A retrospective study of pulseless electrical activity, bedside ultrasound identifies interventions during resuscitation associated with improved survival to hospital admission. A REASON Study

Ultrasound in Cardiopulmonary Arrest and Resuscitation: Constructing Comprehensive Implementation Frameworks in High-Risk Settings

OBJECTIVES

Information obtained from point-of-care ultrasound during cardiopulmonary arrest and resuscitation (POCUS-CA) can be used to identify underlying pathophysiology and provide life-sustaining interventions. However, integration of POCUS-CA into resuscitation care is inconsistent. We used expert consensus building methodology to help identify discrete barriers to clinical integration. We subsequently applied implementation science frameworks to generate generalizable strategies to overcome these barriers.

MEASURES AND MAIN RESULTS

Two multidisciplinary expert working groups used KJ Reverse-Merlin consensus building method to identify and characterize barriers contributing to failed POCUS-CA utilization in a hypothetical future state. Identified barriers were organized into affinity groups. The Center for Implementation Research (CFIR) framework and Expert Recommendations for Implementing Change (CFIR-ERIC) tool were used to identify strategies to guide POCUS-US implementation.

RESULTS

Sixteen multidisciplinary resuscitation content experts participated in the working groups and identified individual barriers, consolidated into 19 unique affinity groups that mapped 12 separate CFIR constructs, representing all 5 CFIR domains. The CFIR-ERIC tool identified the following strategies as most impactful to address barriers described in the affinity groups: identify and prepare champions, conduct local needs assessment, conduct local consensus discussions, and conduct educational meetings.

CONCLUSIONS

KJ Reverse-Merlin consensus building identified multiple barriers to implementing POCUS-CA. Implementation science methodologies identified and prioritized strategies to overcome barriers and guide POCUS-CA implementation across diverse clinical settings.

Artificial Intelligence-Based Left Ventricular Ejection Fraction by Medical Students for Mortality and Readmission Prediction

INTRODUCTION

Point-of-care ultrasound has become a universal practice, employed by physicians across various disciplines, contributing to diagnostic processes and decision-making.

AIM

To assess the association of reduced (<50%) left-ventricular ejection fraction (LVEF) based on prospective point-of-care ultrasound operated by medical students using an artificial intelligence (AI) tool and 1-year primary composite outcome, including mortality and readmission for cardiovascular-related causes.

METHODS

Eight trained medical students used a hand-held ultrasound device (HUD) equipped with an AI-based tool for automatic evaluation of the LVEF of non-selected patients hospitalized in a cardiology department from March 2019 through March 2020.

RESULTS

The study included 82 patients (72 males aged 58.5 ± 16.8 years), of whom 34 (41.5%) were diagnosed with AI-based reduced LVEF. The rates of the composite outcome were higher among patients with reduced systolic function compared to those with preserved LVEF (41.2% vs. 16.7%, p = 0.014). Adjusting for pertinent variables, reduced LVEF independently predicted the composite outcome (HR 2.717, 95% CI 1.083-6.817, p = 0.033). As compared to those with LVEF ≥ 50%, patients with reduced LVEF had a longer length of stay and higher rates of the secondary composite outcome, including in-hospital death, advanced ventilatory support, shock, and acute decompensated heart failure.

CONCLUSION

AI-based assessment of reduced systolic function in the hands of medical students, independently predicted 1-year mortality and cardiovascular-related readmission and was associated with unfavorable in-hospital outcomes. AI utilization by novice users may be an important tool for risk stratification for hospitalized patients.

Can absence of cardiac activity on point-of-care echocardiography predict death in out-of-hospital cardiac arrest? A systematic review and meta-analysis

AIM

The purpose of this systematic review and meta-analysis was to evaluate the accuracy of the absence of cardiac motion on point-of-care echocardiography (PCE) in predicting termination of resuscitation (TOR), short-term death (STD), and long-term death (LTD), in adult patients with cardiac arrest of all etiologies in out-of-hospital and emergency department setting.

METHODS

A systematic review and meta-analysis was conducted based on PRISMA guidelines. A literature search in Medline, EMBASE, Cochrane, WHO registry, and ClinicalTrials.gov was performed from inspection to August 2022. Risk of bias was evaluated using QUADAS-2 tool. Meta-analysis was divided into medical cardiac arrest (MCA) and traumatic cardiac arrest (TCA). Sensitivity and specificity were calculated using bivariate random-effects, and heterogeneity was analyzed using I2 statistic.

RESULTS

A total of 27 studies (3657 patients) were included in systematic review. There was a substantial variation in methodologies across the studies, with notable difference in inclusion criteria, PCE timing, and cardiac activity definition. In MCA (15 studies, 2239 patients), the absence of cardiac activity on PCE had a sensitivity of 72% [95% CI 62-80%] and specificity of 80% [95% CI 58-92%] to predict LTD. Although the low numbers of studies in TCA preluded meta-analysis, all patients who lacked cardiac activity on PCE eventually died.

CONCLUSIONS

The absence of cardiac motion on PCE for MCA predicts higher likelihood of death but does not have sufficient accuracy to be used as a stand-alone tool to terminate resuscitation. In TCA, the absence of cardiac activity is associated with 100% mortality rate, but low number of patients requires further studies to validate this finding. Future work would benefit from a standardized protocol for PCE timing and agreement on cardiac activity definition.

