Pre-hospital ECPR in an Australian metropolitan setting: a single-arm feasibility assessment-The CPR, pre-hospital ECPR and early reperfusion (CHEER3) study

INTRODUCTION

Survival from refractory out of hospital cardiac arrest (OHCA) without timely return of spontaneous circulation (ROSC) utilising conventional advanced cardiac life support (ACLS) therapies is dismal. CHEER3 was a safety and feasibility study of pre-hospital deployed extracorporeal membrane oxygenation (ECMO) during cardiopulmonary resuscitation (ECPR) for refractory OHCA in metropolitan Australia.

METHODS

This was a single jurisdiction, single-arm feasibility study. Physicians, with pre-existing ECMO expertise, responded to witnessed OHCA, age < 65 yrs, within 30 min driving-time, using an ECMO equipped rapid response vehicle. If pre-hospital ECPR was undertaken, patients were transported to hospital for investigations and therapies including emergent coronary catheterisation, and standard intensive care (ICU) therapy until either cardiac and neurological recovery or palliation occurred. Analyses were descriptive.

RESULTS

From February 2020 to May 2023, over 117 days, the team responded to 709 "potential cardiac arrest" emergency calls. 358 were confirmed OHCA. Time from emergency call to scene arrival was 27 min (15-37 min). 10 patients fulfilled the pre-defined inclusion criteria and all were successfully cannulated on scene. Time from emergency call to ECMO initiation was 50 min (35-62 min). Time from decision to ECMO support was 16 min (11-26 min). CPR duration was 46 min (32-62 min). All 10 patients were transferred to hospital for investigations and therapy. 4 patients (40%) survived to hospital discharge neurologically intact (CPC 1/2).

CONCLUSION

Pre-hospital ECPR was feasible, using an experienced ECMO team from a single-centre. Overall survival was promising in this highly selected group. Further prospective studies are now warranted.

Temperature-related chest pain presentations and future projections with climate change

Background

Climate change has led to increased interest in studying adverse health effects relating to ambient temperatures. It is unclear whether incident chest pain is associated with non-optimal temperatures and how chest pain presentation rates might be affected by climate change.

Methods

The study included ambulance data of chest pain presentations in Melbourne, Australia from 1/1/2015 to 30/6/2019 with linkage to hospital and emergency discharge diagnosis data. A time series quasi-Poisson regression with a distributed lag nonlinear model was fitted to assess the temperature-chest pain presentation associations, after adjusting for season, day of the week and long-term trend. Future excess chest pain presentations associated with cold and heat were projected under six general circulation models under medium and high emission scenarios.

Results

In 206,789 chest pain presentations, mean (SD) age was 61.2 (18.9) years and 50.3% were female. Significant heat- and cold-related increased risk of chest pain presentations were observed for mean air temperatures above and below 20.8°C, respectively (Figure 1). Excess chest pain presentations related to heat were observed in all subgroups, but appeared to be attenuated for older patients (≥70 years) and patients of higher socioeconomic status (SES). We projected no significant change in net temperature-related chest pain presentations with climate change under medium- and high-emission scenarios, with increases in heat-related chest pain presentations offset by decreases in chest pain presentations related to cold temperatures.

Conclusions

Heat- and cold-exposure appear to increase risk of chest pain presentations, especially among younger patients and patients of lower SES. In Melbourne, Australia, chest pain presentations overall were not projected to increase with climate change, but increases in heat-related chest pain presentations highlight the importance of risk mitigation strategies to minimise adverse health impacts on hotter days.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Alfred Health.

Impact of ambulance off-load delays on mortality in patients with chest pain

Background

Ambulance off-load delays in transferring patient care to emergency departments (EDs) are increasingly common, but it is unclear whether clinical outcomes are impacted.

Methods

Population-based cohort study of ambulance attendances for non-traumatic chest pain transported to ED in Victoria, Australia (1/1/2015–30/6/2019) excluding patients transported to hospital with “lights and sirens” or triaged as ED category 1. Multivariable models were used to assess the relationship between ambulance off-load times and 30-day mortality and ambulance re-attendance for chest pain.

