Sex differences in the association of comorbidity with shockable initial rhythm in out-of-hospital cardiac arrest.

BACKGROUND: Lower survival chances after out-of-hospital cardiac arrest (OHCA) in women is associated with lower odds of a shockable initial rhythm (SIR). We hypothesized that sex differences in the prevalence of SIR are due to sex differences in comorbidities. We aimed to establish to what extent sex differences in the cumulative comorbidity burden, measured using the Charlson Comorbidity Index (CCI), or in individual comorbidities, account for the lower proportion of SIR in women. METHODS: The association between CCI or its constituent comorbidities, and presence of SIR was studied using data (2010-2014) from a Dutch community-based OHCA registry, and included 2510 OHCA patients aged ≥18y with presumed cardiac cause. RESULTS: The mean age was 67.8 ± 13.8y, 71% were men. Women were more often in high CCI categories than men. However, moderate or high disease burden was associated with lower odds of SIR compared to no disease burden only in men (OR 99 %CI 0.73 [0.53-1.00] and OR 0.54 [0.37-0.80] P-trend < 0.001), but not in women (1.00 [0.58-1.72] and 1.02 [0.57-1.84 P-trend 0.93). Adding CCI to a multivariable model did not alter the OR of sex with SIR. Of the individual comorbidities, only previous myocardial infarction was both differently distributed between sexes (men 22.7% vs. women 13.1%, p < 0.001) and associated with odds of SIR (higher in both sexes). Adding this variable to the model changed the association of sex with initial rhythm from 0.49 (0.38-0.64) to 0.53 (0.41-0.69). CONCLUSION: Sex differences in comorbidities explained lower odds of SIR in women only modestly: differences in previous myocardial infarction contributed little, and cumulative comorbidity not at all.

To transport or to terminate resuscitation on-site. What factors influence EMS decisions in patients without ROSC? A mixed-methods study.

BACKGROUND: If a patient in out-of-hospital cardiac arrest (OHCA) does not achieve return of spontaneous circulation (ROSC) despite advanced life support, emergency medical services can decide to either transport the patient with ongoing CPR or terminate resuscitation on scene. PURPOSE: To determine differences between patients without ROSC to be transported vs. terminated on scene and explore medical and nonmedical factors that contribute to the decision-making of paramedics on scene. METHODS: Mixed-methods approach combining quantitative and qualitative data. Quantitative data on all-cause OHCA patients without ROSC on scene, between January 1, 2012, and December 31, 2016, in the Amsterdam Resuscitation Study database, were analyzed to find factors associated with decision to transport. Qualitative data was collected by performing 16 semi-structured interviews with paramedics from the study region, transcribed and coded to identify themes regarding OHCA decision-making on the scene. RESULTS: In the quantitative Utstein dataset, of 5870 OHCA patients, 3190 (54%) patients did not achieve ROSC on scene. In a multivariable model, age (OR 0.98), public location (OR 2.70), bystander witnessed (OR 1.65), EMS witnessed (OR 9.03), and first rhythm VF/VT (OR 11.22) or PEA (OR 2.34), were independently associated with transport with ongoing CPR. The proportion of variance explained by the model was only 0.36. With the qualitative method, four main themes were identified: patient-related factors, local circumstances, paramedic-related factors, and the structure of the organization. CONCLUSION: In patients without ROSC on scene, besides known resuscitation characteristics, the decision to transport a patient is largely determined by non-protocollized factors.

Analyzing the heart rhythm during chest compressions: Performance and clinical value of a new AED algorithm.

