Assessing feasibility of proposed extracorporeal cardiopulmonary resuscitation programmes for out-of-hospital cardiac arrest in Scotland via geospatial modelling.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (ECPR) can improve survival for refractory out-of-hospital cardiac arrest (OHCA). We sought to assess the feasibility of a proposed ECPR programme in Scotland, considering both in-hospital and pre-hospital implementation scenarios. METHODS: We included treated OHCAs in Scotland aged 16-70 between August 2018 and March 2022. We defined those clinically eligible for ECPR as patients where the initial rhythm was ventricular fibrillation, ventricular tachycardia, or pulseless electrical activity, and where pre-hospital return of spontaneous circulation was not achieved. We computed the call-to-ECPR access time interval as the amount of time from emergency medical service (EMS) call reception to either arrival at an ECPR-ready hospital or arrival of a pre-hospital ECPR crew. We determined the number of patients that had access to ECPR within 45 min, and estimated the number of additional survivors as a result. RESULTS: A total of 6,639 OHCAs were included in the geospatial modelling, 1,406 of which were eligible for ECPR. Depending on the implementation scenario, 52.9-112.6 (13.8-29.4%) OHCAs per year had a call-to-ECPR access time within 45 min, with pre-hospital implementation scenarios having greater and earlier access to ECPR for OHCA patients. We further estimated that an ECPR programme in Scotland would yield 11.8-28.2 additional survivors per year, with the pre-hospital implementation scenarios yielding higher numbers. CONCLUSION: An ECPR programme for OHCA in Scotland could provide access to ECPR to a modest number of eligible OHCA patients, with pre-hospital ECPR implementation scenarios yielding higher access to ECPR and higher numbers of additional survivors.

Factors affecting public access defibrillator placement decisions in the United Kingdom: A survey study.

Aim: This study aimed to understand current community PAD placement strategies and identify factors which influence PAD placement decision-making in the United Kingdom (UK). Methods: Individuals, groups and organisations involved in PAD placement in the UK were invited to participate in an online survey collecting demographic information, facilitators and barriers to community PAD placement and information used to decide where a PAD is installed in their experiences. Survey responses were analysed through descriptive statistical analysis and thematic analysis. Results: There were 106 included responses. Distance from another PAD (66%) and availability of a power source (63%) were most frequently used when respondents are deciding where best to install a PAD and historical occurrence of cardiac arrest (29%) was used the least. Three main themes were identified influencing PAD placement: (i) the relationship between the community and PADs emphasising community engagement to create buy-in; (ii) practical barriers and facilitators to PAD placement including securing consent, powering the cabinet, accessibility, security, funding, and guardianship; and (iii) 'risk assessment' methods to estimate the need for PADs including areas of high footfall, population density and type, areas experiencing health inequalities, areas with delayed ambulance response and current PAD provision. Conclusion: Decision-makers want to install PADs in locations that maximise impact and benefit to the community, but this can be constrained by numerous social and infrastructural factors. The best location to install a PAD depends on local context; work is required to determine how to overcome barriers to optimal community PAD placement.

Optimizing outcomes after out-of-hospital cardiac arrest with innovative approaches to public-access defibrillation: A scientific statement from the International Liaison Committee on Resuscitation.

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Optimizing Outcomes After Out-of-Hospital Cardiac Arrest With Innovative Approaches to Public-Access Defibrillation: A Scientific Statement From the International Liaison Committee on Resuscitation.

Out-of-hospital cardiac arrest is a global public health issue experienced by ≈3.8 million people annually. Only 8% to 12% survive to hospital discharge. Early defibrillation of shockable rhythms is associated with improved survival, but ensuring timely access to defibrillators has been a significant challenge. To date, the development of public-access defibrillation programs, involving the deployment of automated external defibrillators into the public space, has been the main strategy to address this challenge. Public-access defibrillator programs have been associated with improved outcomes for out-of-hospital cardiac arrest; however, the devices are used in <3% of episodes of out-of-hospital cardiac arrest. This scientific statement was commissioned by the International Liaison Committee on Resuscitation with 3 objectives: (1) identify known barriers to public-access defibrillator use and early defibrillation, (2) discuss established and novel strategies to address those barriers, and (3) identify high-priority knowledge gaps for future research to address. The writing group undertook systematic searches of the literature to inform this statement. Innovative strategies were identified that relate to enhanced public outreach, behavior change approaches, optimization of static public-access defibrillator deployment and housing, evolved automated external defibrillator technology and functionality, improved integration of public-access defibrillation with existing emergency dispatch protocols, and exploration of novel automated external defibrillator delivery vectors. We provide evidence- and consensus-based policy suggestions to enhance public-access defibrillation and guidance for future research in this area.

