Avoidable Delays Research Articles

Extraspinal articular tuberculosis: An 11-year retrospective study of demographic features and clinical outcomes in East London

ObjectivesTo describe demographic features, clinical outcomes and diagnostic delay amongst patients with extra-spinal articular tuberculosis (TB) in a low-incidence setting. MethodsCases of TB treated at our institution between 2004 and 2014 were identified via the London TB register (LTBR). Demographic features of extra-spinal articular TB cases were compared to controls with TB at all other sites. For articular cases (excluding individuals <16 years or with spinal TB without peripheral joint involvement) clinical data were retrospectively collected. Results6,146 TB patients were identified over the study period; 146 (2.4%) cases had extra-spinal articular infection. There was no difference in median age between extra-spinal articular TB cases and controls with TB at other sites (31 vs 32 years, p = 0.57). Articular cases were more likely to be male (70.6% vs 59.5%, p = 0.007), Bangladeshi (28.7% vs 18.0%) or Pakistani (24.0% vs 16.1%) and were less likely to be Black-African (9.5% vs 19.8%) (p < 0.001). 93 cases were included in the case series; 85 (88.5%) were migrants and 83 (89.2%) were South Asian. Knee and elbow joints were affected in 22 (23.7%) and 18 (19.4%) cases respectively. The median durations of pre-healthcare and healthcare associated delay were 16 and 6 weeks respectively. Where mycobacterial culture was performed, 57/75 (76%) were positive for Mycobacterium tuberculosis. 86 (92.5%) cases received standard quadruple therapy for a median of 6 months (IQR 6–9). Recurrence of TB infection occurred in 4 (4.3%) cases and there were no TB related deaths. Seven (7.6%) cases required surgical intervention. ConclusionsExtra-spinal articular TB more commonly affected men and people of South Asian ethnicity. Significant diagnostic delays were identified, including avoidable healthcare-associated delays.

Terrorist attack training exercise-What can be learned? : Baden-Württemberg counterterrorism exercise (BWTEX)

There is arisk of terror attacks in the Federal Republic of Germany, which might increase in the future. Atimely comprehensive strategy for treatment and care of alarge number of casualties helps minimize chaos and improve the outcome of patients. Adequate training is vital for successful implementation of an emergency plan. Therefore, the effectiveness of training should be assessed and evaluated; however, data collection capabilities for training events are extremely limited, so that publications on the topic are almost impossible to find. This study aimed to collect data from asimulated terrorist attack in order to draw conclusions from aclinical point of view concerning the improvement of preclinical and clinical management, taking interface problems into consideration. On 19 October 2019 the Ministry of the Interior, Digitalization and Migration of Baden-Württemberg conducted alarge-scale simulation of aterrorist attack in the city center of Constance, called the Baden-Württemberg counterterrorism exercise (BWTEX). The simulation included an explosion of acar bomb as well as the use of firearms by terrorists. The large scale of the simulation with the high number of participants in combination with close cooperation between military and civil forces was unprecedented. The police force, the armed forces, civil protection forces, air rescue teams and staff from Constance, Friedrichshafen and Sigmaringen regional hospitals in southwest Germany worked together to treat simulated injuries to victims of the attack. The following parameters were recorded when the injured patients arrived at the hospital: prehospital triage time, prehospital triage score, initial treatment and quality of documentation on site as well as triage time, triage score, injury severity scale (ISS) score based on the specified injury pattern, treatment, and quality of documentation on hospital arrival. Out of atotal of 84 "injured patients" 55 were admitted to hospital and 80% were triaged at the scene. Injured patients of triage category1 (TK1 red: life-threatening injury, immediate treatment) arrived at the hospital 198 ± 50 min after the attack, injured patients of triage category2 (TK2 yellow: severely injured, urgent treatment) after 131 ± 44 min and injured patients of triage category3 (TK3 green: slightly injured, non-urgent treatment) arrived after 157 ± 46 min. There was no significant difference in terms of arrival time at the hospital between the triage scores (r = 0.2) or between the ISS scores (r = 0.43). The authors assume that approximately 44% of TK1 patients would have died due to avoidable time delays. Prehospital medical documentation was insufficient in 78% and insufficient in 65% in the hospitals. Amass casualty incident resulting from aterrorist attack differs greatly from aconventional mass casualty incident. The scene of the attack has to be evacuated as quickly as possible, which means that alarge number of patients arrive untreated at the nearest hospitals. The setting up of treatment facilities in city centers and areas close to the city seems to be counterproductive because the time delay may result in higher mortality rates of victims. The particularities of mass casualties caused by aterrorist attack have to be incorporated into terrorist attack training.

