PURPOSE:Increasing ED-CT Pulmonary Angiography (CTPA) use raises concerns about overuse and low yield. CTPA numbers at Sir Charles Gairdner ED were seemingly increasing. This single-site, retrospective, observational study looked for increasing usage over ten years, and whether lower yields suggested over-testing. METHODS:Two linked hypotheses: (1) CTPA rates increased over a decade and (2) if CTPA is increasing significantly, yield reduces suggesting overuse. For Hypothesis 1, ED-CTPA per 1000 attendances 2014-2023 were calculated from radiology imaging data. For Hypothesis 2, 2023/24 CTPA results were reviewed for demographics, PE diagnosis, imaging quality, and largest vessel with PE, using similar methods to previous studies. We calculated 700 cases needed reviews if CTPA increased 5%-6% annually (previous regional studies) and yield decreased inversely. Statistical analysis compared rates over time and compared 2012-2013 versus 2023-2024 for Hypothesis 1. For Hypothesis 2, analysis was for difference in proportions for yield (and largest vessel with PE) versus previous 2012-2013 data. RESULTS:Rates of ED-CTPA increased 65% over 2014-2023 but yield was stable (16.3% vs. 15.7%). PE diagnoses increased by over 60% (1.3-2.1 PE/1000). Large vessel PE (≥ lobar) decreased significantly (59.9%-40.5%), intermediate-vessel PE increased (20%-35.1%), but small vessel PE was unchanged (19.2 vs. 24.3%). Women ≤ 50 years had significantly lower yield (5.4%). CONCLUSIONS:CTPA use increased markedly, without expected decreased yield. Increased PE diagnosis rates suggest maintained diagnostic discrimination. Large vessel PE proportions reduced, but small PE rates didn't increase significantly. Younger women seem over-investigated with low yield (5.6%) versus all other groups.

This editorial highlights three studies that collectively offer a roadmap towards system-level improvement in access, flow and quality of care. These studies used linked data from several Queensland hospitals and explored emergency department (ED)-hospital capacity associations with ambulance, ED and hospital dysfunction. One study found ED occupancy was strongly associated with ambulance dysfunction (ramping, response times). The second study associated hospital occupancy with ED dysfunction. Larger hospitals with occupancies above 85%-90% became dysregulated with rapid overcrowding. The modelling study in three tertiary hospitals reported that reduced admissions (ED or elective procedures), improved discharges (earlier, quicker community discharge, home care) and flexible bed use (any ward, over-census) improved flow. Diverting general practice-type attendances and weekend surgery seemed ineffective. Rapid, adequate flexible admitting capacity seems important for safe, efficient hospital-ED care and ambulance function.

OBJECTIVE:To determine ED clinician's current management for five common minor self-limiting fractures (MSLF) and evaluate practice against evidence-informed direct discharge pathway (DD) protocols. METHODS:A survey was provided to doctors, nurse practitioners and advanced scope physiotherapists working in seven metropolitan, public health EDs in Perth, Australia. The relative odds of ED location (e.g. which facility) and clinician level factors (e.g. country of initial training, years of ED experience, profession) on recommending care completely consistent with evidence informed direct discharge pathway protocols were estimated. RESULTS:Two hundred sixty-two clinicians completed the survey. There was variability in practice across all sites, with most reported care assessed at 60%-76% consistency with individual elements of DD care provision. Highest consistency was seen in lower limb immobilisation and DVT prophylaxis. Lowest consistency was seen in weight bearing advice, pain management and (boxer's) fracture reduction and immobilisation. There were very low levels of complete consistency, ranging from 9% (boxer's fracture) to 25% (radial head fracture). Two factors were associated with increased odds of completely consistent care: (i) clinician experience working in ED, with greater duration of practice associated with increased odds ratios (OR range, 1.6-3.3); and (ii) profession, where advanced scope physiotherapy was associated with increased odds ratios (OR range, 3.2-25.0). CONCLUSIONS:Survey results suggested system wide variation in ED fracture management practice and target areas for service improvement. Avenues for service improvement could include hospital wide agreed management plans for specific fractures and support for less experienced clinicians.