PURPOSE: Automated external defibrillators (AED) prompt the rescuer to stop chest compressions (CC) for ECG analysis during out-of-hospital cardiac arrest (OHCA). We assessed the diagnostic accuracy and clinical benefit of a new AED algorithm (cprINSIGHT), which analyzes ECG and impedance signals during CC, allowing rhythm analysis with ongoing chest compressions. METHODS: Amsterdam Police and Fire Fighters used a conventional AED in 2016-2017 (control) and an AED with cprINSIGHT in 2018-2019 (intervention). In the intervention AED, cprINSIGHT was activated after the first (conventional) analysis. This algorithm classified the rhythm as "shockable" (S) and "non-shockable" (NS), or "pause needed". Sensitivity for S, specificity for NS with 90% lower confidence limit (LCL), chest compression fractions (CCF) and pre-shock pause were compared between control and intervention cases accounting for multiple observations per patient. RESULTS: Data from 465 control and 425 intervention cases were analyzed. cprINSIGHT reached a decision during CC in 70% of analyses. Sensitivity of the intervention AED was 96%, (LCL 93%) and specificity was 98% (LCL 97%), both not significantly different from control. Intervention cases had a shorter median pre-shock pause compared to control cases (8 s vs 22 s, p < 0.001) and higher median CCF (86% vs 80%, P < 0.001). CONCLUSION: AEDs with cprINSIGHT analyzed the ECG during chest compressions in 70% of analyses with 96% sensitivity and 98% specificity when it made a S or a NS decision. Compared to conventional AEDs, cprINSIGHT leads to a significantly shorter pre-shock pause and a significant increase in CCF.

Time to Return of Spontaneous Circulation and Survival: When to Transport in out-of-Hospital Cardiac Arrest?

BACKGROUND: In out-of-hospital cardiac arrest (OHCA), 10-50% of patients have return of spontaneous circulation (ROSC) before hospital arrival. It is important to investigate the relation between time-to-ROSC and survival to determine the optimal timing of transport to the hospital in patients without ROSC. Methods: We analyzed data of OHCA patients with a presumed cardiac cause (excluding traumatic and other obvious non-cardiac causes) and ROSC before hospital arrival from the Amsterdam Resuscitation Study (ARREST) database. ROSC included those patients whose ROSC was persistent or transient before or during transport, lasting ≥1 min. Of these data, we analyzed the association between the time of emergency medical services (EMS) arrival until ROSC (time-to-ROSC) and 30-day survival. Results: Of 3632 OHCA patients with attempted resuscitation, 810 patients with prehospital ROSC were included. Of these, 332 (41%) survived 30 days. Survivors had a significant shorter time-to-ROSC compared to non-survivors of median 5 min (IQR 2,10) vs. median 12 min (IQR 9,17) (p < 0.001). Of the survivors, 90% achieved ROSC within 15 min compared to 22 min of non-survivors. In a multivariable model adjusted for known system determinants time-to-ROSC per minute was significantly associated with 30-day survival (OR 0.89; 95%CI 0.86-0.91). A ROC curve showed 8 min as the time-to-ROSC with the best test performance (sensitivity of 0.72 and specificity of 0.77). Conclusion: In OHCA patients with prehospital ROSC survival significantly decreases with increasing time-to-ROSC. Of all patients, 90% of survivors had achieved ROSC within the first 15 min of EMS resuscitation. The optimal time for the decision to transport is between 8 and 15 min after EMS arrival.

Comorbidity and survival in the pre-hospital and in-hospital phase after out-of-hospital cardiac arrest.

INTRODUCTION: Cumulative disease burden may be associated with survival chances after out-of-hospital cardiac arrest (OHCA). The relative contributions of cumulative disease burden on survival rates at the pre-hospital and in-hospital phases of post-resuscitation care are unknown. METHODS: The association between cumulative comorbidity burden as measured by the Charlson Comorbidity Index (CCI) and pre-hospital and in-hospital survival rates was studied using data (2010-2014) from a prospective OHCA registry in the Netherlands. The association between CCI and survival rate (overall survival [OHCA-hospital discharge], pre-hospital survival [OHCA-hospital admission] and in-hospital survival [hospital admission-hospital discharge]) was assessed using logistic regression analyses. The relative contributions of CCI on pre-hospital and in-hospital survival rates were determined using the Nagelkerke test. RESULTS: We included 2510 OHCA patients aged ≥18y. CCI was significantly associated with overall survival rate (OR 0.71; 95%CI 0.61-0.83; P < 0.01). CCI was not associated with pre-hospital survival rate (OR 0.96; 95%CI 0.76-1.23; P = 0.92) whereas high CCI was significantly associated with low in-hospital survival rate (OR 0.41; 95%CI 0.27-0.62; P = 0.01). The relative contributions of CCI on pre-hospital and in-hospital survival were 1.1% and 8.1%, respectively. CONCLUSION: Pre-existing high comorbidity burden plays a modest role in reducing survival rate after OHCA, and only in the in-hospital phase. The present study offers data that may guide clinicians in discussing resuscitation options during advance care planning with patients with high comorbidity burden. This may be helpful in creating a patients' informed choice.

