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Detection of Pulmonary Embolism During Cardiac Arrest-Ultrasonographic Findings Should Be Interpreted With Caution
Abstract
Objectives:
The aim of this study was to test the hypothesis that the right ventricle is more dilated during resuscitation from cardiac arrest caused by pulmonary embolism, compared with hypoxia and primary arrhythmia.
Design:
Twenty-four pigs were anesthetized and cardiac arrest was induced using three different methods. Pigs were resuscitated after 7 minutes of untreated cardiac arrest. Ultrasonographic images were obtained and the right ventricular diameter was measured.
Setting:
University hospital animal laboratory.
Subjects:
Female crossbred Landrace/Yorkshire/Duroc pigs (27-32 kg).
Interventions:
Pigs were randomly assigned to cardiac arrest induced by pulmonary embolism, hypoxia, or primary arrhythmia.
Measurements and main results:
There was no difference at baseline. During induction of cardiac arrest, the right ventricle dilated in all groups (p < 0.01 for all). The primary endpoint was right ventricle diameter at the third rhythm analysis: 32 mm (95% CI, 29-36) for pulmonary embolism which was significantly larger than both hypoxia: 23 mm (95% CI, 20-27) and primary arrhythmia: 25 mm (95% CI, 22-28)-the absolute difference was 7-9 mm. Physicians with basic training in focused cardiac ultrasonography were able to detect a difference in right ventricle diameter of approximately 10 mm with a sensitivity of 79% (95% CI, 64-94) and a specificity of 68% (95% CI, 56-80).
Conclusions:
The right ventricle was more dilated during resuscitation when cardiac arrest was caused by pulmonary embolism compared with hypoxia and primary arrhythmia. However, the right ventricle was dilated, irrespective of the cause of arrest, and diagnostic accuracy by physicians with basic training in focused cardiac ultrasonography was modest. These findings challenge the paradigm that right ventricular dilatation on ultrasound during cardiopulmonary resuscitation is particularly associated with pulmonary embolism.
... However, patients without cardiac activity had longer resuscitation attempts, of which 11% regained cardiac activity during the resuscitation attempts meaning that the sonographic findings are not static [21]. Therefore, cardiac sonographic findings must be cautiously interpreted [37,38]. ...
... In addition, POCUS can be used to identify reversible causes of PEA and asystole, such as hypovolemia, pulmonary embolism, and pericardial effusion. However, detecting pulmonary embolism during resuscitation is modest at best since the right ventricle is usually dilated [37,38]. ...
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.
... However, identification of certain underlying pathologies with POCUS might not be possible due to changes caused by the arrest. [8,9] Further, the interpretation of point-of-care (POC) laboratory results may pose significant challenges, and the appropriate treatment can vary [10,11]. A recent study on POC laboratory analyses during OHCA found a small improvement in survival among patients who underwent POC laboratory analyses during resuscitation. ...
... This is consistent with previous studies, which have demonstrated the feasibility of ultrasound and its capability as a diagnostic tool during CPR [5,[15][16][17][18][19]. However, diagnosing pulmonary embolism by POCUS is highly unspecific method since the dilation of right ventricle can be caused by several other aetiologies demonstrated in animal studies [8,9]. Further, the prognostic effects of identifying these pathologies with POC ultrasounds is unknown. ...
Background
The cardiopulmonary resuscitation (CPR) guidelines recommend identifying and correcting the underlying reversible causes of out-of-hospital cardiac arrest (OHCA). However, it is uncertain how often these causes can be identified and treated. Our aim was to estimate the frequency of point of care ultrasound examinations, blood sample analyses and cause-specific treatments during OHCA.
Methods
We performed a retrospective study in a physician-staffed helicopter emergency medical service (HEMS) unit. Data on 549 non-traumatic OHCA patients who were undergoing CPR at the arrival of the HEMS unit from 2016 to 2019 were collected from the HEMS database and patient records. We also recorded the frequency of ultrasound examinations, blood sample analyses and specific therapies provided during OHCA, such as procedures or medications other than chest compressions, airway management, ventilation, defibrillation, adrenaline or amiodarone.
Results
Of the 549 patients, ultrasound was used in 331 (60%) and blood sample analyses in 136 (24%) patients during CPR. A total of 85 (15%) patients received cause-specific treatment, the most common ones being transportation to extracorporeal CPR and percutaneous coronary intervention (PCI) (n = 30), thrombolysis (n = 23), sodium bicarbonate (n = 17), calcium gluconate administration (n = 11) and fluid resuscitation (n = 10).
Conclusion
In our study, HEMS physicians deployed ultrasound or blood sample analyses in 84% of the encountered OHCA cases. Cause-specific treatment was administered in 15% of the cases. Our study demonstrates the frequent use of differential diagnostic tools and relatively infrequent use of cause-specific treatment during OHCA. Effect on protocol for differential diagnostics should be evaluated for more efficient cause specific treatment during OHCA.
... Recent studies have shown that right ventricular (RV) dilation in cardiac arrest can be caused by a myriad of factors that range from primary dysrhythmias to hyperkalemia, challenging the historical assumption that RV dilation in cardiac arrest equates to pulmonary emboli [1][2][3][4]. Further porcine models have demonstrated that RV dilation does not meaningfully differ regardless of the possible underlying cause, whether it be hypovolemia, hyperkalemia, primary dysrhythmias, or pulmonary embolism [3]. ...
... Pulmonary embolism was low on the differential as the patient did not have escalating oxygen requirements and remained normoxic on the ventilator throughout the resuscitation. Studies have elucidated that hyperkalemia, hypovolemia, and hypoxia could also cause dilation [1][2][3]. Hyperkalemia was part of the differential, as our patient suffered from CKD, and therefore, we administered calcium chloride. Ultimately, laboratory findings did not reveal hyperkalemia. ...
Right ventricular (RV) dilation has been observed in patients in cardiac arrest. Historically, this phenomenon is almost always attributed to massive pulmonary embolism. However, recent advancements have revealed that there are many other causes of RV dilation in cardiac arrest. In this case report, we present the case of an elderly woman who was found in cardiac arrest with an initial normal left ventricle to RV ratio with subsequent development of RV dilation in the midst of resuscitation without changes to other hemodynamic parameters. This case further bolsters the complex nature of cardiac physiology in cardiac arrest and the need for further investigation.
... The evaluation of the inferior vena cava (IVC) and hypovolemia are not included by many protocols, due that a distended IVC can be found with no forward flow (8) . Small pneumothoraces can occur from rib fractures during CPR that do not need acute intervention (8) and a distended right ventricle (RV) during resuscitation is often due to hypoxia, acidosis or arrhythmias, and this RV strain is not necessarily due to pulmonary embolism (2,8,9) . ...
... 3. Start to review the vi deos during the cardiac compressions: look for pericardial fluid, RV: left ventricular size ratio, cardiac standstill, fine VF (11) . 4. Report your results to the CPR leader (9) . This communication must be done during ongoing CPR with statements such as «no significant observation», «bad quality», «heart is squeezing/contracting», «cardiac standstill», «enlarged right ventricle», «pericardial effusion» (11) . 5. Leader must close the loop that the information was received and do changes accordingly. ...
The incidence of cardiac arrest associated with anesthesia is approximately 5.6 per 10,000 cases and the precipitating causes are often known. Transesophageal echocardiography is the modality of choice during unexplained hemodynamic instability or cardiac arrest; but its utility is limited by the need of extensive user training. On the other hand, surface ultrasound has the advantage of simpler user training requirements and offers evaluation of multiple organs. Although its use intraoperatively is limited by poor access to the patient, and postoperatively by dressing and air, it still can be feasible if transesophageal echocardiography is not possible. This manuscript develops a protocol for using POCUS during a cardiac arrest, and emphasizes practical tips for image acquisition and communication of its interpretation. RESUMEN. La incidencia de paro cardíaco asociado a la anestesia es de aproximadamente 5.6 por 10,000 casos y las causas son a menudo desconocidas. La ecocardiografía transesofágica es la modalidad de elección durante la inestabilidad hemodinámica no explicada; pero su utilidad es limitada por la necesidad de un entrenamiento extensi-vo del usuario. Por otra parte, el ultrasonido de superficie tiene la ventaja de requerimientos de entrenamiento más simples y ofrece la evaluación de múltiples órganos. Aunque su uso intraoperatorio es limitado por el pobre acceso al paciente y postoperatoriamente por los apósitos y el aire, ésta puede ser confiable si la ecocardiografía tran s esofágica no es posible. How to cite: Berrio-Valencia MI. Perioperative POCUS when the heart stops: futility or utility? Rev Mex Anestesiol. 2022; 45 (1): 71-73. https://dx.
... Whilst historically a dilated RV was felt to be akin to the diagnosis of PE, multiple studies have shown this not to be the case. 44,45 Animal studies have demonstrated the RV to be dilated in cardiac arrest of almost any aetiology. 44,45 Whilst the RV appears to be more dilated in the presence of a PE, this cannot be accurately relied upon in a resuscitation scenario. ...
