Bystander interventions and survival following out-of-hospital cardiac arrest at Copenhagen International Airport

AIM

To examine incidence and outcome following out-of-hospital cardiac (OHCA) arrest in a high-risk area characterised by high density of potential bystanders and easy access to nearby automated external defibrillators (AEDs).

METHODS

This retrospective observational study investigated pre-hospital and in-hospital treatment, as well as survival amongst persons with OHCA at Copenhagen International Airport between May 25, 2015 and May 25, 2019. OHCA data from pre- and in-hospital medical records were obtained and compared with public bystander witnessed OHCAs in Denmark.

RESULTS

Of the 23 identified non-traumatic OHCAs, 91.3% were witnessed by bystanders, 73.9% received bystander cardiopulmonary resuscitation (CPR), and 43.5% were defibrillated by a bystander. Survival to hospital discharge was 56.5%, with 100% survival among persons with an initial shockable heart rhythm. Compared with nationwide bystander witnessed OHCAs, persons with OHCA at the airport were less likely to receive bystander CPR (73.9% vs. 89.4%, OR 0.33; 95% CI, 0.13-0.86), more likely to receive bystander defibrillation (43.5% vs. 24.8%, OR 2.32; 95% CI, 1.01-5.31), to achieve return of spontaneous circulation (78.2% vs. 50.6%, OR 3.51; 95% CI, 1.30-9.49), and survive to hospital discharge (56.5% vs. 45.2%, OR 1.58; 95% CI, 0.69-3.62).

CONCLUSION

We found a high proportion of bystander defibrillation indicating that bystanders will quickly apply an AED, when accessible. Importantly, 56% of all persons, and all persons with a shockable heart rhythm survived. These findings suggest increased potential for survival following OHCA and support current guidelines to strategically deploy accessible AEDs in high-risk OHCA areas.

Single tests of implantable cardioverter defibrillators can be performed in selected patients at a low risk of neuronal damage

BACKGROUND

Defibrillator testing (DFT) is still used in selected patients to ensure adequate therapy. To do so, ventricular fibrillation is induced and terminated by the implanted cardioverter defibrillator (ICD). Studies have shown increases in neuronal damage markers without a measurable clinical effect in patients after defibrillator threshold testing with multiple shocks.

OBJECTIVE

The aim of this study was to measure clinical outcomes, neuronal damage parameters (NSE and S100), and intraoperative cerebral perfusion (Doppler, near infra-red spectroscopy [NIRS]) in patients undergoing single DFT after transvenous ICD implantation and comparing them to untested patients.

METHOD

We included 23 patients. Nine underwent surgery with a single DFT, 14 were not tested. Cognitive impairment was tested using the Mini-Mental-Status Test (MMST) and the DEMTECt 24 h prior and postsurgery. We also measured S100 and Neuron-Specific Enolase (NSE) at these timepoints. During surgery we measured medial cerebral artery velocity and cerebral tissue oxygen saturation (rSO₂ ).

RESULTS

We found no significant differences between the patient groups except for a significant increase in mean arterial blood pressure and an increase in rSO₂ after testing. One patient with cerebral vasculopathy had a significant increase in his NSE values without showing clinical symptoms. This patient also had low rSO₂ measurements and a decrease in medial cerebral artery velocity after DFT, other than the other patients.

CONCLUSION

Single DFT did not lead to signs of neuronal damage or cognitive impairment except in one case with pre-existing cerebral vasculopathy. Therefore, our results support the use of DFT in carefully selected patients.

Association between prehospital prognostic factors on out-of-hospital cardiac arrest in different age groups

Background

The prognosis of out-of-hospital cardiac arrest (OHCA) is very poor. While several prehospital factors are known to be associated with improved survival, the impact of prehospital factors on different age groups is unclear. The objective of the study was to access the impact of prehospital factors and pre-existing comorbidities on OHCA outcomes in different age groups.

Methods

A retrospective observational analysis was conducted using the emergency medical service (EMS) database from January 2015 to December 2019. We collected information on prehospital factors, underlying diseases, and outcome of OHCAs in different age groups. Kaplan-Meier type survival curves and multivariable logistic regression were used to analyze the association between modifiable pre-hospital factors and outcomes.