Impact of geography on Scottish cancer diagnoses in primary care: Results from a national cancer diagnosis audit

BackgroundA recent meta-analysis of global research found cancer patients living in rural locations are 5% less likely to survive than their urban counterparts, a survival disadvantage that has never been satisfactorily explained. Aims[1] To describe and compare primary-care involvement in the diagnosis of cancer between rural and urban patients in Scotland. [2] To compare the length of key diagnostic pathway intervals between rural and urban cancer patients in Scotland. MethodsParticipating GPs in the Scottish National Cancer Audit of cancer diagnosis (2017) collected data from primary-care medical records on the diagnostic pathway of patients diagnosed in 2014. Residential postcodes designated the patients as rural or urban dwellers. Key cancer diagnostic pathway intervals (primary, diagnostic, secondary, and treatment) were compared using binary logistic regression. Descriptive analysis included comparison of patient characteristics, and routes to diagnosis. Results73 Scottish general practices provided data on 1,905 cancer diagnoses. Rural patients did not have higher odds of prolonged diagnostic intervals compared to urban patients but were significantly more likely to have had a cancer alarm feature at presentation and three or more primary-care consultations prior to referral. Rural GPs were significantly more likely to perceive an avoidable delay in their patient’s diagnostic pathway. ConclusionThere was no evidence that rural patients were more likely to be subject to prolonged cancer diagnostic delays than urban patients. Rural patients may experience primary care differently in the lead-up to a cancer diagnosis. The effect on outcome is probably negligible, but further research is required to confirm this.

Challenges to stroke care 5 years after endovascular therapy became the standard.

Endovascular therapy is a highly effective and safe treatment for patients with acute ischemic stroke with large vessel occlusion (LVO) and is now considered the standard of care. Complication rates of endovascular therapy are low, but its efficacy is highly time-dependent and declines rapidly as time from symptom onset to treatment increases. Thus, it seems logical that patients with acute stroke due to LVO should get treated with endovascular therapy, if indicated, as soon as possible. At the same time, providers of this highly specialised treatment should be well-trained and meet minimum quality standards. However, in the USA, the reality of endovascular therapy is different depending on the setting: in metropolitan regions, geographically close centres capable of delivery this therapy compete with each other and struggle to find enough patients to treat, while in some rural areas access to this specialised treatment is lacking. Establishing new thrombectomy-capable stroke centres has been suggested as a solution to close this gap, but whether the quality standards of these centres would be good enough has been questioned. To make matters worse, just as endovascular therapy centres are clustered in metropolitan areas, the same is true for primary stroke centres (ie, stroke centres that provide treatment with intravenous alteplase, but cannot provide endovascular therapy), but initial transfer of patients with LVO to primary stroke centres can lead to avoidable treatment delays.

The frequency, nature and impact of GP-assessed avoidable delays in a population-based cohort of cancer patients

