniques and is reported to give more reproducible results than methods that use time-dependent sleep and wake periods. However, cusum parameters (cusum-derived circadian alteration magnitude (CDCAM) and cusum plot height (CPH)) are affected by the implementation of the method and by the quality of ambulatory blood pressure recordings. This study quantifies the effects of using interval blood pressure values, changing the time used for calculating the cusum plot slope (CPS) and using incomplete data recordings. Significant effects are reported in all cases. Using interval rather than recorded blood pressures causes a mean reduction in CPH and CDCAM of approximately 6%. Altering the CPS time by 1 h (from 6 h) results in a mean change in CDCAM of approximately 7%. In recordings with hourly readings, the coefficient of variation in CPH and CDCAM ranges from 4% (one missing reading) to 13% (five missing readings).

Objectives: Measurement of blood pressure by a trained observer using a mercury sphygmomanometer is accepted as the gold standard, but there has been an increase in the use of automated devices employing the oscillometric technique. Not all such devices have been clinically validated, and some do not carry an appropriate CE mark. This survey aimed to assess the state of the European Union market for automated non-invasive blood pressure devices in terms of information provided by companies relating to compliance, validation and intended use., Methods: A total of 116 companies were identified as being potentially active (i.e. manufacturer, supplier, agent or distributor). Of these, 110 that could be contacted were asked to provide details of their company and their non-invasive blood pressure products via a questionnaire., Results: Eighty-six companies were found to be actively involved in the supply of 158 different models of automated non-invasive blood pressure device. These included 54 devices for use on the arm and 62 for use on the wrist (total 116 in our main categories), and 42 others (ambulatory monitors, patient monitors, defibrillators or finger devices). We received responses for 61% (71/116) of the main category arm and wrist devices and 80% (57/71) of these provided claims for CE marking. Of the CE marked devices for which we received a response, 41% (12/29) of arm devices and 39% (11/28) of wrist devices claimed some form of clinical validation, or evidence was found subsequent to the survey. Of these claims, 65% (15/23) related to an earlier, or similar, product and 48% (11/23) were based on published studies. Inconsistencies were found between claims for diagnostic suitability and claims for clinical validation., Conclusions: A majority of models available on the European Union market were not validated by clinical trial to one of the recognized protocols.

Automated non-invasive blood pressure measuring devices based on the oscillometric technique are used widely for self-measurement and are often used in clinics in place of the manual, auscultatory method. Oscillometry was originally developed for monitoring purposes and there are questions over its suitability for making diagnostic measurements. This study measured the differences between automated devices, in the absence of physiological variability. We studied 19 low-cost, automated, non-invasive blood pressure devices, using a repeatable artificial arm simulator, and measured the within-device repeatability and between-device differences. We found that the devices were repeatable (mean within-device difference 1 mmHg), but between-device differences were 4.4 mmHg (systolic pressure) and 3.6 mmHg (diastolic pressure), for normal and high-normal blood pressures. Individual devices are sufficiently repeatable for clinical trend use, but differences between devices are sufficiently large that they may be misinterpreted as clinically significant.

Pancreatic cancer is frequently associated with intense growth of fibrous tissue at the periphery of tumours, but the histopathological quantification of this stromal reaction has not yet been used as a prognostic factor because of the difficulty of obtaining quantitative measures using manual methods. Manual histological grading is a poor indicator of outcome in this type of cancer and there is a clinical need to establish a more sensitive indicator. Recent pancreatic tumour biology research has focused upon the stromal reaction and there is an indication that its histopathological quantification may lead to a new prognostic indicator. Histological samples from 21 cases of pancreatic carcinoma were stained using the sirius red, light-green method. Multiple images from the centre and periphery of each tumour were automatically segmented using colour cluster analysis to subdivide each image into representative colours. These were classified manually as stroma, cell cytoplasm or lumen in order to measure the area of each component in each image. Measured areas were analysed to determine whether the technique could detect spatial differences in the area of each tissue component over all samples, and within individual samples. Over all 21 cases, the area of stromal tissue at the periphery of the tumours exceeded that at the centre by an average of 10.0 percentage points (P < 0.001). Within individual tumours, the algorithm was able to detect significantly more stroma (P < 0.05) at the periphery than the centre in 11 cases, whilst none of the remaining cases had significantly more stromal tissue at the centre than the periphery. The results demonstrate that semi-automated analysis can be used to detect spatial differences in the area of fibrous tissue in routinely stained sections of pancreatic cancer.

Objective measurements of tissue area during histological examination of carcinoma can yield valuable prognostic information. However, such measurements are not made routinely because the current manual approach is time consuming and subject to large statistical sampling error. In this paper, a semi-automated image analysis method for measuring tissue area in histological samples is applied to the measurement of stromal tissue, cell cytoplasm and lumen in samples of pancreatic carcinoma and compared with the standard manual point counting method. Histological samples from 26 cases of pancreatic carcinoma were stained using the sirius red, light-green method. Images from each sample were captured using two magnifications. Image segmentation based on colour cluster analysis was used to subdivide each image into representative colours which were classified manually into one of three tissue components. Area measurements made using this technique were compared to corresponding manual measurements and used to establish the comparative accuracy of the semi-automated image analysis technique, with a quality assurance study to measure the repeatability of the new technique. For both magnifications and for each tissue component, the quality assurance study showed that the semi-automated image analysis algorithm had better repeatability than its manual equivalent. No significant bias was detected between the measurement techniques for any of the comparisons made using the 26 cases of pancreatic carcinoma. The ratio of manual to semi-automatic repeatability errors varied from 2.0 to 3.6. Point counting would need to be increased to be between 400 and 1400 points to achieve the same repeatability as for the semi-automated technique. The results demonstrate that semi-automated image analysis is suitable for measuring tissue fractions in histological samples prepared with coloured stains and is a practical alternative to manual point counting.