Results

The study included 213,544 ambulance attendances for chest pain (mean age 62 [SD 18] years; 51% female). Median ambulance off-load times increased across the study period from 21 minutes (interquartile range [IQR] 15–30) in 2015 to 24 minutes (IQR 17–37) in 2019. Patients were divided into tertiles according to off-load times with 69,247 patients included in tertile 1 (0–17 minutes), 73,109 patients in tertile 2 (18–28 minutes), and 71,188 patients in tertile 3 (&gt;28 minutes). In multivariable models, ambulance off-load delays were associated with higher unadjusted and adjusted rates of 30-day mortality (1.57% tertile 3 vs. 1.29% tertile 1, adjusted risk difference 0.28% [95% CI 0.16% - 0.42%], p&lt;0.001) and ambulance re-attendance for chest pain (9.89% tertile 3 vs. 8.59% tertile 1, adjusted risk difference 1.30% [95% CI 1.00% - 1.61%], p&lt;0.001). Similarly, in analysis using off-load times as a continuous variable with restricted cubic splines, a non-linear increase in adjusted odds ratio for mortality was observed (Figure 1).

Conclusions

Delays in ambulance off-load times appear to be associated with increased mortality and ambulance re-attendance risk among chest pain cohorts. This study has important policy implications given the increasing frequency of off-load delays in many healthcare settings.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): Alfred health

Variation in health-care quality and outcomes according to time of chest pain presentation: a state-wide prospective cohort study

Background

Previous studies examining temporal variation in cardiovascular care have largely been limited to assessing weekend and after-hours effects whereby those presenting on the weekend or after-hours have a poorer outcome. However, emerging evidence suggests more complex patterns in patterns and outcomes may exist.

Purpose

We aimed to determine patterns of temporal variation in chest pain presentations and subsequent health-care quality and outcomes.

Methods

This was an observational, prospective-cohort study of adult patients aged 18 and over who were attended by emergency medical services for non-traumatic chest pain between 1 January 2015 and 30 June 2019 in Victoria, Australia. Major exclusion criteria included pre-hospital diagnosis of ST elevation myocardial infarction or an out of hospital cardiac arrest. The exposure variable was time of day and day of week stratified into 168 hourly time periods. The primary outcome measure was 30-day mortality.

Results

The study cohort comprised 196,365 ambulance attendances for acute non-traumatic chest pain; mean age 62.4 years (SD 18.3) and 99,497 (50.7%) females. Three temporal patterns were observed for chest pain presentations (Figure 1): (1) a diurnal pattern with a sharp increase in presentations from 8 am, peaking around midday, before decreasing into late evening with a nadir between 3–4 am, (2) a weekend effect where Saturday and Sunday had a relatively lower rate of presentations compared to during the week, and (3) a Monday – Sunday gradient where more presentations were likely earlier in the week, than later. Six patterns were identified across pre-hospital and hospital key performance indicators (KPI) (diurnal, in/after-hours, weekend effect, Monday – Sunday gradient, a peak period and morning vs afternoon/evening effect. Risk of 30-day mortality was associated with weekend presentation (OR 1.15, 95% CI 1.06–1.24, p=0.001) and morning presentation between midnight and midday (OR 1.17, 95% CI 1.09–1.25, p&lt;0.001) (Figure 2).

Conclusion

Chest pain presentations, care quality and outcomes demonstrate complex temporal variation beyond the already established weekend and after-hours effect. Such relationships should be considered during resource allocation and quality improvement programs in order to improve treatment quality across all days and times of the week.

Funding Acknowledgement

Type of funding sources: None.

Sex differences in pre-hospital analgesia and outcomes in patients presenting with acute coronary syndromes

Background

Opioid analgesia remains the mainstay of pain management in acute coronary syndromes (ACS). Significant sex differences persist in ACS presentation, management and outcomes, but the impact of sex-differences on pre-hospital pain management of ACS with opioids is unknown. There is increasing awareness of the importance of pre-hospital factors in ACS, as well as emerging concerns with opioid use impairing the gastrointestinal absorption of oral P2Y12 inhibitors.

Purpose

This study examined if sex-differences in pre-hospital pain scores, opioid administration and clinical outcomes exist in ACS patients.