... 44,45 Animal studies have demonstrated the RV to be dilated in cardiac arrest of almost any aetiology. 44,45 Whilst the RV appears to be more dilated in the presence of a PE, this cannot be accurately relied upon in a resuscitation scenario. ...
Echocardiography is being increasingly deployed as a diagnostic and monitoring tool in the critically ill. This rise in popularity has led to its recommendation as a core competence in intensive care, with several training routes available. In the peri-arrest and cardiac arrest population, point of care focused echocardiography has the potential to transform patient care and improve outcomes. Be it via diagnosis of shock aetiology and reversibility or assessing response to treatment and prognostication. This narrative review discusses current and future applications of echocardiography in this patient group and provides a structure with which one can approach such patients.
... After ROSC, one may intuitively think that an empty heart, a right ventricular (RV) dilation, or left wall motion abnormalities may respectively suggest acute hypovolemia, pulmonary embolism, and myocardial infarction as the root cause for cardiac arrest. A recent animal study by Aagaard et al (5) and a second study (6) published in this issue of Critical Care Medicine challenge these beliefs by suggesting that echo imaging may actually leave us in the dark. ...
... Once a diagnosis has been established and patients are stabilizing, repeated echo evaluations, with classical probes or single-use transesophageal probes, may have value to track myocardial recovery and guide hemodynamic therapy (8). Nevertheless, findings from Aagaard et al (5,6) challenge the diagnosis value of echocardiography right after cardiac arrest. As in many other critical situations, a preventive strategy is highly desirable. ...
... As an example, animal models have been developed that mimic different causes of cardiac arrest to address specific research questions for each cause, that cannot be answered in a clinical trial. [46][47][48][49] ...
The purpose of this narrative review is to provide an overview of lessons learned from experimental cardiac arrest studies, limitations, translation to clinical studies, ethical considerations and future directions.
Cardiac arrest animal studies have provided valuable insights into the pathophysiology of cardiac arrest, the effects of various interventions, and the development of resuscitation techniques. However, there are limitations to animal models that should be considered when interpreting results. Systematic reviews have demonstrated that animal models rarely reflect the clinical condition seen in humans, nor the complex treatment that occurs during and after a cardiac arrest. Furthermore, animal models of cardiac arrest are at a significant risk of bias due to fundamental issues in performing and/or reporting critical methodological aspects. Conducting clinical trials targeting the management of rare cardiac arrest causes like e.g. hyperkalemia and pulmonary embolism is challenging due to the scarcity of eligible patients. For these research questions, animal models might provide the highest level of evidence and can potentially guide clinical practice.
To continuously push cardiac arrest science forward, animal studies must be conducted and reported rigorously, designed to avoid bias and answer specific research questions. To ensure the continued relevance and generation of valuable new insights from animal studies, new approaches and techniques may be needed, including animal register studies, systematic reviews and multilaboratory trials.
... Although RV dilation has been advocated as a sign of acute obstructive cause, RV acutely dilates after a few minutes of cardiac arrest as blood is shifted from vena cava to right cardiac cavities along its pressure gradient. Accordingly, the diagnosis of massive pulmonary embolism should not solely rely on RV dilatation in patients with prolonged CPR [9]. Focused TEE can advantageously be used during CPR since it does not interfere with chest compressions and provides high-quality images and additional windows to the heart and great vessels [3]. ...
... According to research, cardiac arrest patients have 3-4 folds more chance of survival if initial cardiac activity is reported (Gaspari et al., 2016). These patients receive long resuscitation attempts, and 10% of patients with cardiac standstill survived, proving that ultrasound findings are not definite (Aagaard et al., 2017). Thus, ultrasound findings should not be a basis for terminating CPR. ...
The study aimed to evaluate the competence and knowledge of the cardiac arrest team regarding CPR termination and the factors that influence this termination. A cross-sectional study was conducted in the Department of Cardiology, Shifa International Hospital April 2022-April 2023). A total of 300 cardiac arrest team members (physicians and nurses) designated to perform advanced cardiac life support were included in the study. Questionnaires were distributed among the participants inquiring about their competence and knowledge about terminating CPR. Of 100 physicians, 40 (40%) were not competent enough to decide on CPR termination. 10% of physicians and 5% of nurses agreed to be aware of the ERC termination guidelines, and only one physician and one nurse could state the contents. The majority of the participants reported terminating resuscitation if the patient was older than 90 years, absent direct pupillary reflex, true asystole, and witnessed cardiac arrest without bystander resuscitation in 10 minutes. Based on the results, the physicians and nurses in Pakistan are not competent in decision-making regarding CPR termination in cardiac arrest patients and are unaware of the factors and guidelines while making such decisions.
... Echocardiography during the cardiac arrest may identify a distended right ventricle with a flattened interventricular septum in cases of PE large enough to precipitate arrest, [78] although right ventricular dilatation in arrest should be interpreted with caution. [121] In terms of the treatment of the PE in the cardiac arrest Li et al published a meta-analysis in 2006 [79] of 8 papers that demonstrated that thrombolytics administered during cardiopulmonary resuscitation did improve survival, although inevitably there was also an increase in bleeding complications. In an RCT of 1000 patients with out of hospital arrests randomised to thrombolytic therapy, no improvement in survival was seen but the percentage of patients who actually had PE may have been low in this study. ...
More than 300 000 procedures are performed in cardiac catheter laboratories in the UK each year. The variety and complexity of percutaneous cardiovascular procedures have both increased substantially since the early days of invasive cardiology, when it was largely focused on elective coronary angiography and single chamber (right ventricular) permanent pacemaker implantation. Modern-day invasive cardiology encompasses primary percutaneous coronary intervention, cardiac resynchronisation therapy, complex arrhythmia ablation and structural heart interventions. These procedures all carry the risk of cardiac arrest.
We have developed evidence-based guidelines for the management of cardiac arrest in adult patients in the catheter laboratory. The guidelines include recommendations which were developed by collaboration between nine professional and patient societies that are involved in promoting high-quality care for patients with cardiovascular conditions. We present a set of protocols which use the skills of the whole catheter laboratory team and which are aimed at achieving the best possible outcomes for patients who suffer a cardiac arrest in this setting. We identified six roles and developed a treatment algorithm which should be adopted during cardiac arrest in the catheter laboratory. We recommend that all catheter laboratory staff undergo regular training for these emergency situations which they will inevitably face.
... 31 While PE is often included in the differential diagnosis of the patient in cardiac arrest, it is important to exercise caution in the interpretation of RV dilation during cardiac arrest as all causes of arrest are likely to result in some degree of RV dilation. 32,33 POCUS may also be used to evaluate for evidence of cardiac activity during a "code blue" scenario. Signs of cardiac activity during cardiac arrest are associated with increased survival compared to patients with no sonographic signs of cardiac activity. ...
Jake A Rice,1,2 Jonathan Brewer,2 Tyler Speaks,1 Christopher Choi,1 Peiman Lahsaei,1 Bryan T Romito1 1Department of Anesthesiology and Pain Management, The University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Department of Emergency Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USACorrespondence: Bryan T RomitoDepartment of Anesthesiology and Pain Management, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX, 75390-9068, USATel +1 214 648 7674Fax +1 214 648 5461Email Bryan.Romito@UTSouthwestern.eduAbstract: Point of care ultrasound (POCUS) allows for rapid, real-time evaluation of cardiovascular and respiratory pathology. The advent of portable, handheld devices and increased recognition by accrediting bodies of the importance of POCUS in guiding clinical decision making has expanded its use across the hospital setting and within medical training programs. POCUS allows clinicians to begin immediate investigation into their differential diagnoses without waiting for a formal imaging study, enhancing the speed of clinical interpretation. In addition to its diagnostic utility, POCUS can also inform clinicians of patients’ response to interventions when serial exams are obtained. This review examines the role of POCUS in the context of frequently encountered patients and highlights the key clinical questions that can be readily answered by POCUS.Keywords: hemodynamics, trauma, respiratory failure, hypotension
... Aagaard et al showed that the right ventricular was more dilated when CA was caused by pulmonary embolism compared with other etiologies such as primary arrhythmia. 14 Thrombolysis is a potentially beneficial treatment option for patients in cardiac arrest due to presumed PE. Javaudin et al showed that thrombolysis during cardiopulmonary resuscitation may contribute to survival. ...
We present the case of a 60-year-old woman who suddenly suffered a witnessed cardiac arrest and did not achieve return of spontaneous circulation despite being given 150-minute ultra-long cardiopulmonary resuscitation (CPR). During CPR, pulmonary embolism was suspected and was eventually diagnosed based on refractory pulseless electrical activity, elevated serum D-dimmer, and a markedly enlarged right ventricle chamber. After rescue thrombolytic alteplase therapy, the patient was successfully resuscitated and had a good neurological recovery.