BackgroundThere is a growing emphasis on the speed of diagnosis as an aspect of cancer prognosis. While epidemiological data in the last decade have quantified diagnostic timeliness and its variation, whether and how often prolonged diagnostic intervals can be considered avoidable is unknown. MethodsWe used data from the English National Cancer Diagnosis Audit (NCDA) on 17,042 patients diagnosed with cancer in 2014. Participating primary care physicians were asked to identify delays in diagnosis that they deemed avoidable, together with the ‘setting’ of the avoidable delay and key attributable factors. We used descriptive analysis and regression frameworks to assess validity and examine variation in the frequency and nature of avoidable delays. ResultsAmong 14,259 patients, 24% were deemed to have had an avoidable delay to their diagnosis. Patients with a reported avoidable delay had a longer median diagnostic interval (92 days) than those without (30 days). Of all avoidable delays, 13% were deemed to have occurred pre-consultation, 49% within primary care, and 38% within secondary care. Avoidable delays were mostly attributed to the test request/performance phase (25%). Multimorbidity was associated with greater odds of avoidable delay (OR for 3+ vs no comorbidity: 1.43 (95% CI 1.25–1.63)), with heterogeneous associations with cancer site. ConclusionWe have shown that GP-identified instances of avoidable delay have construct validity. Whilst the causes of avoidable diagnostic delays are multi-factorial and occur in different settings and phases of the diagnostic process, their analysis can guide improvement initiatives and enable the examination of any prognostic implications.

Differences in attitudes to feeding post repair of Gastroschisis and development of a standardized feeding protocol

BackgroundThe purpose of this study was to examine differences in attitudes to feeding in neonates with Gastroschisis between clinical groups and to develop a standardized feeding protocol. Confusion, inconsistencies in practice and lack of evidence could be contributing to avoidable delays in the establishment of enteral feeds resulting in lengthy requirements for central venous access, dependence on total parenteral nutrition (TPN), increased risk of sepsis, TPN related cholestasis and prolongation in length of hospital stay.MethodsA national survey of clinicians (neonatologists, neonatal intensive care nurses and paediatric surgeons), looking after neonates with gastroschisis was undertaken to determine differences in feeding practice post repair. In addition, an audit of practice in one hospital was undertaken to examine variations in practices between clinicians. A feeding protocol was then developed using inputs from surgeons and neonatologists.ResultsGastric aspirates and residuals were typically used as indicators of feed readiness and feed tolerance; however, there was very little consistency within and between clinical groups in definitions of tolerance or intolerance of feeds and in how to initiate and progress feeds. A feeding protocol with clear definition of feed readiness and a clear pathway to progression of feeds was developed to help overcome these variations in practice with the possibility that this might reduce the length of stay (LOS) and have other secondary benefits. The protocol included early introduction of enteral feeds particularly direct breast or sucking feeds.ConclusionsWide differences in attitudes to feeding neonates post Gastroschsis repair exist and the need for a consistent protocolized approach was felt. The feeding protocol we developed requires a change of practice and further clinical trials are needed to evaluate its effectiveness.

Identifying avoidable switchboard delays in England’s NHS hospitals: phase one of the national SWITCH project

Background: Inter-hospital communication frequently requires mediation via a switchboard. Identifying and eliminating switchboard inefficiencies may improve patient care. Methods: All 175 acute hospital switchboards in England were contacted six times. Call contents and duration were recorded. No clinician calls or bleeps were connected. Results: The mean delay before contacting a switchboard operative was 55±46 seconds. 115 hospitals (66%) used automated switchboards; 34 of these (30%) had infection control messages. Robot operators introduced an additional 40 second delay versus humans (mean 70.3±28 versus 29.8±23 seconds, p&lt;0.0001). Multivariate analysis identified robot operators (HR 5.1, p&lt;0.0001) and infection control messages (HR 2.9, p=0.003) as predictors of delays over 60 seconds. Conclusions: There are significant avoidable delays in contacting switchboard operatives across England. Quality improvement is underway.