Occurrence of shockable rhythm in out-of-hospital cardiac arrest over time: A report from the COSTA group.

BACKGROUND: Prior research suggests that the proportion of a shockable initial rhythm in out-of-hospital cardiac arrest (OHCA) declined during the last decades. This study aims to investigate if this decline is still ongoing and explore the relationship between location of OHCA and proportion of a shockable initial rhythm as initial rhythm. METHODS: We calculated the proportion of patients with a shockable initial rhythm between 2006-2015 using pooled data from the COSTA-group (Copenhagen, Oslo, Stockholm, Amsterdam). Analyses were stratified according to location of OHCA (residential vs. public). RESULTS: A total of 19,054 OHCA cases were included. Overall, the total proportion of cases with a shockable initial rhythm decreased from 42% to 37% (P < 0.01) from 2006 to 2015. When stratified according to location, the proportion of cases with a shockable initial rhythm decreased for OHCAs at a residential location (34% to 27%; P = 0.03), while the proportion of a shockable initial rhythm was stable among OHCAs in public locations (59%-57%; P = 0.2). During the last years of the study period (2011-2015), the overall proportion of a shockable initial rhythm remained stable (38%-37%; P = 0.45); this was observed for both residential and public OHCA. CONCLUSION: We found a decline in the proportion of patients with a shockable initial rhythm in OHCAs at a residential location; this decline levelled off during the second half of the study period (2011-2015). In public locations, we observed no decline in shockable initial rhythm over time.

The contribution of comorbidity and medication use to poor outcome from out-of-hospital cardiac arrest at home locations.

INTRODUCTION: Out-of-hospital cardiac arrest (OHCA) at home is associated with lower rates of shockable initial rhythm and survival than OHCA in a public location. We determined whether medical history and medication use explain the association between OHCA location and presence of shockable initial rhythm and survival rate. METHODS: Data from ARREST, an OHCA registry in the Netherlands, were used (January 2009-December 2012). We assessed if OHCA location remained associated with a) presence of shockable initial rhythm and b) survival when taking medical history, medication use, resuscitation characteristics and demographics into account in a multivariable regression analysis. The relative contributions of the above mentioned variables to variance in both outcome measures was estimated using the Nagelkerke test. RESULTS: We included 1404 patients (1034 [73.6%] home OHCA, 370 [26.4%] public OHCA). OHCA location remained significantly associated with shockable initial rhythm (home 42.7%, public 78.1%; P < 0.01) and survival to hospital discharge (home 14.0%, public 45.7%; P < 0.01). Adding resuscitation characteristics to models of shockable initial rhythm and survival rate resulted in an increase in explained variance (13.0%-23.6%), whereas adding medical history or medication use to these models resulted in only a limited increase in explained variance (medical history to 27.6%, medication use to 30.0%). CONCLUSIONS: Comorbidity and medication use do not substantially contribute in explaining the poor outcome from out-of-hospital cardiac arrest occurring at home. Even when adjusted for medical history, medication use, resuscitation characteristics, and demographics, a large gap of unexplained variance in shockable initial rhythm and survival remains.

Transfer of essential AED information to treating hospital (TREAT).