Background To investigate what factors contribute to a working age adult with a simple fracture seeking care in an Australian metropolitan Emergency Department (ED) Methods In this Qualitative Descriptive study, we interviewed ED patients with simple fractures including 5th metacarpal, 5th metatarsal, toe, radial head and clavicle fractures. Results We interviewed 30 patients aged 18-65. Two thirds of participants were aware they might have a minor injury. Many were well informed health consumers and convenience was the most important decision-making factor. Participants focussed on organising imaging, diagnosis and immobilisation. This sequence of care was often perceived as more complex and inefficient in primary care. ED was trusted and preferred to urgent primary care with an unknown doctor. Some patients defaulted to attending ED without considering alternatives due to poor health system knowledge or from escalating anxiety. Conclusions ED is safe, free and equipped to manage simple and complex injuries. Patients would attend primary care if comprehensive fracture management was easily accessible from a trusted clinician. To effectively divert simple fracture presentations from ED, primary care requires collocated imaging, imaging interpretation, orthopaedic expertise, and fracture management resources. Services need to operate 7 days a week and must have accessible 'urgent' appointments.

The authors describe an open innovation model that can be an organizing principle for future computing research, explain how high-performance computing as a lead user can guide public–private partnerships, and address workforce development.

OBJECTIVES:To assess the benefits of the Emergency Department Information System (EDIS)-linked fracture liaison service (FLS). METHODS:Patients identified through EDIS were invited to attend an FLS at the intervention hospital, the Sir Charles Gairdner Hospital (SCGS-FLS). The intervention group was compared to usual care. Retrospective control (RC) at this hospital determined historical fracture risk (SCGH-RC). Prospective control (PC) was from a comparator, Fremantle Hospital (FH-PC). The main outcome measures were cost-effectiveness from a health system perspective and quality of life by EuroQOL (EQ-5D). Bottom-up cost of medical care, against the cost of managing recurrent fracture (weighted basket), was determined from the literature and 2013/14 Australian Refined Diagnosis Related Groups (AR-DRG) prices. Mean incremental cost-effectiveness ratios were simulated from 5000 bootstrap iterations. Cost-effectiveness acceptability curves were generated. RESULTS:The SCGH-FLS program reduced absolute re-fracture rates versus control cohorts (9.2-10.2%), producing an estimated cost saving of AUD$750,168-AUD$810,400 per 1000 patient-years in the first year. Between-groups QALYs differed with worse outcomes in both control groups (p < 0.001). The SCGH-FLS compared with SCGH-RC and FH-PC had a mean incremental cost of $8721 (95% CI -$1218, $35,044) and $8974 (95% CI -$26,701, $69,929), respectively, per 1% reduction in 12-month recurrent fracture risk. The SCGH-FLS compared with SCGH-RC and FH-PC had a mean incremental cost of $292 (95% CI -$3588, $3380) and -$261 (95% CI -$1521, $471) per EQ-5D QALY gained at 12 months respectively. With societal willingness to pay of $16,000, recurrent fracture is reduced by 1% in >80% of patients. CONCLUSIONS:This simple and easy model of identification and intervention demonstrated efficacy in reducing rates of recurrent fracture and was cost-effective and potentially cost saving.