Methods

Patients presenting with ACS via ambulance (2014–2018) that underwent percutaneous coronary intervention (PCI) were prospectively collected via the Victorian Cardiac Outcomes Registry (VCOR), the Melbourne Interventional Group (MIG), and linked to the Ambulance Victoria database. The primary outcome was 30-day major adverse cardiac events (MACE). Secondary outcomes were descriptive analyses of pre-hospital pain score, intravenous morphine equivalent analgesic dosing, plus predictors of MACE and Thrombolysis In Myocardial Infarction (TIMI) 0–1 flow pre-PCI using logistic regression.

Results

10,547 patients were included (female: 2,775 [26.3%]). Opioids were administered to 1,585 (57%) females and 5,068 (65%) males (p&lt;0.001). Adjusted 30-day MACE was similar between opioid groups in both sexes (female: OR 1.21, CI 0.82–1.79, p=0.34; male: OR 0.89, 0.68–1.16, p=0.40). Median pain score at presentation was 6 (IQR 4,8) for both sexes. Median opioid dose was 2.5 mg (IQR 0,10) in females and 5 mg (IQR 0,10) in males (p&lt;0.001), with similar pain relief achieved. Adjusted rates of TIMI 0–1 pre-PCI were higher in patients administered opioids (female: OR 2.83, CI 2.14–3.56, p&lt;0.001; male: OR 2.95, CI 2.49–3.49, p&lt;0.001).

Conclusions

Female patients undergoing PCI received less opioid analgesia, but no sex-differences in pre-hospital pain scores were seen. Opioid administration was associated with impaired antegrade flow in the culprit artery in both sexes, but not short-term MACE. Randomised trials evaluating the clinical implications of opioid administration in ACS with sex subgroup analyses are needed to guide clinical practice.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Melbourne Interventional GroupVictorian Cardiac Outcomes Registry

Lignocaine versus opioids in coronary intervention: assessing antiplatelet activity and ticagrelor levels (LOCAL) study

Background

Opioid analgesia impairs the bioavailability and antiplatelet effect of oral P2Y12 inhibitors prompting investigation of mitigation strategies including identifying alternative analgesic agents.

Purpose

To assess the impact of intravenous fentanyl and lignocaine on the bioavailability and antiplatelet effect of ticagrelor in patients with unstable angina and non-ST elevation myocardial infarction, as well as their procedural analgesic efficacy and safety.

Methods

The LOCAL trial was a prospective, single centre, double-blind, randomized, controlled trial where intravenous lignocaine was the experimental analgesic agent assessed in this trial compared to intravenous fentanyl as procedural analgesia during coronary angiography and percutaneous coronary intervention. Patients with an indication for dual antiplatelet therapy and no contraindication were given 180mg of ticagrelor orally as integral tablets with 250 mL of tap water at the end of the case. Blood was sampled at time 0, 0.5, 1, 2 and 4 hours post administration of ticagrelor for pharmacokinetic and comprehensive pharmacodynamic analysis.

Results

Seventy patients undergoing coronary angiography with an indication for ticagrelor loading were included in the pharmacokinetic and pharmacodynamic analysis. Plasma ticagrelor levels at 2 h post loading dose were significantly lower in the fentanyl compared to lignocaine treatment arm (476 vs. 792 ng/mL, p=0.02, see figure 1). The area under the plasma-time curves for ticagrelor (987 vs. 2189 ng.h/mL, p=0.001) and its active metabolite (173 vs. 394 ng.h/mL, p&lt;0.001) were both significantly lower in the fentanyl arm. Platelet reactivity assessed by the VerifyNow assay was higher at all time points after baseline in the fentanyl compared to lignocaine arm. The VASP flow cytometry assay demonstrated higher platelet reactivity at 2 hours in the fentanyl group (40% vs. 22% platelet reactivity index, p=0.001). The Multiplate Analyzer demonstrated higher platelet reactivity in the fentanyl arm at 60 minutes (43 vs. 26 area under the curve units, p=0.001) as did expression of activated platelet GpIIb/IIIa receptor (2829 vs. 1426 geometric mean fluorescence intensity (GMFI), p=0.006) and P-selectin (439 vs. 211 GMFI, p=0.001). High on-treatment platelet reactivity (HPR) was significantly higher in the fentanyl arm at 60 min using the MPA (41% vs. 9%, p=0.002) and 120 min using the VFN (30% vs. 3%, p=0.003) and VASP (37% vs. 6%, p=0.002) assays (see figure 2). Both drugs were well tolerated with a high level of patient satisfaction (fentanyl 94% vs. lignocaine 97%, p=0.56).