The role of point-of-care ultrasound (POCUS) imaging in clinical outcomes during cardiac arrest: a systematic review

BACKGROUND

Cardiac arrest in hospital and out-of-hospital settings is associated with high mortality rates. Therefore, a bedside test that can predict resuscitation outcomes of cardiac arrest patients is of great value. Point-of-care ultrasound (POCUS) has the potential to be used as an effective diagnostic and prognostic tool during cardiac arrest, particularly in observing the presence or absence of cardiac activity. However, it is highly susceptible to "self-fulfilling prophecy" and is associated with prolonged cardiopulmonary resuscitation (CPR), which negatively impacts the survival rates of cardiac arrest patients. As a result, the current systematic review was created to assess the role of POCUS in predicting the clinical outcomes associated with out-of-hospital and in-hospital cardiac arrests.

METHODS

The search for scientific articles related to our study was done either through an electronic database search (i.e., PubMed, Medline, ScienceDirect, Embase, and Google Scholar) or manually going through the reference list of the relevant articles. A quality appraisal was also carried out with the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2), and the prognostic test performance (sensitivity and sensitivity) was tabulated.

RESULTS

The search criteria yielded 3984 articles related to our topic, of which only 22 were eligible for inclusion. After reviewing the literature, we noticed a wide variation in the definition of cardiac activity, and the statistical heterogeneity was high; therefore, we could not carry out meta-analyses. The tabulated clinical outcomes based on initial cardiac rhythm and definitions of cardiac activity showed highly inconsistent results.

CONCLUSION

POCUS has the potential to provide valuable information on the management of cardiac arrest patients; however, it should not be used as the sole predictor for the termination of resuscitation efforts.

POCUS literature primer: key papers on POCUS in cardiac arrest and shock

OBJECTIVE

The objective of this study is to identify the top five most influential papers published on the use of point-of-care ultrasound (POCUS) in cardiac arrest and the top five most influential papers on the use of POCUS in shock in adult patients.

METHODS

An expert panel of 14 members was recruited from the Canadian Association of Emergency Physicians (CAEP) Emergency Ultrasound Committee and the Canadian Ultrasound Fellowship Collaborative. The members of the panel are ultrasound fellowship trained or equivalent, are engaged in POCUS research, and are leaders in POCUS locally and nationally in Canada. A modified Delphi process was used, consisting of three rounds of sequential surveys and discussion to achieve consensus on the top five most influential papers for the use of POCUS in cardiac arrest and shock.

RESULTS

The panel identified 39 relevant papers on POCUS in cardiac arrest and 42 relevant papers on POCUS in shock. All panel members participated in all three rounds of the modified Delphi process, and we ultimately identified the top five most influential papers on POCUS in cardiac arrest and also on POCUS in shock. Studies include descriptions and analysis of safe POCUS protocols that add value from a diagnostic and prognostic perspective in both populations during resuscitation.

CONCLUSION

We have developed a reading list of the top five influential papers on the use of POCUS in cardiac arrest and shock to better inform residents, fellows, clinicians, and researchers on integrating and studying POCUS in a more evidence-based manner.

Femoral Arterial Doppler Use During Active Cardiopulmonary Resuscitation

STUDY OBJECTIVE

This study explored femoral arterial Doppler during active cardiopulmonary resuscitation (CPR) to identify and characterize the resumptions of cardiac activity without stopping CPR.

METHODS

This was a proof-of-concept study exploring arterial Doppler during cardiac arrest. Patients in cardiac arrest undergoing active CPR were prospectively enrolled. Arterial Doppler of the common femoral artery was recorded during CPR and during pauses in CPR. CPR-induced arterial tracings and native cardiac-induced tracings were analyzed for rate and peak systolic velocity. Cardiac activity on echocardiogram during pause in CPR was classified as "absent," "disorganized," or "organized." Descriptive data and survival are presented as mean and 95% confidence intervals (CI), as well as sensitivity and specificity of Doppler during active CPR in detecting native cardiac pulsations.

RESULTS

Sixteen patients with 48 paired Doppler recordings during active CPR, pause in CPR, and associated echocardiogram were enrolled. Native cardiac-induced tracings were visible during 39.6% of pauses in CPR (19 of 48) and during 18.8% of the periods of active CPR (9 of 48). Arterial pulsations were more frequently visualized with organized contractions by echocardiogram (10 of 14, 71%) than disorganized contractions (9 of 22, 41%). Arterial Doppler was 100% specific and 50% sensitive in detecting organized cardiac activity during active CPR. Patients with visible native cardiac pulsations during active CPR demonstrated 0% mortality compared with 67% mortality without visible arterial pulsations.

CONCLUSION

Arterial Doppler tracings may identify the resumption of native cardiac activity during active CPR; however, more research is needed.