... Although pulmonary embolism is suggested by significant right ventricular dilation or right ventricular thrombus on point-of-care ultrasound in patients not in cardiac arrest, animal data show right ventricular dilation during CPR is not specific for pulmonary embolism. 32,33 Large pulmonary embolisms also increase ventilatory dead-space and a 2018 animal study found a decreased end-tidal carbon dioxide (CO 2 ) to partial pressure of arterial CO 2 ratio in cardiac arrest from pulmonary embolism caused by an increased ventilation dead-space. 34 Thrombolysis improves outcome in patients with confirmed massive pulmonary embolism without cardiac arrest and is recommended for cardiac arrest secondary to pulmonary embolism, with thrombectomy recom mended when thrombolysis is contraindicated or ineffective. ...
Cardiopulmonary resuscitation prioritises treatment for cardiac arrests from a primary cardiac cause, which make up the majority of treated cardiac arrests. Early chest compressions and, when indicated, a defibrillation shock from a bystander give the best chance of survival with a good neurological status. Cardiac arrest can also be caused by special circumstances, such as asphyxia, trauma, pulmonary embolism, accidental hypothermia, anaphylaxis, or COVID-19, and during pregnancy or perioperatively. Cardiac arrests in these circumstances represent an increasing proportion of all treated cardiac arrests, often have a preventable cause, and require additional interventions to correct a reversible cause during resuscitation. The evidence for treating these conditions is mostly of low or very low certainty and further studies are needed. Irrespective of the cause, treatments for cardiac arrest are time sensitive and most effective when given early-every minute counts.
... The thrombi are therefore less heterogeneous, less rigid, and less fibrotic compared with a chronic thrombus from a patient (53). The thrombus size varies between models from small clots, which lodge distally (25,26,(31)(32)(33)(34)(35)(36)54), to large central PEs (37). The hemodynamic phenotype entails ranges of RV strain (37,54) and decompensated RV failure (21)(22)(23). ...
Right heart failure may be the ultimate cause of death in patients with acute or chronic pulmonary hypertension (PH). As PH is often secondary to other cardiovascular diseases, the treatment goal is to target the underlying disease. We do however know, that right heart failure is an independent risk factor, and therefore, treatments that improve right heart function may improve morbidity and mortality in patients with PH. There are no therapies that directly target and support the failing right heart and translation from therapies that improve left heart failure have been unsuccessful, with the exception of mineralocorticoid receptor antagonists. To understand the underlying pathophysiology of right heart failure and to aid in the development of new treatments we need solid animal models that mimic the pathophysiology of human disease. There are several available animal models of acute and chronic PH. They range from flow induced to pressure overload induced right heart failure and have been introduced in both small and large animals. When initiating new pre-clinical or basic research studies it is key to choose the right animal model to ensure successful translation to the clinical setting. Selecting the right animal model for the right study is hence important, but may be difficult due to the plethora of different models and local availability. In this review we provide an overview of the available animal models of acute and chronic right heart failure and discuss the strengths and limitations of the different models.
... However, an increasing amount of evidence suggests that this may be an ineffective method to rule in the diagnosis. While it has been well established that the presence of a pulmonary embolus can undoubtedly result in right heart strain that could manifest as a dilated RV, a number of other factors, such as hypovolemia, hyperkalemia, primary arrhythmias and pre-existing chronic right ventricular strain, have also been shown to produce similar right-sided enlargement during cardiac arrest [30][31][32]. ...
Patients with cardiac arrest present as a relatively frequent occurrence in the Emergency Department. Despite the advances in our understanding of the pathophysiology of cardiac arrest, managing the condition remains a stressful endeavor and currently implemented interventions, while beneficial, are still associated with a disappointingly low survivability. The majority of modern Advanced Life Support algorithms employ a standardized approach to best resuscitate the 'crashed' patient. However, management during resuscitation often encourages a 'one-size-fits-all' policy for most patients, with lesser attention drawn towards causality of the disease and factors that could alter resuscitative care. Life support providers are also often challenged by the limited bedside predictors of survival to guide the course and duration of resuscitation. Over the recent decades, point-of-care ultrasonography (PoCUS) has been gradually proving itself as a useful adjunct that could potentially bridge the gap in the recognition and evaluation of precipitants and end-points in resuscitation, thereby facilitating an improved approach to resuscitation of the arrested patient. Point-of-care ultrasound applications in the critical care field have tremendously evolved over the past four decades. Today, bedside ultrasound is a fundamental tool that is quick, safe, inexpensive and reproducible. Not only can it provide the physician with critical information on reversible causes of arrest, but it can also be used to predict survival. Of note is its utility in predicting worse survival outcomes in patients with cardiac standstill, i.e., no cardiac activity witnessed with ultrasound. Unfortunately, despite the increasing evidence surrounding ultrasound use in arrest, bedside ultrasound is still largely underutilized during the resuscitation process. This article reviews the current literature on cardiac standstill and the application of bedside ultrasound in cardiac arrests.
... AHA and ERC guidelines therefore suggest the use of ultrasound during resuscitation for diagnostic and prognostic purposes [38,39]. However, acute pulmonary heart can be related to acute circulatory failure and be non-specific of pulmonary embolism as recently highlighted [40]. ...
Background:
Pulmonary embolism (PE) represents 2% to 5% of all causes of out-of-hospital cardiac arrest (OHCA) and is associated with extremely unfavorable prognosis. In PE-related OHCA, inconsistent data showed that thrombolysis during cardiopulmonary resuscitation may favor survival.
Methods:
This was a retrospective, observational, multicenter study from July 2011 to March 2018. All adults with OHCA, treated by a mobile ICU and with a diagnosis of PE confirmed on hospital admission, were included. The primary end point was 30-day survival in a weighted population.
Results:
Of the 14,253 patients admitted to hospitals, 328 had a final diagnosis of PE and 246 were included in the analysis. In the group that received thrombolysis during resuscitation (n = 58), 14 (24%) received alteplase, 43 (74%) received tenecteplase, and one (2%) received streptokinase. Thirty-day survival was higher in the thrombolysis group than in the control group (16% vs 6%; P = .005; adjusted log-rank test) but the good neurologic outcome was not significantly different (10% vs 5%; adjusted relative risk, 1.97; 95% CI, 0.70-5.56). Median duration of stay in the ICU was 1 (0-5) day for the thrombolysis group and 1 (0-3) day for the control group (P = .23).
Conclusions:
In patients with OHCA with confirmed PE and admitted with recuperation of spontaneous circulation in the hospital, there was significantly higher 30-day survival in those who received thrombolysis during cardiopulmonary resuscitation compared with patients who did not receive thrombolysis.
... In case of cardiac arrest, signs are difficult to interpret because right ventricle (RV) is dilated during resuscitation, irrespective of the cause of arrest. But in studding model of cardiac arrest caused by PE, hypoxia or primary arrhythmia, the RV was more dilated when cardiac arrest was caused by PE [6]. Ultrasonographic findings of RV dilation during cardiac arrest should be interpreted with caution and integrated in the whole clinical context. ...
... Therefore, cardiac ultrasound findings during resuscitation should be used and interpreted with caution. 23,24 Finally, 1 in 12 physicians reported that they would terminate in case of prolonged cardiac arrest with a shockable rhythm, which is contrary to guideline recommendations. 17 This last finding corresponds well with a previous study examining termination decisions in inhospital cardiac arrests demonstrating that 3 (8%) of 36 resuscitation attempts were terminated with a shockable rhythm present. ...
Introduction
Many cardiopulmonary resuscitation (CPR) attempts are unsuccessful and must be terminated. On the contrary, premature termination results in a self-fulfilling prophecy. This study aimed to investigate 1) physicians’ self-assessed competence in terminating CPR, 2) physicians’ and nurses’ knowledge of the European Resuscitation Council guidelines on termination, and 3) single factors leading to termination.
Methods
Questionnaires were distributed at advanced cardiac life support (ACLS) courses at a university hospital in Denmark. Participants included ACLS health care providers, ie, physicians and nurses from cardiac arrest teams, intensive care and anesthetic units or medical wards with a duty to provide ACLS. Physicians were divided into junior physicians (house officers) and experienced physicians (specialist registrars and consultants).
Results
Overall, 308 participants responded (104 physicians and 204 nurses, response rate: 98%). Among physicians, 37 (36%) did not feel competent to decide when to terminate CPR (junior physicians: n=16, 64%, compared with experienced physicians: n=21, 28%, P=0.002). Two (2%) physicians and one (0.5%) nurse were able to state the contents of termination guidelines. Several factors were reported to impact termination, including absence of a pupillary light reflex (physicians: 17%, nurses: 22%) and cardiac standstill on echocardiography (physicians: 18%, nurses: 20%). Moreover, nine (9%) physicians and 35 (17%) nurses would terminate prolonged CPR despite a shockable rhythm present.
Conclusion
One-third of all physicians did not feel competent to decide when to terminate CPR. Physicians’ and nurses’ knowledge of termination guidelines was poor, and both professions reported unvalidated or controversial factors as a single reason for terminating CPR.
