Wolf Creek XVII Part 2: The origin, evolution, and impact of the Wolf Creek Conference

The Wolf Creek Conference is a seminal meeting of resuscitation researchers that has significantly influenced scientific advances and patient care in the field of cardiac arrest resuscitation over nearly half a century. Originating in 1975 at the Wolf Creek Lodge in Georgia, the conference was founded by Drs. James Elam, James Jude, and Peter Safar with the aim of improving clinical practices in cardiopulmonary resuscitation (CPR) by stimulating laboratory and clinical research. Over 17 conferences to date, the scope has broadened to encompass the growing field of resuscitation science, participation has expanded to include thought leaders and scientists from both academia and industry, and the proceedings have catalyzed numerous innovations in field. This narrative review highlights the genesis, objectives, proceedings, and impact of the Wolf Creek Conference from 1975 to the present.

Association of pre-left ventricular assist device defibrillator shocks for ventricular arrhythmia with clinical outcomes after left ventricular assist device implantation

Background

Implantable cardioverter-defibrillation (ICD) shocks after left ventricular assist device therapy (LVAD) are associated with adverse clinical outcomes. Little is known about the association of pre-LVAD ICD shocks on post-LVAD clinical outcomes and whether LVAD therapy affects the prevalence of ICD shocks.

Objectives

The purpose of this study was to determine whether pre-LVAD ICD shocks are associated with adverse clinical outcomes post-LVAD and to compare the prevalence of ICD shocks before and after LVAD therapy.

Methods

Patients 18 years or older with continuous-flow LVADs and ICDs were retrospectively identified within the University of Pittsburgh Medical Center system from 2006-2020. We analyzed the association between appropriate ICD shocks within 1 year pre-LVAD with a primary composite outcome of death, stroke, and pump thrombosis and secondary outcomes of post-LVAD ICD shocks and ICD shock hospitalizations.

Results

Among 309 individuals, average age was 57 ± 12 years, 87% were male, 80% had ischemic cardiomyopathy, and 42% were bridge to transplantation. Seventy-one patients (23%) experienced pre-LVAD shocks, and 69 (22%) experienced post-LVAD shocks. The overall prevalence of shocks pre-LVAD and post-LVAD were not different. Pre-LVAD ICD shocks were not associated with the composite outcome. Pre-LVAD ICD shocks were found to predict post-LVAD shocks (hazard ratio [HR] 5.7; 95% confidence interval [CI] 3.42-9.48; P <.0001) and hospitalizations related to ICD shocks from ventricular arrhythmia (HR 10.34; 95% CI 4.1-25.7; P <.0001).

Conclusion

Pre-LVAD ICD shocks predicted post-LVAD ICD shocks and hospitalizations but were not associated with the composite outcome of death, pump thrombosis, or stroke at 1 year. The prevalence of appropriate ICD shocks was similar before and after LVAD implantation in the entire cohort.

Amplitude spectral area of ventricular fibrillation and defibrillation success at low energy in out-of-hospital cardiac arrest

The optimal energy for defibrillation has not yet been identified and very often the maximum energy is delivered. We sought to assess whether amplitude spectral area (AMSA) of ventricular fibrillation (VF) could predict low energy level defibrillation success in out-of-hospital cardiac arrest (OHCA) patients. This is a multicentre international study based on retrospective analysis of prospectively collected data. We included all OHCAs with at least one manual defibrillation. AMSA values were calculated by analyzing the data collected by the monitors/defibrillators used in the field (Corpuls 3 and Lifepak 12/15) and using a 2-s-pre-shock electrocardiogram interval. We run two different analyses dividing the shocks into three tertiles (T1, T2, T3) based on AMSA values. 629 OHCAs were included and 2095 shocks delivered (energy ranging from 100 to 360 J; median 200 J). Both in the "extremes analysis" and in the "by site analysis", the AMSA values of the effective shocks at low energy were significantly higher than those at high energy (p = 0.01). The likelihood of shock success increased significantly from the lowest to the highest tertile. After correction for age, call to shock time, use of mechanical CPR, presence of bystander CPR, sex and energy level, high AMSA value was directly associated with the probability of shock success [T2 vs T1 OR 3.8 (95% CI 2.5-6) p < 0.001; T3 vs T1 OR 12.7 (95% CI 8.2-19.2), p < 0.001]. AMSA values are associated with the probability of low-energy shock success so that they could guide energy optimization in shockable cardiac arrest patients.