Breast tuberculosis in East London: A 13‐year retrospective observational study

Breast tuberculosis (TB) is rare in Western Europe, and its diagnosis may be delayed through lack of awareness of presenting features. Our institution serves a large East London population with a highincidenceof TB. To characterize presenting features and avoidable diagnostic delayin breast TB patients. We conducted a 13-year retrospective study of breast TB patients treated at our institution including demographic, clinical, microbiology, and pathology data. Forty-seven cases were included; 44 (94%) were female, with a median age of 33years (IQR 28.5-39.5). The main presenting feature was a breast lump in 41 cases (87%); which were predominantly solitary unilateral lesions (25, 61%) and frequently located in the upper outer quadrant (28, 68%). Where performed,Mycobacterium tuberculosis was cultured in 15/36 (42%)cases. Granulomata were present on biopsy or aspirate in 21 (47%) and 17 (36%) cases, respectively. The median duration between symptom onset and treatment was 20 weeks (IQR 15-30). Forty-six (98%) completed treatment successfully and one relapsed. A high index of suspicion for TB is required for individuals presenting with breast symptoms from countrieswhere TB is endemic. Development of standardized pathways may improve detection and management of breast TBmay reduce diagnostic delay.

CODE STROKE ALERT—Concept and Development of a Novel Open-Source Platform to Streamline Acute Stroke Management

Introduction: Effective, time-critical intervention in acute stroke is crucial to mitigate mortality rate and morbidity, but delivery of reperfusion treatments is often hampered by pre-, in-, or inter-hospital system level delays. Disjointed, repetitive, and inefficient communication is a consistent contributor to avoidable treatment delay. In the era of rapid reperfusion therapy for ischemic stroke, there is a need for a communication system to synchronize the flow of clinical information across the entire stroke journey.Material/Methods: A multi-disciplinary development team designed an electronic communications platform, integrated between web browsers and a mobile application, to link all relevant members of the stroke treatment pathway. The platform uses tiered notifications, geotagging, incorporates multiple clinical score calculators, and is compliant with security regulations. The system safely saves relevant information for audit and research.Results: Code Stroke Alert is a platform that can be accessed by emergency medical services (EMS) and hospital staff, coordinating the flow of information during acute stroke care, reducing duplication, and error in clinical information handover. Electronic data logs provide an auditable trail of relevant quality improvement metrics, facilitating quality improvement, and research.Discussion: Code Stroke Alert will be freely available to health networks globally. The open-source nature of the software offers valuable potential for future development of plug-ins and add-ons, based on individual institutional needs. Prospective, multi-site implementation, and measurement of clinical impact are underway.

National Cancer Diagnosis Audit: avoidable delays to diagnosis

BackgroundA prolonged time taken to diagnose cancer can lead to poorer survival and reduced quality of life. Characterising avoidable delays to a patient’s diagnosis could help to direct quality improvement initiatives aimed at enhancing patient safety and ultimately patient outcomes.AimTo assess the validity of data on avoidable delays collected as part of the English National Cancer Diagnosis Audit (NCDA) and to estimate the predictors of avoidable delays to diagnosis by patient demographics and cancer type.MethodParticipating general practices (n = 439; 5% practices) submitted primary care data on patients (n = 17 042) diagnosed with cancer in 2014 in England. GPs reported delays to the diagnosis that they considered avoidable. Quantile regression was used to understand the impact of an avoidable delay on the diagnostic interval. Logistic regression models were used to investigate the factors associated with avoidable delay.ResultsThe GP recorded an avoidable delay to cancer diagnosis in 24% of cases (n = 3372). The median diagnostic interval was 57 days longer in patients where an avoidable delay was recorded. Results have shown significant associations between avoidable delay and certain cancer types (odds ratio [OR] 1.73 for stomach versus lung cancer) and an increasing number of comorbidities (OR 1.43 for patients with ≥3 versus 0).ConclusionGP-reported data showed a longer diagnostic interval in patients thought to have had an avoidable delay to their diagnosis, indicating construct validity of the data collected. Data from the NCDA is being used to better understand avoidable delays to diagnosis, and identify possible solutions for improving the diagnostic pathway in some cases.