... Chez le porc, le ventricule droit se dilate dès la première minute après l'apparition d'une fibrillation ventriculaire, alors que le ventricule gauche se dilate plus tardivement [24,25]. Cette dilatation persiste pendant la réanimation, y compris en cas d'ACR hypoxique et d'EP, même si elle semble plus marquée dans ce dernier cas [26]. Ainsi, dans le cas de l'ACR avec absence de mouvement cardiaque, la dilatation seule des cavités droites n'est pas toujours synonyme d'EP, sauf en cas de mise en évidence d'un thrombus ou d'une prise en charge très précoce (ACR intrahospitalier ou devant une équipe médicale) [27,28]. ...
L’arrêt cardiorespiratoire (ACR) est une situation fréquente pour les structures d’urgences et de réanimation, et l’utilisation de l’échographie y est recommandée par les sociétés savantes. Elle doit impérativement se faire sans augmentation des temps d’interruption du massage cardiaque externe. Après formation, elle permet de détecter rapidement et facilement la présence d’une contractilité myocardique qui est un élément pronostique important pouvant aider dans la décision d’arrêter la RCP. Le recours à des protocoles bien établis avec des équipes entraînées permet d’éviter une interruption prolongée de la RCP. Cependant, aucune étude humaine de grande ampleur n’a permis de décrire de manière fiable pendant l’ACR la sémiologie échographique des causes curables que constituent l’hypovolémie, l’embolie pulmonaire, la tamponnade et le pneumothorax compressif.
... Some of the same authors from this group have reported previously, in a porcine model of cardiac arrest, that right ventricular dilation is common in all causes of arrest (although more extreme in pulmonary embolism) and can be seen in hypovolemic arrest instead of collapsing ventricles. [14,15] Thus, the absence of collapsing ventricles on POCUS may not contradict the clinical assessment of hypovolemia as a cause. ...
In circulatory arrest, the first minutes and hours are crucial - rapid and adequate care can significantly increase the chances of survival. A large number of disciplines are involved in the recommendations and guidelines for out-of-hospital resuscitation. In particular, the European Resuscitation Council (ERC) as well as the European Society of Cardiology (ESC) and the American Heart Association (AHA) are leading the way. Both the ambulance service and the accepting hospital are faced with major challenges in this regard. This article will illustrate the most important steps during and after resuscitation and discuss innovations.
Rapid diagnostic tools available to the emergency physician caring for cardiac arrest patients are limited. Focused ultrasound (US), and in particular, focused echocardiography, is a useful tool in the evaluation of patients in cardiac arrest. It can help identify possible causes of cardiac arrest like tamponade and pulmonary embolism, which can guide therapy. US can also yield prognostic information, with lack of cardiac activity being highly specific for failure to achieve return of spontaneous circulation. US may also be used to aid in procedural guidance. Recently, focused transesophageal echocardiography has been used in the emergency department setting.
Point-of-care ultrasound (POCUS) involves different ultrasound modalities and is useful to assist management in emergent clinical situations such as cardiac arrest. The use of POCUS in cardiac arrest has mainly been described using transthoracic echocardiography (TTE) both as a diagnostic and prognostic tool. However, cardiac evaluation using TTE may be challenging due to 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 (CPR). In this narrative review we describe the role of TEE during CPR in four different applications: (1) Chest compression quality feedback; (2) Rhythm characterization; (3) Diagnosis of reversible causes and (4) Procedural guidance. Considering its own limitations, we propose an algorithm for the integration of TEE in cardiac arrest focusing on these four applications and extending its reach to extra-cardiac applications.
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.
High-risk pulmonary embolism (PE) is a life-threatening condition that must be recognised and treated rapidly. The importance of correct risk stratification to guide therapeutic decisions has prompted the introduction of multidisciplinary PE response teams (PERTs). The recommended first-line treatment for high-risk PE is intravenous thrombolysis. Alternatives to consider if thrombolysis has insufficient effect or may cause significant haemorrhagic complications include catheter-directed intervention (CDI) and surgical thrombectomy. For patients in deep shock or cardiac arrest, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can be instituted for cardiopulmonary rescue and support during CDI, thrombectomy or pharmacological treatment. We present a complex case of high-risk PE that illustrates the importance of an early PERT conference and repeated decision-making when the initial therapy fails. After a trial of thrombolysis with insufficient effect, VA-ECMO was used to reverse circulatory and respiratory collapse in a patient with PE and recurrent episodes of cardiac arrest.
Background
Some researchers have reported thatapplying compressioncloser to the maximum diameter of the left ventricle (Point_max.LV) isassociated with worse clinical outcomes, challenging its traditional position as optimum compression point (Point_optimum). By locatingthe mid‐sternum (the actual compression site)in terms of Point_max.LV and its right ventricular equivalent (Point_max.RV),we aimed to determine its optimumhorizontal position associated with increased chances of returnofspontaneouscirculation (ROSC).
Methods
A retrospective,cross‐sectional study was performed at a university hospital from 2014 to 2019 on non‐traumatic out‐of‐hospital cardiac arrest (OHCA)victims who underwent chest computed tomography. On absolute x‐axis, we designatedthe x‐coordinate of the mid‐sternum (x_mid‐sternum) as 0 and leftward direction as positive. Re‐definingthe x‐coordinateof Point_max.RV and Point_max.LV as 0 and 1 interventricular unit (IVU), respectively, wecould convert x_mid‐sternumto‘−x_max.RV/(x_max.LV − x_max.RV) (IVU)’.Using multiple logistic regression analysis, we investigated whether this converted x_mid‐sternum was associated with clinical outcomes, adjusting core elements of the Utstein template.
Results
Among 887 non‐traumatic OHCAvictims, 124[64.4 ± 16.7 years, 43 women (34.7%)]were enrolled. Of these, 80 (64.5%) exhibitedROSC. X_mid‐sternum ranging from − 1.71 to 0.58(−0.36 ± 0.38) IVU was categorised into quintiles: <−0.60, −0.60–−0.37, −0.37–−0.22, −0.22–−0.07 and ≥−0.07 (reference) IVU. The first quintile was positively associated with ROSC(odds ratio [95% confidence interval], 9.43 [1.44, 63.3]).
Conclusion
Point_optimum mightbe located far rightwards to Point_max.RV, challenging the traditional assumption identifying Point_optimum as Point_max.LV.
Introduction::
In massive pulmonary embolism (PE) with circulatory collapse or with cardiac arrest, treatment can be difficult. Often, the diagnosis is unclear, and the time to treatment is crucial. Our institution has had an out-of-hospital team intended for the treatment of accidental hypothermia with extra corporeal membrane oxygenation (ECMO) since 2004. The team has occasionally been involved in patients suffering massive PE.
Methods::
We were called to 38 patients with PE, but two were assessed as untreatable. Seventeen were treated with cardiopulmonary resuscitation followed by veno-arterial ECMO. Nineteen were prepared for ECMO with sheaths in the femoral vessels and were intensively observed during diagnosis and treatment. Five of these patients later progressed to ECMO due to cardiac arrest during treatment with thrombolytic medication. Most of the patients were treated with heparin and thrombolytic medication, but if the medications were contraindicated, they were treated with either surgical thrombectomy or only with heparin awaiting spontaneous thrombolysis.
Results::
Of the 36 patients we intended to treat, 25 (69%) survived one month and 20 survived one year (56%). Of the 22 patients treated with ECMO, 11 survived one month (50%) and 10 survived one year (45%).
Discussion::
The treatment could have been more uniform. It seems reasonable to build up a PE alert team with ECMO capability to take care of patients with massive PE.
Conclusion::
The treatment of thrombolytic medications in massive PE is risky, but if the patient is treated or prepared for ECMO, it can be lifesaving.
We describe the case of a 3-week postpartum 27-year-old woman who presented with chest pain to the emergency department shortly before developing cardiac arrest with refractory ventricular fibrillation. She was initially misdiagnosed and treated for presumed pulmonary embolism (PE) with thrombolysis. A total of 14 direct current cardioversion shocks were given and return of spontaneous circulation (ROSC) was achieved post thrombolysis. Subsequent CT pulmonary angiography excluded PE. A post-ROSC ECG demonstrated anterolateral ST elevation and she was transferred to the local cardiac unit for angiography. This revealed extensive dissection of the left anterior descending artery (LAD) with proximal occlusion. The diagnosis therefore was pregnancy-associated spontaneous artery dissection, a type of acute coronary syndrome. She received percutaneous intervention to her LAD with five drug-eluting stents. The patient survived and was discharged 5 days later. Her ventricular function is now grossly impaired, and had the correct diagnosis been arrived at sooner, this loss of function would have been less severe.
Introduction:
Identifying reversible causes of cardiac arrest is challenging. The diagnosis of pulmonary embolism is often missed. Pulmonary embolism increases alveolar dead space resulting in low end-tidal CO2 (EtCO2) relative to arterial CO2 (PaCO2) tension. Thus, a low EtCO2/PaCO2 ratio during resuscitation may be a sign of pulmonary embolism.
Methods:
Post hoc analysis of data from two porcine studies comparing ultrasonographic measurements of right ventricular diameter during resuscitation from cardiac arrest of different causes. Pigs were grouped according to cause of arrest (pulmonary embolism, hypovolemia, primary arrhythmia, hypoxia, or hyperkalaemia) and EtCO2/PaCO2 ratios were compared.
