Accuracy of etiological classification of out-of-hospital cardiac arrest: A scoping review.

INTRODUCTION: The Utstein reporting template classifies the etiology of OHCA into "presumed cardiac" and "obvious non-cardiac" or "medical" and "non-medical" categories; however, the accuracy of these classifications is unclear. Ascertaining more accurately the etiology of OHCA is important to tailor advanced life support and identify etiologically consistent patient cohorts for reporting incidence and outcome and enrollment in clinical trials. This scoping review was proposed to identify the state of agreement on etiological classification based on emergency medical service (EMS) data using the Utstein format against other sources. METHOD: We searched Medline, EBM-Cochrane, and Embase databases from 1946-2023 to identify studies that reported initial and confirmed etiologies of OHCA. A descriptive review of the included studies was conducted. RESULT: The search yielded 22,994 citations. After excluding duplicates, 16,932 citations were reviewed for titles and abstracts. Twelve studies met the inclusion criteria of this review. The frequency of presumed cardiac etiologies based on EMS data was higher than confirmed cardiac etiologies (88% vs 33%) with 83-94% sensitivity and 73-76% specificity. In contrast, the frequency of presumed non-cardiac etiologies was lower than confirmed non-cardiac etiologies (3% vs 27%) with 52-74% sensitivity and 90-97.7% specificity estimated for respiratory disease. CONCLUSION: Major disparities exist between current etiological classifications based on the Utstein reporting template and robust sources such as autopsy and medical records. Data linkage and validation are necessary to confirm the etiology of OHCA. Further research is needed on how this misclassification affects reported incidence and outcomes, and how contributing factors may improve etiological classifications.

Cardiovascular changes induced by targeted mild hypercapnia after out of hospital cardiac arrest. A sub-study of the TAME cardiac arrest trial.

AIM: Hypercapnia may elicit detrimental haemodynamic effects in critically ill patients. We aimed to investigate the consequences of targeted mild hypercapnia versus targeted normocapnia on pulmonary vascular resistance and right ventricular function in patients resuscitated from out-of-hospital cardiac arrest (OHCA). METHODS: Pre-planned, single-centre, prospective, sub-study of the Targeted Therapeutic Mild Hypercapnia After Resuscitated Cardiac Arrest (TAME) trial. Patients were randomised to mild hypercapnia (PaCO2 = 6.7-7.3 kPa) or normocapnia (PaCO2 = 4.7-6.0 kPa) for 24 hours. Haemodynamic assessment was performed with right heart catheterisation and serial blood-gas analyses every4th hour for 48 hours. RESULTS: We studied 84 patients. Mean pH was 7.24 (95% CI 7.22-7.30) and 7.32 (95% CI 7.31-7.34) with hypercapnia and normocapnia, respectively (P-group < 0.001). Pulmonary vascular resistance index (PVRI), pulmonary artery pulsatility index, and right atrial pressure did not differ between groups (P-group > 0.05). Mean cardiac index was higher with mild hypercapnia (P-group < 0.001): 2.0 (95% CI 1.85-2.1) vs 1.6 (95% CI 1.52-1.76) L/min/m2. Systemic vascular resistance index was 2579 dyne-sec/cm-5/ m2 (95% CI 2356-2830) with hypercapnia, and 3249 dyne-sec/cm-5/ m2 (95% CI 2930-3368) with normocapnia (P-group < 0.001). Stroke volumes (P-group = 0.013) and mixed venous oxygen saturation (P-group < 0.001) were higher in the hypercapnic group. CONCLUSION: In resuscitated OHCA patients, targeting mild hypercapnia did not increase PVRI or worsen right ventricular function compared to normocapnia. Mild hypercapnia comparatively improved cardiac performance and mixed venous oxygen saturation.

Basic life support and systems saving lives.

PURPOSE OF REVIEW: To describe recent science in basic life support (BLS) after cardiac arrest and how evolving knowledge in resuscitation is changing current guidelines and practices. RECENT FINDINGS: The core elements of BLS have remained mostly unchanged since 2005 when Cardiopulmonary Resuscitation recommendations were changed from 2 ventilations to 15 compressions and up to three stacked shocks for shockable rhythms, to 30 compressions to 2 ventilations and single shocks. Since 2010, basic life support has largely focused on the importance of providing high-quality CPR for professional and lay rescuers alike. The most recent resuscitation updates has seen an increased focus on the systems perspective. The 'Systems Saving Lives' concept emphasizes the interconnection between community and Emergency Medical Services (EMS). The main changes in current resuscitation practice are within three important basic life support domains: recognition of cardiac arrest, interaction between rescuers and EMS and improving resuscitation quality. SUMMARY: This review highlights the importance of strengthening both community and emergency medical services efforts to improve outcomes in cardiac arrest. Strategies that enhance the communication and collaboration between lay rescuers and professional resuscitation systems are important new avenues to pursue in developing systems that save more lives.