Socioeconomically equitable public defibrillator placement using mathematical optimization.

BACKGROUND: Mathematical optimization can be used to place automated external defibrillators (AEDs) in locations that maximize coverage of out-of-hospital cardiac arrests (OHCAs). We sought to determine whether optimization can improve alignment between AED locations and OHCA counts across levels of socioeconomic deprivation. METHODS: All suspected OHCAs and registered AEDs in Scotland between Jan. 2011 and Sept. 2017 were included and mapped to a corresponding socioeconomic deprivation level using the Scottish Index of Multiple Deprivation (SIMD). We used mathematical optimization to determine optimal locations for placing 10%, 25%, 50%, and 100% additional AEDs, as well as locations for relocating existing AEDs. For each AED placement policy, we examined the impact on AED distribution and OHCA "coverage" (suspected OHCA occurring within 100 m of AED) with respect to SIMD quintiles. RESULTS: We identified 49,432 suspected OHCAs and 1532 AEDs. The distribution of existing AED locations across SIMD quintiles significantly differed from the distribution of suspected OHCAs (P < 0.001). Optimization-guided AED placement increased coverage of suspected OHCAs compared to existing AED locations (all P < 0.001). Optimization resulted in more AED placements and increased OHCA coverage in areas of greater socioeconomic deprivation, such that resulting distributions across SIMD quintiles matched the shape of the OHCA count distribution. Optimally relocating existing AEDs achieved similar OHCA coverage levels to that of doubling the number of total AEDs. CONCLUSIONS: Mathematical optimization results in AED locations and suspected OHCA coverage that more closely resembles the suspected OHCA distribution and results in more equitable coverage across levels of socioeconomic deprivation.

Association of measures of socioeconomic position with survival following out-of-hospital cardiac arrest: A systematic review.

BACKGROUND: Survival following out-of-hospital cardiac arrest (OHCA) is low, and poor survival appears associated with low socioeconomic position (SEP). We aimed to synthesise the evidence regarding association of specific SEP measures with OHCA survival, as well as effect modification and potential mediators, with the goal of informing efforts to improve survival by highlighting characteristics of populations requiring additional resources, and identifying modifiable factors. METHODS: MEDLINE and Embase databases were searched on 23 May 2019. Quantitative primary studies considering the association of any SEP measure with any OHCA survival measure were eligible. SEP could be measured at the level of the patient, their residential area, or OHCA location. Data on study characteristics and outcomes were extracted and a narrative review performed; this considered the evidence for overall SEP-survival association, variation in association of different SEP measures with survival, effect modification, and mediation. RESULTS: Twenty-three studies were included. These were highly heterogeneous, particularly regarding SEP measures and eligibility criteria. Several studies report a SEP-survival association, with this being almost exclusively in the direction of lower survival with lower SEP. There is some indication that the education-survival association is particularly consistent but further work is needed to increase confidence here. No evidence of effect modification by age, sex or other factors was seen, although few studies considered this. No mediators were conclusively identified. CONCLUSIONS: Low SEP is associated with poorer OHCA survival in at least some settings. It may be appropriate to consider populations' socioeconomic characteristics when targeting interventions to improve OHCA survival.

Lessons from a pilot for uncontrolled donation after circulatory death in the ED in the UK.

Worldwide there is a shortage of available organs for patients requiring transplants. However, some countries such as France, Italy and Spain have had greater success by allowing donations from patients with unexpected and unrecoverable circulatory arrest who arrive in the ED. Significant advances in the surgical approach to organ recovery from donation after circulatory death (DCD) led to the establishment of a pilot programme for uncontrolled DCD in the ED of the Royal Infirmary of Edinburgh. This paper describes the programme and discusses the lessons learnt.

Optimising clinical performance during resuscitation using video evaluation.

Video evaluation of resuscitation is becoming increasingly integrated into practice in a number of clinical settings. The purpose of this review article is to examine how video may enhance clinical care during resuscitation. As healthcare and available therapeutic interventions evolve, re-evaluation of accepted paradigms requires data to describe current practice and support change. Analysis of video recordings affords creation of a framework to evaluate individual and team performance and develop unique and tailored strategies to optimise care delivery. While video has been used in a number of non-clinical settings, there has been a recent increase of video systems in the prehospital and other clinical areas. This paper reviews the key opportunities in the emergency department-based resuscitation setting to enhance ergonomics, technical and non-technical skills-at both team and individual level-through video-assisted care performance analysis and feedback.