Effectiveness of rescue Me CPR! smartphone app providing real-time guidance to untrained bystanders performing CPR

Background

Out-of-hospital cardiac arrest (OHCA) is a persistent global health challenge, owing, in part, to low rates of population CPR training. Smartphone applications have the potential to widely disseminate CPR basic training to a populace, but other studies have found multiple limitations in previously developed CPR guidance applications (CPR-GA). This study aims to use medical simulation to assess the relative CPR performance of novices using the 'Rescue Me CPR!' (RMC) app, a custom CPR-GA designed by this research team, to novices using 'PG-CPR!' (PGC), the most downloaded CPR-GA available in the USA, and to CPR certified medical personnel.

Methods

In a prospective randomized experimental trial of 60 individuals, subjects were either given the RMC app, the PGC app, or had active CPR certification. They were presented a cardio-pulmonary arrest scenario and were observed while performing CPR on a high-fidelity manikin. Data was collected through four cycles of CPR, during which time 24 pertinent performance metrics and CPR steps were timed and recorded. These metrics were assessed on their own and used to calculate average time to compressions, average chest compression fraction, and rate of high-quality CPR for each study group.

Results

CPR certified subjects called 911 in 100 % of simulation cases, started compressions 34 ± 10 s after first seeing the simulated patient, had an average chest compression fraction of 0.52, and performed high-quality CPR in 25 % of aggregate compression cycles. PGC app users called 911 in 70 % of simulation cases, started compressions 86 ± 17 s after first seeing the simulated patient, had an average chest compression fraction that could not be assessed due to inconsistent pauses during CPR, and performed high-quality CPR in 2.5 % of aggregate compression cycles. RMC app users called 911 in 100 % of simulation cases, started compressions 55 ± 6 s after first seeing the simulated patient, had an average chest compression fraction of 0.48, and performed high-quality CPR in 50 % of aggregate compression cycles.

Conclusion

The results of this study demonstrate that in all studied metrics, except time-to-first-compression, CPR provided by individuals using the RMC app is statistically equivalent or superior to CPR performed by a CPR certified individual and, in almost every metric, superior to CPR performed by users of the most downloaded android CPR guidance application, PG-CPR.

Amplitude spectrum area measured in real-time during cardiopulmonary resuscitation - How does this technology work?

Amplitude spectrum area (AMSA) is one of the most accurate predictors of defibrillation outcome. Details on functioning and use of the available technology to measure AMSA during cardiopulmonary resuscitation (CPR) in the real clinical scenario are described. During chest compression (CC) pauses for ventilations, AMSA is promptly calculated and values displayed through a modified defibrillator. In addition, real-time AMSA analysis has the additional promise to monitor CPR quality, being AMSA threshold values contingent on CC depth. Future larger studies employing this new technology are now needed to demonstrate the impact of AMSA on survival of cardiac arrest.

A novel artificial intelligence based algorithm to reduce wearable cardioverter-defibrillator alarms

BACKGROUND

The wearable cardioverter defibrillator (WCD) is an important tool in mitigating sudden cardiac death (SCD). The WCD provides patient alarms for detected arrhythmias or electrical noise/artifact. Some patients experience frequent alarms for artifact. We sought to evaluate the effects of a novel artificial intelligence algorithm to reduce alarms related to electrical noise or artifact (advanced arrhythmia discrimination algorithm, AArD).

METHODS

A retrospective review of a large commercial database of prescribed WCD. Patients prescribed the WCD during the years 2017 (discrimination algorithm, DA group) or during 2019 (advanced arrhythmia discrimination algorithm, AArD) were analyzed. A total of 96,000 patients were sampled, 48,000 in the control group (using standard direct algorithm, DA) and compared to 48,000 in the intervention AArD (4000 per group per month) for 12 months. The AArD further discriminates ECG signals based on a machine-learning algorithm utilizing intensity and frequency beyond the standard DA. Outcomes regarding alarms, arrhythmias, and safety were analyzed.