Results

A total of 4188 witnessed adult OHCAs were analyzed. For the age group 1 (age ≦75 years old), after adjustment for confounding factors, EMS response time (odds ratio [OR] = 0.860, 95% confidence interval [CI]: 0.811–0.909, p < 0.001), public location (OR = 1.843, 95% CI: 1.179–1.761, p < 0.001), bystander CPR (OR = 1.329, 95% CI: 1.007–1.750, p = 0.045), attendance by an EMT-Paramedic (OR = 1.666, 95% CI: 1.277–2.168, p < 0.001), and prehospital defibrillation by automated external defibrillator (AED)(OR = 1.666, 95% CI: 1.277–2.168, p < 0.001) were prognostic factors for survival to hospital discharge in OHCA patients. For the age group 2 (age > 75 years old), age (OR = 0.924, CI:0.880–0.966, p = 0.001), EMS response time (OR = 0.833, 95% CI: 0.742–0.928, p = 0.001), public location (OR = 4.290, 95% CI: 2.450–7.343, p < 0.001), and attendance by an EMT-Paramedic (OR = 2.702, 95% CI: 1.704–4.279, p < 0.001) were independent prognostic factors for survival to hospital discharge in OHCA patients.

Conclusions

There were variations between younger and older OHCA patients. We found that bystander CPR and prehospital defibrillation by AED were independent prognostic factors for younger OHCA patients but not for the older group.

Delay to initiation of out-of-hospital cardiac arrest EMS treatments

BACKGROUND

Time to initial treatment is important in any response to out-of-hospital cardiac arrest (OHCA). The purpose of this paper was to quantify the time delay for providing initial EMS treatments supplemented by comparison with those of other EMS systems conducting clinical trials.

METHODS

Data were collected between 1/1/16-2/15/19. Dispatched, EMS-worked, adult OHCA cases occurring before EMS arrival were included and compared with published treatment time data. Response time and time-to-treatment intervals were profiled in both groups. Time intervals were calculated by subtracting the following timepoints from 9-1-1 call receipt: ambulance in route; at curb; patient contact; first defibrillation; first epinephrine; and first antiarrhythmic.

RESULTS

342 subjects met study inclusion/exclusion. Mean time intervals (min [95%CI]) from 9-1-1 call receipt to the following EMS endpoints were: dispatch 0.1 [0.05-0.2]; at curb 5.0 [4.5, 5.5]; at patient 6.7 [6.1, 7.2];, first defibrillation initially shockable 11.7 [10.1, 13.3]; first epinephrine (initially shockable 15.0 [12.8, 17.2], initially non-shockable 14.8 [13.5, 15.9]), first antiarrhythmic 25.1 [22.0, 28.2]. These findings were similar to data in 5 published clinical trials involving 12,954 subjects.

CONCLUSIONS

Delay to EMS treatments are common and may affect clinical outcomes. Neither Utstein out-of-hospital guidelines [1] nor U.S. Cardiac Arrest Registry to Enhance Survival (CARES) databases require capture of these elements. EMS is often not providing treatments quickly enough to optimize clinical outcomes. Further regulatory change/research are needed to determine whether OHCA outcome can be improved by novel changes such as enhancing bystander effectiveness through drone-delivered drugs/devices & real-time dispatcher direction on their use.

Aerosol generation during chest compression and defibrillation in a swine cardiac arrest model

Aim

It remains unclear whether cardiac arrest (CA) resuscitation generates aerosols that can transmit respiratory pathogens. We hypothesize that chest compression and defibrillation generate aerosols that could contain the SARS-CoV-2 virus in a swine CA model.

Methods

To simulate witnessed CA with bystander-initiated cardiopulmonary resuscitation, 3 female non-intubated swine underwent 4 min of ventricular fibrillation without chest compression or defibrillation (no-flow) followed by ten 2-min cycles of mechanical chest compression and defibrillation without ventilation. The diameter (0.3–10 μm) and quantity of aerosols generated during 45-s intervals of no-flow and chest compression before and after defibrillation were analyzed by a particle analyzer. Aerosols generated from the coughs of 4 healthy human subjects were also compared to aerosols generated by swine.

Results

There was no significant difference between the total aerosols generated during chest compression before defibrillation compared to no-flow. In contrast, chest compression after defibrillation generated significantly more aerosols than chest compression before defibrillation or no-flow (72.4 ± 41.6 × 10⁴ vs 12.3 ± 8.3 × 10⁴ vs 10.5 ± 11.2 × 10⁴; p < 0.05), with a shift in particle size toward larger aerosols. Two consecutive human coughs generated 54.7 ± 33.9 × 10⁴ aerosols with a size distribution smaller than post-defibrillation chest compression.

Conclusions

Chest compressions alone did not cause significant aerosol generation in this swine model. However, increased aerosol generation was detected during chest compression immediately following defibrillation. Additional research is needed to elucidate the clinical significance and mechanisms by which aerosol generation during chest compression is modified by defibrillation.

ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients

The provided database of 260 ECG signals was collected from patients with out-of-hospital cardiac arrest while treated by the emergency medical services. Each ECG signal contains a 9 second waveform showing ventricular fibrillation, followed by 1 min of post-shock waveform. Patients’ ECGs are made available in multiple formats. All ECGs recorded during the prehospital treatment are provided in PFD files, after being anonymized, printed in paper, and scanned. For each ECG, the dataset also includes the whole digitized waveform (9 s pre- and 1 min post-shock each) and numerous features in temporal and frequency domain extracted from the 9 s episode immediately prior to the first defibrillation shock. Based on the shock outcome, each ECG file has been annotated by three expert cardiologists, - using majority decision -, as successful (56 cases), unsuccessful (195 cases), or indeterminable (9 cases). The code for preprocessing, for feature extraction, and for limiting the investigation to different temporal intervals before the shock is also provided. These data could be reused to design algorithms to predict shock outcome based on ventricular fibrillation analysis, with the goal to optimize the defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation and/or drug administration) for enhancing resuscitation.

A method to predict ventricular fibrillation shock outcome during chest compressions

BACKGROUND

Out-of-hospital ventricular fibrillation (VF) cardiac arrest is a leading cause of death. Quantitative analysis of the VF electrocardiogram (ECG) can predict patient outcomes and could potentially enable a patient-specific, guided approach to resuscitation. However, VF analysis during resuscitation is confounded by cardiopulmonary resuscitation (CPR) artifact in the ECG, challenging continuous application to guide therapy throughout resuscitation. We therefore sought to design a method to predict VF shock outcomes during CPR.

METHODS

Study data included 4577 5-s VF segments collected during and without CPR prior to defibrillation attempts in N = 1151 arrest patients. Using training data (460 patients), an algorithm was designed to predict the VF shock outcomes of defibrillation success (return of organized ventricular rhythm) and functional survival (Cerebral Performance Category 1-2). The algorithm was designed with variable-frequency notch filters to reduce CPR artifact in the ECG based on real-time chest compression rate. Ten ECG features and three dichotomous patient characteristics were developed to predict outcomes. These variables were combined using support vector machines and logistic regression. Algorithm performance was evaluated by area under the receiver operating characteristic curve (AUC) to predict outcomes in validation data (691 patients).

RESULTS

AUC (95% Confidence Interval) for predicting defibrillation success was 0.74 (0.71-0.77) during CPR and 0.77 (0.74-0.79) without CPR. AUC for predicting functional survival was 0.75 (0.72-0.78) during CPR and 0.76 (0.74-0.79) without CPR.

CONCLUSION

A novel algorithm predicted defibrillation success and functional survival during ongoing CPR following VF arrest, providing a potential proof-of-concept towards real-time guidance of resuscitation therapy.

Out-of-hospital cardiac arrest patients with implantable cardioverter-defibrillators: What are their outcomes?

THE AIM OF THE STUDY

To identify the prognostic factors and effects of implantable cardioverter-defibrillators (ICDs) in out-of-hospital cardiac arrest (OHCA) patients with ICDs because the clinical characteristics and outcomes of OHCA patients with ICDs are unknown.

METHODS

The North American Resuscitation Outcomes Consortium (ROC) Cardiac Epistry Version 3 dataset was analyzed. Eligible patients were divided into OHCA patients with and without ICDs. Multivariable regressions were employed to analyze.

RESULTS

Of 51,634 eligible OHCA patients, 581 (1.13%) had implanted ICDs. Among them, 53 (9.1%) patients survived to hospital discharge, and 40 (6.9%) patients had favorable neurological outcome at hospital discharge. Multivariable regression showed ICDs were not associated with OHCA outcomes in the total OHCA patients. In the OHCA patients with ICDs, shockable initial emergency medical services (EMS)-recorded rhythms and the ICD-shock-only defibrillation pattern were independent favorable factors for survival to hospital discharge(OR = 3.3, 95%CI 1.7-6.2, P < 0.001; OR = 2.4, 95%CI 1.1-5.5, P = 0.035, respectively) and neurological outcome at hospital discharge (OR = 6.5, 95%CI 2.9-14.4, P < 0.001; OR = 3.6, 95%CI 1.4-9.1, P = 0.006, respectively). During field resuscitation in OHCA patients with ICDs, at least 34.9% of total patients and 64.6% of patients with initial EMS-recorded VT/VF rhythms needed additional external shocks.

CONCLUSIONS

Shockable initial EMS-recorded rhythms and ICD-shock-only defibrillation pattern were independent factors for the favorable outcomes of OHCA patients with ICDs. ICDs were not associated with the outcomes of OHCA, and additional external shocks were needed in a substantial number of OHCA patients with ICDs during field resuscitation.