Results:
Data from 54 pigs were analysed. EtCO2 levels at the third rhythm analysis were significantly lower when cardiac arrest was caused by pulmonary embolism than by primary arrhythmia, hypoxia and hyperkalaemia, but there was no significant difference between pulmonary embolism and hypovolemia. In contrast, PaCO2 levels were higher in cardiac arrest caused by pulmonary embolism than in the other causes of cardiac arrest. Consequently, the EtCO2/PaCO2 ratio was lower in pulmonary embolism 0.2 (95%CI 0.1-0.4), than in hypovolaemia 0.5 (95%CI 0.3-0.6), primary arrhythmia 0.7 (95%CI 0.7-0.8), hypoxia 0.5 (95%CI 0.4-0.6), and hyperkalaemia 0.6 (95%CI 0.6-0.7).
Conclusion:
A low EtCO2/PaCO2 ratio during cardiopulmonary resuscitation suggests pulmonary embolism.
Objectives:
Pulmonary embolism is a rarely reported and potentially treatable cause of cardiac arrest in children and adolescents. The objective of this case series is to describe the course of five adolescent patients with in-hospital cardiac arrest secondary to pulmonary embolism.
Design:
Case series.
Setting:
Single, large academic children's hospital.
Patients:
All patients under the age of 18 years (n = 5) who experienced an in-hospital cardiac arrest due to apparent pulmonary embolism from August 1, 2013, to July 31, 2017.
Interventions:
All five patients received systemic thrombolytic therapy (IV tissue plasminogen activator) during cardiac arrest or periarrest during ongoing resuscitation efforts.
Measurements and main results:
Five adolescent patients, 15-17 years old, were treated for pulmonary embolism-related cardiac arrests during the study period. These accounted for 6.3% of all children and 25% of adolescents (12-17 yr old) receiving at least 5 minutes of in-hospital cardiopulmonary resuscitation during the study period. All five had venous thromboembolism risk factors. Two patients had known, extensive venous thrombi at the time of cardiac arrest, and one was undergoing angiography at the time of arrest. The diagnoses of pulmonary embolism were based on clinical suspicion, bedside echocardiography (n = 4), and low end-tidal CO2 levels relative to arterial CO2 values (n = 5). IV tissue plasminogen activator was administered during cardiopulmonary resuscitation in three patients and after the return of spontaneous circulation, in the setting of severe hemodynamic instability, in the other two patients. Four of five patients were successfully resuscitated and survived to hospital discharge.
Conclusions:
Pulmonary embolism was recognized as the etiology of multiple adolescent cardiac arrests in this single-center series and may be more common than previously reported. Recognition, high-quality cardiopulmonary resuscitation, and treatment with thrombolytic therapy resulted in survival in four of five patients.
Introduction:
Advanced life support (ALS) guidelines recommend ultrasound to identify reversible causes of cardiac arrest. Right ventricular (RV) dilatation during cardiac arrest is commonly interpreted as a sign of pulmonary embolism. The RV is thus a focus of clinical ultrasound examination. Importantly, in animal studies ventricular fibrillation and hypoxia results in RV dilatation. Tension pneumothorax (tPTX) is another reversible cause of cardiac arrest, however, the impact on RV diameter remains unknown.
Aim:
To investigate RV diameter evaluated by ultrasound in cardiac arrest caused by tPTX or hypoxia.
Methods:
Pigs were randomized to cardiac arrest by either tPTX (n = 9) or hypoxia (n = 9) and subsequently resuscitated. Tension pneumothorax was induced by injection of air into the pleural cavity. Hypoxia was induced by reducing tidal volume. Ultrasound images of the RV were obtained throughout the study. Tension pneumothorax was decompressed after the seventh rhythm analysis. The primary endpoint was RV diameter after the third rhythm analysis.
Results:
At cardiac arrest the RV diameter was 17 mm (95% CI: 13; 21) in the tPTX group and 36 mm (95% CI: 33; 40) in the hypoxia group (P < 0.01, n = 9 for both). At third rhythm analysis RV diameter was smaller in the tPTX group: 12 mm (95% CI: 7; 16) vs. hypoxia group: 28 mm (25; 32) (P < 0.01). After decompression no difference existed between groups: tPTX 29 mm (95% CI: 23; 34) vs. hypoxia 29 mm (95% CI: 20; 38).
Conclusion:
The RV diameter is smaller during cardiopulmonary resuscitation in cardiac arrest caused by tPTX when compared with hypoxia. The difference disappears after tPTX decompression.
Objectives:
Dilation of the right ventricle during cardiac arrest and resuscitation may be inherent to cardiac arrest rather than being associated with certain causes of arrest such as pulmonary embolism. This study aimed to compare right ventricle diameter during resuscitation from cardiac arrest caused by hypovolemia, hyperkalemia, or primary arrhythmia (i.e., ventricular fibrillation).
Design:
Thirty pigs were anesthetized and then randomized to cardiac arrest induced by three diffrent methods. Seven minutes of untreated arrest was followed by resuscitation. Cardiac ultrasonographic images were obtained during induction of cardiac arrest, untreated cardiac arrest, and resuscitation. The right ventricle diameter was measured. Primary endpoint was the right ventricular diameter at the third rhythm analysis.
Setting:
University hospital animal laboratory.
Subjects:
Female crossbred Landrace/Yorkshire/Duroc pigs (27-32 kg).
Interventions:
Pigs were randomly assigned to cardiac arrest caused by either hypovolemia, hyperkalemia, or primary arrhythmia.
Measurements and main results:
At the third rhythm analysis during resuscitation, the right ventricle diameter was 32 mm (95% CI, 29-35) in the hypovolemia group, 29 mm (95% CI, 26-32) in the hyperkalemia group, and 25 mm (95% CI, 22-28) in the primary arrhythmia group. This was larger than baseline for all groups (p = 0.03). When comparing groups at the third rhythm analysis, the right ventricle was larger for hypovolemia than for primary arrhythmia (p < 0.001).
Conclusions:
The right ventricle was dilated during resuscitation from cardiac arrest caused by hypovolemia, hyperkalemia, and primary arrhythmia. These findings indicate that right ventricle dilation may be inherent to cardiac arrest, rather than being associated with certain causes of arrest. This contradicts a widespread clinical assumption that in hypovolemic cardiac arrest, the ventricles are collapsed rather than dilated.
Objective:
Pulmonary embolism often causes cardiac arrest. When this occurs, thrombolytic therapy is not routinely administered. There are multiple reasons for this, including difficulty with rapidly adequately diagnosing the embolus, the lack of good data supporting the use of thrombolytics during resuscitation, the belief that thrombolytic therapy is ineffective once a patient has already arrested, the difficulty of obtaining thrombolytics at the bedside rapidly enough to administer during a code, and the increased risks of bleeding, particularly with ongoing chest compressions. In this case report, we present a patient who was successfully treated with thrombolytic therapy during pulmonary embolism-induced cardiopulmonary arrest and discuss the role of thrombolytics in cardiopulmonary resuscitation.
Design:
Case report.
Setting:
Surgical ICU in a comprehensive cancer center.
Patient:
A 56-year-old man who developed hypotension, dyspnea, hypoxia, and pulseless electrical activity 10 days after resection of a benign colon lesion with a right hemicolectomy and primary end-to-end anastomosis.
Interventions:
After a rapid bedside echocardiogram suggesting pulmonary embolus, thrombolytic therapy was administered during cardiopulmonary resuscitative efforts.
Measurements and main results:
The patient had a return of spontaneous circulation and showed improvement in repeat echocardiographic imaging. He had a prolonged course in the ICU and hospital, but eventually made an essentially complete clinical recovery.
Conclusion:
As bedside echocardiographic technology becomes more rapidly and readily available, the rapid diagnosis of pulmonary embolism and use of thrombolytics during cardiopulmonary resuscitation may need to be more routinely considered a potential therapeutic adjunctive measure.
End tidal carbon dioxide (ETCO(2)) monitoring during advanced life support (ALS) using capnography, is recommended in the latest international guidelines. However, several factors might complicate capnography interpretation during ALS. How the cause of cardiac arrest, initial rhythm, bystander cardiopulmonary resuscitation (CPR) and time impact on the ETCO(2) values are not completely clear. Thus, we wanted to explore this in out-of-hospital cardiac arrested (OHCA) patients.
The study was carried out by the Emergency Medical Service of Haukeland University Hospital, Bergen, Norway. All non-traumatic OHCAs treated by our service between January 2004 and December 2009 were included. Capnography was routinely used in the study, and these data were retrospectively reviewed together with Utstein data and other clinical information.
Our service treated 918 OHCA patients, and capnography data were present in 575 patients. Capnography distinguished well between patients with or without return of spontaneous circulation (ROSC) for any initial rhythm and cause of the arrest (p<0.001). Cardiac arrests with a respiratory cause had significantly higher levels of ETCO(2) compared to primary cardiac causes (p<0.001). Bystander CPR affected ETCO(2)-recordings, and the ETCO(2) levels declined with time.