RESULTS

The AArD algorithm was associated with a significant decrease in frequency of alarms over the course of WCD use; 54% of patients in the AARD versus 27% of DA had 0 alarms (P < .001). In the entire cohort, there was a 56% relative reduction in alarms with the use of AArD. Appropriate arrhythmia treatment time was not significantly different between the groups (44 s DA vs 45 s AArD [p = ns]).

CONCLUSIONS

A novel artificial intelligence algorithm reduces alarms without delaying appropriate therapy for VT/VF. These changes may improve compliance and quality of life in patients with a WCD.

Police as first reponders improve out-of-hospital cardiac arrest survival

BACKGROUND

Police forces are abundant circulating and might arrive before the emergency services to Out-of-Hospital-Cardiac-Arrest victims. If properly trained, they can provide basic life support and early defibrillation within minutes, probably increasing the survival of the victims. We evaluated the impact of local police as first responders on the survival rates of out-of-hospital cardiac arrest victims in Navarra, Spain, over 7 years.

METHODS

A retrospective analysis of an ongoing Out-of-Hospital Cardiac registry to compare the characteristics and survival of Out-of-Hospital-Cardiac-Arrest victims attended to in first place by local police, other first responders, and emergency ambulance services between 2014 and 2020.

RESULTS

Of 628 cases, 73.7% were men (aged 68.9 ± 15.8), and 26.3% were women (aged 65,0 ± 14,7 years, p < 0.01). Overall survival of patients attended to by police in the first place was 17.8%, other first responders 17.4% and emergency services 13.5% with no significant differences (p > 0.1). Time to initiating cardiopulmonary resuscitation is significant for survival. When police arrived first and started CPR before the emergency services, they arrived at a mean of 5.4 ± 3 min earlier (SD = 3.10). This early police intervention showed an increase in the probability of survival by 10.1%.

CONCLUSIONS

The privileged location and the sole amount of personnel of local police forces trained in life support and their fast delivery of defibrillators as first responders can improve the survival of out-of-hospital cardiac arrest victims.

Instantaneous amplitude: Association of ventricular fibrillation waveform measures at time of shock with outcome in out-of-hospital cardiac arrest

BACKGROUND

Prompt defibrillation is key to successful resuscitation from ventricular fibrillation out-of-hospital cardiac arrest (VF-OHCA). Preliminary evidence suggests that the timing of shock relative to the amplitude of the VF ECG waveform may affect the likelihood of resuscitation. We investigated whether the VF waveform amplitude at the time of shock (instantaneous amplitude) predicts outcome independent of other validated waveform measures.

METHODS

We conducted a retrospective study of VF-OHCA patients ≥18 old. We evaluated three VF waveform measures for each shock: instantaneous amplitude at the time of shock, and maximum amplitude and amplitude spectrum area (AMSA) over a 3-s window preceding the shock. Linear mixed-effects modeling was used to determine whether instantaneous amplitude was associated with shock-specific return of organized rhythm (ROR) or return of spontaneous circulation (ROSC) independent of maximum amplitude or AMSA.

RESULTS

The 566 eligible patients received 1513 shocks, resulting in ROR of 62.0% (938/1513) and ROSC of 22.3% (337/1513). In unadjusted regression, an interquartile increase in instantaneous amplitude was associated with ROR (Odds ratio [OR] [95% confidence interval] = 1.27 [1.11-1.45]) and ROSC (OR = 1.27 [1.14-1.42]). However, instantaneous amplitude was not associated with ROR (OR = 1.13 [0.97-1.30]) after accounting for maximum amplitude, nor with ROR (OR = 1.00 [0.87-1.15]) or ROSC (OR = 1.05 [0.93-1.18]) after accounting for AMSA. By contrast, AMSA and maximum amplitude remained independently associated with ROR and ROSC.

CONCLUSIONS

We did not observe an independent association between instantaneous amplitude and shock-specific outcomes. Efforts to time shock to the maximal amplitude of the VF waveform are unlikely to affect resuscitation outcome.

Evaluation of junior doctors' retention of knowledge and skills after simulation training in shockable rhythm cardiac arrest in a low-resource setting in Nepal

Aims

To test junior doctors' abilities to retain advanced life support psychomotor skills and theoretical knowledge in management of shockable rhythm cardiac arrest.