Active compression versus standard anterior-posterior defibrillation for external cardioversion of atrial fibrillation: A prospective randomized study

BACKGROUND

Electrical cardioversion is the first-line rhythm control therapy for symptomatic persistent atrial fibrillation (AF). Contemporary use of biphasic shock waveforms and anterior-posterior positioning of defibrillation electrodes have improved cardioversion efficacy; however, it remains unsuccessful in >10% of patients.

OBJECTIVE

The purpose of this study was to assess the efficacy of applying active compression on defibrillation electrodes during AF cardioversion.

METHODS

We performed a bicenter randomized study including patients referred for persistent AF cardioversion. Elective external cardioversion was performed by a standardized step-up protocol with increasing biphasic shock energy (50-100-150-200 J). Patients were randomly assigned to standard anterior-posterior defibrillation or to defibrillation with active compression applied over the anterior electrode. If sinus rhythm was not achieved at 200 J, a single crossover shock (200 J) was applied. Defibrillation threshold, total delivered energy, number of shocks, and success rate were compared between groups.

RESULTS

We included 100 patients, 50 in each group. In the active compression group, defibrillation threshold was lower (103.1 ± 49.9 J vs 130.4 ± 47.7 J; P = .008), as well as total delivered energy (203 ± 173.3 J vs 309 ± 213.5 J; P = .0076) and number of shocks (2.2 ± 1.1 vs 2.9 ± 1.2; P = .0033), and cardioversion was more often successful (48 of 50 patients [96%] vs 42 of 50 patients [84%]; P = .0455) than that in the standard anterior-posterior group. Crossover from the compression group to the standard group was not successful (0 of 2 patients), whereas crossover from the standard group to the compression group was successful in 50% of patients (4 of 8).

CONCLUSION

Active compression applied to the anterior defibrillation electrode is more effective for persistent AF cardioversion than standard anterior-posterior cardioversion, with lower defibrillation threshold and higher success rate.

ILCOR's revised Covid-19 defibrillation recommendation requires a new approach to training

In-hospital resuscitation practices have changed by necessity in the Covid-19 era, principally due to precautions intended to protect caregivers from infection. This has resulted in serious delays in resuscitation response.ILCOR has recently modified its guidelines to separate defibrillation from other interventions, recognizing that shock success is extremely time-dependent and that defibrillation poses relatively little risk of Covid-19 transmission. The new recommendation calls for sending one caregiver into the isolation room in order to initiate bedside monitoring and defibrillate if indicated, while the code team is donning their personal protective equipment. Implementing this change requires focused training in that specific role. This can be accomplished by intensively training a subset of clinical staff to assume the responsibility and act without hesitation when a code occurs.Focused defibrillation training promises to avoid compromising the care of patients experiencing tachyarrhythmic arrests in the setting of Covid-19. Such a training program might even result in better survival than before the pandemic for this subset of patients.

Spontaneous torsade de pointes and ventricular fibrillation in a dog during pacemaker implantation

Torsade de pointes is an unusual complication seen in dogs during pacemaker implantation, although ventricular fibrillation has been previously reported. This case report describes torsade de pointes in a dog during pacemaker implantation that degenerated into ventricular fibrillation and discusses the possible contributory factors. It also illustrates the relevance of a pre-emptive resuscitation plan and how this might have affected the outcome in the patient.

Defibrillator charging before rhythm analysis causes peri-shock pauses exceeding guideline recommended maximum 5 s : A randomized simulation trial

INTRODUCTION

Charging defibrillators prior to analyzing heart rhythms may decrease the no-flow time during rhythm check pauses while resuscitating in cardiac arrest. Although this anticipatory method is already used in some centers little is known about its safety. This study was carried out to confirm the safety and feasibility of the anticipatory method. It was hypothesized that this anticipatory method results in shorter total no-flow times, while other parameters of defibrillation efficacy including defibrillator safety and minimization of peri-shock pauses are unchanged.

METHODS

This manikin study assigned 243 medical students randomly to study groups, 121 to the anticipatory method and 122 to the recommended European Resuscitation Council (ERC) algorithm. Of these 237 students ultimately underwent training (112 anticipatory method vs. 125 ERC algorithm). Participants were assessed and video recorded during a simulated cardiac arrest scenario which included three different heart rhythms (ventricular fibrillation [VF], pulseless ventricular tachycardia [pVT], asystole) in randomized order. Video and software analyses were performed. Defibrillation safety was assessed using a 17-item checklist defined beforehand.

RESULTS

A total of 203 simulated cardiac arrests (75 anticipatory method and 128 ERC 2010 algorithm) were analyzed. The anticipatory method did not significantly reduce no-flow time (25.8 s, standard deviation, SD 7.4 s vs. 27.4 s SD 8.4 s, p = 0.19); however, peri-shock pauses were significantly longer in the anticipatory group compared to the ERC 2010 group (9.5 s SD 2.8 s vs. 3.3 s SD 1.9 s, p < 0.001). No significant difference concerning defibrillation safety between the groups was observed according to the 17-item checklist (14.6 SD 1.6 vs. 15.0 SD 1.4, p = 0.07).