Introduction of paramedic led Echo in Life Support into the pre-hospital environment: The PUCA study.

OBJECTIVES: Can pre-hospital paramedic responders perform satisfactory pre-hospital Echo in Life Support (ELS) during the 10-s pulse check window, and does pre-hospital ELS adversely affect the delivery of cardiac arrest care. METHODS: Prospective observational study of a cohort of ELS trained paramedics using saved ultrasound clips and wearable camera videos. RESULTS: Between 23rd June 2014 and 31st January 2016, seven Resuscitation Rapid Response Unit (3RU) paramedics attended 45 patients in Lothian suffering out-of-hospital CA where resuscitation was attempted and ELS was available and performed. 80% of first ELS attempts by paramedics produced an adequate view which was excellent/good or satisfactory in 68%. 44% of views were obtained within the 10-s pulse check window with a median time off the chest of 17 (IQR 13-20) seconds. A decision to perform ELS was communicated 67% of the time, and the 10-s pulse check was counted aloud in 60%. A manual pulse check was observed in around a quarter of patients and the rhythm on the monitor was checked 38% of the time. All decision changing scans involved a decision to stop resuscitation. CONCLUSIONS: Paramedics are able to obtain good ELS views in the pre-hospital environment but this may lead to longer hands off the chest time and possibly less pulse and monitor checking than is recommended. Future studies will need to demonstrate either improved outcomes or a benefit from identifying patients in whom further resuscitation and transportation is futile, before ELS is widely adopted in most pre-hospital systems.

Feasibility of EEG to monitor cognitive performance during venous cannulation: EEG Distracted Intravenous Access (E-DIVA).

Background: The feasibility study aims to evaluate the use of EEG in measuring workload during a simulated intravenous cannulation task. Cognitive workload is strongly linked to performance, but current methods to assess workload are unreliable. The paper presents the use of EEG to compare the cognitive workload between an expert and novice group completing a simple clinical task. Methods: 2 groups of volunteers (10 final year medical students and 10 emergency medicine consultants) were invited to take part in the study. Each participant was asked to perform 3 components of the simulation protocol: intravenous cannulation, a simple arithmetic test and finally these tasks combined. Error rate, speed of task completion and an EEG-based measure of cognitive workload were recorded for each element. Results: EEG cognitive workload during the combined cannulation and arithmetic task is significantly greater in novice participants when compared with expert operators performing the same task combination. EEG workload mean measured for novice and experts was 0.62 and 0.54, respectively (p=0.001, 95% CI 0.09 to 0.30). There was no significant difference between novice and expert EEG workload when the tasks were performed individually. Conclusions: EEG provides the opportunity to monitor and analyse the impact of cognitive load on clinical performance. Despite the significant challenges in set up and protocol design, there is a potential to develop educational interventions to optimise clinician's awareness of cognitive load. In addition, it may enable the use of metrics to monitor the impact of different interventions and select those that optimise clinical performance.

The combined use of mechanical CPR and a carry sheet to maintain quality resuscitation in out-of-hospital cardiac arrest patients during extrication and transport.

BACKGROUND: Quality of manual cardiopulmonary resuscitation (CPR) during extrication and transport of out-of-hospital cardiac arrest victims is known to be poor. Performing manual CPR during ambulance transport poses significant risk to the attending emergency medical services crew. We sought to use pre-hospital video recording to objectively analyse the impact of introducing mechanical CPR with an extrication sheet (Autopulse, Zoll) to an advanced, second-tier cardiac arrest response team. METHODS: The study was conducted prospectively using defibrillator downloads and analysis of pre-hospital video recording to measure the quality of CPR during extrication from scene and ambulance transport of the OHCA patient. Adult patients with non-traumatic OHCA were included. The interruption to manual CPR to during extrication and to deploy the mechanical CPR device was analysed. RESULTS: In the manual CPR group, 53 OHCA cases were analysed for quality of CPR during extrication. The median time that chest compression was interrupted to allow the patient to be carried from scene to the ambulance was 270 s (IQR 201-387 s). 119 mechanical CPR cases were analysed. The median time interruption from last manual compression to first Autopulse compression was 39 s (IQR 29-47 s). The range from last manual compression to first Autopulse compression was 14-118 s. CONCLUSION: Mechanical CPR used in combination with an extrication sheet can be effectively used to improve the quality of resuscitation during extrication and ambulance transport of the refractory OHCA patient. The time interval to deploy the mechanical CPR device can be shortened with regular simulation training.