Transesophageal Echocardiography in Patients in Cardiac Arrest: The Heart and Beyond

Point of care ultrasound involves different ultrasound modalities and is useful to assist management in emergent clinical situations such as cardiac arrest. The use of point of care ultrasound in cardiac arrest has mainly been described using transthoracic echocardiography as a diagnostic and as a prognostic tool. However, cardiac evaluation using transthoracic echocardiography might be challenging because of patient-related or technical factors. Furthermore, its use during pulse check pauses has been associated with delays in chest compression resumption. Transesophageal echocardiography (TEE) overcomes these limitations by providing reliable and continuous imaging of the heart without interfering with cardiopulmonary resuscitation. In this narrative review we describe the role of TEE during cardiopulmonary resuscitation in 4 different applications: (1) chest compression quality feedback; (2) rhythm characterization; (3) diagnosis of reversible causes; and (4) procedural guidance. Considering its limitations, we propose an algorithm for the integration of TEE in patients with cardiac arrest with a focus on these 4 applications and extend its use to extracardiac applications.

Paramedic-Performed Carotid Artery Ultrasound Heralds Return of Spontaneous Circulation in Out-of-Hospital Cardiac Arrest: A Case Report

Point-of-Care Ultrasound (POCUS) has been demonstrated to have multiple applications in the care of critically ill and injured patients, especially given its portability and ease of use. These characteristics of POCUS make it ideal for use in the prehospital environment as well. We present a case that highlights a novel application of ultrasound in the prehospital management of out-of-hospital cardiac arrest (OHCA).

[Prehospital ultrasound and cardiological emergencies]

Technological advances over the past two decades have paved the way for the prehospital use of ultrasound. This practice was first developed in traumatology and then in a multitude of other indications, including cardiology. The development of pulmonary ultrasound is certainly the most visible illustration of this. Firstly, because it is an extra-cardiac examination that provides the answer to a cardiac question. Secondly because from a theoretical point of view this ultrasound indication was a bad indication for the use of ultrasound due to the air contained in the thorax. Thirdly, because this indication has become a 'standard of care' when caring for a patient with dyspnea - a practice that has become widespread during the COVID epidemic. In patients with heart failure, ultrasound has a high diagnostic power (including for alternative diagnoses) which is all the more precise since the technique is non-invasive, the response is obtained quickly, the examination can be repeated at desire to follow the evolution of the patient. The main other indications for prehospital ultrasound are cardiac arrest to search for a curable cause, identification of residual mechanical cardiac activity, monitoring of cerebral perfusion; chest pain, for both positive and negative diagnoses; shock for the search for an etiology and therapeutic follow-up or even pulmonary embolism or ultrasound for the search for dilation of the right ventricle which is now at the forefront of the recommendation algorithm.

An Innovative Curriculum For Teaching Transesophageal Echocardiography (TEE) to Emergency Medicine Residents

BACKGROUND

Focused transesophageal echocardiogram (TEE) can be a valuable tool for emergency physicians (EP) during cardiac arrest.

OBJECTIVES

We sought to demonstrate the ability of emergency medicine (EM) residents without prior TEE experience to perform a simulated four-view TEE following a short, flipped conference curriculum.

METHODS

This was a prospective, simulation-based study where EM residents participated in the following four-view TEE curriculum: 1 h of online content reviewed prior to a 20-min in-person lecture and 30-min hands-on practice using a TEE trainer. Each resident attended four testing sessions over an 8-week period and performed a total of 25 TEE scans. Each TEE scan was graded in real time using a 10-point checklist by a TEE-credentialed EP. Interrater reliability of the checklist was calculated using the kappa coefficient (κ). A random sample of 10% of the TEE scans were reviewed by a TEE expert using a standard ultrasound 1-5 scale for image acquisition quality, with a "3" considered to be satisfactory. Residents completed an online pretest and posttest.

RESULTS

Twenty-four residents participated. Mean pre- and posttest scores were 52% (SD 16) and 92% (SD 12), respectively. Mean TEE scores using the 10-point checklist after sessions one and four were 9.4 (SD 0.4) and 9.7 (SD 0.3), respectively. Mean time to complete each TEE scan after sessions one and four were 118.1 (SD 28.3) and 57.1 (SD 17.0) s, respectively. The κ for the checklist was 1. The median score for the image acquisition review was 3 (interquartile range 3-4).

CONCLUSIONS

This simplified flipped conference curriculum can train EM residents to competently perform TEE in a simulated environment.

Cardiac Tamponade: A Case for Point-of-Care Ultrasound

•

POCUS is increasingly being used in the evaluation of critically ill patients.

•

POCUS can shorten pulse check duration and prognosticate outcomes in cardiac arrest.

•

POCUS can identify the etiology of cardiac arrest after the first image.

•

POCUS can be used without delay or interrupting treatment.

Point-of-Care Ultrasound Use by EMS Providers in Out-of-Hospital Cardiac Arrest

AIM

Paramedics received training in point-of-care ultrasound (POCUS) to assess for cardiac contractility during management of medical out-of-hospital cardiac arrest (OHCA). The primary outcome was the percentage of adequate POCUS video acquisition and accurate video interpretation during OHCA resuscitations. Secondary outcomes included POCUS impact on patient management and resuscitation protocol adherence.

METHODS

A prospective, observational cohort study of paramedics was performed following a four-hour training session, which included a didactic lecture and hands-on POCUS instruction. The Prehospital Echocardiogram in Cardiac Arrest (PECA) protocol was developed and integrated into the resuscitation algorithm for medical non-shockable OHCA. The ultrasound (US) images were reviewed by a single POCUS expert investigator to determine the adequacy of the POCUS video acquisition and accuracy of the video interpretation. Change in patient management and resuscitation protocol adherence data, including end-tidal carbon dioxide (EtCO2) monitoring following advanced airway placement, adrenaline administration, and compression pauses under ten seconds, were queried from the prehospital electronic health record (EHR).