CONCLUSION

Charging defibrillators before rhythm analysis did not decrease total no-flow time in simulated cardiac arrests but resulted in significantly longer peri-shock pauses exceeding 5 s. No significant differences in defibrillation safety were observed between the groups.

Combination of internal (epicardial) and external (transthoracic) defibrillation during heart surgery

Objectives

This report describes a modified defibrillation technique during cardiac surgery using a combined internal (epicardial) and external (transthoracic) defibrillation system.

Methods

We routinely used 30 J (J) shock between the epicardial pad placed directly onto the right atrium and the left anterolateral transthoracic pad placed in the left anterolateral chest wall directly to the skin in the area of the cardiac apex under the nipple.

Results

Thirty-two patients whom developed ventricular fibrillation (VF) during surgery were managed in theatre using this method. A single 30 J shock was successfully given in 29 patients while the remaining three required an additional shock with the same amount (30 J).

Conclusions

We believe that this technique is safe and complications free. It is easy to perform especially in patients with difficult access such as redo operations.

Deep Brain Stimulation Generator Failure due to External Defibrillation in a Patient with Essential Tremor

There exist only two case reports to date of open cardiac defibrillation with deep brain stimulator system (DBS) implantation. We report a 64-year-old male with DBS system in place for essential tremor who underwent cardiac defibrillation after cardiac arrest. Afterwards, his device impedances were all high and his tremor symptoms returned. Both problems resolved with implantation of a new generator and required no changes to the intracranial leads or extension cables. This is significantly different from the two previous reports. One included a significantly different DBS system relying on transcutaneous RF transmission and reported a lesioning effect after cardioversion. The other utilized a modern DBS system but reported damage to the generator and intracranial leads. We report that only the generator sustained damage, and that there were no intracranial changes that occurred.

Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design

OBJECTIVE

Optimizing timing of defibrillation by evaluating the likelihood of a successful outcome could significantly enhance resuscitation. Previous studies employed conventional machine learning approaches and hand-crafted features to address this issue, but none have achieved superior performance to be widely accepted. This study proposes a novel approach in which predictive features are automatically learned.

METHODS

A raw 4s VF episode immediately prior to first defibrillation shock was feed to a 3-stage CNN feature extractor. Each stage was composed of 4 components: convolution, rectified linear unit activation, dropout and max-pooling. At the end of feature extractor, the feature map was flattened and connected to a fully connected multi-layer perceptron for classification. For model evaluation, a 10 fold cross-validation was employed. To balance classes, SMOTE oversampling method has been applied to minority class.

RESULTS

The obtained results show that the proposed model is highly accurate in predicting defibrillation outcome (Acc = 93.6 %). Since recommendations on classifiers suggest at least 50 % specificity and 95 % sensitivity as safe and useful predictors for defibrillation decision, the reported sensitivity of 98.8 % and specificity of 88.2 %, with the analysis speed of 3 ms/input signal, indicate that the proposed model possesses a good prospective to be implemented in automated external defibrillators.

CONCLUSIONS

The learned features demonstrate superiority over hand-crafted ones when performed on the same dataset. This approach benefits from being fully automatic by fusing feature extraction, selection and classification into a single learning model. It provides a superior strategy that can be used as a tool to guide treatment of OHCA patients in bringing optimal decision of precedence treatment. Furthermore, for encouraging replicability, the dataset has been made publicly available to the research community.

Time to change the times? Time of recurrence of ventricular fibrillation during OHCA

AIM OF THE STUDY

For out-of-hospital-cardiac-arrest (OHCA) due to ventricular fibrillation (VF) guidelines recommend early defibrillation followed by chest compressions for two minutes before analyzing shock success. If rhythm analysis reveals VF again, it is obscure whether VF persisted or reoccurred within the two-minutes-cycle of chest compressions after successful defibrillation. We investigated the time of VF-recurrence in OHCA.

METHODS

We examined all cases of OHCA presenting with initial VF rhythm at arrival of ALS-ambulance (Marburg-Biedenkopf-County, 246.648 inhabitants) from January 2014 to March 2018. Three independent investigators analyzed corpuls3® ECG-recordings. We included ECG-data from CPR-beginning until four minutes after the third shock. VF termination was defined as the absence of a VF-waveform within 5 s of shock delivery. VF recurrence was defined as the presence of a VF-waveform in the interval 5 s post shock delivery.