BackgroundPain communication should be an integral part of every clinical consultation, particularly in paediatric rheumatology where children/young people often present complex long-term conditions in which chronic pain is a feature. Researchers investigating pain communication in paediatric healthcare encounters have been focused on healthcare professionals, yielding inconsistent findings about the occurrence and nature of pain discussions with children/young people. There has been limited research examining children/young peoples’ own experiences and perspectives on this in the literature to date.ObjectivesThe objective of this study was to investigate children/young peoples’ experiences and perceptions of communicating about pain with paediatric rheumatology healthcare professionals in the UK.MethodsTwenty-six children/young people were recruited from three UK paediatric rheumatology centres. Data were collected using semi-structured telephone interviews between April-October, 2021. A framework analysis approach was used to explore similarities and divergences in participants’ narrative accounts.ResultsThe mean age of children/young people was 14.0 years (SD=3.6 years, Range= 6-18 years, 58% female). Diagnoses included; Juvenile Idiopathic Arthritis, Chronic Regional Pain Syndrome, diffuse idiopathic chronic pain, localised idiopathic pain, hypermobility (including Ehlers Danlos Syndrome) and Raynaud’s disease.Findings are organised into four themes.1) Nature and focus of appointments. Children/young people talked about pain with several professionals from the team. Participants reported that pain conversations predominantly occurred during physical examinations.2) Co-ordination of pain communication. Children/young people identified how professionals mostly started pain conversations. They explained how they were often asked to verbally rate pain rather than use a written assessment tool. For some, questions about pain were directed to parents. Participants reported that this was problematic as parents “can’t feel” pain.3) Reflections on pain communication. There were expectations that pain should always be asked about as it was considered a main reason for a consultation. Participants discussed how these conversations gave them an opportunity to “get it off their chest” and made them feel “reassured” that professionals “care”. Being asked about pain reminded them that they were different to peers and they were concerned it could highlight “something else is wrong”. Children/young people talked about how it became easier to talk about pain with familiar professionals.4) Moving forward after pain communication. Children/young people discussed how professionals could give mixed messages about how to manage pain at home following consultations, offering advice which was difficult to put into practice (e.g. “doing too much” vs “not doing enough”). Children/young people expressed their need to discuss the emotional as well as the physical effects of their pain.ConclusionThese study findings highlight a range of effective and ineffective pain communication approaches from the experiences and perspectives of children/young people. These will be used to create recommendations for improving the communication of chronic pain in paediatric rheumatology in the future, in a way that is acceptable and valuable to children/young people.AcknowledgementsThe authors would like to thank the children/young people for kindly taking the time to share their experiences and perceptions about their interactions with healthcare professionals in paediatric rheumatology. The views expressed herein are those of the authors and not necessarily those of the National Health Service, the National Institute for Health Research, or the UK Department of Health. This work was supported by a Foundation Fellowship award from Versus Arthritis (Grant 22433). Aspects of this work were also supported by funding from the Centre for Epidemiology Versus Arthritis (Grant 20380) and the NIHR Manchester Biomedical Research Centre.Disclosure of InterestsNone declared.