RESULTS

Captured images were deemed adequate in 42/49 (85.7%) scans and paramedic interpretation of sonography was accurate in 43/49 (87.7%) scans. The POCUS results altered patient management in 14/49 (28.6%) cases. Paramedics adhered to EtCO2 monitoring in 36/36 (100.0%) patients with an advanced airway, adrenaline administration for 38/38 (100.0%) patients, and compression pauses under ten seconds for 36/38 (94.7%) patients.

CONCLUSION

Paramedics were able to accurately obtain and interpret cardiac POCUS videos during medical OHCA while adhering to a resuscitation protocol. These findings suggest that POCUS can be effectively integrated into paramedic protocols for medical OHCA.

Comparison of outcomes between pulseless electrical activity by electrocardiography and pulseless myocardial activity by echocardiography in out-of-hospital cardiac arrest; secondary analysis from a large, prospective study

OBJECTIVE

To measure prevalence of discordance between electrical activity recorded by electrocardiography (ECG) and myocardial activity visualized by echocardiography (echo) in patients presenting after cardiac arrest and to compare survival outcomes in cohorts defined by ECG and echo.

METHODS

This is a secondary analysis of a previously published prospective study at twenty hospitals. Patients presenting after out-of-hospital arrest were included. The cardiac electrical activity was defined by ECG and contemporaneous myocardial activity was defined by bedside echo. Myocardial activity by echo was classified as myocardial asystole--the absence of myocardial movement, pulseless myocardial activity (PMA)--visible myocardial movement but no pulse, and myocardial fibrillation--visualized fibrillation. Primary outcome was the prevalence of discordance between electrical activity and myocardial activity.

RESULTS

793 patients and 1943 pauses in CPR were included. 28.6% of CPR pauses demonstrated a difference in electrical activity (ECG) and myocardial activity (echo), 5.0% with asystole (ECG) and PMA (echo), and 22.1% with PEA (ECG) and myocardial asystole (echo). Twenty-five percent of the 32 pauses in CPR with a shockable rhythm by echo demonstrated a non-shockable rhythm by ECG and were not defibrillated. Survival for patients with PMA (echo) was 29.1% (95%CI-23.9-34.9) compared to those with PEA (ECG) (21.4%, 95%CI-17.7-25.6).

CONCLUSION

Patients in cardiac arrest commonly demonstrate different electrical (ECG) and myocardial activity (echo). Further research is needed to better define cardiac activity during cardiac arrest and to explore outcome between groups defined by electrical and myocardial activity.

Quantitative characterization of left ventricular function during pulseless electrical activity using echocardiography during out-of-hospital cardiac arrest

BACKGROUND

Several prospective studies have demonstrated that the echocardiographic detection of any myocardial activity during PEA is strongly associated with higher rates of return of spontaneous circulation (ROSC). We hypothesized that PEA represents a spectrum of disease in which not only the presence of myocardial activity, but more specifically that the degree of left ventricular (LV) function would be a predictor of outcomes. The purpose of this study was to retrospectively assess the association between LV function and outcomes in patients with OHCA.

MATERIALS AND METHODS

Using prospectively obtained data from an observational cohort of patients receiving focused echocardiography during cardiopulmonary resuscitation (CPR) in the Emergency Department (ED) setting, we analyzed 312 consecutive subjects with available echocardiography images with initial rhythm of PEA. We used left ventricular systolic fractional shortening (LVFS), a unidimensional echocardiographic parameter to perform the quantification of LV function during PEA. Regression analyses were performed independently to evaluate for relationships between LVFS and a primary outcome of ROSC and secondary outcome of survival to hospital admission. We analyzed LVFS both as a continuous variable and as a categorial variable using the quartiles and the median to perform multiple different comparisons and to illustrate the relationship of LVFS and outcomes of interest. We performed survival analysis using Cox proportional hazards model to evaluate the hazard corresponding to length of resuscitation.

RESULTS

We found a positive association between LVFS and the primary outcome of ROSC (OR 1.04, 95%CI 1.01-1.08), but not with the secondary outcome of survival to hospital admission (OR 1.02, 95%CI 0.96-1.08). Given that the relationship was not linear and that we observed a threshold effect in the relationship between LVFS and outcomes, we performed an analysis using quartiles of LVFS. The predicted probability of ROSC was 75% for LVFS between 23.4-96% (fourth quartile) compared to 47% for LVFS between 0-4.7% (first quartile). The hazard of not achieving ROSC was significantly greater for subjects with LVFS below the median (13.1%) compared to the subgroup with LVFS greater than 13.1% (p < 0.05), with the separation of the survival curves occurring at approximately 40 min of resuscitation duration.

CONCLUSIONS

Left ventricular function measured by LVFS is positively correlated with higher probability of ROSC and may be associated with higher chances of survival in patients with PEA arrest.