Training paramedics in focussed echo in life support.

OBJECTIVES: The aim of this study was to determine whether paramedics can be trained to perform and interpret focussed Echo in Life Support (ELS) for the assessment of cardiac movement and the recognition of reversible causes of cardiac arrest. METHODS: This study is a prospective observational pilot study. Data were collected during a 1-day course training 11 paramedics to perform ELS scans on healthy volunteers. The students were assessed on image acquisition skills and theoretical knowledge (including interpretation). Level 1 ultrasound-trained emergency medicine physicians undertook the training and assessment. RESULTS: All paramedics could obtain images in the parasternal and subxiphoid views. When performing scans in the 10-s pulse check window, 88% of attempts in both views were successful (subxiphoid mean image quality 3.8 out of 5, parasternal 4.0). Theoretical knowledge improved (mean precourse score 54%, postcourse score 89%; P<0.001). There was no apparent association between theoretical and practical performances. At 10 weeks, theoretical knowledge was nonsignificantly reduced (82%; P=0.13) but less when compared with practical performance (75% subxiphoid success, mean quality 3.0; 25% parasternal success, mean quality 4.0). CONCLUSION: Paramedics can perform focused ELS, integrate attempts into simulated cardiac arrest scenarios and retain some of this knowledge. Further work is required to assess the feasibility of incorporating this into real-world cardiac arrest management.

A specialist, second-tier response to out-of-hospital cardiac arrest: setting up TOPCAT2.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is the most common, immediately life-threatening, medical emergency faced by ambulance crews. Survival from OHCA is largely dependent on quality of prehospital resuscitation. Non-technical skills, including resuscitation team leadership, communication and clinical decision-making are important in providing high quality prehospital resuscitation. We describe a pilot study (TOPCAT2, TC2) to establish a second tier, expert paramedic response to OHCA in Edinburgh, Scotland. METHODS: Eight paramedics were selected to undergo advanced training in resuscitation and non-technical skills. Simulation and video feedback was used during training. The designated TC2 paramedic manned a regular ambulance service response car and attended emergency calls in the usual manner. Emergency medical dispatch centre dispatchers were instructed to call the TC2 paramedic directly on receipt of a possible OHCA call. Call and dispatch timings, quality of cardiopulmonary resuscitation and return-of-spontaneous circulation were all measured prospectively. RESULTS: Establishing a specialist, second-tier paramedic response was feasible. There was no overall impact on ambulance response times. From the first 40 activations, the TC2 paramedic was activated in a median of 3.2 min (IQR 1.6-5.8) and on-scene in a median of 10.8 min (8.0-17.9). Bimonthly team debrief, case review and training sessions were successfully established. OHCA attended by TC2 showed an additional trend towards improved outcome with a rate of return of spontaneous circulation of 22.5%, compared with a national average of 16%. CONCLUSIONS: Establishing a specialist, second-tier response to OHCA is feasible, without impacting on overall ambulance response times. Improving non-technical skills, including prehospital resuscitation team leadership, has the potential to save lives and further research on the impact of the TOPCAT2 pilot programme is warranted.

Dispatch-assisted CPR: where are the hold-ups during calls to emergency dispatchers? A preliminary analysis of caller-dispatcher interactions during out-of-hospital cardiac arrest using a novel call transcription technique.

BACKGROUND: Survival from out-of-hospital cardiac arrest (OHCA) is dependent on the chain of survival. Early recognition of cardiac arrest and provision of bystander cardiopulmonary resuscitation (CPR) are key determinants of OHCA survival. Emergency medical dispatchers play a key role in cardiac arrest recognition and giving telephone CPR advice. The interaction between caller and dispatcher can influence the time to bystander CPR and quality of resuscitation. We sought to pilot the use of emergency call transcription to audit and evaluate the holdups in performing dispatch-assisted CPR. METHODS: A retrospective case selection of 50 consecutive suspected OHCA was performed. Audio recordings of calls were downloaded from the emergency medical dispatch centre computer database. All calls were transcribed using proprietary software and voice dialogue was compared with the corresponding stage on the Medical Priority Dispatch System (MPDS). Time to progress through each stage and number of caller-dispatcher interactions were calculated. RESULTS: Of the 50 downloaded calls, 47 were confirmed cases of OHCA. Call transcription was successfully completed for all OHCA calls. Bystander CPR was performed in 39 (83%) of these. In the remaining cases, the caller decided the patient was beyond help (n = 7) or the caller said that they were physically unable to perform CPR (n = 1). MPDS stages varied substantially in time to completion. Stage 9 (determining if the patient is breathing through airway instructions) took the longest time to complete (median = 59 s, IQR 22-82 s). Stage 11 (giving CPR instructions) also took a relatively longer time to complete compared to the other stages (median = 46 s, IQR 37-75 s). Stage 5 (establishing the patient's age) took the shortest time to complete (median = 5.5s, IQR 3-9s). CONCLUSION: Transcription of OHCA emergency calls and caller-dispatcher interaction compared to MPDS stage is feasible. Confirming whether a patient is breathing and completing CPR instructions required the longest time and most interactions between caller and dispatcher. Use of call transcription has the potential to identify key factors in caller-dispatcher interaction that could improve time to CPR and further research is warranted in this area.