Methods

A repeated measure pre-post study design was used with 43 junior doctors, recruited after notifying them with robust method of attraction through flyers, brochures, email and phone calls. Written and performance tests, initial pre-test, immediate post-training, 30-days post-training and 60-days post-training, using simulation-based scenarios with a low-fidelity manikin were used with recording performance of ALS.

Instrumentation

Resuscitation Council UK ALS algorithms and guidelines1 were used in a simulated testing environment.

Results

There was a highly significant improvement in knowledge immediately after training (p < 0.00), with a net gain of marks from a mean value of 63.2% before training to 87.7% after training by 24.5% (95% CI 19.4, 29.6).There was a gradual decline of retained knowledge with time from immediate post-training over, 30-days and 60-days post-training (p < 0.00). The simulation pre-training assessments and immediate post-training assessments results were statistically significant (p < .00). The mean difference was 44.1% (95% CI 50.11, 38.10). There was a statistically significant decline of the competency with time (p < .00). Unlike for the knowledge test, the drop was significant on the 30th day (p < .00) with a mean difference of -10.5% (95% CI -13.55, -7.40).

Conclusion

The training of junior doctors in shockable rhythm cardiac arrest in a low resource setting, improved knowledge and skills in the participants after training. However, retention of knowledge declined at 30 days and more significantly after 60 days and retention of skill was declined more significantly at 30 days.

Defibrillation in the Cardiac Arrest Patient

Defibrillation is one of the few interventions known to favorably impact survival in cardiac arrest. In witnessed arrest, survival improves with defibrillation as early as possible, whereas it may improve outcomes to administer high-quality chest compressions for 90 seconds before defibrillation in unwitnessed arrest. Minimizing pre-, peri-, and post-shock pauses has been shown to have mortality benefits. Refractory ventricular fibrillation has high mortality rates, and there is ongoing research into promising adjunctive treatment modalities. There remains no consensus on optimal pad positioning and defibrillation energy level, however, recent data suggest anteroposterior pad placement may be superior to anterolateral placement.

Exploiting SMART pass filter deactivation detection to minimize inappropriate subcutaneous implantable cardioverter defibrillator therapies: a real-world single-centre experience and management guide

AIMS

The SMART Pass™ (SP) algorithm is a high-pass filter that aims to reduce inappropriate therapy (IT) in subcutaneous internal cardiac defibrillator (S-ICD), but SP can deactivate due to low amplitude sensed R waves or asystole. The association between IT and SP deactivation and management strategies were evaluated, hypothesizing SP deactivation increases the risk of IT and device re-programming, or lead/generator re-positioning could reduce this risk.

METHODS AND RESULTS

Retrospective single-centre audit of Emblem™ S-ICD devices implanted 2016 to 2020 utilizing health records and remote monitoring data. Cox regression models evaluated associations between SP deactivation and IT. A total of 348 patients (27 ± 16.6 months follow-up) were studied: 73% primary prevention. Thirty-eight patients (11.8%) received 83 shocks with 27 patients (7.8%) receiving a total of 44 IT. Causes of IT were oversensing (98%) and aberrantly conducted atrial fibrillation (2%). SP deactivation occurred in 32 of 348 patients (9%) and was significantly associated with increased risk of IT (hazard ratio 5.36, 95% CI 2.37-12.13). SP deactivation was due to low amplitude R waves (94%), associated with a higher defibrillation threshold at implant and presence of arrhythmogenic right ventricular cardiomyopathy. No further IT occurred 16 ± 15.5 months after corrective interventions, with changing the sensing vector being successful in 59% of cases.

CONCLUSION

To reduce the risk of IT, the cause of the SP deactivation should be investigated, and appropriate reprogramming, device, or lead modifications made. Utilizing the alert for SP deactivation and electrograms could pro-actively prevent IT.

Causes and Clinical Consequences of Inappropriate Shocks Experienced by Patients Wearing a Cardioverter-Defibrillator

BACKGROUND

The LifeVest® wearable cardioverter-defibrillator (WCD) prevents sudden cardiac death in at-risk patients who are not candidates for an implantable defibrillator. The WCD's safety and efficacy may be impacted by inappropriate shocks (IAS).

OBJECTIVE

Assess causes and clinical consequences of WCD inappropriate shocks in survivors of IAS events.

METHODS

The FDA Manufacturers and User Facility Device Experience (MAUDE) database was searched for IAS adverse events (AE) that were reported during 2021 and 2022.