Transoesophageal echocardiography in cardiac arrest: A systematic review

AIMS

To identify, appraise and synthesize all available clinical evidence to evaluate the diagnostic role of transoesophageal echocardiography (TEE) during resuscitation of in-hospital (IHCA) and out-of-hospital cardiac arrest (OHCA) in the identification of reversible causes of cardiac arrest and cardiac contractility.

METHODS

We conducted a systematic review following PRISMA guidelines. Medline, EMBASE, Web of Science Core Collection, Proquest Dissertations, Open Grey, CDSR, Cochrane Central, Cochrane Clinical Answers, and the clinicaltrials.gov registry were searched for eligible studies. Studies involving adult patients, with non-traumatic cardiac arrest in whom TEE was used for intra-arrest evaluation, were included. Case studies and case series, animal studies, reviews, guidelines and editorials were excluded. The QUADAS-2 tool was used for quality assessment of all studies.

RESULTS

Eleven studies with a total of 358 patients were included. Four studies involved perioperative IHCA, three involved OHCA, and four were mixed population settings. Overall, the risk of bias in the selected studies was either high or unclear due to evidence or lack of information. In all 11 studies, TEE allowed the identification of reversible causes of arrest. We found significant heterogeneity in the criteria used to interpret findings, TEE protocol used, and timing of TEE.

CONCLUSION

Due to heterogeneity of studies, small sample size and inconsistent reference standard, the evidence for TEE in cardiac arrest resuscitation is of low certainty and is affected by a high risk of bias. Further studies are needed to better understand the true diagnostic accuracy of TEE in identifying reversible causes of arrest and cardiac contractility.

Utilization of Point-of-care Echocardiography in Cardiac Arrest: A Cross-sectional Pilot Study

INTRODUCTION

Point-of-care (POC) echocardiography (echo) is a useful adjunct in the management of cardiac arrest. However, the practice pattern of POC echo utilization during management of cardiac arrest cases among emergency physicians (EP) is unclear. In this pilot study we aimed to characterize the utilization of POC echo and the potential barriers to its use in the management of cardiac arrest among EPs.

METHODS

This was a cross-sectional survey of attending EPs who completed an electronic questionnaire composed of demographic variables (age, gender, year of residency graduation, practice setting, and ultrasound training) and POC echo utilization questions. The first question queried participants regarding frequency of POC echo use during the management of cardiac arrest. Branching logic then presented participants with a series of subsequent questions regarding utilization and barriers to use based on their responses.

RESULTS

A total of 155 EPs participated in the survey, with a median age of 39 years (interquartile range 31-67). Regarding POC echo utilization, participants responded that they always (66%), sometimes (30%), or never (4.5%) use POC echo during cardiac arrest cases. Among participants who never use POC echo, 86% reported a lack of training, competency, or credentialing as a barrier to use. Among participants who either never or sometimes use POC echo, the leading barrier to use (58%) reported was a need for improved competency. Utilization was not different among participants of different age groups (P = 0.229) or different residency graduation dates (P = 0.229). POC echo utilization was higher among participants who received ultrasound training during residency (P = 0.006) or had completed ultrasound fellowship training (P <0.001) but did not differ by gender (P = 0.232), or practice setting (0.231).

CONCLUSION

Only a small minority of EPs never use point-of-care echocardiography during the management of cardiac arrest. Lack of training, competency, or credentialing is reported as the leading barrier to use among those who do not use POC echo during cardiac arrest cases. Participants who do not always use ultrasound are less likely to have received ultrasound training during residency.

Feasibility of focused cardiac ultrasound during cardiac arrest in the emergency department

Background

Focused cardiac ultrasound (FOCUS) can aid in evaluation and management of patients with cardiac arrest, but image quality in this population has been questioned. Our goal was to determine how often adequate imaging can be obtained in cardiac arrest patients.

Methods

We conducted a prospective cohort study to examine the utility of FOCUS in cardiac arrest. All patients who presented to the Emergency Department (ED) in cardiac arrest or who had cardiac arrest while in the ED over 6 months were prospectively identified. FOCUS images were obtained as part of routine clinical care. Patients with images obtained were paired with age- and gender-matched controls who underwent FOCUS for another indication during the study period. Image quality was scored by two blinded reviewers using a 0–4 scale, with a score of ≥ 2 considered adequate.

Results

There were 137 consecutive cardiac arrests, 121 out-of-hospital and 16 in-hospital, during the study period. FOCUS images were recorded in 126 (92%), who were included in the analysis. The average age was 58 years, and 45% were female. Ninety-seven studies (77%) were obtained during advanced cardiac life support while 29 (23%) were obtained after return of spontaneous circulation. The controls were appropriately matched. Of the cardiac arrest studies, 106 (84%) were rated adequate, compared to 116 (92%) in controls (p = 0.08). When compared to control FOCUS studies, the scores given to studies of cardiac arrest patients were lower (p = 0.001).

Conclusions

FOCUS can reliably be used during cardiac arrest to obtain images adequate to answer clinical questions and guide therapies.

Epinephrine plus chest compressions is superior to epinephrine alone in a hypoxia-induced porcine model of pseudo-pulseless electrical activity

Aim

Pseudo-pulseless electrical activity (pseudo-PEA) is a global hypotensive ischemic state with retained coordinated myocardial contractile activity and an organized ECG with no clinically detectable pulses. The role of standard external chest compressions (CPR) and its associated intrinsic hemodynamics remains unclear in the setting of pseudo-PEA. We undertook an experimental trial to compare epinephrine alone versus epinephrine with CPR in the treatment of pseudo-PEA.