Early in-hospital management of out-of-hospital cardiac arrest in Scotland: a national survey.

Guidelines recommend the use of mild therapeutic hypothermia (MTH) and percutaneous coronary intervention (PCI) in the early post-resuscitation management of select out-of-hospital cardiac arrest (OHCA) cases. This study aims to assess the current use of MTH and PCI in Scottish Emergency Departments (ED) and Intensive Care Units (ICU). We conducted a questionnaire survey of all the Scottish Emergency Medicine Consultants, EDs and ICUs. MTH was more commonly initiated in ICU than in the ED (19; 91 vs. 7; 37%, P<0.05). Only a minority two (11%) EDs routinely referred OHCA patients for early PCI and only three (16%) EDs receiving patients after OHCA had on-site access to PCI facilities. The use of MTH after OHCA appears to be widespread, although it is infrequently initiated in the ED. The utilization of PCI in OHCA management has yet to be widely established. Increased awareness may increase the use of promising therapies such as MTH and PCI following OHCA to save lives.

The utility of routine D-dimer measurement in syncope.

AIM: To establish whether D-dimer is an independent predictor of 1-month serious outcome and all-cause death in syncope patients presenting to the emergency department (ED). METHODS: This was a prospective cohort study of all adults presenting with syncope to an ED in the UK. Plasma D-dimer concentrations were determined in citrated plasma obtained at presentation. The primary endpoint was the combination of serious outcome and all-cause death at 1 month. RESULTS: Of 237 patients enrolled, 205 patients had a suitable plasma sample and had complete follow-up. Seventeen patients had a serious outcome or death at 1 month including three patients with a pulmonary embolus and eight with a serious cardiovascular outcome. Nearly a half of all patients (n=94; 46%) had a plasma D-dimer concentration above the upper limit of normal, 10 of whom had a serious outcome or death at 1 month. Receiver-operator characteristic curve analysis showed no relationship between plasma D-dimer concentration and serious outcome or death at 1 month. An elevated plasma D-dimer concentration was found in all patients with a pulmonary embolus. CONCLUSION: Plasma D-dimer is frequently raised in patients presenting with syncope to the ED and consequently does not predict 1-month serious outcome or death. We conclude that there is no role for the routine measurement of D-dimer in the management of patients presenting to the ED with syncope.

T-wave alternans found in preventricular tachyarrhythmias in CCU patients using a wavelet transform-based methodology.

Ventricular tachyarrhythmias are potentially lethal cardiac pathologies and the commonest cause of sudden cardiac death. Efforts to predict the onset of such events are based on feature extraction from the surface ECG. T-wave alternans (TWAs) are considered a marker of abnormal ventricular function that may be associated with ventricular tachycardia (VT) and ventricular fibrillation. A novel TWA detection algorithm utilizing the continuous wavelet transform is described in this paper. Simulated ECGs containing artificial TWA were used to test the algorithm that achieved a sensitivity of 91.40% and a specificity of 94.00%. The algorithm was subsequently used to analyze the ECGs of eight patients prior to the onset of VT. Of these, the algorithm indicated that five patients exhibited TWA prior to the onset of the tachyarrhythmic events, while the remaining three patients did not exhibit identifiable TWA. Healthy individuals were also studied in which one short TWA episode was detected by the algorithm. However, closer visual inspection of the data revealed this to be a likely false positive result.

Paroxysmal sympathetic surge associated with gamma hydroxybutyrate.

Gamma hydroxybutyrate is increasingly being used recreationally in the United Kingdom. We present a case of gamma hydroxybutyrate overdose associated with paroxysmal sympathetic storm, a phenomenon usually confined to patients who have sustained traumatic brain injury.