The design of the PRINCESS 2 trial: A randomized trial to study the impact of ultrafast hypothermia on complete neurologic recovery after out-of-hospital cardiac arrest with initial shockable rhythm.

BACKGROUND: Delayed hypothermia, initiated after hospital arrival, several hours after cardiac arrest with 8-10 hours to reach the target temperature, is likely to have limited impact on overall survival. However, the effect of ultrafast hypothermia, i.e., delivered intra-arrest or immediately after return of spontaneous circulation (ROSC), on functional neurologic outcome after out-of-hospital cardiac arrest (OHCA) is unclear. In two prior trials, prehospital trans-nasal evaporative intra-arrest cooling was safe, feasible and reduced time to target temperature compared to delayed cooling. Both studies showed trends towards improved neurologic recovery in patients with shockable rhythms. The aim of the PRINCESS2-study is to assess whether cooling, initiated either intra-arrest or immediately after ROSC, followed by in-hospital hypothermia, significantly increases survival with complete neurologic recovery as compared to standard normothermia care, in OHCA patients with shockable rhythms. METHODS/DESIGN: In this investigator-initiated, randomized, controlled trial, the emergency medical services (EMS) will randomize patients at the scene of cardiac arrest to either trans-nasal cooling within 20 minutes from EMS arrival with subsequent hypothermia at 33°C for 24 hours after hospital admission (intervention), or to standard of care with no prehospital or in-hospital cooling (control). Fever (>37,7°C) will be avoided for the first 72 hours in both groups. All patients will receive post resuscitation care and withdrawal of life support procedures according to current guidelines. Primary outcome is survival with complete neurologic recovery at 90 days, defined as modified Rankin scale (mRS) 0-1. Key secondary outcomes include survival to hospital discharge, survival at 90 days and mRS 0-3 at 90 days. In total, 1022 patients are required to detect an absolute difference of 9% (from 45 to 54%) in survival with neurologic recovery (80% power and one-sided α=0,025, ß=0,2) and assuming 2,5% lost to follow-up. Recruitment starts in Q1 2024 and we expect maximum enrolment to be achieved during Q4 2024 at 20-25 European and US sites. DISCUSSION: This trial will assess the impact of ultrafast hypothermia applied on the scene of cardiac arrest, as compared to normothermia, on 90-day survival with complete neurologic recovery in OHCA patients with initial shockable rhythm. TRIAL REGISTRATION: NCT06025123.

Effects of cardiopulmonary resuscitation training on mortality rates after out-of-hospital cardiac arrest: protocol for a systematic review and meta-analysis.

INTRODUCTION: An out-of-hospital cardiac arrest occurs at a rate of 67-170 cases per 100 000 inhabitants per year in Europe. The early recognition of the occurrence of a cardiac arrest, placing an emergency call, performing cardiopulmonary resuscitation (CPR) and performing defibrillation are the most important response measures. The objective of this systematic review and meta-analysis is to assess the effects of laypersons' CPR training with respect to CPR initiation rates, cardiovascular mortality rates, survival rate and the use of an automated external defibrillator. METHODS AND ANALYSIS: The literature search will be performed in the following databases: MEDLINE, Web of Science, the Cochrane Central Register of Controlled Studies, CINAHL, HBI, TESEO and NTX. Intervention studies and quasi-experimental studies in which CPR training interventions were performed will be included. We will exclude studies in which the participants do not meet the inclusion criteria, without a control group and in which the methodology of the intervention applied is unclear. There will be no restrictions on publication date or language of publication. The risk of bias will be assessed using the Risk of Bias in Non-randomized Studies of Interventions tool for randomised controlled trials (RCT), non-RCT and quasi-experimental trials. Data analysis and synthesis will be performed using RevMan V.5.4.1 software. The findings will be reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. ETHICS AND DISSEMINATION: Ethical approval is not required, as only secondary data will be used. The findings will be published in a journal and presented at conferences. PROSPERO REGISTRATION NUMBER: CRD42022365288.

A classification system for identifying patients dead on ambulance arrival: a prehospital medical record review.