Conclusion(s)

Unlike fentanyl, lignocaine does not impair the bioavailability or delay the antiplatelet effect of ticagrelor. Both drugs were well tolerated and effective with a high level of patient satisfaction for procedural analgesia. Systemic pain medication during PCI should be reconsidered and if performed, lignocaine is a beneficial alternative to fentanyl.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): TBA Figure 1. Ticagrelor and AM pharmacokineticsFigure 2. Ticagrelor pharmacodynamics

Out-of-hospital cardiac arrest in elderly individuals

Background

Out-of-hospital cardiac arrest (OHCA) is associated with poor outcome, particularly in elderly people. Due to the shift in global demographics towards an ageing population, understanding risk factors for OHCA is essential for the development of primary prevention strategies. Thus, we aimed to identify predictors for OHCA in a large, community-dwelling cohort of elderly individuals.

Methods

We analyzed data from 11,156 participants enrolled in a randomized, placebo-controlled primary prevention trial, investigating the effect of low-dose aspirin in individuals aged 70 years or above. At baseline all participants had no prior cardiovascular disease events, dementia or major physical disability. OHCA events occurring within 5 years were identified by probabilistic data-linkage with a state-wide out-of-hospital cardiac arrest registry. Possible predictors included age, sex, anthropometric measures, conventional cardiovascular risk factors, renal function and frailty. To evaluate the association with OHCA, we performed univariable and multivariable Cox regression analyses. In exploratory analyses we also evaluated the effect of low-dose aspirin on OHCA events.

Results

In the cohort 54.7% were female and median age was 74.1 years (Interquartile Range [IQR] 71.8–77.7). During a median follow up time of 4.7 years (IQR 3.4–6.0) we recorded 67 OHCA events with presumed cardiac cause. The incidence rate was 1.07 per 1,000 person-years (95% Confidence-Interval [CI] 0.80–1.40). The mortality rate following OHCA was 91.2% (n=62). Univariable Cox regression analyses identified age, sex, weight, abdominal circumference, serum creatinine, diabetes, arterial hypertension, intake of antihypertensive medication and pre-frailty as predictors for the outcome. In multivariable Cox regression analyses we identified age (Hazard Ratio [HR] 1.06, CI 1.00–1.13), female sex (HR 0.49, CI 0.26–0.94) and pre-frailty (HR 1.92, CI 1.03–3.58) to be independent predictors (Table). In exploratory analyses there was no effect of low-dose aspirin on OHCA (HR 1.52, CI 0.87–2.70).

Conclusion

In a large, contemporary cohort of healthy, elderly individuals we describe a significant incidence of OHCA events associated with a very high mortality. We identified age, sex and pre-frailty, but interestingly not conventional cardiovascular risk factors as independent predictors of OHCA. We could not show a benefit of low-dose aspirin treatment, although the number of events was small. Our findings emphasize the importance of preventive strategies for pre-frailty in elderly individuals.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The ASPREE study was primarily funded by the National Institute of Aging and National Cancer Institute at the National Institutes of Health (grant number U01AG029824), the Australian National Health & Medical Research Council (grants 334047 & 1127060), Monash University (Australia) and the Victorian Cancer Agency (Australia). Multivariable Cox regression analyses

Collateral damage: Hidden impact of the COVID-19 pandemic on the out-of-hospital cardiac arrest system-of-care

AIM

Out-of-hospital cardiac arrest (OHCA) during COVID-19 has been reported by countries with high case numbers and overwhelmed healthcare services. Imposed restrictions and treatment precautions may have also influenced OHCA processes-of-care. We investigated the impact of the COVID-19 pandemic period on incidence, characteristics, and survival from OHCA in Victoria, Australia.

METHODS

Using data from the Victorian Ambulance Cardiac Arrest Registry, we compared 380 adult OHCA patients who received resuscitation between 16th March 2020 and 12th May 2020, with 1218 cases occurring during the same dates in 2017-2019. No OHCA patients were COVID-19 positive. Arrest incidence, characteristics and survival rates were compared. Regression analysis was performed to understand the independent effect of the pandemic period on survival.