An architecture is presented which provides clinical information systems with access to vital sign information from medical devices. Middleware components encapsulate details of communicating with devices whilst adoption of de facto and international standards maximizes interoperability with client software. An application in routine clinical use is described.

The Cosmic Radiation Environment and Dosimetry experiment (CREDO) has been operational on board the Advanced Photovoltaics & Electronics Experiment Spacecraft since August 1994. Extensive measurements of cosmic ray linear energy transfer spectra (using data to January 1996) and total dose (using data to November 1994) have been made, and compared with predictions of standard models. Detailed consideration of spacecraft shielding effects have been made. Predictions are shown to overestimate the measured linear energy transfer spectra. The CREAM experiment was flown on STS-63 in the SpaceHab module. Results show penetration of high energy electrons into the SpaceHab module.

The Cosmic Radiation Effects and Activation Monitor has flown on six Shuttle flights between September 1991 and February 1995 covering the full range of inclinations as well as altitudes between 220 and 570 km, while a version has flown at supersonic altitudes on Concorde between 1988 and 1992 and at subsonic altitudes on a SAS Boeing 767 between May and August 1993. The Shuttle flights have included passive packages in addition to the active cosmic ray monitor which comprises an array of pin diodes. These are positioned at a number of locations to investigate the influence of shielding and local materials. Use of both metal activation foils and scintillator crystals enables neutron fluences to be inferred from the induced radioactivity which is observed on return to Earth. Supporting radiation transport calculations are performed to predict secondary neutron spectra and the energy deposition due to nuclear reactions in silicon pin diodes and the induced radioactivity in the various scintillator crystals. The wide variety of orbital and atmospheric locations enables investigation of the influence of shielding on cosmic ray, trapped proton and solar flare proton spectra.

We measured binocular rivalry between dichoptic, orthogonal, sinusoidal gratings both having spatial frequencies of 0.5, 1, 2, 4, 8 or 16 c deg-1 in fields ranging from 0.5 to 8 deg of visual angle in diameter. Total time that one or the other grating was exclusively visible had an inverted U-shaped relationship with spatial frequency, with the peak shifting to coarser spatial frequencies as the field size increased. We computed for each spatial frequency the maximum field size over which a criterion duration of exclusive visibility would spread. When expressed as areas, these sizes were inversely proportional to spatial frequency. This dependence of rivalry on spatial frequency is similar to those for stereopsis and fusion, consistent with the notion that all three binocular phenomena have a common mechanism.

The Cosmic Radiation Environment & Activation Monitor (CREAM) was carried in high inclination (57.1 degrees) orbits on Shuttle missions STS-48 in September 1991 (altitude 570 km) and STS-53 (altitude 325 to 385 km) in December 1992. On both occasions the instrument observed an excess of counts due to protons of greater than 30 MeV in energy in the region off of South Africa where field lines of L=2.5 intersect low earth orbit. Meanwhile the Cosmic Radiation Environment and Dosimetry Experiment (CREDO) carried to 840 km, 98.7 degrees orbit on UOSAT-3 has continued to sample the high field portions of the L-shells around L = 2.5 from April 1990 until the present time. When careful subtraction of cosmic-ray contributions is made it can be seen that the March 91 enhancement persisted for approximately 8 months and explains the STS-48 observation. There would appear to have been a further increase produced by the 31 October 1992 flare event and seen by STS-53.

Secondary radiations produced by the interactions of primary cosmic rays and trapped protons with spacecraft materials and detectors provides an important, and sometimes dominant, radiation environment for sensitive scientific instruments and biological systems. In this paper the success of a number of calculations in predicting a variety of effects will be examined. The calculation techniques include Monte Carlo transport codes and semi-empirical fragmentation calculations. Observations are based on flights of the Cosmic Radiation Environment and Activation Monitor at a number of inclinations and altitudes on Space Shuttle. The Shuttle experiments included an active cosmic-ray detector as well as metal activation foils and passive detector crystals of sodium iodide which were counted for induced radioactivity soon after return to earth. Results show that cosmic-ray secondaries increase the fluxes of particles of linear energy transfer less than 200 MeV/(gm cm-2), while the activation of the crystals is enhanced by about a factor of three due to secondary neutrons. Detailed spectra of induced radioactivity resulting from spallation products have been obtained. More than a hundred significant radioactive nuclides are included in the calculation and overall close agreement with the observations is obtained.

The dietary intake of 42 dietitians studied in 1977 was compared with recent recommendations for the composition of a healthful diet proposed by a working party of the National Advisory Committee for Nutrition Education (NACNE). Mean daily sucrose intake was 35 g, compared with a present national intake of around 100 g and a proposed goal of 55 g; it is argued that a national goal of 65 g is a more realistic goal. Mean fibre intake was 23 g, compared with a present national intake of 20 g and a proposed goal of 30 g; it is argued that while 30 g is a realistic goal for a national mean intake, it is not realistic for subgroups of the population with below average energy intake, and 26-27 g is suggested as a realistic goal for an adult female population. Fat energy intake was 40 per cent of total energy, compared with a present national average of 38 per cent and 30 per cent as a long-term goal; but if national sucrose and alcohol intakes were as low as the dietitians', national fat energy would be 42 per cent. It is argued that 34 per cent fat energy is a more appropriate long-term goal for the dietitians and similar subgroups of the population; however, it is thought that 36 per cent (or 32 per cent nationally) would be more realistic.