BACKGROUND: Patients dead before arrival of the ambulance or before arrival at hospital may be in- or excluded in mortality analyses, making comparison of mortality difficult. Often only physicians are allowed to declare death, thereby impeding uniform registration of prehospital death. Many studies do not report detailed definitions of prehospital mortality. Our aim was to define criteria to identify and categorize prehospital patients' vital status, and to estimate the proportion of these groups, primarily the proportion of patients dead on ambulance arrival. METHODS: Prehospital medical records review for patients receiving an ambulance in the North Denmark Region from 2019 to 2021 and registered dead on the same or the following day. We defined three vital status categories: (1) Dead on Ambulance Arrival (DOAA), (2) Out-of-Hospital Cardiac Arrest (OHCA) divided into OHCA Basic Life Support (OHCA BLS) and OHCA Advanced treatment, and 3) Alive on Ambulance Arrival. RESULTS: Among 3 174 dead patients, DOAA constituted 28.8%, OHCA BLS 13.4%, OHCA Advanced treatment 31.3%, and Alive on Ambulance Arrival 26.6%. CONCLUSION: We defined exhaustive and mutually exclusive criteria to define vital status, DOAA, OHCA, and Alive on Ambulance Arrival based on prehospital medical records. More than one out of four patients receiving an ambulance and registered dead on the same or the following day were dead already at ambulance arrival. Adding OHCA BLS where resuscitation was terminated without defibrillation or other treatment, increased the proportion of patients dead on ambulance arrival to 42%. We recommend reporting similar categories of vital status to improve valid comparisons of prehospital mortality rates.

Cardiac Arrest Survival at Emergency Medical Service Agencies in Catchment Areas With Primarily Black and Hispanic Populations.

Importance: Black and Hispanic patients are less likely to survive an out-of-hospital cardiac arrest (OHCA) than White patients. Given the central importance of emergency medical service (EMS) agencies in prehospital care, a better understanding of OHCA survival at EMS agencies that work in Black and Hispanic communities and White communities is needed to address OHCA disparities. Objective: To examine whether EMS agencies serving catchment areas with primarily Black and Hispanic populations (Black and Hispanic catchment areas) have different rates of OHCA survival than agencies serving catchment areas with primarily White populations (White catchment areas). Design, Setting, and Participants: A cohort study including adults with nontraumatic OHCA from January 1, 2015, to December 31, 2019, in the Cardiac Arrest Registry to Enhance Survival was conducted. Data analysis was conducted from August 17, 2022, to July 7, 2023. Exposure: Emergency medical service agencies, categorized as working in catchment areas where the combination of Black and Hispanic residents made up more than 50% of the population or where White residents made up more than 50% of the population. Main Outcomes and Measures: The unit of analysis was the EMS agency. The primary outcome was agency-level risk-standardized survival rates (RSSRs) to hospital admission for OHCA at each EMS agency, which were calculated using hierarchical logistic regression and compared between agencies serving Black and Hispanic and White catchment areas. Whether differences in OHCA survival were explained by EMS and first responder measures was evaluated with additional adjustment for these factors. Results: Among 764 EMS agencies representing 258 342 OHCAs, 82 EMS agencies (10.7%) had a Black and Hispanic catchment area. Overall median age of the patients was 63.0 (IQR, 52.0-75.0) years, 36.1% were women, and 63.9% were men. Overall, the mean (SD) RSSR was 27.5% (3.6%), with lower survival at EMS agencies with Black and Hispanic catchment areas (25.8% [3.6%]) compared with agencies with White catchment areas (27.7% [3.5%]; P < .001). Among the 82 EMS agencies with Black and Hispanic catchment areas, a disproportionately higher number (32 [39.0%]) was in the lowest survival quartile, whereas a lower number (12 [14.6%]) was in the highest survival quartile. Additional adjustment for EMS response times, EMS termination of resuscitation rates, and first responder rates of initiating cardiopulmonary resuscitation or applying an automated external defibrillator before EMS arrival did not meaningfully attenuate differences in RSSRs between agencies with Black and Hispanic compared with White catchment areas (mean [SD] RSSRs after adjustment, 25.9% [3.3%] vs 27.7% [3.1%]; P < .001). Conclusions and Relevance: Risk-standardized survival rates for OHCA were 1.9% lower at EMS agencies working in Black and Hispanic catchment areas than in White catchment areas. This difference was not explained by EMS response times, rates of EMS termination of resuscitation, or first responder rates of initiating cardiopulmonary resuscitation or applying an automated external defibrillator. These findings suggest there is a need for further assessment of these discrepancies.