Description of call handling in emergency medical dispatch centres in Scandinavia: recognition of out-of-hospital cardiac arrests and dispatcher-assisted CPR.

BACKGROUND: The European resuscitation council have highlighted emergency medical dispatch centres as an important key player for early recognition of Out-of-Hospital Cardiac Arrest (OHCA) and in providing dispatcher assisted cardiopulmonary resuscitation (CPR) before arrival of emergency medical services. Early recognition is associated with increased bystander CPR and improved survival rates. The aim of this study is to describe OHCA call handling in emergency medical dispatch centres in Copenhagen (Denmark), Stockholm (Sweden) and Oslo (Norway) with focus on sensitivity of recognition of OHCA, provision of dispatcher-assisted CPR and time intervals when CPR is initiated during the emergency call (NO-CPRprior), and to describe OHCA call handling when CPR is initiated prior to the emergency call (CPRprior). METHODS: Baseline data of consecutive OHCA eligible for inclusion starting January 1st 2016 were collected from respective cardiac arrest registries. A template based on the Cardiac Arrest Registry to Enhance Survival definition catalogue was used to extract data from respective cardiac arrest registries and from corresponding audio files from emergency medical dispatch centres. Cases were divided in two groups: NO-CPRprior and CPRprior and data collection continued until 200 cases were collected in the NO-CPRprior-group. RESULTS: NO-CPRprior OHCA was recognised in 71% of the calls in Copenhagen, 83% in Stockholm, and 96% in Oslo. Abnormal breathing was addressed in 34, 7 and 98% of cases and CPR instructions were started in 50, 60, and 80%, respectively. Median time (mm:ss) to first chest compression was 02:35 (Copenhagen), 03:50 (Stockholm) and 02:58 (Oslo). Assessment of CPR quality was performed in 80, 74, and 74% of the cases. CPRprior comprised 71 cases in Copenhagen, 9 in Stockholm, and 38 in Oslo. Dispatchers still started CPR instructions in 41, 22, and 40% of the calls, respectively and provided quality assessment in 71, 100, and 80% in these respective instances. CONCLUSIONS: We observed variations in OHCA recognition in 71-96% and dispatcher assisted-CPR were provided in 50-80% in NO-CPRprior calls. In cases where CPR was initiated prior to emergency calls, dispatchers were less likely to start CPR instructions but provided quality assessments during instructions.

European Resuscitation Council and European Society of Intensive Care Medicine guidelines 2021: post-resuscitation care.

The European Resuscitation Council (ERC) and the European Society of Intensive Care Medicine (ESICM) have collaborated to produce these post-resuscitation care guidelines for adults, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include the post-cardiac arrest syndrome, diagnosis of cause of cardiac arrest, control of oxygenation and ventilation, coronary reperfusion, haemodynamic monitoring and management, control of seizures, temperature control, general intensive care management, prognostication, long-term outcome, rehabilitation and organ donation.

Ventilatory support for hypoxaemic intensive care patients with COVID-19. / Ventilasjonsstøtte for hypoksemiske intensivpasienter med covid-19.

BACKGROUND: COVID-19 pneumonia can result in severe hypoxaemic respiratory failure that requires intensive medical care. We wished to describe COVID-19 intensive care patients who were treated with and without invasive ventilatory support. MATERIAL AND METHOD: The material was retrieved from the local quality register and comprises data on patients with COVID-19 admitted to the intensive care department at Oslo University Hospital Ullevål from 5 March-28 May 2020. The patients were categorised in three groups on the basis of the treatment they received for respiratory failure (oxygen alone, supplemental non-invasive ventilation (NIV), and intubation/ventilator) and described using descriptive statistics. RESULTS: Of 165 hospitalised COVID-19 patients, a total of 26 (16 %) were treated in our intensive care department. Four of them had do-not-resuscitate-orders and were excluded. The 22 patients included in this study had an average age of 56 years (range 25 to 78 years); 17 (77 %) were men. Eleven patients received ventilator treatment, seven oxygen by mask, and four supplemental NIV. In the ventilator group, as of 28 May 2020 two had died, and the remainder had been discharged alive from the intensive care department, with one remaining hospitalised on a ward. All patients treated with oxygen and NIV were alive and had been discharged from hospital. INTERPRETATION: For many patients with COVID-19 respiratory failure and need for intensive care, increased oxygen and NIV are sufficient, but the need for intubation must be continuously assessed. More than 90 % of actively treated intensive care patients survived.

