Numerical experiments in semi-infinite programming

A quasi-Newton algorithm for semi-infinite programming using an L∞ exact penalty function is described, and numerical results are presented. Comparisons with three Newton algorithms and one other quasi-Newton algorithm show that the algorithm is very promising in practice

Preferences for centralised emergency medical services: discrete choice experiment

Objectives It is desirable that public preferences are established and incorporated in emergency healthcare reforms. The aim of this study was to investigate preferences for local versus centralised provision of all emergency medical services (EMS) and explore what individuals think are important considerations for EMS delivery. Design A discrete choice experiment was conducted. The attributes used in the choice scenarios were: travel time to the hospital, waiting time to be seen, length of stay in the hospital, risks of dying, readmission and opportunity for outpatient care after emergency treatment at a local hospital. Setting North East England. Participants Participants were a randomly sampled general population, aged 16 years or above recruited from Healthwatch Northumberland network database of lay members and from clinical contact with Northumbria Healthcare National Health Service Foundation Trust via Patient Experience Team. Primary and secondary outcome measures Analysis used logistic regression modelling techniques to determine the preference of each attribute. Marginal rates of substitution between attributes were estimated to understand the trade-offs individuals were willing to make. Results Responses were obtained from 148 people (62 completed a web and 86 a postal version). Respondents preferred shorter travel time to hospital, shorter waiting time, fewer number of days in hospital, low risk of death, low risk of readmission and outpatient follow-up care in their local hospital. However, individuals were willing to trade off increased travel time and waiting time for high-quality centralised care. Individuals were willing to travel 9 min more for a 1-day reduction in length of stay in the hospital, 38 min for a 1% reduction in risk of death and 112 min for having outpatient follow-up care at their local hospital. Conclusions People value centralised EMS if it provides higher quality care and are willing to travel further and wait longer

Impact of emergency care centralisation on mortality and efficiency: a retrospective service evaluation

Objective: Evidence favours centralisation of emergency care for specific conditions, but it remains unclear whether broader implementation improves outcomes and efficiency. Routine healthcare data examined consolidation of three district general hospitals with mixed medical admission units (MAU) into a single high-volume site directing patients from the ED to specialty wards with consultant presence from 08:00 to 20:00. Methods: Consecutive unscheduled adult index admissions from matching postcode areas were identified retrospectively in Hospital Episode Statistics over a 3-year period: precentralisation baseline (from 16 June 2014 to 15 June 2015; n=18 586), year 1 postcentralisation (from 16 June 2015 to 15 June 2016; n=16 126) and year 2 postcentralisation (from 16 June 2016 to 15 June 2017; n=17 727). Logistic regression including key demographic covariates compared baseline with year 1 and year 2 probabilities of mortality and daily discharge until day 60 after admission and readmission within 60 days of discharge. Results: Relative to baseline, admission postcentralisation was associated with favourable OR (95% CI) for day 60 mortality (year 1: 0.95 (0.88 to 1.02), p=0.18; year 2: 0.94 (0.91 to 0.97), p<0.01), mainly among patients aged 80+ years (year 1: 0.88 (0.79 to 0.97); year 2: 0.91 (0.87 to 0.96)). The probability of being discharged alive on any day since admission increased (year 1: 1.07 (1.04 to 1.10), p<0.01; year 2: 1.04 (1.02 to 1.05), p<0.01) and the risk of readmission decreased (year 1: 0.90 (0.87 to 0.94), p<0.01; year 2: 0.92 (0.90 to 0.94), p<0.01). Conclusion: A centralised site providing early specialist care was associated with improved short-term outcomes and efficiency relative to lower volume ED admitting to MAU, particularly for older patients