Methods

Using a porcine model of hypoxic pseudo-PEA, we randomized 12 Yorkshire male swine to resuscitation with epinephrine only (control) (0.0015 mg/kg) versus epinephrine plus standard CPR (intervention). Animals who achieved return of spontaneous circulation (ROSC) were stabilized, fully recovered to hemodynamic and respiratory baseline, and rearrested up to 6 times. Primary outcome was ROSC defined as a sustained systolic blood pressure (SBP) of 60 mmHg for 2 min. Secondary outcomes included time to ROSC, coronary perfusion pressure (CoPP), and end-tidal carbon dioxide (ETCO₂).

Results

Among 47 events of pseudo-PEA in 12 animals, we observed significantly higher proportion of ROSC when treatment included CPR (14/21 – 67%) compared to epinephrine alone (4/26 – 15%) (p = 0.0007). CoPP, aortic pressures and ETCO₂ were significantly higher, and right atrial pressures were lower in the intervention group.

Conclusions

In a swine model of hypoxia-induced pseudo-PEA, epinephrine plus CPR was associated with improved intra-arrest hemodynamics and higher probability of ROSC. Thus, epinephrine plus CPR may be superior to epinephrine alone in the treatment of patients with pseudo-PEA.

Development and validation of a novel image quality rating scale for echocardiography during cardiac arrest

Objective

Research into echocardiography (echo) during cardiac arrest has suffered from methodological flaws that limit aggregation of findings. We developed and validated a novel image rating scale for qualitative analysis of echo images obtained during resuscitation.

Methods

A novel 5-point ordinal rating scale was developed and validated using recorded echo images from 145 consecutive cardiac arrest patients. Recorded echo images were reviewed in a blinded fashion by investigators experienced in cardiac arrest echo, and image quality was rated using this scale. Cardiac activity was subsequently classified as no activity, disorganized activity and organized activity. The primary outcome was inter-rater agreement using the image quality rating scale. Secondary outcome was the qualitative evaluation of the type of cardiac activity.

Results

A total of 235 ultrasounds were analyzed by study investigators using the image quality rating scale. The overall image quality agreement between reviewers using the scale was good with a weighted kappa of 0.65. Agreement for image quality in subxyphoid images was greater than in parasternal images (0.65-0.52). Echo analysis of cardiac activity showed no activity (33%), disorganized activity (18%), and organized activity (49%). Agreement was great for presence or absence of "cardiac activity" and "organized cardiac activity" with a kappa of 0.84 and 0.78.

Conclusions

A novel image quality rating scale for echo during cardiac arrest demonstrates substantial agreement between reviewers. Agreement regarding the presence or absence, as well as the organization of cardiac activity was substantial.

Echocardiographic pre-pause imaging and identifying the acoustic window during CPR reduces CPR pause time during ACLS - A prospective Cohort Study

Objectives

Pre-pause imaging during cardiopulmonary resuscitation (CPR) involves the acquisition of poor-quality, brief images immediately prior to stopping CPR to allow shorter, better-quality images during the pause. We hypothesize that pre-pause imaging is associated with a decrease in CPR pause length and shorter image acquisition time.

Methods

Prospective, interventional cohort study enrolling out-of-hospital (OOH) cardiac arrest patients. Pre-pause imaging involves pre-localizing of the approximate sonographic window during CPR to support subsequent fine tuning when CPR pauses. Physicians were educated on pre-pause imaging and data was recorded prior- and post- introduction of pre-pause imaging into American cardiac life support (ACLS). Timing of CPR pauses and identification of interventions and events during pause were recorded (e.g., intubation, defibrillation, multiple cardiac ultrasounds). Ultrasound (US) images were reviewed for image quality using a 5-point scale. Primary outcome was length of CPR pause with and without pre-pause imaging. Secondary outcome included US length.

Results

One hundred and forty five subjects presenting after OOH cardiac arrest were enrolled over 13 months, 70 during the baseline period prior to pre-pause imaging and 75 after pre-pause imaging was integrated into ACLS. Pre-pause imaging decreased CPR pause length from 28.3 s (95%CI 25.1–31.5) to 12.8 s (95%CI 11.9–13.7). US image acquisition time decreased with pre-pause imaging from 20.4 (95%CI 18.0–22.7) to 11.0 s (95%CI 10.1–11.8). US image quality was unchanged despite the decrease in image acquisition time. (3.0 (95%CI 2.8–3.2) vs 2.7 (95%CI 2.5–2.9)). Multivariate modeling showed that ultrasound did not prolong CPR pause length.

Conclusion

Pre-pause imaging was associated with significant decrease in CPR pause length and US image acquisition time. Pre-pause imaging should be encouraged for any clinicians who use ultrasound during ACLS.

Cardiac Arrest Secondary to Accidental Hypothermia: Who Should We Resuscitate?