RESULTS

We included 185 shocks in 82 patients. 74.1% (n = 137) of all shocks terminated VF, but VF recurred in 81% (n = 111). The median (IQR) time of VF-recurrences was 27 s (13.5 s/80.5 s) after shock. 51.4% (n = 57) of VF-recurrence occurred 5-30 s after shock, 13.5% (n = 15) VF-recurrence occurred 31-60 s after shock, 21.6% (n = 24) of VF-recurrence occurred 61-120 s after shock, 13.5% (n = 15) of VF-recurrence occurred 121-240 s after shock.

CONCLUSIONS

Although VF was terminated by defibrillation in 74.1%, VF recurred in 81% subsequent to the chest compression interval. Thus, VF reappears frequently and early. It is unclear to which extend chest compressions influence VF-relapse. Further studies need to re-evaluate the algorithm, timing of antiarrhythmic therapy or novel defibrillation strategies to minimize refibrillation during shockable OHCA.

Evaluation of a novel cardioversion intervention for atrial fibrillation: the Ottawa AF cardioversion protocol

AIMS

Electrical cardioversion is commonly performed to restore sinus rhythm in patients with atrial fibrillation (AF), but it is unsuccessful in 10-12% of attempts. We sought to evaluate the effectiveness and safety of a novel cardioversion protocol for this arrhythmia.

METHODS AND RESULTS

Consecutive elective cardioversion attempts for AF between October 2012 and July 2017 at a tertiary cardiovascular centre before (Phase I) and after (Phase II) implementing the Ottawa AF cardioversion protocol (OAFCP) as an institutional initiative in July 2015 were evaluated. The primary outcome was cardioversion success, defined as ≥2 consecutive sinus beats or atrial-paced beats in patients with implanted cardiac devices. Secondary outcomes were first shock success, sustained success (sinus or atrial-paced rhythm on 12-lead electrocardiogram prior to discharge from hospital), and procedural complications. Cardioversion was successful in 459/500 (91.8%) in Phase I compared with 386/389 (99.2%) in Phase II (P < 0.001). This improvement persisted after adjusting for age, body mass index, amiodarone use, and transthoracic impedance using modified Poisson regression [adjusted relative risk 1.08, 95% confidence interval (CI) 1.05-1.11; P < 0.001] and when analysed as an interrupted time series (change in level +9.5%, 95% CI 6.8-12.1%; P < 0.001). The OAFCP was also associated with greater first shock success (88.4% vs. 79.2%; P < 0.001) and sustained success (91.6% vs 84.7%; P=0.002). No serious complications occurred.

CONCLUSION

Implementing the OAFCP was associated with a 7.4% absolute increase in cardioversion success and increases in first shock and sustained success without serious procedural complications. Its use could safely improve cardioversion success in patients with AF.

CLINICAL TRIAL NUMBER

www.clinicaltrials.gov ID: NCT02192957.

Factors Affecting Attitudes Toward Defibrillator Use Among Clinical Nurses in South Korea: A Cross-Sectional Study

INTRODUCTION

Nurses are often first responders to in-hospital cardiac arrests. However, many nurses do not perform defibrillation even when required. Nurses' attitudes toward defibrillator use are influenced by social and psychological context. This descriptive, cross-sectional study explored factors affecting attitudes toward defibrillator use among nurses in South Korea.

METHODS

A total of 280 nurses with a minimum of 6 months' clinical experience were included. The data were acquired through a self-administered questionnaire. Regression analysis was used to determine factors significantly associated with attitudes toward defibrillator use.

RESULTS

Only 13.6% of the participating nurses had experience with defibrillator use in a cardiopulmonary resuscitation situation, whereas 94.6% of the nurses had received training on defibrillator use. Attitudes toward defibrillator use accounted for 37% of variance in measures of self-confidence, image, and job fit.

DISCUSSION

To improve clinical nurses' attitudes toward defibrillator use, improving their self-confidence, image, and job fit through ongoing assessment and retraining on defibrillation is required. In addition, relevant institutional support and systematic guidelines should be provided.

Updates in Cardiac Arrest Resuscitation

There are approximately 350,000 out-of-hospital cardiac arrests and 200,000 in-hospital cardiac arrests annually in the United States, with survival rates of approximately 5% to 10% and 24%, respectively. The critical factors that have an impact on cardiac arrest survival include prompt recognition and activation of prehospital care, early cardiopulmonary resuscitation, and rapid defibrillation. Advanced life support protocols are continually refined to optimize intracardiac arrest management and improve survival with favorable neurologic outcome. This article focuses on current treatment recommendations for adult nontraumatic cardiac arrest, with emphasis on the latest evidence and controversies regarding intracardiac arrest management.