RESULTS

A total of 2,568 IAS-AE were found (average # IAS/event: 1.5±1.9; range: 1-48). IAS were caused by tachycardias (1,255, 48.9%), motion artifacts (840, 32.7%), and oversensing (OS) of low-level electrical signals (473, 18.4%) (p<0.001). Tachycardias included atrial fibrillation (AF; 828,32.2%), supraventricular tachycardia (SVT; 333,13.0%), and non-sustained ventricular tachycardia/fibrillation (NSVT/VF; 87, 3.4%). Activities responsible for motion-induced IAS included riding a motorcycle, lawnmower, or tractor (n=128). IAS induced sustained VT or VF in 19 patients that were subsequently terminated by appropriate WCD shocks.Thirty patients fell and suffered physical injuries. Conscious patients (n=1905) did not use the response buttons to abort shocks (47.9%) or used them improperly (20.2%). IAS resulted in 1,190 emergency room visits or hospitalizations, and 17.3% (421/2440) of patients discontinued the WCD after experiencing IAS, especially multiple IAS.

CONCLUSIONS

The LifeVest WCD may deliver IAS caused by AF, SVT, NSVT/VF, motion artifacts and oversensing of electrical signals. These shocks may be arrhythmogenic, result in injuries, precipitate WCD discontinuation, and they consume medical resources. Improved WCD sensing, rhythm discrimination, and methods to abort IAS are needed.

Electrical Stimulation for Low-Energy Termination of Cardiac Arrhythmias: a Review

Cardiac arrhythmias are a leading cause of morbidity and mortality in the developed world, estimated to be responsible for hundreds of thousands of deaths annually. Our understanding of the electrophysiological mechanisms of such arrhythmias has grown since they were formally characterized in the late nineteenth century, and this has led to the development of numerous devices and therapies that have markedly improved outcomes for patients affected by such conditions. Despite these advancements, the application of a single large shock remains the clinical standard for treating deadly tachyarrhythmias. Such defibrillating shocks are undoubtedly effective in terminating such arrhythmias; however, they are applied without forewarning, contributing to the patient's stress and anxiety; they can be intensely painful; and they can have adverse psychological and physiological effects on patients. In recent years, there has been interest in developing defibrillation protocols that can terminate arrhythmias without crossing the human pain threshold for energy delivery, generally estimated to be between 0.1 and 1 J. In this article, we review existing literature on the development of such low-energy defibrillation methods and their underlying mechanisms, in an attempt to broadly describe the current landscape of these technologies.

The ability of machine learning algorithms to predict defibrillation success during cardiac arrest: A systematic review

OBJECTIVE

To evaluate the existing knowledge on the effectiveness of machine learning (ML) algorithms inpredicting defibrillation success during in- and out-of-hospital cardiac arrest.

METHODS

MEDLINE, Embase, CINAHL and Scopus were searched from inception to August 30, 2022. Studies were included that utilized ML algorithms for prediction of successful defibrillation, observed as return of spontaneous circulation (ROSC), survival to hospital or discharge, or neurological status at discharge.Studies were excluded if involving a trauma, an unknown underlying rhythm, an implanted cardiac defibrillator or if focused on the prediction or onset of cardiac arrest. Risk of bias was assessed using the PROBAST tool.

RESULTS

There were 2399 studies identified, of which 107 full text articles were reviewed and 15 observational studies (n = 5680) were included for final analysis. 29 ECG waveform features were fed into 15 different ML combinations. The best performing ML model had an accuracy of 98.6 (98.5 - 98.7)%, with 4 second ECG intervals. An algorithm incorporating end-tidal CO2 reported an accuracy of 83.3% (no CI reported). Meta-analysis was not performed due to heterogeneity in study design, ROSC definitions, and characteristics.

CONCLUSION

Machine learning algorithms, specifically Neural Networks, have been shown to have potential to predict defibrillation success for cardiac arrest with high sensitivity and specificity.Due to heterogeneity, inconsistent reporting, and high risk of bias, it is difficult to conclude which, if any, algorithm is optimal. Further clinical studies with standardized reporting of patient characteristics, outcomes, and appropriate algorithm validation are still required to elucidate this. PROSPERO 2020 CRD42020148912.