Cardiac arrest with a degree of concurrent hypothermia is not a rare presentation. This presentation, often in remote areas, poses a challenge for the prehospital physician because the cause of the arrest will significantly alter decision making and prognostication. Survival from cardiac arrest secondary to accidental hypothermia is significantly greater than that of normothermic arrests when appropriate triage and management decisions are made. The complexity of this decision benefits from a specific algorithm to follow in the event of such a casualty presenting. This article systematically reviews the literature on cardiac arrest secondary to accidental hypothermia and provides recommendations in addition to a novel algorithm to aid the responding prehospital clinician in deciding if a hypothermic resuscitation standard operating procedure should be implemented.

Synchronized Chest Compressions for Pseudo-PEA: Proof of Concept and a Synching Algorithm

Objective: The two objectives of this report are: first, to describe a comparison of chest compressions unsynchronized or synchronized to native cardiac activity in a porcine model of hypotension, and second, to develop an algorithm to provide synchronized chest compressions throughout a range of native heart rates likely to be encountered when treating PEA cardiac arrest. Methods: We adapted our previously developed signal-guided CPR system to provide compressions synchronized to native electrical activity in a porcine model of hypotension as a surrogate of PEA arrest. We describe the first comparison of unsynchronized to synchronized compressions in a single animal as a proof-of-concept. We developed an algorithm to provide optimal synchronized chest compressions regardless of intrinsic PEA heart rate while simultaneously maintaining the chest compression rate within a desired range. We tested the algorithm with computer simulations measuring the proportion of intrinsic and compression beats that were synchronized, and the compression rate and its standard deviation, as a function of intrinsic heart rate and heart rate jitter. Results: We demonstrate and compare unsynchronized versus synchronized chest compressions in a single porcine model with an intrinsic rhythm and hypotension. Synchronized, but not unsynchronized, chest compressions were associated with increased blood pressure and coronary perfusion pressure. Our synchronized chest compression algorithm is able to provide synchronized chest compressions to over 90% of intrinsic beats for most heart rates while maintaining an average compression rate between 90 and 140 compressions per minute with relatively low variability. Conclusions: Synchronized chest compression therapy for pulseless electrical rhythms is feasible. A high degree of synchronization can be maintained over a broad range of intrinsic heart rates while maintaining the compression rate within a satisfactory range. Further investigation to assess benefit for treatment of PEA is warranted.

Sudden cardiac arrest and ventricular arrhythmias following first type I myocardial infarction in the contemporary era

INTRODUCTION

Myocardial infarction (MI) is associated with an increase in subsequent heart failure (HF), recurrent ischemic events, sudden cardiac arrest, and ventricular arrhythmias (SCA-VA). The primary objective of the study to determine the role of intercurrent HF and ischemic events on the development of SCA-VA following first type I MI.

METHODS AND RESULTS

A retrospective cohort study of patients experiencing first type 1 MI in Olmsted County, Minnesota (2002-2012) was conducted by identifying patients using the medical records linkage system (Rochester epidemiology project). Patients aged ≥18 years were followed from the time of MI till death or 31 July, 2017. Intercurrent HF and ischemic events were the primary exposures following MI and their association with outcome SCA-VA was assessed. Eight hundred and sixty-seven patients (mean age was 63 ± 14.5 years; 69% male; 49.8% ST-elevation myocardial infarction) who had their first type I MI during the study period were included. Majority of acute MI patients were revascularized using percutaneous coronary intervention and bypass surgery (628 [72.43%] and 87 [10.03%] respectively). During a mean follow-up of 7.69 ± 4.17 years, HF, recurrent ischemic events and SCA-VA occurred in 155 (17.9%), 245 (28.3%), and 40 (4.61%) patients respectively. Low ejection fraction (adjusted hazard ratio [HR] 0.95; 95% confidence interval [CI], 0.93-0.98; P < .001), intercurrent HF (adjusted HR 3.11; 95% CI, 1.39-6.95; P = .006) and recurrent ischemic events (adjusted HR 3.47; 95% CI, 1.68-7.18; P < .001) were associated with subsequent SCA-VA.

CONCLUSION

SCA-VA occurred in a small proportion of patients after MI and is associated with intercurrent HF and recurrent ischemic events.

Resuscitative Cardiopulmonary Ultrasound and Transesophageal Echocardiography in the Emergency Department

Resuscitative ultrasound describes point-of-care applications that provide diagnostic information, physiologic monitoring, and procedural guidance in critically ill patients. This article reviews the evaluation of ventricular function, identification of pericardial effusion and tamponade, evaluation of preload and fluid responsiveness, and hemodynamic monitoring, as some of the main applications where this modality can help emergency physicians during resuscitation of critically ill patients.

Does Point-of-care Ultrasound Use Impact Resuscitation Length, Rates of Intervention, and Clinical Outcomes During Cardiac Arrest? A Study from the Sonography in Hypotension and Cardiac Arrest in the Emergency Department (SHoC-ED) Investigators

Introduction

This third study in the Sonography in Hypotension and Cardiac Arrest in the Emergency Department (SHoC-ED) series examined potential relationships between point-of-care ultrasound (PoCUS) use and the length of resuscitation, the frequency of interventions, and clinical outcomes during cardiac arrest.