BACKGROUND: Defibrillation in out-of-hospital cardiac arrest (OHCA) is increasingly performed by using an Automated External Defibrillator (AED). Therefore presence of a shockable rhythm is recurrently only documented by the AED. However, AED-information is rarely available to the treating physician. PURPOSE: To determine (1) how often a shockable rhythm was recorded only in the AED; (2) if so, how often information that a shockable rhythm had been present reached the physician. METHODS: Data on OHCA patients with (presumed) cardiac cause with an AED connected in the years 2012-2014 (Study period 1) and 2016 (Study period 2) in the Amsterdam Resuscitation Study (ARREST) database were collected. We determined how often only the AED had defibrillated. In these patients, we retrospectively analyzed EMS run sheets and hospital discharge letters to determine if a shockable rhythm and/or AED use was correctly noted. In Study period 2, we prospectively contacted the physicians to study whether AED defibrillation was known. RESULTS: In Study period 1, of 2840 OHCA CPR attempts with (presumed) cardiac cause, 1521 (54%) patients had a shockable rhythm, with 356 patients (13%) receiving AED defibrillation only. Of these patients, 11 hospital discharge letters (4%) contained no information about a shockable rhythm. In Study period 2, 125/1128 patients (11%) received AED defibrillation only; of these, in two cases the shockable rhythm was unknown by the physician. CONCLUSION: In 11-13% of OHCAs, a shockable rhythm is only seen on the AED-ECG. Adequate transfer to the physician of vital AED-information is essential but not always accomplished.

First-response treatment after out-of-hospital cardiac arrest: a survey of current practices across 29 countries in Europe.

BACKGROUND: In Europe, survival rates after out-of-hospital cardiac arrest (OHCA) vary widely. Presence/absence and differences in implementation of systems dispatching First Responders (FR) in order to arrive before Emergency Medical Services (EMS) may contribute to this variation. A comprehensive overview of the different types of FR-systems used across Europe is lacking. METHODS: A mixed-method survey and information retrieved from national resuscitation councils and national EMS services were used as a basis for an inventory. The survey was sent to 51 OHCA experts across 29 European countries. RESULTS: Forty-seven (92%) OHCA experts from 29 countries responded to the survey. More than half of European countries had at least one region with a FR-system. Four categories of FR types were identified: (1) firefighters (professional/voluntary); (2) police officers; (3) citizen-responders; (4) others including off-duty EMS personnel (nurses, medical doctors), taxi drivers. Three main roles for FRs were identified: (a) complementary to EMS; (b) part of EMS; (c) instead of EMS. A wide variation in FR-systems was observed, both between and within countries. CONCLUSIONS: Policies relating to FRs are commonly implemented on a regional level, leading to a wide variation in FR-systems between and within countries. Future research should focus on identifying the FR-systems that most strongly influence survival. The large variation in local circumstances across regions suggests that it is unlikely that there will be a 'one-size fits all' FR-system for Europe, but examining the role of FRs in the Chain of Survival is likely to become an increasingly important aspect of OHCA research.

Time of on-scene resuscitation in out of-hospital cardiac arrest patients transported without return of spontaneous circulation.

BACKGROUND: In out-of-hospital cardiac arrest (OHCA), return of spontaneous circulation (ROSC) on scene occurs only in a minority of patients. The optimal duration of resuscitation on scene before transport with ongoing cardiopulmonary resuscitation (CPR) is unknown. PURPOSE: To determine the time of resuscitation on scene ('time on scene') and survival in patients transported with ongoing CPR in the Netherlands. METHODS: Data on OHCA patients (>18 years) without ROSC on scene, where resuscitation was started between January 1, 2012 and December 31, 2016 in the Amsterdam Resuscitation Study (ARREST) database were analyzed. Time on scene was related to 30-day survival. RESULTS: Of the 5871 OHCA patients where resuscitation was started, 2437 did not achieve ROSC on scene. Of these, 655 patients were transported with ongoing CPR and 606 (93%) had complete rhythm data. At the moment of transport, 199 (33%) patients had a shockable rhythm, 299 (49%) pulseless electrical activity (PEA) and 108 (18%) asystole as rhythm. Twenty-nine patients (4%) were alive at 30 days. Patients who survived 30 days had a higher proportion of a shockable first monitored rhythm (89% vs. 52%, p < 0.001). Survivors had a significantly shorter time on scene (20 min vs. 26 min, p = 0.004), with the highest survival rate (8%) in patients transported within 20 min. In a multivariable model time on scene (OR 0.94; 95%CI 0.89-0.99) was independently associated with 30-day survival. CONCLUSION: In OHCA patients transported with ongoing CPR the survival rate significantly declines when time on scene increases.