RESULTS

Incidence of OHCA did not differ during the pandemic period. However, initiation of resuscitation by Emergency Medical Services (EMS) significantly decreased (46.9% versus 40.6%, p = 0.001). Arrests in public locations decreased in the pandemic period (20.8% versus 10.0%; p < 0.001), as did initial shocks by public access defibrillation/first-responders (p = 0.037). EMS caseload decreased during the pandemic period, however, delays to key interventions (time-to-first defibrillation, time-to-first epinephrine) significantly increased. Survival-to-discharge decreased by 50% during the pandemic period (11.7% versus 6.1%; p = 0.002). Survivors per million person-years dropped in 2020, resulting in 35 excess deaths per million person-years. On adjusted analysis, the pandemic period remained associated with a 50% reduction in survival-to-discharge.

CONCLUSION

The COVID-19 pandemic period did not influence OHCA incidence but appears to have disrupted the system-of-care in Australia. However, this could not completely explain reductions in survival.

AB0121 ASSESSMENT OF GLOBAL DNA METHYLATION IN PERIPHERAL BLOOD CELL SUBPOPULATIONS OF PATIENTS WITH AXIAL SPONDYLOARTHRITIS: PRELIMINARY RESULTS

Background:

Axial spondyloarthritis (ax-SpA) corresponds to a group of chronic inflammatory disease mainly affecting the axial skeleton. TNFα and IL-17A have been identified as key inflammatory mediators driving the inflammatory process of ax-SpA. Epigenetics refers to different mechanisms that alter gene expression without involving changes in DNA sequence. The mechanisms of epigenetics include microRNA, histone modifications or DNA methylation. DNA methylation is associated with a repressed chromatin state and inhibition of gene expression. It is recognized that aberrant DNA methylation can result in immune cell autoreactivity.

Objectives:

Epigenetics have been rarely evaluated in ax-SpA. We previoulsy reported that patients with ankysloing spondylitis (AS) had an imbalance between HAT and HDAC activities. In this study, we aimed to evaluate the global DNA methylation of patients with ax-SpA.

Methods:

Case-control study (NCT03092583). Patients with radiographic (AS) or non radiographic (nr) ax-SpA (ASAS criteria) and healthy controls (HC) were evaluated. All the patients were biologic naïve and under NSAIDs. Disease activity was evaluated by BASDAI and ASDAS. CD4+T cells and CD14+ monocytes were isolated form peripheral blood and then DNA was extracted (E.Z.N.A. Blood DNA kit, Omega Bio-Tek). Global DNA methylation (5-mC) was determined using MethylAmp global DNA methylation quantification kit (Epigentek) using 150ng of total DNA.

Results:

25 patients with AS (18 M; mean age ± SEM: 48.9 ± 3.5 y; mean disease duration: 14.9 ± 2.2 y; B27+: 84%), 21 with nr-axSpA (11 M; age: 42 ± 3.3 y; disease duration: 7.9 ± 2.3 y; B27+: 68%) and 11 HC (7 M; age: 48.4 ± 3.9 y) were evaluated. Patients had active disease (BASDAI and ASDAS in AS and nr-axSpA: 5.1 ± 0.4 and 5.4 ± 0.5; 4.7 ± 0.4 and 5 ± 0.4, respectively). In CD4+ T lymphocytes, global DNA methylation was lower in the whole group of patients (AS and nr-ax-SpA) compared to HC (0.91 ± 0.26vs1.08 ± 0.19 % of 5-mC) (NS). Conversely, DNA methylation was higher in monocytes from patients compared to HC (1.43 ± 0.16vs1.15 ± 0.5 % of 5-mC) (NS). When analysing the results between ax-SpA subgroups, an hypomethylation was more evident in the CD4+T lymphocytes from patients with nr-axSpA compared to AS and HC, a result that was not observed in the monocyte subpopulation (Figures).

Conclusion:

A global DNA hypomethylation is observed in patients with ax-SpA, especially in the nr-axSpA subgroup. These results are more evident in T CD4+ lymphocytes. Additional analysis on a larger series of patients is required to confirm these preliminary results. In addition, we aim to examine the specific DNA methylation status of the TNF promoter gene.