Weaknesses and Capacities Affecting the Prehospital Emergency Care for Victims of Road Traffic Incidents in the Greater Kampala Metropolitan Area: A Cross-Sectional Study

Introduction:Prehospital emergency care is a vital and integral component of health systems, particularly in resource-constrained countries like Uganda. It can help to minimize deaths, injuries, morbidities, disabilities, and trauma caused by road traffic incidents (RTIs). This study identifies the weaknesses and capacities affecting the prehospital emergency care for the victims of RTIs in the Greater Kampala Metropolitan Area (GKMA).Methods:A cross-sectional study was conducted in the GKMA using a three-part structured questionnaire. Data related to the demographics, nature of RTIs and victims’ pre-hospital experience and existing Emergency Medical Services (EMS) were collected from victims and EMS specialists in 3 hospitals and 5 EMS institutions, respectively. Data were descriptively analyzed, and a principal component analysis was employed to identify the most influential weaknesses and capacities affecting the prehospital emergency care for the victims of RTI in the GKMA.Results:From 459 RTI victims (74.7% males and 25.3% females) and 23 EMS specialists (91.3% males and 8.7% females) who participated in the study between May and June 20164. key weaknesses and 5 key capacities were identified to affect the prehospital emergency care for RTI victims in the GKMA. Although some strengths exist, (e.g., ambulance facilitation, EMS structuring, and coordination), the key weaknesses affecting the pre-hospital care for victims were noted to relate to the absence of predefined EMS systems, particularly in the GKMA and Uganda as a whole. They were identified to involve poor quality first aid treatment, insufficient skills/training of the first responders, inadequate EMS resources, and avoidable delays to respond and transport RTI victims to medical facilities.Discussion:Though some strengths exist, the weaknesses affecting prehospital care for RTI victims primarily emanate from the absence of predefined and well-organized EMS systems in the GKMA and Uganda as a whole.

Prehospital ECG transmission results in shorter door-to-wire time for STEMI patients in a remote mountainous region

BackgroundPre-hospital triage with ECG-transmission may reduce time to reperfusion in patients with ST-elevation acute myocardial infarction (STEMI). Less, however, is known on potential benefit of ECG-transmission triage in mountain areas, with complex orography. MethodsPatients admitted for STEMI and primary coronary angioplasty (pPCI) in a mountain area served by a single cathlab and triaged with ECG-transmission were enrolled in the study and compared with controls: patients' demographics and time to coronary wire were recorded. ResultsForty-seven consecutive patients were enrolled in the study: 23 patients following ECG transmission and 24 STEMI patients who presented directly to the Emergency Department. At multivariable regression analysis, pre-hospital ECG-transmission electrocardiogram was an independent predictor of shorter time-to-wire (beta −0.34, p < 0.05). In case of transport times >30 min, ECG-transmission triage achieved time-to-wire times 20% shorter. Excluding unreducible transport time, avoidable delay was reduced by 38% in the whole population, by 48% in case of peripheral areas (transport time > 30 min from cathlab) and elderly (>80 years) patients (p < 0.05 in all cases). ConclusionsPre-hospital triage with ECG-transmission is associated with shorter ischemic time even in mountain areas with a complex orography profile. The benefit is greater in elderly patients and remote areas.

Diagnostic delays in Middle East respiratory syndrome coronavirus patients and health systems

BackgroundAlthough Middle East respiratory syndrome coronavirus (MERS-CoV) diagnostic delays remain a major challenge in health systems, the source of delays has not been recognized in the literature. The aim of this study is to quantify patient and health-system delays and to identify their associated factors. MethodsThe study of 266 patients was based on public source data from the World Health Organization (WHO) (January 2, 2017–May 16, 2018). The diagnostic delays, patient delays, and health-system delays were calculated and modelled using a Poisson regression analysis. ResultsIn 266 MERS-CoV patients reported during the study period, the median diagnostic delays, patient delays, and health-system delays were 5 days (interquartile [IQR] range: 3–8 days), 4 days (IQR range: 2–7 days), and 2 days (IQR range: 1–2 days), respectively. Both patient delay (r = 0.894, P = 0.001) and health-system delay (r = 0.163, P = 0.025) were positively correlated with diagnostic delay. Older age was associated with longer health-system delay (adjusted relative ratios (aRR), 1.011; 95% confidence intervals (CI), 1.004–1.017). Diagnostic delay (aRR, 1.137; 95% CI, 1.006–1.285) and health-system delays (aRR, 1.217; 95% CI, 1.003–1.476) were significantly longer in patients who died. ConclusionDelays in MERS-CoV diagnosis exist and may be attributable to patient delay and health-system delay as both were significantly correlated with longer diagnosis delay. Early MERS-CoV diagnosis may require more sensitive risk assessment tools to reduce avoidable delays, specifically those related to patients and health system.