Time-based targets (TBTs) for ED length of stay (LOS) in Australia and New Zealand (NZ) are based on the English model known as the ‘Four Hour Rule’, which arose in response to concerns that prolonged ED LOS was associated with poor patient outcomes. There is a large body of evidence that suggests that long waits to assessment and admission are associated with an increased rate of adverse events, including excess mortality.1 By 2011, every jurisdiction in Australia and NZ had a policy that a proportion of patients presenting to the ED should be discharged home or admitted to an inpatient ward within 4 h (Australia) or 6 h (NZ).2 The Australasian College for Emergency Medicine (ACEM) has taken the position that TBTs are a useful tool to drive systematic changes in care and improve patient journeys. Clinicians, however, have expressed concerns about the potential negative impacts of TBTs on patients and staff. In 2018, ACEM asked a team of experts to convene to review all available research literature on TBTs. The aim was to work out whether targets were effective in improving patient quality of care and whether ACEM should be advocating for targets when lobbying governments and health departments regarding reducing access block. The team who undertook this analysis consisted of emergency physicians from NZ, and from most states and territories of Australia (including rural, regional and urban representatives); as well as non-FACEM health service researchers; consumers; and inpatient specialists. Since TBTs were initially introduced, multiple studies have been published. The research team were able to review data from nearly 50 studies, including over 34 million patients from Australia, Canada, England, Ireland and NZ. Despite massive patient numbers in studies, the quantitative evidence in the literature informing this review was mostly low and, in some cases, very low quality. This is typical for evaluations of complex health service interventions. The strongest and most consistent finding was that targets were associated with a reduction in ED LOS for admitted patients and reduced access block. Other positive findings include a significant reduction in the proportion of patients who ‘did-not-wait’.3 Targets may also save lives. High quality evidence from NZ demonstrated a significant reduction in mortality for patients in ED after the introduction of targets, but no effect on mortality for inpatients or post-discharge. Some studies from Australia and Ireland showed that targets were associated with small to moderate reductions in mortality for in-patients but results were inconsistent and some studies were considered to be of very low quality. There was not a clear, consistent association between TBTs and reduction in mortality for patients after discharge across different sites in Australia, NZ and Ireland. Although there were some studies showing a strong positive association between targets and reduction in mortality, differing findings between settings indicates that there is variability in how targets have been implemented and the impact of targets. Where TBTs are used as a goal to drive whole-of-hospital changes, such as improving inpatient bed capacity, ED crowding is reduced and patients experience better outcomes. The qualitative data supports the interpretation that targets have a positive impact on quality of care when they are used to drive whole-of-hospital systems reforms and are supported by adequate resourcing including funding and staffing. Potential negative impacts of the targets occur when achieving the target is prioritised over patient care activities, and staff suffer increased workload and reduced morale.2 After undertaking the review, physician members of the research team individually undertook a structured appraisal process to determine whether TBTs were something that ACEM should pursue. A consensus was reached that targets should be used. This was conditional on appropriate safeguards being built into the performance measurement regimen, both at local and regional levels, to reduce gaming.4 We hope that the evidence provided in the systematic reviews2, 3 will redirect conversations about targets towards how to improve patient care rather than arguing about the usefulness of targets. There is considerable heterogeneity in the detail of targets and the regimes implemented around them in different jurisdictions. This raises the questions: which targets? and which thresholds should be used? ED LOS is most associated with safety, effectiveness of care and equity compared to alternate measures of patient flow and is likely to be the best performing metric.1 Unachievable targets that have short time frames and high thresholds, coupled with excessive top-down pressure and financial incentives will lead to a high risk of target gaming.5 If these traps are avoided, then the exact details of the target become less important. The key factor is that all actors within the system understand the rationale for the target (to improve patient outcomes by improving acute care systems) and work together to improve their system of care. This requires state and/or national government support, local health authority attention and most importantly engagement of acute care clinicians in the hospital and the ED. Get this right and whichever target is chosen will look after itself. Targets fail when there is insufficient understanding of the rationale for them and there is too much focus on the number rather than the process of system improvement. It is important to remember that TBTs were never intended to be the only way to measure quality of care in an ED. They should be used in conjunction with a suite of acute care quality indicators chosen for local relevance, preferably using a quality indicator appraisal tool designed for that purpose.6 On the basis of this body of work, ACEM reviewed its policy position on TBTs for Australian and NZ EDs. The weight of the evidence suggests that TBTs stand to enhance the safety and quality of emergency care, but must be implemented using sufficiently resourced, whole-of-hospital approaches to systems improvement. PJ has received funding for TBTs research from the Health Research Council of New Zealand. ACEM provided infrastructure and administrative support for the review of TBTs. We would like to acknowledge Nicola Ballenden, Allison Roper, Helena Mayer, Frances Sutherland, Lee Moskwa and Sarah Smith for their help to enable the successful completion of this work. PJ and KW have published research on TBTs and are emergency physicians working in Australian and NZ EDs. PJ and KW are section editors for Emergency Medicine Australasia.