Capnography is a useful tool to optimise and individualise ALS in cardiac arrested patients. Confounding factors including cause of cardiac arrest, initial rhythm, bystander CPR and time from cardiac arrest until quantitative capnography had an impact on the ETCO(2) values, thereby complicating and limiting prognostic interpretation of capnography during ALS.
A reliable, animal model of massive, totally occlusive, pulmonary embolism (PE) is lacking.
To design an animal model of totally occlusive PE and to challenge the model by a plasminogen activator.
In eight anaesthetized pigs (approximately 90 kg) a massive preformed autologous thrombus was injected into the caval vein. One animal was autopsied to assess the extent of injected clot, whereas in the other animals extracorporeal life support (ECLS) was initiated and continued for three hours. These animals received 100 mg rt-PA. Blood gases, coagulation tests, creatine kinase (CK), lactate dehydrogenase (LDH), end-tidal CO2, systemic and pulmonary artery blood pressures and flow were registered.
All animals went into circulatory arrest within 2 minutes after injection of the thrombus. In the animal where ECLS was not started, autopsy relieved a totally occlusive embolus of the pulmonary artery. The ECLS maintained a systemic blood flow of 6-8 L/min with adequate oxygenation and CO2-removal. However, lactate increased and base-excess became negative. Ddimer increased, fibrinogen decreased, and CK and LDH increased. All seven animals were weaned from ECLS. Despite the rt-PA treatment, the animals had at that time low end tidal CO2/PaCO2 ratio and increased mean pulmonary arterial pressure, suggesting a significant amount of embolic material remaining in the pulmonary artery.
This model of massive, totally occlusive, pulmonary embolism mimics well fatal PE seen in the clinic, and has the potential for use in testing of new therapeutic interventions.
Basic life support (BLS), advanced cardiovascular life support (ACLS), and post–cardiac arrest care are labels of convenience that each describe a set of skills and knowledge that are applied sequentially during the treatment of patients who have a cardiac arrest. There is overlap as each stage of care progresses to the next, but generally ACLS comprises the level of care between BLS and post–cardiac arrest care.
ACLS training is recommended for advanced providers of both prehospital and in-hospital medical care. In the past, much of the data regarding resuscitation was gathered from out-of-hospital arrests, but in recent years, data have also been collected from in-hospital arrests, allowing for a comparison of cardiac arrest and resuscitation in these 2 settings. While there are many similarities, there are also some differences between in- and out-of-hospital cardiac arrest etiology, which may lead to changes in recommended resuscitation treatment or in sequencing of care. The consideration of steroid administration for in-hospital cardiac arrest (IHCA) versus out-of-hospital cardiac arrest (OHCA) is one such example discussed in this Part.
The recommendations in this 2015 American Heart Association (AHA) Guidelines Update for Cardiopulmonary Resuscitation (CPR) and Emergency Cardiovascular Care (ECC) are based on an extensive evidence review process that was begun by the International Liaison Committee on Resuscitation (ILCOR) after the publication of the ILCOR 2010 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations 1 and was completed in February 2015.2
In this in-depth evidence review process, the ILCOR task forces examined topics and then generated prioritized lists of questions for systematic review. Questions were first formulated in PICO (population, intervention, comparator, outcome) format,3 and then a search strategy and inclusion and exclusion criteria were defined and a search for relevant articles was performed. The evidence was evaluated by using …
The International Liaison Committee on Resuscitation (ILCOR) Advanced Life Support (ALS) Task Force performed detailed systematic reviews based on the recommendations of the Institute of Medicine of the National Academies1 and using the methodological approach proposed by the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) Working Group.2 Questions to be addressed (using the PICO [population, intervention, comparator, outcome] format)3 were prioritized by ALS Task Force members (by voting). Prioritization criteria included awareness of significant new data and new controversies or questions about practice. Questions about topics no longer relevant to contemporary practice or where little new research has occurred were given lower priority. The ALS Task Force prioritized 42 PICO questions for review. With the assistance of information specialists, a detailed search for relevant articles was performed in each of 3 online databases (PubMed, Embase, and the Cochrane Library).
By using detailed inclusion and exclusion criteria, articles were screened for further evaluation. The reviewers for each question created a reconciled risk of bias assessment for each of the included studies, using state-of-the-art tools: Cochrane for randomized controlled trials (RCTs),4 Quality Assessment of Diagnostic Accuracy Studies (QUADAS)-2 for studies of diagnostic accuracy,5 and GRADE for observational studies that inform both therapy and prognosis questions.6
GRADE evidence profile tables7 were then created to facilitate an evaluation of the evidence in support of each of the critical and important outcomes. The quality of the evidence (or confidence in the estimate of the effect) was categorized as high, moderate, low, or very low,8 based on the study methodologies and the 5 core GRADE domains of risk of bias, inconsistency, indirectness, imprecision, and other considerations (including publication bias).9
These evidence profile tables were then used to create a …
IntroductionIn critical care, early diagnosis and correct treatment are of the utmost importance. Focused ultrasonography has gained acceptance as a pivotal tool for this by elucidating the underlying pathology. For example, massive pulmonary embolism is characterised by right ventricular dilatation. However, theoretically these characteristics might also be generated by asphyxia and the consequent hypoxia. We aimed to evaluate the ultrasonographic characteristics of asphyxia in a porcine model.Methods
Nineteen (13 intervention, 6 control) piglets were subjected to asphyxia until cardiac arrest, by disconnecting the ventilator tube. Ultrasonographic short-axis cine loops of the left ventricle were obtained every 30 seconds. The left ventricular (LV) eccentricity index (index of LV D-shaping) was quantified along with LV end-diastolic/end-systolic areas. Invasive pressures were measured throughout.ResultsThe LV eccentricity index increased from 1.14 (1.10–1.31) to 1.86 (1.48–2.38), (P = 0.002), after 1.5 min, receded thereafter to baseline levels followed by a second increase after 5.5 min. LV end-diastolic area decreased from 11.6 cm2 (11.1–13.2) to 6.3 cm2 (3.3 –11.0) after 2.0 min (P = 0.009). Subsequently, values returned to the baseline level.DiscussionThe early and transient acute dilatation of the RV, coinciding with D-shaping of the LV and decrease in LV end-diastolic area seen in our study represent a combination of ultrasonographic characteristics normally attributed to pulmonary embolism. Early changes in ventricular chamber sizes and shape with septal flattening related to asphyxia can occur, but appear to be transient and disappear as circulatory collapse progresses, in an animal model. Despite this, asphyxia may represent a cause of ultrasonographic misinterpretation.
The present study aimed to elucidate RV function and structure in COPD patients without PH.
There is little knowledge of RV function and remodeling in COPD without PH.
Thirty-four controls and 98 patients with COPD were included. The patient population was divided in two groups by right heart catheterization, no-PH (mPAP) <25 mmHg) and PH (mPAP≥25 mmHg). Echocardiographic TDI variables as RV isovolumic acceleration, peak systolic strain and RV myocardial performance index were measured at basal free wall, and RV wall thickness and RV internal dimension in the RV outflow tract.
The increase of RV wall thickness and RV dimension were more evident from controls to no PH, 3.5±0.5 to 5.5±1.0 mm (p<0.01) and 1.5±0.2 to 2.0±0.5 cm (p<0.01), than from no-PH to PH, 5.5±1.0 to 6.6±1.1mm (p<0.01) and 2.0±0.5 to 2.1±0.3 cm (NS), respectively. Similarly, RV isovolumic acceleration, performance index and strain deteriorated significantly from controls to no-PH and from no-PH to PH (p<0.01). Significant correlations were observed between mPAP and RV isovolumic acceleration, performance index and strain and RV wall thickness (p<0.01). RV impairment and increased RV wall thickness and RV dimensions were present even at slight elevations of mPAP, 18±3mmHg, in no-PH.
The present study has demonstrated that impaired RV systolic function, hypertrophy and dilatation were present even at slight increase of mPAP, which indicates early impact on RV function and structure in patients with COPD. RV isovolumic acceleration, performance index and strain could detect subclinical disease and separate controls from no-PH.
Objectives:
We sought to establish the diagnostic accuracy of transesophageal echocardiography (TEE) during cardiopulmonary resuscitation.
Background:
Because of its bedside diagnostic capabilities, excellent cardiac images and lack of interference with resuscitation efforts, TEE is ideally suited to determine the cause of a circulatory arrest that is not due to severe arrhythmia. However, the diagnostic accuracy of TEE during resuscitation is unknown.
Methods:
TEE was performed in patients with prolonged circulatory arrest. The TEE diagnoses were compared with diagnoses from autopsy, surgery and clinical follow-up.