Automated external defibrillator electrode size and termination of ventricular fibrillation in out-of-hospital cardiac arrest

Smaller electrodes allow more options for design of automated external defibrillator (AED) user interfaces. However, previous studies employing monophasic-waveform defibrillators found that smaller electrode sizes have lower defibrillation shock success rates. We hypothesize that, for impedance-compensated, biphasic truncated exponential (BTE) shocks, smaller electrodes increase transthoracic impedance (TTI) but do not adversely affect defibrillation success rates. METHODS AND RESULTS: In this prospective before-and-after clinical study, Amsterdam police and firefighters used AEDs with BTE waveforms: an AED with larger electrodes in 2016-2017 (113 cm²), and an AED with smaller electrodes in 2017-2020 (65 cm²). We analyzed 157 and 178 patient cases with an initial shockable rhythm where the larger and smaller electrodes were used, respectively. A single 200-J shock terminated ventricular fibrillation (VF) in 86% of patients treated with large electrodes and 89% of patients treated with smaller electrodes. Small electrodes had a non-inferior first shock defibrillation success rate compared to large electrodes, with a difference of 3% (95% CI: -3% -9%) with the lower confidence limit remaining above the defined non-inferiority threshold. TTI was significantly higher for the smaller electrodes (median: 100 Ω) compared to the larger electrodes (median: 88 Ω) (p < 0.001). CONCLUSIONS: For AEDs with impedance-compensating BTE waveforms, TTI was higher for smaller electrodes than the large electrode electrodes. Overall defibrillation shock success for AEDs with smaller electrodes was non-inferior to the AEDs with larger electrodes.

AED delivery at night - Can drones do the Job? A feasibility study of unmanned aerial systems to transport automated external defibrillators during night-time

BACKGROUND

In their recent guidelines the European Resuscitation Council have recommended the use of Unmanned Aerial systems (UAS) to overcome the notorious shortage of AED. Exploiting the full potential of airborne AED delivery would mandate 24 h UAS operability. However, current systems have not been evaluated for nighttime use. The primary goal of our study was to evaluate the feasibility of night-time AED delivery by UAS. The secondary goal was to obtain and compare operational and safety data of night versus day missions.

METHODS

We scheduled two (one day, one night) flights each to ten different locations to assess the feasibility of AED delivery by UAS during night-time. We also compared operational data (mission timings) and safety data (incidence of critical events) of night versus day missions.

RESULTS

All missions were completed without safety incident. The flights were performed automatically without pilot interventions, apart from manually choosing the landing site and correcting the descent. Flight distances ranged from 910 m to 6.960 m, corresponding mission times from alert to AED release between 3:48 min and 11:20 min. Night missions (T¯_m:night = 7:26 ± 2:29 min) did not take longer than day missions (T¯_m:day = 7:59 ± 2:27 min). Despite slightly inferior visibility of the target site, night landings (T¯_land:night = 64 ± 15 sec) were on average marginally quicker than day landings (T¯_land:day = 69 ± 11sec).

CONCLUSIONS

Our results demonstrate the feasibility of UAS supported AED delivery during nighttime. Operational and safety data indicate no major differences between day- and night-time use. Future research should focus on integration of drone technology into the chain of survival.

Impact of defibrillation with automated external defibrillator by bystander before defibrillation by emergency medical system personnel on neurological outcome of out-of-hospital cardiac arrest with non-cardiac etiology

Aim of the study

Although defibrillation using automated external defibrillator (AED) by bystander prior to emergency medical system (EMS) arrival was associated with favorable outcomes in out-of-hospital cardiac arrest (OHCA) of cardiac cause, whether it improves outcomes of OHCA due to non-cardiac cause is not clear. We aimed to investigate the impact of defibrillation with AED by bystander before defibrillation by EMS personnel on the outcomes of OHCA of presumed non-cardiac cause.

Methods

This was a retrospective cohort study using the All-Japan Utstein registry (reference period: 2013 to 2017). We included adult patients with OHCA of presumed non-cardiac cause, who had initial shockable rhythm, and who received witnessed arrest bystander cardiopulmonary resuscitation (CPR). Exposure variable was defibrillation with AED by bystander in comparison with initial defibrillation by EMS. Logistic regression analyses were conducted to assess the association between bystander AED shock and favorable neurological outcome (Cerebral Performance Category scale 1 or 2) at one month.