Decline in physical activity in the weeks preceding sustained ventricular arrhythmia in women

Background

Heightened risk of cardiac arrest following physical exertion has been reported. Among patients with an implantable defibrillator, an appropriate shock for sustained ventricular arrhythmia was preceded by a retrospective self-report of engaging in mild-to-moderate physical activity. Previous studies evaluating the relationship between activity and sudden cardiac arrest lacked an objective measure of physical activity and women were often underrepresented.

Objective

To determine the relationship between physical activity, recorded by accelerometer in a wearable cardioverter-defibrillator (WCD), and sustained ventricular arrhythmia among female patients.

Methods

A dataset of female adult patients prescribed a WCD for a diagnosis of myocardial infarction or dilated cardiomyopathy was compiled from a commercial database. Curve estimation, to include linear and nonlinear interpolation, was applied to physical activity as a function of time (days before arrhythmia).

Results

Among women who received an appropriate WCD shock for sustained ventricular arrhythmia (N = 120), a quadratic relationship between time and activity was present prior to shock. Physical activity increased starting at the beginning of the 30-day period up until day -16 (16 days before the ventricular arrhythmia) when activity begins to decline.

Conclusion

For patients who received treatment for sustained ventricular arrhythmia, a decline in physical activity was found during the 2 weeks preceding the arrhythmic event. Device monitoring for a sustained decline in physical activity may be useful to identify patients at near-term risk of a cardiac arrest.

Improved survival to hospital discharge in pediatric in-hospital cardiac arrest using 2 Joules/kilogram as first defibrillation dose for initial pulseless ventricular arrhythmia

The American Heart Association (AHA) recommends first defibrillation energy dose of 2 Joules/kilogram (J/kg) for pediatric cardiac arrest with ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT). However, optimal first energy dose remains unclear.

METHODS

Using AHA Get With the Guidelines-Resuscitation® (GWTG-R) database, we identified children ≤12 years with IHCA due to VF/pVT. Primary exposure was energy dose in J/kg. We categorized energy doses: 1.7-2.5 J/kg as reference (reflecting 2 J/kg intended dose), <1.7 J/kg and >2.5 J/kg. We compared survival for reference doses to all other doses. We constructed models to test association of energy dose with survival; adjusting for age, location, illness category, initial rhythm and vasoactive medications.

RESULTS

We identified 301 patients ≤12 years with index IHCA and initial VF/pVT. Survival to discharge was significantly lower with energy doses other than 1.7-2.5 J/kg. Individual dose categories of <1.7 J/kg or >2.5 J/kg were not associated with differences in survival. For patients with initial VF, doses >2.5 J/kg had worse survival compared to reference. For all patients ≤18 years (n = 422), there were no differences in survival between dosing categories. However, all ≤18 with initial VF receiving >2.5 J/kg had worse survival.

CONCLUSIONS

First energy doses other than 1.7-2.5 J/kg are associated with lower rate of survival to hospital discharge in patients ≤12 years old with initial VF/pVT, and first doses >2.5 J/kg had lower survival rates in all patients ≤18 years old with initial VF. These results support current AHA guidelines for first pediatric defibrillation energy dose of 2 J/kg.

Anticipatory manual defibrillator charging during advanced life support: A scoping review

Background

Some resuscitation services advocate or teach routine manual defibrillator charging prior to a rhythm check during cardiopulmonary resuscitation.

Objectives

We aimed to review the evidence for anticipatory defibrillator charging compared with charging after a shockable rhythm is confirmed.

Methods

This scoping review was performed according to a specific methodological framework and the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews. Grey literature was also reviewed using similar methodology and included in the results.

Results

There are no randomized clinical trials studying anticipatory manual defibrillator charging. The limited available data does not address critical or important patient outcomes such as defibrillation success, return of spontaneous circulation, survival to hospital discharge or neurological outcomes. Evidence primarily from manikin studies and the grey literature suggests that anticipatory charging is feasible, safe, and can reduce the total pause duration during the period of chest compression between rhythm checks, but can increase the pre-shock pause and total peri-shock pause duration.

Conclusions

Anticipatory manual defibrillator charging appears to be feasible in the clinical setting, although its impact on clinical outcomes is uncertain. Future studies of anticipatory charging should focus on clinical outcomes.

Care and outcomes of urban and non-urban out-of-hospital cardiac arrest patients during the HeartRescue Project in Washington state and North Carolina

AIM

We examined overall and temporal differences in out-of-hospital cardiac arrest (OHCA) care and outcomes by urban versus non-urban setting separately for North Carolina (NC) and Washington State (WA) during HeartRescue initiatives and associations of urban/non-urban settings with outcome by state.