Results:
Of the 48 study patients (29 male, 19 female, mean age +/- SD 61 +/- 20 years), 28 had an in-hospital cardiac arrest and 20 an out-of-hospital onset of arrest. Forty-four patients eventually died; four survived to discharge. The diagnoses made with TEE were cardiac tamponade (n = 6), myocardial infarction (n = 21), pulmonary embolism (n = 6), ruptured aorta (n = 1), aortic dissection (n = 4), papillary muscle rupture (n = 1), other diagnosis (n = 2) and absence of structural cardiac abnormalities (n = 7). A definite diagnosis from a reference standard was available in 31 patients. The TEE diagnosis was confirmed in 27 of the 31-by postmortem examination (n = 19), operation (n = 2), angiography (n = 2) or clinical course (n = 4). In the other four patients the TEE diagnosis proved incorrect by postmortem examination. The sensitivity, specificity and positive predictive value of TEE were 93%, 50% and 87%, respectively. In 15 patients (31%), major therapeutic decisions were based on TEE findings.
Conclusions:
TEE can reliably establish the cause of a circulatory arrest during cardiopulmonary resuscitation.
In a large U.S. sample, this study measured the presentation features, testing, treatment strategies, and outcomes of patients diagnosed with pulmonary embolism (PE) in the emergency department (ED).
No data have quantified the demographics, clinical features, management, and outcomes of outpatients diagnosed with PE in the ED in a large, multicenter U.S. study.
Patients of any hemodynamic status were enrolled from the ED after confirmed acute PE or with a high clinical suspicion prompting anticoagulation before imaging for PE. Exclusions were inability to provide informed consent (where required) or unavailability for follow-up.
A total of 1,880 patients with confirmed acute PE were enrolled from 22 U.S. EDs. Diagnosis of PE was based upon positive results of computerized tomographic pulmonary angiogram in most cases (n = 1,654 [88%]). Patients represented both sexes equally, and racial and ethnic composition paralleled the overall U.S. ED population. Most (79%) patients with PE were employed, and one-third were older than age 65 years. The mortality rate directly attributed to PE was 20 in 1,880 (1%; 95% confidence interval [CI]: 0% to 1.6%). Mortality from hemorrhage was 0.2%, and the all-cause 30-day mortality rate was 5.4% (95% CI: 4.4% to 6.6%). Only 3 of 20 patients with major PE that ultimately proved fatal had systemic anticoagulation initiated before diagnostic confirmation, and another 3 of these 20 received a fibrinolytic agent.
Patients diagnosed with acute PE in U.S. EDs have high functional status, and their mortality rate is low. These registry data suggest that appropriate initial medical management of ED patients with severe PE with anticoagulation is poorly standardized and indicate a need for research to determine the appropriate threshold for empiric treatment when PE is suspected before diagnostic confirmation.
Several previous studies have focused on establishing the cause of cardiac arrest (CA) during cardiopulmonary resuscitation (CPR) provided in an out-of-hospital setting.
To analyze the ability of professional advanced life support providers to correctly establish the aetiology of cardiac arrest during out-of-hospital CPR.
A retrospective cohort study analysing 211 cases of out-of-hospital cardiac arrest.
The aetiology assumed by out-of-hospital physicians was compared with the diagnosis that was later established by clinicians or pathologists.
Cases were sorted into five diagnostic groups and the overall diagnostic concordance was 74.4% (157 of 211 cases). The cardiac aetiology was presumed in 132 out of 211 patients and confirmed in 135 out of 211 patients. However, an analysis of individual cases of the cardiac causes of cardiac arrest revealed diagnostic matches in only 112 cases. Acute myocardial infarction (AMI) or pulmonary embolism (PE), both of which represent cases that can be potentially influenced by thrombolytic therapy, were presumed in 74 (53+21) and confirmed in 97 (77+20) cases, however with individual diagnostic matches in only 55 cases.
This study demonstrates the importance of analysing concordance in presumed and definitive diagnosis of individual cases, since an overall comparison in a cohort of cases may be highly misleading. It introduces the method of the crosscheck table for visualization and comparison of presumed and final diagnoses. The two alternative approaches of inclusion rule for applying the thrombolytic therapy in out-of-hospital care were discussed with regard to the recent TROICA study.
Treatment of nontraumatic cardiac arrest in the hospital setting depends on the recognition of heart rhythm and differential diagnosis of the underlying condition while maintaining a constant oxygenated blood flow by ventilation and chest compression. Diagnostic process relies only on patient's history, physical findings, and active electrocardiography. Ultrasound is not currently scheduled in the resuscitation guidelines. Nevertheless, the use of real-time ultrasonography during resuscitation has the potential to improve diagnostic accuracy and allows the physician a greater confidence in deciding aggressive life-saving therapeutic procedures. This article reviews the current opinions and literature about the use of emergency ultrasound during resuscitation of nontraumatic cardiac arrest. Cardiac and lung ultrasound have a great potential in identifying the reversible mechanical causes of pulseless electrical activity or asystole. Brief examination of the heart can even detect a real cardiac standstill regardless of electrical activity displayed on the monitor, which is a crucial prognostic indicator. Moreover, ultrasound can be useful to verify and monitor the tracheal tube placement. Limitation to the use of ultrasound is the need to minimize the no-flow intervals during mechanical cardiopulmonary resuscitation. However, real-time ultrasound can be successfully applied during brief pausing of chest compression and first pulse-check. Finally, lung sonographic examination targeted to the detection of signs of pulmonary congestion has the potential to allow hemodynamic noninvasive monitoring before and after mechanical cardiopulmonary maneuvers.
Focused ultrasound is increasingly used in the emergency setting, with an ALS-compliant focused echocardiography algorithm proposed as an adjunct in peri-resuscitation care (FEEL). The purpose of this study was to evaluate the feasibility of FEEL in pre-hospital resuscitation, the incidence of potentially treatable conditions detected, and the influence on patient management.
A prospective observational study in a pre-hospital emergency setting in patients actively undergoing cardio-pulmonary resuscitation or in a shock state. The FEEL protocol was applied by trained emergency doctors, following which a standardised report sheet was completed, including echo findings and any echo-directed change in management. These reports were then analysed independently.
A total of 230 patients were included, with 204 undergoing a FEEL examination during ongoing cardiac arrest (100) and in a shock state (104). Images of diagnostic quality were obtained in 96%. In 35% of those with an ECG diagnosis of asystole, and 58% of those with PEA, coordinated cardiac motion was detected, and associated with increased survival. Echocardiographic findings altered management in 78% of cases.
Application of ALS-compliant echocardiography in pre-hospital care is feasible, and alters diagnosis and management in a significant number of patients. Further research into its effect on patient outcomes is warranted.
The right ventricle plays an important role in the morbidity and mortality of patients presenting with signs and symptoms of cardiopulmonary disease. However, the systematic assessment of right heart function is not uniformly carried out. This is due partly to the enormous attention given to the evaluation of the left heart, a lack of familiarity with ultrasound techniques that can be used in imaging the right heart, and a paucity of ultrasound studies providing normal reference values of right heart size and function. In all studies, the sonographer and physician should examine the right heart using multiple acoustic windows, and the report should represent an assessment based on qualitative and quantitative parameters. The parameters to be performed and reported should include a measure of right ventricular (RV) size, right atrial (RA) size, RV systolic function (at least one of the following: fractional area change [FAC], S′, and tricuspid annular plane systolic excursion [TAPSE]; with or without RV index of myocardial performance [RIMP]), and systolic pulmonary artery (PA) pressure (SPAP) with estimate of RA pressure on the basis of inferior vena cava (IVC) size and collapse. In many conditions, additional measures such as PA diastolic pressure (PADP) and an assessment of RV diastolic function are indicated. The reference values for these recommended measurements are displayed in Table 1. These reference values are based on values obtained from normal individuals without any histories of heart disease and exclude those with histories of congenital heart disease. Many of the recommended values differ from those published in the previous recommendations for chamber quantification of the American Society of Echocardiography (ASE). The current values are based on larger populations or pooled values from several studies, while several previous normal values were based on a single study. It is important for the interpreting physician to recognize that the values proposed are not indexed to body surface area or height. As a result, it is possible that patients at either extreme may be misclassified as having values outside the reference ranges. The available data are insufficient for the classification of the abnormal categories into mild, moderate, and severe. Interpreters should therefore use their judgment in determining the extent of abnormality observed for any given parameter. As in all studies, it is therefore critical that all information obtained from the echocardiographic examination be considered in the final interpretation. Essential Imaging Windows and Views: Apical 4-chamber, modified apical 4-chamber, left parasternal long-axis (PLAX) and parasternal short-axis (PSAX), left parasternal RV inflow, and subcostal views provide images for the comprehensive assessment of RV systolic and diastolic function and RV systolic pressure (RVSP).
Successful resuscitation requires potentially reversible causes to be diagnosed and reversed, and many of these can readily be diagnosed using echocardiography. Although members of the resuscitation team routinely use adjuncts to their clinical examination in order to differentiate these causes, the use of echocardiography is not yet considered standard. The purpose of this review is to discuss the potential for echocardiography to aid diagnosis and treatment during resuscitation, together with some of the perceived challenges that currently limit its widespread use.