Early Extracorporeal CPR for Refractory Out-of-Hospital Cardiac Arrest.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation (CPR) restores perfusion and oxygenation in a patient who does not have spontaneous circulation. The evidence with regard to the effect of extracorporeal CPR on survival with a favorable neurologic outcome in refractory out-of-hospital cardiac arrest is inconclusive. METHODS: In this multicenter, randomized, controlled trial conducted in the Netherlands, we assigned patients with an out-of-hospital cardiac arrest to receive extracorporeal CPR or conventional CPR (standard advanced cardiac life support). Eligible patients were between 18 and 70 years of age, had received bystander CPR, had an initial ventricular arrhythmia, and did not have a return of spontaneous circulation within 15 minutes after CPR had been initiated. The primary outcome was survival with a favorable neurologic outcome, defined as a Cerebral Performance Category score of 1 or 2 (range, 1 to 5, with higher scores indicating more severe disability) at 30 days. Analyses were performed on an intention-to-treat basis. RESULTS: Of the 160 patients who underwent randomization, 70 were assigned to receive extracorporeal CPR and 64 to receive conventional CPR; 26 patients who did not meet the inclusion criteria at hospital admission were excluded. At 30 days, 14 patients (20%) in the extracorporeal-CPR group were alive with a favorable neurologic outcome, as compared with 10 patients (16%) in the conventional-CPR group (odds ratio, 1.4; 95% confidence interval, 0.5 to 3.5; P = 0.52). The number of serious adverse events per patient was similar in the two groups. CONCLUSIONS: In patients with refractory out-of-hospital cardiac arrest, extracorporeal CPR and conventional CPR had similar effects on survival with a favorable neurologic outcome. (Funded by the Netherlands Organization for Health Research and Development and Maquet Cardiopulmonary [Getinge]; INCEPTION ClinicalTrials.gov number, NCT03101787.).

Efficacy and safety of corticosteroids in cardiac arrest: a systematic review, meta-analysis and trial sequential analysis of randomized control trials.

BACKGROUND: Post-cardiac arrest, outcomes for most patients are poor, regardless of setting. Many patients who do achieve spontaneous return of circulation require vasopressor therapy to maintain organ perfusion. There is some evidence to support the use of corticosteroids in cardiac arrest. RESEARCH QUESTION: Assess the efficacy and safety of corticosteroids in patients following in- and out-of-hospital cardiac arrest. STUDY DESIGN AND METHODS: We searched databases CINAHL, EMBASE, LILACS, MEDLINE, Web of Science, CENTRAL, ClinicalTrails.gov, and ICTRP. We included randomized controlled trials (RCTs) that examined the efficacy and safety of corticosteroids, as compared to placebo or usual care in patients post-cardiac arrest. We pooled estimates of effect size using random effects meta-analysis and report relative risk (RR) with 95% confidence intervals (CIs). We assessed risk of bias (ROB) for the included trials using the modified Cochrane ROB tool and rated the certainty of evidence using Grading of Recommendations Assessment, Development and Evaluation methodology. RESULTS: We included 8 RCTs (n = 2213 patients). Corticosteroids administered post-cardiac arrest had an uncertain effect on mortality measured at the longest point of follow-up (RR 0.96, 95% CI 0.90-1.02, very low certainty, required information size not met using trial sequential analysis). Corticosteroids probably increase return of spontaneous circulation (ROSC) (RR 1.32, 95% CI 1.18-1.47, moderate certainty) and may increase the likelihood of survival with good functional outcome (RR 1.49, 95% CI 0.87-2.54, low certainty). Corticosteroids may decrease the risk of ventilator associated pneumonia (RR 0.76, 95% CI 0.46-1.09, low certainty), may increase renal failure (RR 1.29, 95% CI 0.84-1.99, low certainty), and have an uncertain effect on bleeding (RR 2.04, 95% CI 0.53-7.84, very low certainty) and peritonitis (RR 10.54, 95% CI 2.99-37.19, very low certainty). CONCLUSIONS: In patients during or after cardiac arrest, corticosteroids have an uncertain effect on mortality but probably increase ROSC and may increase the likelihood of survival with good functional outcome at hospital discharge. Corticosteroids may decrease ventilator associated pneumonia, may increase renal failure, and have an uncertain effect on bleeding and peritonitis. However, the pooled evidence examining these outcomes was sparse and imprecision contributed to low or very low certainty of evidence.