ED crowding has been reported to reduce the quality of care. There are many proposed crowding metrics, but the metric most strongly associated with care quality remains unknown. The present study aims to determine the crowding metric with the strongest links with processes and outcomes of care linked to the Institute of Medicine quality domains. Systematic searches in healthcare databases were conducted using terms for 'crowding', 'metrics' and 'performance', supplemented by grey literature and citation searches. The level of evidence for each association was assessed using an explicit tool. The body of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. Evidence was synthesised using harvest plots. Titles and abstracts of 2052 studies were screened, 452 selected for full-text review and 183 included. Interobserver agreement was moderate kappa = 0.54 (95% confidence interval 0.50-0.59). Two thirds were from urban tertiary hospitals in North America (65%), Australasia (13%), Europe (12%) and Asia (8%). One third provided Level 3 or higher evidence. Metrics were based on occupancy (38%), time (31%), workload (19%) or combinations (9%). Data were synthesised from 25 607 375 patients, 2368 staff, 9089 hospitals and 101 177 sampling times. Almost all crowding metrics were patient-centred and reflect timeliness and efficiency. ED length of stay, boarding time and total occupancy had the strongest association with safety and effectiveness of care. ED length of stay was also associated with equity. The certainty of evidence for associations between crowding measures varied across domains of quality, from very low to moderate certainty.

Time-based targets (TBTs) for ED stays were introduced to improve quality of care but criticised as having harmful unintended consequences. The aim of the review was to determine whether implementation of TBTs influenced quality of care. Structured searches in medical databases were undertaken (2000-2019). Studies describing a state, regional or national TBTs that reported processes or outcomes of care related to the target were included. Harvest plots were used to summarise the evidence. Thirty-three studies (n = 34 million) were included. In some settings, reductions in mortality were seen in ED, in hospital and at 30 days, while in other settings mortality was unchanged. Mortality reductions were seen in the face of increasing age and acuity of presentations, when short-stay admissions were excluded, and when pre-target temporal trends were accounted for. ED crowding, time to assessment and admission times reduced. Fewer patients left prior to completing their care and fewer patients re-presented to EDs. Short-stay admissions and re-admissions to wards within 30 days increased. There was conflicting evidence regarding hospital occupancy and ward medical emergency calls, while times to treatment for individual conditions did not change. The evidence for associations was mostly low certainty and confidence in the findings is accordingly low. Quality of care generally improved after targets were introduced and when compliance with targets was high. This depended on how targets were implemented at individual sites or within jurisdictions, with important implications for policy makers, health managers and clinicians.

ED crowding has been reported to reduce the quality of care. There are many proposed crowding metrics, but the metric most strongly associated with care quality remains unknown. The present study aims to determine the crowding metric with the strongest links with processes and outcomes of care linked to the Institute of Medicine quality domains. Systematic searches in healthcare databases were conducted using terms for ‘crowding’, ‘metrics’ and ‘performance’, supplemented by grey literature and citation searches. The level of evidence for each association was assessed using an explicit tool. The body of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. Evidence was synthesised using harvest plots. Titles and abstracts of 2052 studies were screened, 452 selected for full-text review and 183 included. Inter-observer agreement was moderate κ  = 0.54 (95% confidence interval 0.50–0.59). Two thirds were from urban tertiary hospitals in North America (65%), Australasia (13%), Europe (12%) and Asia (8%). One third provided Level 3 or higher evidence. Metrics were based on occupancy (38%), time (31%), workload (19%) or combinations (9%). Data were synthesised from 25 607 375 patients, 2368 staff, 9089 hospitals and 101 177 sampling times. Almost all crowding metrics were patient-centred and reflect timeliness and efficiency. ED length of stay, boarding time and total occupancy had the strongest association with safety and effectiveness of care. ED length of stay was also associated with equity. The certainty of evidence for associations between crowding measures varied across domains of quality, from very low to moderate certainty.