Focused Resident Education and Engagement in Quality Improvement Enhances Documentation, Shortens Hospital Length of Stay, and Creates a Culture of Continuous Improvement

System-based practice with an emphasis on quality improvement (QI) is a recent initiative for the American College of Surgeons and a core-competency for surgical trainees. Few surgical training programs have a curriculum for hospital-based QI. Our vascular surgery service implemented several QI initiatives focused on decreasing length of stay (LOS) by targeting resident education and engagement. Residents were educated on terminology and processes impacting hospital and CMS QI metrics such as Medicare geometric mean LOS (CMS GMLOS) and diagnostic-related groups (DRG) with complication or comorbidity (CC/MCC) coding. LOS initiatives focused on identifying, tracking and removing avoidable perioperative delays, and improving accuracy of clinical documentation. Residents were given specific roles in QI initiatives and the impact on LOS was quantified. Patients' CMS GMLOS were compared to actual LOS during daily rounds, with confirmation that resident progress notes contained thorough and accurate documentation of diagnoses, comorbidities, and complications. Ten minutes during weekly preoperative conferences were dedicated to ongoing QI, with LOS metrics for the inpatient census presented by trainees and reviewed by attendings. Feedback was given addressing barriers to avoidable delays and impact on LOS. Data for July 2016-June 2017 (FY17) was compared to preimplementation baseline data (FY16) for vascular discharges overall. Accurate documentation of acuity was evaluated with in-depth review of notes and overall case mix index. Within the first year of implementation, overall vascular admissions demonstrated a 21% reduction in LOS, closing the gap between observed LOS and expected CMS GMLOS, from 2.1days to 0.5days on average. Documentation improved, with a shift in 24% of DRGs to accurately reflect CC/MCC. Overall case mix index increased by 10%, from 3.07 to 3.37. A culture of continuous quality improvement can be created with the establishment of a QI infrastructure that educates and involves trainees as stakeholders. Assigning discrete roles to increase resident accountability supports both formal and informal resident education that can substantially impact hospital benchmarking metrics.

The hidden health care costs of power of attorney legislation in Scotland: what needs to be done?

Current power of attorney legislation in many European countries seeks to protect the rights of adult patients who lack capacity by ensuring that discharge from hospital to an alternative care setting only occurs when there is legal authority to do so, via a named guardian or power of attorney. In Scotland, a clause introduced in 2007 allows some patients who lack capacity to be transferred from hospital to a community care service provided all relevant parties are agreed that this is in keeping with the legislation (the ‘least restrictive option’) and the patient does not resist the move. However, there is variation in the understanding and use of this clause by local authorities across Scotland, often resulting in avoidable hospital delays, which are costly and cause ‘bed blocking’. This essay illustrates the costs of hospital delays due to current power of attorney legislation in Scotland and highlights the need for the systematic monitoring of power of attorney data and related hospital delays, and for alternative legislation to be considered in the future.

Factors Affecting Diagnostic Timeliness and Safety in Symptomatic Patients Subsequently Diagnosed With Bladder and Kidney Cancer: A Systematic Review