Results

Among the 1,053 patients included for analysis, 57 (5.4%) received bystander AED shock. There was no statistically significant difference in the rate of favorable neurological outcome at one month between groups [9 (15.8%) vs 109 (10.9%), p = 0.26]. Logistic regression analysis adjusted for characteristics, intervention, and time course of CPR showed no association between bystander AED shock and favorable neurological outcome [OR (95% CI): 1.63 (0.70-3.77), p = 0.25].

Conclusion

In this study, defibrillation with AED by bystander before defibrillation by EMS personnel was not associated with the favorable outcomes of OHCA of presumed non-cardiac cause.

Esmolol, vector change, and dose-capped epinephrine for prehospital ventricular fibrillation or pulseless ventricular tachycardia

BACKGROUND

Refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT) cardiac arrest describes a subset of patients who do not respond to standard Advanced Cardiac Life Support (ACLS) interventions and are associated with poor outcomes. Esmolol administration and vector change defibrillation have shown promise in improving outcomes in these patients, however evidence is limited.

OBJECTIVES

This study compares clinical outcomes between patients with prehospital refractory VF/pVT who received an Emergency Medical Service (EMS) bundle, comprised of esmolol administration, vector change defibrillation, and dose-capped epinephrine at 3 mg, to patients who received standard ACLS interventions.

METHODS

This multicenter, retrospective, cohort study evaluated medical records between October 18, 2017 and March 15, 2022. Patients were enrolled if they experienced a prehospital cardiac arrest with the rhythm VF or pVT, had received at least three standard defibrillations, at least 3 mg of epinephrine, and 300 mg of amiodarone. Patients who received the EMS bundle after its implementation were compared to patients who received standard ACLS interventions prior to its implementation. The primary outcome was sustained return of spontaneous circulation (ROSC), defined as ROSC lasting 20 min without recurrence of cardiac arrest. Secondary outcomes included the incidence of any ROSC, survival to hospital arrival, survival at hospital discharge, and neurologically intact survival at hospital discharge.

RESULTS

Eighty-three patients were included in the study. Thirty-six were included in the pre-EMS bundle group and 47 patients were included in the post-EMS bundle group. Patients in the pre-EMS bundle group achieved significantly higher rates of sustained ROSC (58.3% vs 17%, p < 0.001), any ROSC (66.7% vs 19.1%, p < 0.001), and survival to hospital arrival (55.6% vs 17%, p < 0.001). The rates of survival to hospital discharge (16.7% vs 6.4%, p = 0.17) and neurologically intact survival at hospital discharge (5.9% vs 4.3%, p = 1.00) were not significantly different between groups.

CONCLUSIONS

Patients who received the EMS bundle achieved sustained ROSC significantly less often and were less likely to have pulses at hospital arrival. The incidence of neurologically intact survival was low and similar between groups.

Annual improvement trends in resuscitation outcome of patients defibrillated by laypersons after out-of-hospital cardiac arrests and compression-only resuscitation of laypersons

AIM

We aimed to investigate the effect of compression-only cardiopulmonary resuscitation (CPR) with conventional CPR in patients who were defibrillated by laypersons.

METHODS

This is a population-based, nationwide observational study. Adult and children who sustained a witnessed out-of-hospital cardiac arrest and defibrillated by laypersons between 2005 to 2019 were identified on the national database. The study used trend analyses, multivariate logistic regression, and inverse probability weighting using propensity score to explore changes in one-month survival and survival with a good neurological outcome over time and the influence of compression-only CPR compared with conventional CPR.

RESULTS

In total, 11,402 patients defibrillated by laypersons were enrolled in this study. The percentages of compression-only resuscitation increased dramatically and more than 50% from 2012 (P < 0.001). The percentages of cases with favorable resuscitation outcomes also increased annually (P < 0.001). By regression analysis, favorable outcomes were associated with recent years, male sex, younger age, and shorter resuscitation start time. In addition, the adjusted odds ratio of compression-only CPR to conventional CPR was 1.23 with a 95% confident interval 1.13-1.34. By inverse probability weighting, compression-only CPR was superior to conventional CPR for the favorable outcomes (P < 0.001). The adjusted outcomes in each year were better in compression-only resuscitation in most of the years. The overall relative risk reduction and the number needed to treat for compression-only resuscitation compared with conventional resuscitation were 7.6% and 22.1, respectively.