Effect of Smartphone Dispatch of Volunteer Responders on Automated External Defibrillators and Out-of-Hospital Cardiac Arrests: The SAMBA Randomized Clinical Trial.

Importance: Smartphone dispatch of volunteer responders to nearby out-of-hospital cardiac arrests (OHCAs) has emerged in several emergency medical services, but no randomized clinical trials have evaluated the effect on bystander use of automated external defibrillators (AEDs). Objective: To evaluate if bystander AED use could be increased by smartphone-aided dispatch of lay volunteer responders with instructions to collect nearby AEDs compared with instructions to go directly to patients with OHCAs to start cardiopulmonary resuscitation (CPR). Design, Setting, and Participants: This randomized clinical trial assessed a system for smartphone dispatch of volunteer responders to individuals experiencing OHCAs that was triggered at emergency dispatch centers in response to suspected OHCAs and randomized 1:1. The study was conducted in 2 main Swedish regions: Stockholm and Västra Götaland between December 2018 and January 2020. At study start, there were 3123 AEDs in Stockholm and 3195 in Västra Götaland and 24 493 volunteer responders in Stockholm and 19 117 in Västra Götaland. All OHCAs in which the volunteer responder system was activated by dispatchers were included. Excluded were patients with no OHCAs, those with OHCAs not treated by the emergency medical services, and those with OHCAs witnessed by the emergency medical services. Interventions: Volunteer responders were alerted through the volunteer responder system smartphone application and received map-aided instructions to retrieve nearest available public AEDs on their way to the OHCAs. The control arm included volunteer responders who were instructed to go directly to the OHCAs to perform CPR. Main Outcomes and Measures: Overall bystander AED attachment, including those attached by volunteer responders and lay volunteers who did not use the smartphone application. Results: Volunteer responders were activated for 947 patients with OHCAs. Of those, 461 were randomized to the intervention group (median [IQR] age of patients, 73 [61-81] years; 295 male patients [65.3%]) and 486 were randomized to the control group (median [IQR] age of patients, 73 [63-82] years; 312 male patients [65.3%]). Primary outcome of AED attachment occurred in 61 patients (13.2%) in the intervention arm vs 46 patients (9.5%) in the control arm (difference, 3.8% [95% CI, -0.3% to 7.9%]; P = .08). The majority of AEDs were attached by lay volunteers who were not using the smartphone application (37 in intervention arm, 28 in control). There were no significant differences in secondary outcomes. Among the volunteer responders using the application, crossover was 11% and compliance to instructions was 31%. Volunteer responders attached 38% (41 of 107) of all AEDs and provided 45% (16 of 36) of all defibrillations and 43% (293 of 666) of all CPR. Conclusions and Relevance: In this study, smartphone dispatch of volunteer responders to OHCAs to retrieve nearby AEDs vs instructions to directly perform CPR did not significantly increase volunteer AED use. High baseline AED attachement rate and crossover may explain why the difference was not significant. Trial Registration: ClinicalTrials.gov Identifier: NCT02992873.

Correspondence: is there an association between centre volume and survival or neurological outcomes among out-of-hospital cardiac arrest patients?

This commentary discusses the findings of a study by Tsuchida et al. on the effect of annual hospital admissions of out-of-hospital cardiac arrest patients on survival and neurological outcomes in OHCA patients in the context of existing literature on the topic, and the implications on future studies investigating the volume-outcome relationship in cardiac arrest.

Defibrillation Strategies for Refractory Ventricular Fibrillation.