Predicting severe COVID-19 in the Emergency Department.

BACKGROUND: COVID-19 may lead to severe disease, requiring intensive care treatment and challenging the capacity of health care systems. The aim of this study was to compare the ability of commonly used scoring systems for sepsis and pneumonia to predict severe COVID-19 in the emergency department. METHODS: Prospective, observational, single centre study in a secondary/tertiary care hospital in Oslo, Norway. Patients were assessed upon hospital admission using the following scoring systems; quick Sequential Failure Assessment (qSOFA), Systemic Inflammatory Response Syndrome criteria (SIRS), National Early Warning Score 2 (NEWS2), CURB-65 and Pneumonia Severity index (PSI). The ratio of arterial oxygen tension to inspiratory oxygen fraction (P/F-ratio) was also calculated. The area under the receiver operating characteristics curve (AUROC) for each scoring system was calculated, along with sensitivity and specificity for the most commonly used cut-offs. Severe disease was defined as death or treatment in ICU within 14 days. RESULTS: 38 of 175 study participants developed severe disease, 13 (7%) died and 29 (17%) had a stay at an intensive care unit (ICU). NEWS2 displayed an AUROC of 0.80 (95% confidence interval 0.72-0.88), CURB-65 0.75 (0.65-0.84), PSI 0.75 (0.65-0.84), SIRS 0.70 (0.61-0.80) and qSOFA 0.70 (0.61-0.79). NEWS2 was significantly better than SIRS and qSOFA in predicating severe disease, and with a cut-off of5 points, had a sensitivity and specificity of 82% and 60%, respectively. CONCLUSION: NEWS2 predicted severe COVID-19 disease more accurately than SIRS and qSOFA, but not significantly better than CURB65 and PSI. NEWS2 may be a useful screening tool in evaluating COVID-19 patients during hospital admission. TRIAL REGISTRATION: : ClinicalTrials.gov Identifier: NCT04345536. (https://clinicaltrials.gov/ct2/show/NCT04345536).

Esmolol for cardioprotection during resuscitation with adrenaline in an ischaemic porcine cardiac arrest model.

BACKGROUND: The effectiveness of adrenaline during resuscitation continues to be debated despite being recommended in international guidelines. There is evidence that the ß-adrenergic receptor (AR) effects of adrenaline are harmful due to increased myocardial oxygen consumption, post-defibrillation ventricular arrhythmias and increased severity of post-arrest myocardial dysfunction. Esmolol may counteract these unfavourable ß-AR effects and thus preserve post-arrest myocardial function. We evaluated whether a single dose of esmolol administered prior to adrenaline preserves post-arrest cardiac output among successfully resuscitated animals in a novel, ischaemic cardiac arrest porcine model. METHODS: Myocardial infarction was induced in 20 anaesthetized pigs by inflating a percutaneous coronary intervention (PCI) balloon in the circumflex artery 15 min prior to induction of ventricular fibrillation. After 10 min of untreated VF, resuscitation with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) was initiated and the animals were randomized to receive an injection of either 1 mg/kg esmolol or 9 mg/ml NaCl, prior to adrenaline. Investigators were blinded to allocation. Successful defibrillation was followed by a 1-h high-flow VA-ECMO before weaning and an additional 1-h stabilization period. The PCI-balloon was deflated 40 min after inflation. Cardiac function pre- and post-arrest (including cardiac output) was assessed by magnetic resonance imaging (MRI) and invasive pressure measurements. Myocardial injury was estimated with MRI, triphenyl tetrazolium chloride (TTC) staining and serum concentrations of cardiac troponin T. RESULTS: Only seven esmolol and five placebo-treated pigs were successfully resuscitated and available for post-arrest measurements (p = 0.7). MRI revealed severe but similar reductions in post-arrest cardiac function with cardiac output 3.5 (3.3, 3.7) and 3.3 (3.2, 3.9) l/min for esmolol and control (placebo) groups, respectively (p = 0.7). The control group had larger left ventricular end-systolic and end-diastolic ventricular volumes compared to the esmolol group (75 (65, 100) vs. 62 (53, 70) ml, p = 0.03 and 103 (86, 124) vs. 87 (72, 91) ml, p = 0.03 for control and esmolol groups, respectively). There were no other significant differences in MRI characteristics, myocardial infarct size or other haemodynamic measurements between the two groups. CONCLUSIONS: We observed similar post-arrest cardiac output with and without a single dose of esmolol prior to adrenaline administration during low-flow VA-ECMO in an ischaemic cardiac arrest pig model.

Relationship between level of CPR training, self-reported skills, and actual manikin test performance-an observational study.