BACKGROUND:This study investigated trends in computed tomography (CT) utilization across different triage categories of injury presentations to tertiary emergency departments (EDs) and associations with diagnostic yield measured by injury severity, hospitalization and length of stay (LOS), and mortality.METHODS:A total of 411,155 injury-related ED presentations extracted from linked records from Western Australia from 2004 to 2015 were included in the retrospective study. The use of CT scanning and diagnostic yield measured by rate of diagnosis with severe injury, hospitalizations and LOS, and mortality were captured annually for injury-related ED presentations. Multivariable regression models were used to calculate the annual adjusted rate of CT scanning for injury presentations and hospitalizations across triage categories, diagnosis with severe injury, LOS, and mortality. The significance of changes observed was compared among patients with CT imaging relative to those without CT.RESULTS:While the number of ED presentations with injury increased by 65% from 2004 to 2015, the use of CT scanning in these presentations increased by 176%. The largest increase in CT use was among ED presentations triaged as semi-/nonurgent (+256%). Injury presentations with CT, compared to those without, had a higher rate of diagnosis with moderate/severe injury and hospitalization but no difference in LOS and mortality. The probability/rate observed in the outcomes of interest had a greater decrease over time in those with CT scanning compared with those without CT scanning across triage categories.CONCLUSIONS:The reduction in diagnostic yield in terms of injury severity and hospitalization found in our study might indicate a shift toward overtesting using CT in ED for injury or a higher use of CT to assist in the management of injuries. This helps health care policymakers consider whether the current increase in CT use meets the desired levels of quality and efficient care.

Time-based targets for ED length of stay were introduced in England in 2000, followed by the rest of the UK, Canada, Ireland, New Zealand, and Australia after ED crowding was associated with poor quality of care and increased mortality. This systematic review evaluates qualitative literature to see if ED time-based targets have influenced patient care quality. We included 13 studies from four countries, incorporating 617 interviews. We conclude that time-based targets have impacted on the quality of emergency patient care, both positively and negatively. Successful implementation depends on whole hospital resourcing and engagement with targets.

Time-based targets (TBTs) for ED stays were introduced to improve quality of care but criticised as having harmful unintended consequences. The aim of the review was to determine whether implementation of TBTs influenced quality of care. Structured searches in medical databases were undertaken (2000–2019). Studies describing a state, regional or national TBTs that reported processes or outcomes of care related to the target were included. Harvest plots were used to summarise the evidence. Thirty-three studies ( n  = 34 million) were included. In some settings, reductions in mortality were seen in ED, in hospital and at 30 days, while in other settings mortality was unchanged. Mortality reductions were seen in the face of increasing age and acuity of presentations, when short-stay admissions were excluded, and when pre-target temporal trends were accounted for. ED crowding, time to assessment and admission times reduced. Fewer patients left prior to completing their care and fewer patients re-presented to EDs. Short-stay admissions and re-admissions to wards within 30 days increased. There was conflicting evidence regarding hospital occupancy and ward medical emergency calls, while times to treatment for individual conditions did not change. The evidence for associations was mostly low certainty and confidence in the findings is accordingly low. Quality of care generally improved after targets were introduced and when compliance with targets was high. This depended on how targets were implemented at individual sites or within jurisdictions, with important implications for policy makers, health managers and clinicians.

EDs play a crucial role as frontline health services throughout public health emergencies, including pandemics. The strength of the Australian public health response to coronavirus disease 2019 (COVID-19) has mitigated the impact of the pandemic on clinical services, but there has still been a substantial impact on EDs and the health system. We revisit major events and lessons from the first wave of COVID-19 in Australia to consider the implications and avenues for system-level improvements for future pandemic and public health emergency response for EDs. Notwithstanding, the remarkable efforts of healthcare workers across the health system, COVID-19 has uncovered structural and planning challenges and highlighted weaknesses and strengths of the Australian federation. In anticipating future pandemics and other public health threats, particularly in the face of climate change, hard-won lessons from the COVID-19 response should be incorporated in future planning, policies, practice and advocacy.