International variation in survival after out-of-hospital cardiac arrest: A validation study of the Utstein template.

INTRODUCTION: Out-of-hospital cardiac arrest (OHCA) survival varies greatly between communities. The Utstein template was developed and promulgated to improve the comparability of OHCA outcome reports, but it has undergone limited empiric validation. We sought to assess how much of the variation in OHCA survival between emergency medical services (EMS) across the globe is explained by differences in the Utstein factors. We also assessed how accurately the Utstein factors predict OHCA survival. METHODS: We performed a retrospective analysis of patient-level prospectively collected data from 12 OHCA registries from 12 countries for the period 1 Jan 2006 through 31 Dec 2011. We used generalized linear mixed models to examine the variation in survival between EMS agencies (n=232). RESULTS: Twelve registries contributed 86,759 cases. Patient arrest characteristics, EMS treatment and patient outcomes varied across registries. Overall survival to hospital discharge was 10% (range, 6% to 22%). Overall survival with Cerebral Performance Category of 1 or 2 (available for 8/12 registries) was 8% (range, 2% to 20%). The area-under-the-curve for the Utstein model was 0.85 (Wald CI: 0.85-0.85). The Utstein factors explained 51% of the EMS agency variation in OHCA survival. CONCLUSIONS: The Utstein factors explained 51% of the variation in survival to hospital discharge among multiple large geographically separate EMS agencies. This suggests that quality improvement and public health efforts should continue to target modifiable Utstein factors to improve OHCA survival. Further study is required to identify the reasons for the variation that is incompletely understood.

Different defibrillation strategies in survivors after out-of-hospital cardiac arrest.

BACKGROUND: In the last decade, there has been a rapid increase in the dissemination of automated external defibrillators (AEDs) for prehospital defibrillation of out-of-hospital cardiac arrest patients. The aim of this study was to study the association between different defibrillation strategies on survival rates over time in Copenhagen, Stockholm, Western Sweden and Amsterdam, and the hypothesis was that non-EMS defibrillation increased over time and was associated with increased survival. METHODS: We performed a retrospective analysis of four prospectively collected cohorts of out-of-hospital cardiac arrest patients between 2008 and 2013. Emergency medical service (EMS)-witnessed arrests were excluded. RESULTS: A total of 22 453 out-of-hospital cardiac arrest patients with known survival status were identified, of whom 2957 (13%) survived at least 30 days postresuscitation. Of all survivors with a known defibrillation status, 2289 (81%) were defibrillated, 1349 (59%) were defibrillated by EMS, 454 (20%) were defibrillated by a first responder AED and 429 (19%) were defibrillated by an onsite AED and 57 (2%) were unknown. The percentage of survivors defibrillated by first responder AEDs (from 13% in 2008 to 26% in 2013, p<0.001 for trend) and onsite AEDs (from 14% in 2008 to 30% in 2013, p<0.001 for trend) increased. The increased use of these non-EMS AEDs was associated with the increase in survival rate of patients with a shockable initial rhythm. CONCLUSION: Survivors of out-of-hospital cardiac arrest are increasingly defibrillated by non-EMS AEDs. This increase is primarily due to a large increase in the use of onsite AEDs as well as an increase in first-responder defibrillation over time. Non-EMS defibrillation accounted for at least part of the increase in survival rate of patients with a shockable initial rhythm.