Background: Timely diagnosis of cancer is important for good clinical outcomes and patient experience. Bladder and kidney cancer, being two relatively common cancers, can pose diagnostic challenges. Symptoms such as hematuria and urinary tract infections in some patients have a higher than 3% positive predictive value for cancer, a threshold above which English GPs are advised to consider the referral of patients for, under the 2015 NICE guidelines. However, the majority of patients with these symptoms will end up not having cancer. Therefore, the decision to perform further investigations or refer patients with these common urinary symptoms may differ despite the existence of guidelines. Studying in whom, and why, some patients may experience a longer than average time to diagnosis is important to understanding how avoidable diagnostic delay can be reduced, so that targeted interventions to improve early diagnosis can be developed to improve, ultimately, the outcome of these cancers. Aim: A systematic review was therefore performed to identify the factors that affect the diagnostic timeliness and safety of patients with urological symptoms that may be suggestive of kidney and bladder cancer. Methods: We searched Embase and Medline (Ovid) between 2000 and January 2018, for publications on symptoms/conditions including hematuria and urinary tract infection (UTI). We focused on clinical features that are listed in the English 2015 NICE guidelines for suspected cancer to examine the population that are most likely to have cancer, and in whom a timely diagnosis is the most crucial for outcomes. We also included symptoms that might be suggestive of a UTI (including dysuria, urinary frequency, urgency, incontinence and nocturia) to be overinclusive in our search. Results: Our initial search identified 7787 articles. Following title and abstract screening, 37 full texts were assessed for eligibility. A final 23 relevant studies were included. Our preliminary findings include evidence on patient, clinician and system factors contributing to diagnostic timeliness and safety issues (such as completeness of evaluation/investigations and referrals) in patients with possible urological cancer. These include patient sociodemographic factors (age, gender, ethnicity), clinician type (generalist, urologist vs gynecologist) and experience, and system factors such as delay in specialist appointment scheduling and patient no-shows. Conclusion: Our findings will provide a granular understanding of the factors contributing to avoidable diagnostic delay of patients with possible urological cancers globally. This is particularly important so that targeted interventions can be developed to help clinicians and health systems to better identify and manage at-risk patients with symptoms, so as to improve early diagnosis and outcomes of urological cancers.

Distributed Estimation and Control for Leader-Following Formations of Nonholonomic Mobile Robots

The problem of the leader-following formation control of nonholonomic mobile robots is addressed in this paper. A distributed formation control strategy using explicitly the coordination errors among robots is proposed without assuming that each follower robot knows the full state of the leader. First, a distributed estimation law is proposed for each follower robot to estimate the states, including the position, orientation, and linear velocity of the leader. The distributed formation control law is then designed based on the estimated states of the leader, and the neighborhood formation tracking error. Under some mild assumptions on the interaction graph among the leader and the follower robots, and the velocity of the leader, asymptotic convergence of formation tracking errors to zero can be achieved. Finally, some numerical simulations and experiments on a group of nonholonomic mobile robots are presented to demonstrate the effectiveness of the proposed strategy. Note to Practitioners —The motivation of this paper is to investigate a practical control strategy for the leader-following formation of multiple autonomous mobile robots subjected to nonholonomic constraints. In most of the existing leader-following formation control schemes for nonholonomic mobile robots, having access to the full state of the leader is a requirement. However, due to limitations in communication bandwidth and range, it is reasonable to assume that the information of the leader is available only to a subset of followers. Hence, this paper suggests a new distributed leader-following formation control strategy based on the distributed estimation of the leader’s states. Moreover, the coordination error between a pair of interacting robots is explicitly used in the control design to weaken the dependence on the estimated state of the leader, and enhance the decentralized nature of the proposed control scheme. The stability and convergence of the system are analyzed mathematically and the experiment using unicycles provides promising results. In ongoing research, we are addressing the issues of collision avoidance and communication delays to provide more realistic setup for the industrial applications of multivehicle systems.