CONCLUSIONS

In Japan, the outcomes of out-of-hospital cardiac arrest patients who were defibrillated by laypersons were considerably better in compression-only resuscitation of laypersons every year.

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.

Current summary of the evidence in drone-based emergency medical services care

Interventions for many medical emergencies including cardiac arrests, strokes, drug overdoses, seizures, and trauma, are critically time-dependent, with faster intervention leading to improved patient outcomes. Consequently, a major focus of emergency medical services (EMS) systems and prehospital medicine has been improving the time until medical intervention in these time-sensitive emergencies, often by reducing the time required to deliver critical medical supplies to the scene of the emergency. Medical indications for using unmanned aerial vehicles, or drones, are rapidly expanding, including the delivery of time-sensitive medical supplies. To date, the drone-based delivery of a variety of time-critical medical supplies has been evaluated, generating promising data suggesting that drones can improve the time interval to intervention through the rapid delivery of automatic external defibrillators (AEDs), naloxone, antiepileptics, and blood products. Furthermore, the improvement in the time until intervention offered by drones in out-of-hospital emergencies is likely to improve patient outcomes in time-dependent medical emergencies. However, barriers and knowledge gaps remain that must be addressed. Further research demonstrating functionality in real-world scenarios, as well as research that integrates drones into the existing EMS structure will be necessary before drones can reach their full potential. The primary aim of this review is to summarize the current evidence in drone-based Emergency Medical Services Care to help identify future research directions.

Subcutaneous implantable cardioverter-defibrillator implantation position predicts successful defibrillation in obese and non-obese patients

BACKGROUND

Subcutaneous implantable cardioverter-defibrillators (S-ICD) are an alternative to transvenous ICDs for patients without a need for cardiac pacing. Obese patients have been proposed to be at higher risk for conversion failure with S-ICDs due to subcutaneous fat underneath the device. Optimal device positioning may promote equivalent outcomes between obese and non-obese patients by minimizing the effects of excess adipose tissue.

METHODS

A retrospective analysis of patients undergoing defibrillation testing at the time of S-ICD implantation was performed. The primary endpoint was the rate of successful conversion of ventricular fibrillation (VF) at the time of implant. The secondary endpoint was shock impedance.

RESULTS

A total of 184 patients were included in the study. The rate of successful conversion of VF was 90.3% for obese patients (n = 72) and 96.4% for non-obese patients (n = 112) (p = 0.086). Compared to non-obese patients, obese patients had a higher mean PRAETORIAN score (78.5 ± 58.1 vs. 48.8 ± 35.5, p < 0.001) and higher measured mean impedance (82.0 ohms ± 26.5 vs. 69.8 ohms ± 19.3, p < 0.001). Patients with a PRAETORIAN score < 90 all had successful defibrillation testing regardless of BMI.

CONCLUSIONS

In this study, a PRAETORIAN score < 90 was associated with a 100% success rate of defibrillation testing following S-ICD implantation regardless of patient body mass index (BMI). Thus, the impact of obesity on impedance and the risk of failed shocks may be minimized with close attention to implantation technique to achieve a low PRAETORIAN score.

Detection and modulation of neurodegenerative processes using graphene-based nanomaterials: Nanoarchitectonics and applications

Neurodegenerative disorders (NDDs) are caused by progressive loss of functional neurons following the aggregation and fibrillation of proteins in the central nervous system. The incidence rate continues to rise alarmingly worldwide, particularly in aged population, and the success of treatment remains limited to symptomatic relief. Graphene nanomaterials (GNs) have attracted immense interest on the account of their unique physicochemical and optoelectronic properties. The research over the past two decades has recognized their ability to interact with aggregation-prone neuronal proteins, regulate autophagy and modulate the electrophysiology of neuronal cells. Graphene can prevent the formation of higher order protein aggregates and facilitate the clearance of such deposits. In this review, after highlighting the role of protein fibrillation in neurodegeneration, we have discussed how GN-protein interactions can be exploited for preventing neurodegeneration. A comprehensive understanding of such interactions would contribute to the exploration of novel modalities for controlling neurodegenerative processes.