Methods

A health records review was completed for adult patients (>19 years, without a do not resuscitate (DNR) order) who presented to a tertiary emergency department in cardiac arrest between 2010 and 2014. Patients were grouped based on PoCUS use and findings for cardiac activity. Data were analyzed for length of resuscitation, frequency of interventions, return of spontaneous circulation (ROSC), survival to hospital admission (SHA), and survival to hospital discharge (SHD).

Results

Of the 223 patients who met inclusion criteria, 180 (80.7%) received assessment by PoCUS during cardiac arrest management in the emergency department (ED). In the PoCUS group, 21 (11.6%) demonstrated cardiac activity and 159 (88.4%) did not. Patients with activity on PoCUS had longer mean resuscitation times (27.3; 95% confidence interval 17.7-37.0 min) than patients with no activity (11.51; 10.2-12.8 min) and patients who did not receive a PoCUS exam (14.36; 9.89-18.8 min). Patients with cardiac activity on PoCUS were more likely to receive endotracheal intubation (ET; 95.23%; 86.13-104.35%) and epinephrine (Epi; 100%; 100-100%) than patients with no activity (ET: 46.54%; 38.8-54.3%; Epi: 82.39%; 76.50-88.31%) and those with no PoCUS (ET: 65.11%; 50.87-79.36%; Epi: 81.39%; 69.76-93.03%). Those with no cardiac activity on PoCUS were much less likely to achieve ROSC (19.5%; 13.4-25.6), SHA (6.9%; 2.97-10.86%) and SHD (0.6%; -0.5-1.8%) compared to those with cardiac activity on PoCUS (ROSC; 76.19%; 57.97-94.4%), SHA (33.3%; 13.2-53.5%), SHD (9.5%; -3-22.07%), and those with no PoCUS (ROSC 39.5%; 24.9-54.1%; SHA 27.9%; 14.5- 41.3%, and SHD 6.9%; -0.6-14.59).

Conclusions

Emergency department cardiac arrest patients with cardiac activity on PoCUS received longer resuscitation with higher rates of intervention as compared to those with negative findings or when no PoCUS was performed. Patients with cardiac activity on PoCUS had improved clinical outcomes as compared with patients not receiving PoCUS, and patients with no activity on PoCUS.

Feasibility of Out-of-Hospital Cardiac Arrest Ultrasound by EMS Physicians

INTRODUCTION

Point-of-care ultrasound (POCUS) has been suggested as a useful tool to predict survival and guide interventions in out-of-hospital cardiac arrest (OHCA). While POCUS has been deployed in prehospital settings, a minimal amount of data exists on prehospital use, particularly by personnel with limited ultrasound experience. We aimed to characterize the feasibility and barriers to prehospital POCUS during OHCA by emergency medicine services (EMS) physicians in training.

METHODS

We deployed the SonoSite iViz portable ultrasound device for use by EMS physicians for OHCA in an urban EMS system. All physicians received POCUS education as part of their graduate medical training and were provided an instructional video on use of the SonoSite iViz device. POCUS use was limited to identifying cardiac motion during pulse checks, without interrupting resuscitation, and the results could be used to supplement management at the physicians' discretion. Data were recorded prospectively by saving images on the device and through a custom electronic form within the patient care report. The primary measure was the frequency of use of POCUS during OHCA. Secondarily, we characterized agreement by expert (ultrasound fellowship trained) faculty (using a kappa statistic) and identified reported barriers to the use of prehospital POCUS.

RESULTS

From November 2016 to March 2017, 348 physician field responses were reviewed, including 127 cases of OHCA. There were 106 patients remaining in arrest on physician arrival, with 56 (52.8%) cases of POCUS use. Still or video images were recorded in 48 cases; video in 34 cases. From video images, agreement in identifying cardiac motion between the EMS physician and expert reviewer occurred in 91% of cases (K = 0.82). Reasons cited for not using POCUS included return of circulation soon before or after arrival, prioritizing clinical interventions, not having the ultrasound device, mechanical failure, and cessation of resuscitation per advanced directives.

CONCLUSION

Use of POCUS by EMS physicians to detect cardiac activity in OHCA is feasible and correlates with expert interpretation. Several avoidable barriers were identified and should be considered in the future implementation of prehospital POCUS. Larger studies are needed to determine what role POCUS may play in prehospital cardiac arrest management.

In-hospital cardiac arrest: are we overlooking a key distinction?

PURPOSE OF REVIEW

To review the epidemiology, peri-arrest management, and research priorities related to in-hospital cardiac arrest (IHCA) and explore key distinctions between IHCA and out-of-hospital cardiac arrest (OHCA) as they pertain to the clinician and resuscitation scientist.

RECENT FINDINGS

IHCA is a common and highly morbid event amongst hospitalized patients in the United States. As compared with patients who experience an OHCA, patients who experience an IHCA tend to have more medical comorbidities, have a witnessed arrest, and be attended to by professional first responders. Further, providers resuscitating patients from IHCA commonly have access to tools and information not readily available to the OHCA responders. Despite these differences, society guidelines for the peri-arrest management of patients with IHCA are often based on data extrapolated from the OHCA population. To advance the care of patients with IHCA, clinicians and investigators should recognize the many important distinctions between OHCA and IHCA.

SUMMARY

IHCA is a unique disease entity with an epidemiology and natural history that are distinct from OHCA. In both research and clinical practice, physicians should recognize these distinctions so as to advance the care of IHCA victims.