BACKGROUND: Despite advances in defibrillation technology, shock-refractory ventricular fibrillation remains common during out-of-hospital cardiac arrest. Double sequential external defibrillation (DSED; rapid sequential shocks from two defibrillators) and vector-change (VC) defibrillation (switching defibrillation pads to an anterior-posterior position) have been proposed as defibrillation strategies to improve outcomes in patients with refractory ventricular fibrillation. METHODS: We conducted a cluster-randomized trial with crossover among six Canadian paramedic services to evaluate DSED and VC defibrillation as compared with standard defibrillation in adult patients with refractory ventricular fibrillation during out-of-hospital cardiac arrest. Patients were treated with one of these three techniques according to the strategy that was randomly assigned to the paramedic service. The primary outcome was survival to hospital discharge. Secondary outcomes included termination of ventricular fibrillation, return of spontaneous circulation, and a good neurologic outcome, defined as a modified Rankin scale score of 2 or lower (indicating no symptoms to slight disability) at hospital discharge. RESULTS: A total of 405 patients were enrolled before the data and safety monitoring board stopped the trial because of the coronavirus disease 2019 pandemic. A total of 136 patients (33.6%) were assigned to receive standard defibrillation, 144 (35.6%) to receive VC defibrillation, and 125 (30.9%) to receive DSED. Survival to hospital discharge was more common in the DSED group than in the standard group (30.4% vs. 13.3%; relative risk, 2.21; 95% confidence interval [CI], 1.33 to 3.67) and more common in the VC group than in the standard group (21.7% vs. 13.3%; relative risk, 1.71; 95% CI, 1.01 to 2.88). DSED but not VC defibrillation was associated with a higher percentage of patients having a good neurologic outcome than standard defibrillation (relative risk, 2.21 [95% CI, 1.26 to 3.88] and 1.48 [95% CI, 0.81 to 2.71], respectively). CONCLUSIONS: Among patients with refractory ventricular fibrillation, survival to hospital discharge occurred more frequently among those who received DSED or VC defibrillation than among those who received standard defibrillation. (Funded by the Heart and Stroke Foundation of Canada; DOSE VF ClinicalTrials.gov number, NCT04080986.).

Effect of Lower vs Higher Oxygen Saturation Targets on Survival to Hospital Discharge Among Patients Resuscitated After Out-of-Hospital Cardiac Arrest: The EXACT Randomized Clinical Trial.

Importance: The administration of a high fraction of oxygen following return of spontaneous circulation in out-of-hospital cardiac arrest may increase reperfusion brain injury. Objective: To determine whether targeting a lower oxygen saturation in the early phase of postresuscitation care for out-of-hospital cardiac arrest improves survival at hospital discharge. Design, Setting, and Participants: This multicenter, parallel-group, randomized clinical trial included unconscious adults with return of spontaneous circulation and a peripheral oxygen saturation (Spo2) of at least 95% while receiving 100% oxygen. The trial was conducted in 2 emergency medical services and 15 hospitals in Victoria and South Australia, Australia, between December 11, 2017, and August 11, 2020, with data collection from ambulance and hospital medical records (final follow-up date, August 25, 2021). The trial enrolled 428 of a planned 1416 patients. Interventions: Patients were randomized by paramedics to receive oxygen titration to achieve an oxygen saturation of either 90% to 94% (intervention; n = 216) or 98% to 100% (standard care; n = 212) until arrival in the intensive care unit. Main Outcomes and Measures: The primary outcome was survival to hospital discharge. There were 9 secondary outcomes collected, including hypoxic episodes (Spo2 <90%) and prespecified serious adverse events, which included hypoxia with rearrest. Results: The trial was stopped early due to the COVID-19 pandemic. Of the 428 patients who were randomized, 425 were included in the primary analysis (median age, 65.5 years; 100 [23.5%] women) and all completed the trial. Overall, 82 of 214 patients (38.3%) in the intervention group survived to hospital discharge compared with 101 of 211 (47.9%) in the standard care group (difference, -9.6% [95% CI, -18.9% to -0.2%]; unadjusted odds ratio, 0.68 [95% CI, 0.46-1.00]; P = .05). Of the 9 prespecified secondary outcomes collected during hospital stay, 8 showed no significant difference. A hypoxic episode prior to intensive care was observed in 31.3% (n = 67) of participants in the intervention group and 16.1% (n = 34) in the standard care group (difference, 15.2% [95% CI, 7.2%-23.1%]; OR, 2.37 [95% CI, 1.49-3.79]; P < .001). Conclusions and Relevance: Among patients achieving return of spontaneous circulation after out-of-hospital cardiac arrest, targeting an oxygen saturation of 90% to 94%, compared with 98% to 100%, until admission to the intensive care unit did not significantly improve survival to hospital discharge. Although the trial is limited by early termination due to the COVID-19 pandemic, the findings do not support use of an oxygen saturation target of 90% to 94% in the out-of-hospital setting after resuscitation from cardiac arrest. Trial Registration: ClinicalTrials.gov Identifier: NCT03138005.