Epichloë endophytes of Poa alsodes employ alternative mechanisms for host defense: insecticidal versus deterrence

Some cool-season pooid grasses partner with symbiotic fungal endophytes in the Epichloe genus for defense against insect herbivores via fungal alkaloids. Poa alsodes, North American woodland grass, independently hosts two species of Epichloe that vary by produced alkaloids. E. alsodes produces insecticidal N-acetylnorloline. E. schardlii var. pennsylvanica (E. schardlii hereafter) has the gene for peramine, an insect-deterring alkaloid, production, but peramine was not detected. We tested the effects of the two endophytes on survival, feeding preference, and plant damage by the generalist herbivore, Spodoptera frugiperda. No larvae survived when feeding on plants harboring E. alsodes. In contrast, survival was only slightly reduced by plants harboring E. schardlii. However, larvae that fed on E. schardlii infected plants experienced delayed development and reduced pupal mass. Uninfected plants and plants infected with E. schardlii were damaged severely when single larvae fed upon them, whereas larvae fed negligibly on plants infected with E. alsodes. Preference did not match performance. Larvae strongly avoided feeding on E. schardlii but not E. alsodes-infected leaves where survival was zero. When E. schardlii was experimentally removed, larval leaf choices suggested that this endophyte is responsible for deterrence. High levels of N-acetylnorloline were detected from E. alsodes infected plants. Peramine was not detected in the experimental plants harboring E. schardlii, so it remains unclear what mechanisms caused avoidance and developmental delays. The two endophytes may protect their common host in different ways: E. alsodes by larval mortality and E. schardlii by deterring feeding and negative effects on development.

High acuity rural transport: findings from a qualitative investigation.

The High Acuity Response Team (HART) was introduced in British Columbia (BC), Canada, to fill a gap in transport for rural patients that was previously being met by nurses and physicians leaving their communities to escort patients in need of critical care. The HART team consists of a critical care registered nurse (CCRN) and registered respiratory therapist (RRT) and attends acute care patients in rural sites by either stabilizing them in their community or transporting them. HART services are deployed in partnership with provincial ambulance services, which provide vehicles and coordination of all requests in the province for patient transport. This article presents the qualitative findings from a research evaluation of the efficacy of the HART model, including staffing and inter-organizational functioning. Open-ended qualitative research interviewing was done with key stakeholders from 21 sites. Research participants included HART CCRNs, RRTs, administrative leads, as well as local emergency department (ED) physicians and nurses. Thematic analysis was done of the transcripts. A total of 107 interviews in 21 study sites were completed. Participants described characteristics of the model, perceptions of efficacy and areas for improvement. Rural sites reported a decrease in physician- and nurse-accompanied transports for high-acuity patients due to the HART team, but also noted challenges in delayed deployment, sometimes leading to adverse patient outcomes. The salient issues for the HART model were grounded in a somewhat artificial distinction between pre-hospital and interfacility transport for rural patients, which leads to a lack of service coordination and potentially avoidable delays. A beneficial systems change would be to move towards dedicated integration of high-acuity transport services into hospital organizational structures and community health services in rural areas.

National Cancer Diagnosis Audit: initial results on avoidable delays

BackgroundAn earlier diagnosis of cancer can increase cancer survival and quality of life. Characterising avoidable delays to a patient’s diagnosis of cancer can help to direct quality improvement initiatives.AimTo evaluate avoidable delays to cancer diagnoses and the variation by cancer type and patient characteristics using primary care data collected as part of the National Cancer Diagnosis Audit (NCDA).MethodEnglish general practices participating in the NCDA (439) entered primary care data on patients (17,042) diagnosed with cancer in 2014. Using a taxonomy developed from the National Audit of Cancer Diagnosis in Primary Care (2011), GPs reported delays to the diagnosis that in their judgement were avoidable.ResultsIn 22% of NCDA patient records (n = 3380), the GP considered there to be an avoidable delay to the patient receiving their cancer diagnosis. There was variation by cancer type; 7% of breast cancer patients experienced delays compared to 34% of stomach cancer patients. 49% of avoidable delays occurred in primary care and 38% in secondary or tertiary care. Of all delays, 28% were attributed to clinician factors and 34% to health care system factors. Results will be presented by patient characteristics.ConclusionPrimary care data from the NCDA can be used to better understand potentially avoidable delays to diagnosis and identify possible solutions for improving the diagnostic pathway. Avoidable delays during cancer diagnosis occur for many reasons. These insights can inform quality improvement initiatives, which should be directed at both clinical and organisational factors in primary care and hospital settings.