BACKGROUND: Quality of bystander cardiopulmonary resuscitation (CPR) skills may influence out of hospital cardiac arrest (OHCA) outcomes. We analyzed how the level of CPR training related to indicators of good CPR quality and also the relationship between self-reported skills and actual CPR performance. METHODS: Two hundred thirty-seven persons trained in standardized BLS curricula were divided into three groups according to the level of training: group I (40 h basic first aid training), group II, and group III (96 h advanced first aid, group III had also some limited additional life support training courses). We recorded the participants' real-life CPR experience and self-reported CPR skills, and then assessed selected CPR quality indicators on a manikin. The data were analyzed with multivariate logistic regression. Differences between groups were analyzed with ANOVA/MANOVA. RESULTS: Out of 237 participants, 125 had basic training (group I), 84 reported advanced training (group II), and 28 advanced training plus additional courses (group III). Group II and III had shorter start-up time, better compression depth and hand positioning, higher fraction of effective rescue ventilations, shorter hands-off time, and thus a higher chest compression fraction. Chest compression rate did not differ between groups. The participants in group I assessed their own skills and preparedness significantly lower than groups II and III both before and after the test. In addition, group III reported higher confidence in examining the critically ill patient and preparedness in doing CPR before the manikin test than both groups I and II. However, the observed differences between groups II and III in self-reported skills and preparedness were not statistically significant after the test. CONCLUSION: As expected, higher levels of BLS training correlated with better CPR quality. However, this study showed that ventilations and hands-on time were the components of CPR that were most affected by the level of training. Self-assessments of CPR ability correlated well to actual test performance and may have a role in probing CPR skills in students. The results may be important for BLS instructors and program developers.

The effect of intravenous adrenaline on electrocardiographic changes during resuscitation in patients with initial pulseless electrical activity in out of hospital cardiac arrest.

INTRODUCTION: Presence of electrocardiographic rhythm in the absence of palpable pulses defines pulseless electrical activity (PEA) and the electrocardiogram (ECG) may provide a source of information during resuscitation. The aim of this study was to examine the development of ECG characteristics during advanced life support (ALS) from Out-of-hospital cardiac arrest (OHCA) with initial PEA, and to explore the potential effects of adrenaline on these characteristics. METHODS: Patients with OHCA and initial PEA, part of randomized controlled trial of ALS with or without intravenous access and medications, were included. A total of 4840 combined observations of QRS complex rate (heart rate) and width were made by examining defibrillator recordings from 170 episodes of cardiac arrest. RESULTS: We found Increased heart rate (47 beats per minute) and reduced QRS complex width (62 ms) during ALS in patients who obtained return of spontaneous circulation (ROSC); while patients who received adrenaline but died increased their heart rate (22 beats per minute) without any concomitant decrease in QRS complex width. CONCLUSION: ECG changes during ALS in cardiac arrest were associated with prognosis, and the administration of adrenaline impacted on these changes.

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.

Optimal loop duration during the provision of in-hospital advanced life support (ALS) to patients with an initial non-shockable rhythm.

BACKGROUND: In advanced life support (ALS), time-cycled "loops" of chest compressions form the basis of action. However, the provider must compromise between interrupting compressions and detecting a change in cardiac rhythm. An "optimal" loop duration would best balance these choices. The current international CPR guidelines recommend 2-min loop durations. The aim of this study was to investigate the "optimal" loop duration in patients with initial asystole or pulseless electrical activity (PEA). MATERIALS AND METHODS: Detailed defibrillator recordings from 249 in-hospital cardiac arrests at the University of Chicago Medicine (Chicago, IL) and St. Olav University Hospital (Trondheim, Norway) were analysed. The clinical states of asystole, PEA, ventricular fibrillation/-tachycardia (VF/VT) and return of spontaneous circulation (ROSC) were annotated along the time axis. PEA and asystole were combined as a single state for the analysis of state development. The probability of staying in PEA/asystole over time was estimated non-parametrically. In addition, to distinguish between initial and secondary PEA/asystole, the latter was defined by the transition from VF/VT or ROSC. RESULTS: Among patients with initial PEA (n=179), 25% and 50% of patients had left PEA/asystole after 4 and 9 min of ALS efforts, respectively. The corresponding time points for patients with initial asystole (n=70) were 7.3 and 13.3 min, respectively. The probability of transition from secondary PEA/asystole to ROSC or VF/VT varied between 10% and 20% in each 2-4 min interval. CONCLUSION: The "optimal" first loop duration may be 4 min in initial PEA and 6-8 min in initial asystole. If secondary PEA/asystole is encountered, 2-min loop duration seems appropriate.