Effect of Intra-arrest Transport, Extracorporeal Cardiopulmonary Resuscitation, and Immediate Invasive Assessment and Treatment on Functional Neurologic Outcome in Refractory Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial.

Importance: Out-of-hospital cardiac arrest (OHCA) has poor outcome. Whether intra-arrest transport, extracorporeal cardiopulmonary resuscitation (ECPR), and immediate invasive assessment and treatment (invasive strategy) is beneficial in this setting remains uncertain. Objective: To determine whether an early invasive approach in adults with refractory OHCA improves neurologically favorable survival. Design, Setting, and Participants: Single-center, randomized clinical trial in Prague, Czech Republic, of adults with a witnessed OHCA of presumed cardiac origin without return of spontaneous circulation. A total of 256 participants, of a planned sample size of 285, were enrolled between March 2013 and October 2020. Patients were observed until death or day 180 (last patient follow-up ended on March 30, 2021). Interventions: In the invasive strategy group (n = 124), mechanical compression was initiated, followed by intra-arrest transport to a cardiac center for ECPR and immediate invasive assessment and treatment. Regular advanced cardiac life support was continued on-site in the standard strategy group (n = 132). Main Outcomes and Measures: The primary outcome was survival with a good neurologic outcome (defined as Cerebral Performance Category [CPC] 1-2) at 180 days after randomization. Secondary outcomes included neurologic recovery at 30 days (defined as CPC 1-2 at any time within the first 30 days) and cardiac recovery at 30 days (defined as no need for pharmacological or mechanical cardiac support for at least 24 hours). Results: The trial was stopped at the recommendation of the data and safety monitoring board when prespecified criteria for futility were met. Among 256 patients (median age, 58 years; 44 [17%] women), 256 (100%) completed the trial. In the main analysis, 39 patients (31.5%) in the invasive strategy group and 29 (22.0%) in the standard strategy group survived to 180 days with good neurologic outcome (odds ratio [OR], 1.63 [95% CI, 0.93 to 2.85]; difference, 9.5% [95% CI, -1.3% to 20.1%]; P = .09). At 30 days, neurologic recovery had occurred in 38 patients (30.6%) in the invasive strategy group and in 24 (18.2%) in the standard strategy group (OR, 1.99 [95% CI, 1.11 to 3.57]; difference, 12.4% [95% CI, 1.9% to 22.7%]; P = .02), and cardiac recovery had occurred in 54 (43.5%) and 45 (34.1%) patients, respectively (OR, 1.49 [95% CI, 0.91 to 2.47]; difference, 9.4% [95% CI, -2.5% to 21%]; P = .12). Bleeding occurred more frequently in the invasive strategy vs standard strategy group (31% vs 15%, respectively). Conclusions and Relevance: Among patients with refractory out-of-hospital cardiac arrest, the bundle of early intra-arrest transport, ECPR, and invasive assessment and treatment did not significantly improve survival with neurologically favorable outcome at 180 days compared with standard resuscitation. However, the trial was possibly underpowered to detect a clinically relevant difference. Trial Registration: ClinicalTrials.gov Identifier: NCT01511666.

Dispatcher-assisted CPR for cardiac arrest in children - Conventional versus compression-only CPR.