COSCA (Core Outcome Set for Cardiac Arrest) in Adults: An Advisory Statement From the International Liaison Committee on Resuscitation.

Cardiac arrest effectiveness trials have traditionally reported outcomes that focus on survival. A lack of consistency in outcome reporting between trials limits the opportunities to pool results for meta-analysis. The COSCA initiative (Core Outcome Set for Cardiac Arrest), a partnership between patients, their partners, clinicians, research scientists, and the International Liaison Committee on Resuscitation, sought to develop a consensus core outcome set for cardiac arrest for effectiveness trials. Core outcome sets are primarily intended for large, randomised clinical effectiveness trials (sometimes referred to as pragmatic trials or phase III/IV trials) rather than for pilot or efficacy studies. A systematic review of the literature combined with qualitative interviews among cardiac arrest survivors was used to generate a list of potential outcome domains. This list was prioritised through a Delphi process, which involved clinicians, patients, and their relatives/partners. An international advisory panel narrowed these down to 3 core domains by debate that led to consensus. The writing group refined recommendations for when these outcomes should be measured and further characterised relevant measurement tools. Consensus emerged that a core outcome set for reporting on effectiveness studies of cardiac arrest (COSCA) in adults should include survival, neurological function, and health-related quality of life. This should be reported as survival status and modified Rankin scale score at hospital discharge, at 30 days, or both. Health-related quality of life should be measured with ≥1 tools from Health Utilities Index version 3, Short-Form 36-Item Health Survey, and EuroQol 5D-5L at 90 days and at periodic intervals up to 1 year after cardiac arrest, if resources allow. © 2018 European Resuscitation Council and American Heart Association, Inc. Published by Elsevier B.V. All rights reserved.

COSCA (Core Outcome Set for Cardiac Arrest) in Adults: An Advisory Statement From the International Liaison Committee on Resuscitation.

Cardiac arrest effectiveness trials have traditionally reported outcomes that focus on survival. A lack of consistency in outcome reporting between trials limits the opportunities to pool results for meta-analysis. The COSCA initiative (Core Outcome Set for Cardiac Arrest), a partnership between patients, their partners, clinicians, research scientists, and the International Liaison Committee on Resuscitation, sought to develop a consensus core outcome set for cardiac arrest for effectiveness trials. Core outcome sets are primarily intended for large, randomized clinical effectiveness trials (sometimes referred to as pragmatic trials or phase III/IV trials) rather than for pilot or efficacy studies. A systematic review of the literature combined with qualitative interviews among cardiac arrest survivors was used to generate a list of potential outcome domains. This list was prioritized through a Delphi process, which involved clinicians, patients, and their relatives/partners. An international advisory panel narrowed these down to 3 core domains by debate that led to consensus. The writing group refined recommendations for when these outcomes should be measured and further characterized relevant measurement tools. Consensus emerged that a core outcome set for reporting on effectiveness studies of cardiac arrest (COSCA) in adults should include survival, neurological function, and health-related quality of life. This should be reported as survival status and modified Rankin scale score at hospital discharge, at 30 days, or both. Health-related quality of life should be measured with ≥1 tools from Health Utilities Index version 3, Short-Form 36-Item Health Survey, and EuroQol 5D-5L at 90 days and at periodic intervals up to 1 year after cardiac arrest, if resources allow.

Safety of mechanical chest compression devices AutoPulse and LUCAS in cardiac arrest: a randomized clinical trial for non-inferiority.