References:

[1]Toussirot Eet al, PlosOne 2013

Figure.

global DNA methylation of CD4+ T lymphocytes and monocyctes from patients with ankylosing spondylitis (AS), non radiographic axial spondyloarthritis (nr-ax-SpA) and healthy controls (HC)

Disclosure of Interests:

None declared

Haemodynamics as a determinant of need for pre-hospital application of a pelvic circumferential compression device in adult trauma patients

INTRODUCTION

Pelvic ring fractures are common following high-energy blunt trauma and can lead to substantial haemorrhage, morbidity and mortality. Pelvic circumferential compression devices (PCCDs) improve position and stability of open-book type pelvic fracture, and can improve haemodynamics in patients with hypovolaemic shock. However, PCCDs may cause adverse outcomes including worsening of lateral compression fracture patterns and routine use is associated with high costs. Controversy regarding indication of PCCDs exists with some centres recommending PCCD in the setting of hypovolaemic shock compared to placement for any suspected pelvic injury.

OBJECTIVE

To assess the need for PCCD application based on pre-hospital vital signs and mechanism of injury.

METHODS

A retrospective cohort study was conducted in a single adult major trauma centre examining a 2-year period. Patients were sub-grouped based on initial pre-hospital and emergency department observations as haemodynamically normal (heart rate <100 bpm, systolic blood pressure ≥100 mmHg and Glasgow Coma Scale ≥13) or abnormal. Diagnostic accuracy of pre-hospital haemodynamics as a predictor of pelvic fracture requiring intervention within 24 h was assessed.

RESULTS

There were 376 patients with PCCD in-situ on hospital arrival. Pelvic fractures were diagnosed in 137 patients (36.4%). Of these, 39 (28.5%) were haemodynamically normal and 98 (71.5%) were haemodynamically abnormal. The most common mechanisms of injury were motor vehicle collision (57.7%) and motorcycle collision (13.8%). Of those with fractures, 40 patients (29.2%) required pelvic intervention within 24 h of admission; of these, 8 (20%) were haemodynamically normal and 32 (80%) were haemodynamically abnormal. As a test for pelvic fracture requiring intervention within 24 h, abnormal pre-hospital haemodynamics had a sensitivity of 0.80 (95% CI 0.64-0.91), specificity of 0.32 (95% CI 0.27-0.38) and negative predictive value (NPV) of 0.93 (95% CI 0.88-0.96). Combined with absence of a major mechanism of injury, normal haemodynamics had a sensitivity 1.00, specificity 0.51 (95% CI 0.36-0.66) and NPV of 1.00 for pelvic intervention within 24 h.

CONCLUSION

Normal haemodynamic status, combined with absence of major mechanism of injury can rule out requirement for urgent pelvic intervention. Ongoing surveillance is recommended to monitor for any adverse effects of this change in practice.

Impact of cardiopulmonary resuscitation duration on survival from paramedic witnessed out-of-hospital cardiac arrests: An observational study

BACKGROUND

Resuscitation guidelines often recommend ongoing cardiopulmonary resuscitation (CPR) efforts to hospital for out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical service (EMS) personnel. In this study, we examine the relationship between EMS CPR duration and survival to hospital discharge in EMS witnessed OHCA patients.

METHODS

Between January 2003 and December 2011, 1035 adult EMS witnessed arrests of presumed cardiac aetiology were included from the Victorian Ambulance Cardiac Arrest Registry. CPR duration was defined as the total sum of prehospital CPR time in minutes. Adjusted logistic regression analyses were used to assess the impact of EMS CPR duration on survival to hospital discharge.

RESULTS

382 (37.3%) patients were discharged alive. The median CPR duration was 12 min (95% CI: 11-13) overall, but was higher in non-survivors compared to survivors (24 min vs. 2 min, p<0.001). The 99th percentile CPR duration in patients surviving to hospital discharge differed by the initial rhythm of arrest: 32 min (95% CI: 27-44) overall, 32 min (95% CI: 23-44) for ventricular fibrillation and pulseless ventricular tachycardia (VF/VT), 34 min (95% CI: 30-34) for pulseless electrical activity (PEA), and 28 min (95% CI: 21-28) for asystole. There were no survivors after 44 min for all rhythms. After adjusting for prehospital confounders, every minute increase in CPR duration was associated with a 13% reduction in the odds of survival to hospital discharge (OR 0.87, 95% CI: 0.84-0.89, p<0.001). The multivariable model predicted no chance of survival at or after a CPR duration of 48 min for VF/VT patients, 47 min for PEA patients and 45 min for asystole patients.