Volume Introduction

Medical devices have historically been less regulated than their drug and biologic counterparts. A benefit of this less demanding regulatory regime is facilitating innovation by making new devices available to consumers in a timely fashion. Nevertheless, there is increasing concern that this approach raises serious public health and safety concerns. The Institute of Medicine in 2011 published a critique of the American pathway allowing moderate-risk devices to be brought to the market through the less-rigorous 501(k) pathway,1 flagging a need for increased postmarket review and surveillance. High-profile recalls of medical devices, such as vaginal mesh products, along with reports globally of nearly two million injuries and more than 80,000 deaths linked to faulty medical devices,2 have raised public health critiques regarding the oversight of these products. Should we follow the recommendation of the Institute of Medicine to reduce the use of the 510(k) pathway, and, if so, what should replace it? What would an ideal regulatory pathway, reflecting the twin goals of innovation and patient protection, look like in the twenty-first century? These questions are complicated by new tools and mechanisms that can be used to achieve our goals. For example, in an era of big data, where we have the capabilities to better follow postmarket incidents, what should postmarket review look like

Estimating the number of UK stroke patients eligible for endovascular thrombectomy

Introduction: Endovascular thrombectomy (EVT) is a highly effective treatment for acute ischemic stroke due to large arterial occlusion. Routine provision will require major changes in service configuration and workforce. An important first step is to quantify the population of stroke patients that could benefit. We estimated the annual UK population suitable for EVT using standard or advanced imaging (AI) for patient selection. Patients and Methods: Evidence from randomised control trials and national registries was combined to estimate UK stroke incidence and define a decision-tree describing the EVT eligible population. Results: Between 9,620 and 10,920 UK stroke patients (approximately 10% of stroke admissions) would be eligible for EVT annually. The majority (9,140 to 9,620) would present within 4 hours of onset and be suitable for intravenous thrombolysis. Advanced Imaging would exclude 500 patients presenting within 4 hours, but identify an additional 1,310 patients as eligible who present later. Discussion: Information from randomised control trials and large registry data provided the evidence criterion for 9 of the 12 decision points. The best available evidence was used for 2 decision-points with sensitivity analyses to determine how key branches of the tree affected estimates. Using the mid-point estimate for eligibility (9.6% of admissions) and assuming national EVT coverage, 4,280 patients would have reduced disability. Conclusion: A model combining published trials and register data suggests approximately 10% of all stroke admissions in the UK are eligible for EVT. The use of AI based on current published evidence did not have a major impact on overall numbers, but could alter eligibility status for 16% of cases

How do interventions to improve the efficiency of acute stroke care affect prehospital times? A systematic review and narrative synthesis

BACKGROUND: Emergency medical services (EMS) are the first point of contact for most acute stroke patients. EMS call to hospital times have increased in recent years for stroke patients in the UK which is undesirable due to the relationship between time and effectiveness of reperfusion treatment. This review aimed to identify and describe interventions devised to improve the efficiency of acute stroke care which reported an impact on ground-based EMS call to hospital times. METHODS: A systematic review of published literature identified from five databases (Medline, EMBASE, CINAHL, the Cochrane library and the Database of Research in Stroke (DORIS)) from January 2000 to December 2020 with narrative synthesis was conducted. Inclusion criteria were primary studies of ground-based EMS, focused on stroke and aiming to improve EMS times. Papers published before 2000, focussing on mobile stroke units or in languages other than English were excluded. Two reviewers independently screened prospective titles. Cochrane ROB2 and ROBINS-I tools were used to assess for risk of bias. This review was funded by a Stroke Association fellowship. RESULTS: From 3767 initial records, 11 studies were included in the review. Included studies were categorised into three groups: studies targeting EMS dispatch and EMS clinicians (n = 4); studies targeting EMS clinicians only (n = 4); and studies targeting whole system change (n = 3). Suspected stroke patients were the primary population studied and most (n = 10) interventions involved clinician education. Only one study (9%) reported a significant decrease in call to hospital time in one subgroup whereas two studies (18%) reported a significant increase in call to hospital time and all other studies (73%) reported no significant change. CONCLUSIONS: Based on the included studies, interventions intended to improve the efficiency of the acute stroke pathway rarely improved EMS call to hospital times. Included studies were heterogenous and rarely focussed on the review topic which limits the usability of the findings. Further research is needed to explore the trade-off between changes to EMS stroke care and call to hospital times and subsequent impacts on in-hospital care and patient outcomes