AIMS: Mechanical chest compression (CC) during cardiopulmonary resuscitation (CPR) with AutoPulse or LUCAS devices has not improved survival from cardiac arrest. Cohort studies suggest risk of excess damage. We studied safety of mechanical CC and determined possible excess damage compared with manual CC. METHODS AND RESULTS: This is a randomized non-inferiority safety study. Randomization to AutoPulse, LUCAS, or manual CC with corrective depth and rate feedback was performed. We included patients with in-hospital cardiac arrest or with out-of-hospital cardiac arrest arriving with manual CPR at the emergency department. The primary outcome was serious or life-threatening visceral resuscitation-related damage, assessed blind by post-mortem computed tomography scan and/or autopsy or by clinical course until discharge. Non-inferiority hypothesis: mechanical CC compared with manual control does not increase the primary outcome by a risk difference of > 10% [upper 95% confidence interval (CI)]. We included 115 patients treated with AutoPulse, 122 with LUCAS, and 137 patients received manual CC. Safety outcome analysis was possible in 337 of 374 (90.1%) included patients. The primary outcome was observed in 12 of 103 AutoPulse patients (11.6%), 8 of 108 LUCAS patients (7.4%), and 8 of 126 controls (6.4%). Rate difference AutoPulse-control: +5.3% (95% CI - 2.2% to 12.8%), P = 0.15. Rate difference LUCAS-control +1.0% (95% CI - 5.5% to 7.6%), P = 0.75. CONCLUSION: LUCAS does not cause significantly more serious or life-threatening visceral damage than manual CC. For AutoPulse, significantly more serious or life-threatening visceral damage than manual CC cannot be excluded.

Automated external defibrillator and operator performance in out-of-hospital cardiac arrest.

AIM: An increasing number of failing automated external defibrillators (AEDs) is reported: AEDs not giving a shock or other malfunction. We assessed to what extent AEDs are 'failing' and whether this had a device-related or operator-related cause. METHODS: We studied analysis periods from AEDs used between January 2012 and December 2014. For each analysis period we assessed the correctness of the (no)-shock advice (sensitivity/specificity) and reasons for an incorrect (no)-shock advice. If no shock was delivered after a shock advice, we assessed the reason for no-shock delivery. RESULTS: We analyzed 1114 AED recordings with 3310 analysis periods (1091 shock advices; 2219 no-shock advices). Sensitivity for coarse ventricular fibrillation was 99% and specificity for non-shockable rhythm detection 98%. The AED gave an incorrect shock advice in 4% (44/1091) of all shock advices, due to device-related (n=15) and operator-related errors (n=28) (one unknown). Of these 44 shock advices, only 2 shocks caused a rhythm change. One percent (26/2219) of all no-shock advices was incorrect due to device-related (n=20) and operator-related errors (n=6). In 5% (59/1091) of all shock advices, no shock was delivered: operator failed to deliver shock (n=33), AED was removed (n=17), operator pushed 'off' button (n=8) and other (n=1). Of the 1073 analysis periods with a shockable rhythm, 67 (6%) did not receive an AED shock. CONCLUSION: Errors associated with AED use are rare (4%) and when occurring are in 72% caused by the operator or circumstances of use. Fully automatic AEDs may prevent the majority of these errors.

The impact of post-resuscitation feedback for paramedics on the quality of cardiopulmonary resuscitation.

PURPOSE: The Guidelines place emphasis on high-quality cardiopulmonary resuscitation (CPR). This study aims to measure the impact of post-resuscitation feedback on the quality of CPR as performed by ambulance personnel. MATERIALS AND METHODS: Two ambulances are dispatched for suspected cardiac arrest. The crew (driver and paramedic) of the first arriving ambulance is responsible for the quality of CPR. The crew of the second ambulance establishes an intravenous access and supports the first crew. All resuscitation attempts led by the ambulance crew of the study region were reviewed by two research paramedics and structured feedback was given based on defibrillator recording with impedance signal. A 12-months period before introduction of post-resuscitation feedback was compared with a 19-months period after introduction of feedback, excluding a six months run-in interval. Quality parameters were chest compression fraction (CCF), chest compression rate, longest peri-shock pause and longest non-shock pause. RESULTS: In the pre-feedback period 55 cases were analyzed and 69 cases in the feedback period. Median CCF improved significantly in the feedback period (79% vs 86%, p<0.001). The mean chest compression rate was within the recommended range of 100-120/min in 87% of the cases in the pre-feedback period and in 90% of the cases in the feedback period (p=0.65). The duration of longest non-shock pause decreased significantly (40s vs 19s, p<0.001), the duration of the longest peri-shock pause did not change significantly (16s vs 13s, p=0.27). CONCLUSION: Post-resuscitation feedback improves the quality of resuscitation, significantly increasing CCF and decreasing the duration of longest non-shock pauses.