This study showed that conventional CPR outcomes in Cerebral Performance Category were better than those compression-onlybystander CPR that were achieved at 1 month post resuscitation. There was no difference in those with an initial shockable rhythm, requiring CPR for 20 minutes before hospital arrival, public defibrillation, advanced airway care or epinephrine administration. However, survival rates in paediatric CPR is low. Ways in which to improve the outcomes are suggested which included bystander CPR, teaching and training of dispatchers and additional technologies.

Dispatcher-assisted CPR can it do harm as well as good?

Outcomes for patients with out-of-hospital cardiac arrest can be improved by bystander cardiopulmonary resuscitation (CPR). Dispatcher-assisted CPR increases both the likelihood of CPR being performed, and the chance of survival for the arrested patient. Due to the urgency of the situation, CPR may be advised in patients who are subsequently found not to be in cardiac arrest. Ng and colleagues look at whether bystander CPR causes harm in this group of patients.

Impact of crowding in local ambulance demand on call-to-ambulance scene arrival in out-of-hospital cardiac arrest.

BACKGROUND: Rapid emergency medical service (EMS) response is an important prognostic factor in out-of-hospital cardiac arrest (OHCA). This study aims to evaluate the association between local hourly EMS demand and ambulance response in OHCA. METHODS: OHCA occurring in 24 districts of Seoul from 2013 to 2018 was analyzed. Hourly ambulance demand per ambulance in each local district of patient location at the hour of cardiac arrest was calculated as the crowding index. The crowding index was categorized according to quartiles (1Q: ≤0.43, 2Q: 0.44-0.67, 3Q: 0.68-0.99, 4Q: ≥1.0 calls/h\r/ambulance). The primary outcome was ambulance dispatched within 1 km of the OHCA scene. Multivariable logistic regression analysis was performed to test the association between the local hourly ambulance demand and outcomes. RESULTS: A total of 26,479 patients were analyzed. The rate of ambulance dispatched within 1 km decreased according to the crowding quartile (1Q: 31.3%, 2Q: 30.0%, 3Q: 28.8%, and 4Q: 26.6%). Compared to 1Q, adjusted odds ratios (95% CIs) of dispatch distance within 1 km in 2Q, 3Q, and 4Q were 0.92 (0.86-0.99), 0.86 (0.80-0.94), and 0.77 (0.71-0.84), respectively. CONCLUSION: Crowding in local ambulance demand was associated with less ambulance dispatched within 1 km and delayed response to the scene in OHCA. Strategies to mitigate and adjust to ambulance demand crowding may be considered for better EMS response performance.

The Role of Brain CT in Patients with Out-of-Hospital Cardiac Arrest with Return of Spontaneous Circulation.

BACKGROUND AND AIM: The diagnosis and treatment process after resuscitation of patients with spontaneous return of circulation (ROSC) after cardiac arrest is important. There is no clear recommendation on utilization of computerized tomography (CT) of the brain in patients with ROSC. In this study, it was aimed to diagnosis the pathology detection rates in the brain tomography of out-of-hospital cardiac arrest (OHCA) patients with ROSC after resuscitation in the emergency department and the effect of these pathologies on treatment management. MATERIALS AND METHODS: 131 patients who were admitted to the Emergency Medicine Clinic with cardiac arrest between 08.05.2019 and 07.12.2020, had ROSC after resuscitation and underwent brain CT in the first 24 h were included in the study. The patients were divided into two groups; those with clinically significant pathology in brain CT who underwent treatment changes and those without clinically significant pathology. All data recorded in the study form were analyzed using IBM SPSS 20.0 (Chicago, IL, USA) statistics program. P < 0.005 value was considered statistically significant. RESULTS: 51.1% (67) of the patients were women. The age median value was 73 (IQR25-IQR75;63-83). The most common comorbidity in patients was hypertension with 42% (55). Patients with clinically significant pathology observed in brain tomography studied after ROSC were 12.2% (16) of all patients. The most common management changes were requesting a consultation from the neurology department (n = 9) and adding a new drug to the treatment (n= 5) The 30-day and 1-year mortality rates showed no significant difference between the two groups (p > 0.05). CONCLUSION: We have seen that the data obtained from the CT studied in the early period after the ROSC was achieved, did not change the management of our patients x in the early and late periods after resuscitation. We conclude that it is not necessary to have a brain CT scan in the emergency department in the early period.