Using intervention mapping to develop and facilitate implementation of a multifaceted behavioural intervention targeting physical activity and sedentary behaviour in stroke survivors: Physical Activity Routines After Stroke (PARAS): intervention development study

Objectives: The benefits of increased physical activity for stroke survivors include improved function and mental health and wellbeing. However, less than 30% achieve recommended physical activity levels, and high levels of sedentary behaviour are reported. We developed a multifaceted behavioural intervention (and accompanying implementation plan) targeting physical activity and sedentary behaviour of stroke survivors. Design: Intervention Mapping facilitated intervention development. Step 1 involved a systematic review, focus group discussions and a review of care pathways. Step 2 identified social cognitive determinants of behavioural change and behavioural outcomes. Step 3 linked determinants of behavioural outcomes with specific behaviour change techniques (BCTs) to target behaviours of interest. Step 4 involved intervention development informed by steps 1–3. Subsequently, an implementation plan was developed (Step 5) followed by an evaluation plan (Step 6). Setting: Community and secondary care settings, North East England. Participants: Stroke survivors and healthcare professionals (HCPs) working in stroke services. Results: Systematic review findings informed selection of nine ‘promising’ BCTs (e.g. problem-solving). Focus groups with stroke survivors (n = 18) and HCPs (n= 24) identified the need for an intervention delivered throughout the rehabilitation pathway, tailored to individual needs with training for HCPs delivering the intervention. Intervention delivery was considered feasible within local stroke services. The target behaviours for the intervention were levels of physical activity and sedentary behaviour in adult stroke survivors. Assessment of acceptability and usability with 11 HCPs and 21 stroke survivors/relatives identified issues with self-monitoring tools and the need for a physical activity repository of local services’ and training for HCPs with feedback on intervention delivery. A feasibility study protocol was designed to evaluate the intervention. Conclusions: A systematic development process using intervention mapping resulted in a multi-faceted evidence- and theory-informed intervention (Physical Activity Routines After Stroke – PARAS) for delivery by community stroke rehabilitation teams

An observational study of patient characteristics associated with the mode of admission to acute stroke services in North East, England

Objective Effective provision of urgent stroke care relies upon admission to hospital by emergency ambulance and may involve pre-hospital redirection. The proportion and characteristics of patients who do not arrive by emergency ambulance and their impact on service efficiency is unclear. To assist in the planning of regional stroke services we examined the volume, characteristics and prognosis of patients according to the mode of presentation to local services. Study design and setting A prospective regional database of consecutive acute stroke admissions was conducted in North East, England between 01/09/10-30/09/11. Case ascertainment and transport mode were checked against hospital coding and ambulance dispatch databases. Results Twelve acute stroke units contributed data for a mean of 10.7 months. 2792/3131 (89%) patients received a diagnosis of stroke within 24 hours of admission: 2002 arrivals by emergency ambulance; 538 by private transport or non-emergency ambulance; 252 unknown mode. Emergency ambulance patients were older (76 vs 69 years), more likely to be from institutional care (10% vs 1%) and experiencing total anterior circulation symptoms (27% vs 6%). Thrombolysis treatment was commoner following emergency admission (11% vs 4%). However patients attending without emergency ambulance had lower inpatient mortality (2% vs 18%), a lower rate of institutionalisation (1% vs 6%) and less need for daily carers (7% vs 16%). 149/155 (96%) of highly dependent patients were admitted by emergency ambulance, but none received thrombolysis. Conclusion Presentations of new stroke without emergency ambulance involvement were not unusual but were associated with a better outcome due to younger age, milder neurological impairment and lower levels of pre-stroke dependency. Most patients with a high level of pre-stroke dependency arrived by emergency ambulance but did not receive thrombolysis. It is important to be aware of easily identifiable demographic groups that differ in their potential to gain from different service configurations