Minimizing pre- and post-shock pauses during the use of an automatic external defibrillator by two different voice prompt protocols. A randomized controlled trial of a bundle of measures.

BACKGROUND: Previous large retrospective analyses have found an association between duration of peri-shock pauses in cardiopulmonary resuscitation (CPR) and survival. In a randomized trial, we tested whether shortening these pauses improves survival after out-of-hospital cardiac arrest (OHCA). METHODS: Patients with OHCA between May 2006 and January 2014 with shockable initial rhythm, treated by first responders, were randomized to two automated external defibrillator (AED) treatment protocols. In the control protocol AEDs performed post-shock analysis and prompted rescuers to a pulse check (Guidelines 2000). In the experimental protocol a 15s period of CPR during and after charging of the AED was added to the voice prompts and CPR was resumed immediately after defibrillation (modification of the Guidelines 2005). Survival was assessed at hospital admission and discharge. RESULTS: Of 1174 OHCA patients, 456 met the inclusion criteria: 227 were randomly assigned to the experimental protocol and 229 to the control protocol. The experimental group experienced shorter pre-shock pauses (6 [5-11]s vs. 20 [18-23]s; P<0.001), and shorter post-shock pauses (7 [6-9]s vs. 27 [16-34]s; P<0.001). Similar proportions of patients survived to hospital admission (experimental: 62% vs. CONTROL: 65%; RR [95%CI] 0.96 [0.83-1.10], P=0.51), and hospital discharge (experimental: 42% vs. CONTROL: 38%; RR [95%CI] 1.09 [0.87-1.37], P=0.46). CONCLUSION: In patients with OHCA and shockable initial rhythms, treatment with AEDs with the experimental protocol shortened pre-shock and post-shock CPR pauses, and increased overall CPR time, but did not improve survival to hospital admission or discharge. CLINICAL TRIAL REGISTRATION: http://www.isrctn.com unique identifier: ISRCTN72257677.

Causes for the declining proportion of ventricular fibrillation in out-of-hospital cardiac arrest.

AIMS: The reported proportion of ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OHCA) has declined worldwide. VF decline may be caused by less VF at collapse and/or faster dissolution of VF into asystole. We aimed to determine the causes of VF decline by comparing VF proportions in relation to delay from emergency medical services (EMS) call to initial ECG (call-to-ECG delay), and VF dissolution rates between two study periods. METHODS: Data from the AmsteRdam REsuscitation STudies (ARREST), an ongoing OHCA registry in the Netherlands, were used. We studied cardiac OHCA in the study periods 1995-1997 (n=917) and 2006-2012 (n=5695). Cases with available ECG and information on call-to-ECG delay were included. We tested whether initial VF proportion and VF dissolution rates differed between both study periods using logistic regression. RESULTS: Despite a 15% VF decline between the periods, VF proportion around EMS call remained high in 2006-2012 (64%). The odds ratio (OR) for VF proportion in 2006-2012 vs. 1995-1997 was 0.52 (95%-CI 0.45-0.60, P<0.001), with similar rates of VF dissolution in both periods (P=0.83). VF decline was higher for unwitnessed collapse (OR 0.41, 95%-CI 0.28-0.58) and collapse at home (OR 0.50, 95%-CI 0.42-0.59), but not for categories of bystander CPR, age or sex. CONCLUSION: VF proportion early after collapse remains high. VF decline is explained by the occurrence of less initial VF, rather than faster dissolving VF. An increase in unwitnessed OHCA and collapse at home contributes to the observed VF decline.