Time-based targets for ED length of stay were introduced in England in 2000, followed by the rest of the UK, Canada, Ireland, New Zealand, and Australia after ED crowding was associated with poor quality of care and increased mortality. This systematic review evaluates qualitative literature to see if ED time-based targets have influenced patient care quality. We included 13 studies from four countries, incorporating 617 interviews. We conclude that time-based targets have impacted on the quality of emergency patient care, both positively and negatively. Successful implementation depends on whole hospital resourcing and engagement with targets.

This paper presents a memristive device model capable of accurately matching a wide range of characterization data collected from a tantalum oxide memristor. Memristor models commonly use a set of equations and fitting parameters to match the complex dynamic conductivity pattern observed in these devices. Along with the proposed model, a procedure is also described that can be used to optimize each fitting parameter in the model relative to an I-V curve. Therefore, model parameters are self-updated based on this procedure when a new cyclic I-V sweep is provided for model optimization. This model will automatically provide the best possible match to the characterization data without any additional optimization from the user. In this paper, multiple cyclic I-V characterizations are modeled from ten different tantalum oxide devices (on the same wafer). Additionally, studies were completed to demonstrate the amount of variation present between devices on a wafer, as well as the amount of variation present within a single device. Methods for modeling this variation are then proposed, resulting in an accurate and complete, automated, memristor modeling approach.

Aim: To describe a tailored qualitative research methodology for exploring the complex interaction of factors driving non-urgent care seeking in the emergency department. Design: Qualitative descriptive design with a literature informed semi-structured interview and analysis structure. Triangulation with the State-Trait Anxiety Inventory allows expedited exploration of biopsychosocial factors. Consolidated criteria for reporting qualitative research requirements integrated. Methods: With a short 10- to 15-min interview and a low-inference analysis process, this methodology offers a structured way to explore the "go to ED" decision, to understand the patient perspective on their healthcare needs and feed into the development of suitable local services that meet patient healthcare needs. Results: This methodology offers a structured way for clinician-researchers to explore the factors that influence patients seeking care in the emergency departments for non-urgent conditions that are specific to their local health service environment. The described methodology is accessible to novice qualitative researchers and includes the semi-structured interview, coding and analysis frameworks.

Introduction Delayed handover of emergency medical services (EMS) patients to EDs is a major issue with hospital crowding considered a primary cause. We explore the impact of the 4-hour rule (the Policy) in Australia, focusing on ambulance and ED delays. Methods EMS (ambulance), ED and hospital data of adult patients presenting to 14 EDs from 2002 to 2013 in three jurisdictions were linked. Interrupted time series ‘Before-and-After’ trend analysis was used for assessing the Policy’s impact. Random effects meta-regression analysis was examined for associations between ambulance delays and Policy-associated ED intake, throughput and output changes. Results Before the Policy, the proportion of ED ambulances delayed increased between 1.1% and 1.7% per quarter across jurisdictions. After Policy introduction, Western Australia’s increasing trend continued but Queensland decreased by 5.1% per quarter. In New South Wales, ambulance delay decreased 7.1% in the first quarter after Policy introduction. ED intake (triage delay) improved only in New South Wales and Queensland. Each 1% ambulance delay reduction was significantly associated with a 0.91% reduction in triage delay (p=0.014) but not ED length of stay ≤4 hours (p=0.307) or access-block/boarding (p=0.605) suggesting only partial improvement in ambulance delay overall. Conclusion The Policy was associated with reduced ambulance delays over time in Queensland and only the immediate period in New South Wales. Associations may be due to local jurisdictional initiatives to improve ambulance performance. Strategies to alleviate ambulance delay may need to focus on the ED intake component. These should be re-examined with longer periods of post-Policy data.