CONCLUSION

Resuscitation efforts exceeding 32 min yielded less than 1% of survivors from EMS witnessed OHCA. On the basis of this data, EMS witnessed OHCA patients may benefit from ongoing CPR efforts up to 48 min in duration.

Public access defibrillation—results from the Victorian Ambulance Cardiac Arrest Registry

AIM

To assess the impact of automated external defibrillator (AED) use by bystanders in Victoria, Australia on survival of adults suffering an out-of-hospital cardiac arrest (OHCA) in a public place compared to those first defibrillated by emergency medical services (EMS).

METHODS

We analysed data from the Victorian Ambulance Cardiac Arrest Registry for individuals aged >15 years who were defibrillated in a public place between 1 July 2002 and 30 June 2013, excluding events due to trauma or witnessed by EMS.

RESULTS

Of 2270 OHCA cases who arrested in a public place, 2117 (93.4%) were first defibrillated by EMS and 153 (6.7%) were first defibrillated by a bystander using a public AED. Use of public AEDs increased almost 11-fold between 2002/2003 and 2012/2013, from 1.7% to 18.5%, respectively (p < 0.001). First defibrillation occurred sooner in bystander defibrillation (5.2 versus 10.0 min, p < 0.001). Unadjusted survival to hospital discharge for bystander defibrillated patients was significantly higher than for those first defibrillated by EMS (45% versus 31%, p < 0.05). Multivariable logistic regression analysis showed that first defibrillation by a bystander using an AED was associated with a 62% increase in the odds of survival to hospital discharge (adjusted odds ratio 1.62, 95% CI: 1.12–2.34, p = 0.010) compared to first defibrillation by EMS.

CONCLUSION

Survival to hospital discharge is improved in patients first defibrillated using a public AED prior to EMS arrival in Victoria, Australia. Encouragingly, bystander AED use in Victoria has increased over time. More widespread availability of AEDs may further improve outcomes of OHCA in public places.

The significance of pre-arrest factors in out-of-hospital cardiac arrests witnessed by emergency medical services: a report from the Victorian Ambulance Cardiac Arrest Registry

BACKGROUND

The significance of pre-arrest factors in out-of-hospital cardiac arrests (OHCA) witnessed by emergency medical services (EMS) is not well established. The purpose of this study was to assess the association between prodromal symptoms and pre-arrest clinical observations on the arresting rhythm and survival in EMS witnessed OHCA.

METHODS

Between 1st January 2003 and 31st December 2011, 1056 adult EMS witnessed arrests of a presumed cardiac aetiology were identified from the Victorian Ambulance Cardiac Arrest Registry. Pre-arrest prodromal features and clinical characteristics were extracted from the patient care record. Backward elimination logistic regression was used to identify pre-arrest factors associated with an initial shockable rhythm and survival to hospital discharge.

RESULTS

The median age was 73.0 years, 690 (65.3%) were male, and the rhythm of arrest was shockable in 465 (44.0%) cases. The most commonly reported prodromal symptoms prior to arrest were chest pain (48.8%), dyspnoea (41.8%) and altered consciousness (37.8%). An unrecordable systolic blood pressure was observed in 34.4%, a respiratory rate <13 or >24min(-1) was present in 43.1%, and 45.5% had a Glasgow coma score <15. In the multivariable analysis, the following pre-arrest factors were significantly associated with survival: age, public location, aged care facility, chest pain, arm or shoulder pain, dyspnoea, dizziness, vomiting, ventricular tachycardia, pulse rate, systolic blood pressure, respiratory rate, Glasgow coma score, aspirin and inotrope administration.

CONCLUSION

Pre-arrest factors are strongly associated with the arresting rhythm and survival following EMS witnessed OHCA. Potential opportunities to improve outcomes exist by way of early recognition and management of patients at risk of OHCA.