METHODS

OHCAs of presumed cardiac etiology from counties with complete registry enrollment in NC during 2010-2014 (catchment population = 3,143,809) and WA during 2011-2014 (catchment population = 3,653,506) were identified. Geospatial arrest location data and US Census classification were used to categorize urban areas with ≥50,000 versus non-urban <50,000 people.

RESULTS

Included were 7731 NC cases (78.9% urban) and 4472 WA cases (85.8% urban). Bystander cardiopulmonary resuscitation (CPR) increased from 36.9% (2010) to 50.3% (2014) in NC non-urban areas versus 58.2% (2011) to 69.2% (2014) in WA; and from 39.3% to 51.1% in NC urban areas versus 52.4% to 61.8% in WA. Crude discharge survival odds ratio (OR) was 2.49 (95%CI 1.96-3.16) for urban versus non-urban NC cases not declared dead in field (N = 4241). Adjusted for age, sex, public location, bystander-witness status, time between emergency call and emergency medical service (EMS) arrival, calendar-year, bystander and first-responder CPR and defibrillation and direct PCI-center transport, OR was 1.30 (95%CI 0.98-1.73). In WA, corresponding crude and adjusted ORs were 1.38 (95%CI 0.99-1.93) and 1.46 (95%CI 1.00-2.13). In both states, bystander and first-responder CPR and defibrillation and direct PCI-hospital transport were associated with increased survival.

CONCLUSIONS

During HeartRescue initiatives, bystander CPR increased in urban and non-urban locations. Bystander and first-responder interventions and direct PCI-hospital transport were associated with improved outcomes, including in non-urban areas.

COVID-19 in cardiac arrest and infection risk to rescuers: A systematic review

Background

There may be a risk of COVID-19 transmission to rescuers delivering treatment for cardiac arrest. The aim of this review was to identify the potential risk of transmission associated with key interventions (chest compressions, defibrillation, cardiopulmonary resuscitation) to inform international treatment recommendations.

Methods

We undertook a systematic review comprising three questions: (1) aerosol generation associated with key interventions; (2) risk of airborne infection transmission associated with key interventions; and (3) the effect of different personal protective equipment strategies. We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and the World Health Organization COVID-19 database on 24th March 2020. Eligibility criteria were developed individually for each question. We assessed risk of bias for individual studies, and used the GRADE process to assess evidence certainty by outcome.

Results

We included eleven studies: two cohort studies, one case control study, five case reports, and three manikin randomised controlled trials. We did not find any direct evidence that chest compressions or defibrillation either are or are not associated with aerosol generation or transmission of infection. Data from manikin studies indicates that donning of personal protective equipment delays treatment delivery. Studies provided only indirect evidence, with no study describing patients with COVID-19. Evidence certainty was low or very low for all outcomes.

Conclusion

It is uncertain whether chest compressions or defibrillation cause aerosol generation or transmission of COVID-19 to rescuers. There is very limited evidence and a rapid need for further studies.

Review registration: PROSPERO CRD42020175594.

Optimal in-hospital defibrillator placement

AIMS

To determine if mathematical optimization of in-hospital defibrillator placements can reduce in-hospital cardiac arrest-to-defibrillator distance compared to existing defibrillators in a single hospital.

METHODS

We identified treated IHCAs and defibrillator placements in St. Michael's Hospital in Toronto, Canada from Jan. 2013 to Jun. 2017 and mapped them to a 3-D computer model of the hospital. An optimization model identified an equal number of optimal defibrillator locations that minimized the average distance between IHCAs and the closest defibrillator using a 10-fold cross-validation approach. The optimized and existing defibrillator locations were compared in terms of average distance to the out-of-sample IHCAs. We repeated the analysis excluding intensive care units (ICUs), operating theatres (OTs), and the emergency department (ED). We also re-solved the model using fewer defibrillators to determine when the average distance matched the performance of existing defibrillators.

RESULTS

We identified 433 treated IHCAs and 53 defibrillators. Of these, 167 IHCAs and 31 defibrillators were outside of ICUs, OTs, and the ED. Optimal defibrillator placements reduced the average IHCA-to-defibrillator distance from 16.1 m to 2.7 m (relative decrease of 83.0%; P = 0.002) compared to existing defibrillator placements. For non-ICU/OT/ED IHCAs, the average distance was reduced from 24.4 m to 11.9 m (relative decrease of 51.3%; P = 0.002. 8-9 optimized defibrillator locations were sufficient to match the average IHCA-to-defibrillator distance of existing defibrillator placements.

CONCLUSIONS

Optimization-guided placement of in-hospital defibrillators can reduce the distance from an IHCA to the closest defibrillator. Equivalently, optimization can match existing defibrillator performance using far fewer defibrillators.