Many studies have demonstrated the value of echocardiography in the assessment of critically ill patients in the intensive care unit and emergency room settings, including more recently the use of focused echocardiography. This can be performed within the time frame allowed during the pulse check of the advanced life support (ALS) algorithm. ALS-compliant focused echocardiography can be taught to nonexpert practitioners such that high-quality cardiopulmonary resuscitation is not compromised while diagnosing/excluding some of the potential causes of cardiac arrest.
Persistent and worsening haemodynamic instability are regarded as clear indications for echocardiography. The focused application of this well established technique within the ALS algorithm provides the resuscitation team with a potentially powerful diagnostic tool that can be used to diagnose/exclude some of the potentially treatable causes of cardiac arrest as well as to guide therapeutic interventions. The impact of routine periresuscitation echocardiography on patient outcomes both for in-hospital and prehospital care remains an exciting avenue for future research.
Abnormal motion of the interventricular septum has been described as an echocardiographic feature of both right ventricular volume and pressure overload. To determine if two-dimensional echocardiography can separate these two entities and distinguish them from normal, geometry and motion of the interventricular septum in short-axis views of the left ventricle were evaluated in 12 normal subjects and 35 patients undergoing cardiac catheterization. Thirteen of the 35 patients had uncomplicated atrial septal defect with associated right ventricular volume overload, but no elevation in pulmonary artery pressure. The 22 remaining patients had a pulmonary artery systolic pressure greater than 40 mm Hg and, thus, constituted the group with right ventricular pressure overload. An eccentricity index, defined as the ratio of the length of two perpendicular minor-axis diameters, one of which bisected and was perpendicular to the interventricular septum, was obtained at end-systole and end-diastole. In all normal subjects, the eccentricity index at both end-systole and end-diastole was essentially 1.0, as would be expected if the left ventricular cavity was circular in the short-axis view. In patients with right ventricular volume overload, the eccentricity index was approximately 1.0 at end-systole, but was significantly increased at end-diastole (mean eccentricity index = 1.26 +/- 0.12) (p less than 0.001). In patients with right ventricular pressure overload, the eccentricity index was significantly greater than 1.0 at both end-systole and end-diastole (1.44 +/- 0.16 and 1.26 +/- 0.11, respectively) (p less than 0.001). These results suggest that an index of eccentric left ventricular shape which reflects abnormal motion of the interventricular septum can be defined.(ABSTRACT TRUNCATED AT 250 WORDS)
The role of echocardiographic right ventricular (RV) dysfunction in predicting clinical outcome in clinically stable patients with pulmonary embolism (PE) is undefined. In this study, we assessed the prevalence and clinical outcome of normotensive patients with RV dysfunction among a broad spectrum of PE patients.
This prospective clinical outcome study included cohort of 209 consecutive patients (age, 65+/-15 years) with documented PE. Acute RV dysfunction was diagnosed in the presence of >/=1 of the following: RV dilatation (without hypertrophy), paradox septal systolic motion, and Doppler evidence of pulmonary hypertension. Four groups were identified: 28 patients presenting with shock or cardiac arrest (13%), 19 hypotensive patients without shock (9%), 65 normotensive patients with echocardiographic RV dysfunction (31%), and 97 normotensive patients without RV dysfunction (47%). Among normotensive patients with RV dysfunction, 6 (10%) developed PE-related shock after admission: 3 of these patients died, and 3 were successfully treated with thrombolytic agents. In comparison, none of the 97 normotensive patients without RV dysfunction developed shock or died as a result of PE.
A significant proportion (31%) of normotensive patients with acute PE presents with RV dysfunction; these patients with latent hemodynamic impairment have a 10% rate of PE-related shock and 5% in-hospital mortality and may require aggressive therapeutic strategies. Conversely, normotensive patients without echocardiographic RV dysfunction have a benign short-term prognosis. Thus, early detection of echocardiographic RV dysfunction is of major importance in the risk stratification of normotensive patients with acute PE.
The cause of many cases of sudden cardiac arrest from pulseless electrical activity is unknown. We hypothesized that pulmonary embolism was responsible for a substantial proportion of these cases and used transesophageal echocardiography to identify pulmonary embolism among patients with sudden cardiac arrest.
We performed a prospective study at a tertiary care, university-operated county hospital, with a level 1 trauma center. Consecutive patients (n = 36) who were admitted with (n = 20) or unexpectedly developed (n = 16) sudden cardiac arrest of unknown cause were studied with transesophageal echocardiography during cardiopulmonary resuscitation. We determined the presence of central pulmonary embolism, right ventricular enlargement, and other causes of sudden cardiac arrest (such as myocardial infarction and aortic dissection) using prospectively defined criteria.
Of the 25 patients with pulseless electrical activity as the initial event, 9 (36%) had pulmonary emboli (8 seen with transesophageal echocardiography and 1 diagnosed at autopsy) compared with none of the 11 patients with other rhythms, such as asystole or ventricular tachycardia or fibrillation (P = 0.02). Of the 8 patients who had pulmonary embolism diagnosed by transesophageal echocardiography, 2 survived to hospital discharge.
Mortality from massive pulmonary embolism is high, particularly if patients present with sudden cardiac arrest. Earlier diagnosis of pulmonary embolus may permit wider use of thrombolytic agents or other interventions and may potentially increase survival.
Most out-of-hospital ventricular fibrillation (VF) is prolonged (>5 minutes), and defibrillation from prolonged VF typically results in asystole or pulseless electrical activity. Recent visual epicardial observations in an open-chest, open-pericardium model of swine VF indicate that blood flows from the high-pressure arterial system to the lower-pressure venous system during untreated VF, thereby overdistending the right ventricle and apparently decreasing left ventricular size. Therefore, inadequate left ventricular stroke volume after defibrillation from prolonged VF has been postulated as a major contributor to the development of pulseless rhythms.
Ventricular dimensions were determined by MRI for 30 minutes of untreated VF in a closed-chest, closed-pericardium model in 6 swine. Within 1 minute of untreated VF, mean right ventricular volume increased by 29% but did not increase thereafter. During the first 5 minutes of untreated VF, mean left ventricular volume increased by 34%. Between 20 and 30 minutes of VF, stone heart occurred as manifested by dramatic thickening of the myocardium and concomitant substantial decreases in left ventricular volume.
In this closed-chest swine model of VF, substantial right ventricular volume changes occurred early and did not result in smaller left ventricular volumes. The changes in ventricular volumes before the late development of stone heart do not explain why defibrillation from brief duration VF (<5 minutes) typically results in a pulsatile rhythm with return of spontaneous circulation, whereas defibrillation from prolonged VF (5 to 15 minutes) does not.
Sudden unexpected intraoperative cardiac arrests in patients undergoing elective non-cardiac operations are rare but catastrophic complications. The efficacy and utility of transoesophageal echocardiography (TOE) in the diagnosis and management of these events have not been reported earlier.
Unexpected intraoperative cardiac arrests in patients undergoing elective non-cardiac operations were prospectively studied during a 6 yr period. In these patients, TOE was performed within 5 min after initiation of external chest compression to identify the causes of the cardiac arrests.
Among a total of 125 965 surgical operations, 10 patients who suffered intraoperative cardiac arrests were studied. The causes of the cardiac arrests including myocardial infarction in five, pulmonary embolism in two, and severe hypovolaemia and ventricular arrhythmia without specific pathology in the other two patients were correctly identified using TOE. Seven patients survived.
We conclude that TOE was useful in cardiac arrest during non-cardiac surgery for identifying or excluding pulmonary embolism and for directing investigations and treatment in those patients who had suffered myocardial infarction.
In 1616, Sir William Harvey was the first to describe the importance of right ventricular (RV) function in his seminal treatise, De Motu Cordis : “Thus the right ventricle may be said to be made for the sake of transmitting blood through the lungs, not for nourishing them.”1,2 For many years that followed, emphasis in cardiology was placed on left ventricular (LV) physiology, overshadowing the study of the RV. In the first half of the 20th century, the study of RV function was limited to a small group of investigators who were intrigued by the hypothesis that human circulation could function adequately without RV contractile function.3 Their studies, however, were based on an open pericardial dog model, which failed to take into account the complex nature of ventricular interaction. In the early 1950s through the 1970s, cardiac surgeons recognized the importance of right-sided function as they evaluated procedures to palliate right-heart hypoplasia. Since then, the importance of RV function has been recognized in heart failure, RV myocardial infarction, congenital heart disease and pulmonary hypertension. More recently, advances in echocardiography and magnetic resonance imaging have created new opportunities for the study of RV anatomy and physiology.
The goal of the present review is to offer a clinical perspective on RV structure and function. In the first part, we discuss the anatomy, physiology, aging, and assessment of the RV. In the second part, we discuss the pathophysiology, clinical importance, and management of RV failure.
### Macroscopic Anatomy of the RV
In the normal heart, the RV is the most anteriorly situated cardiac chamber and lies immediately behind the sternum. In the absence of transposition of great arteries, the RV is delimited by the annulus of the tricuspid valve and by the pulmonary valve. As suggested by Goor and Lillehi,4 the RV can be described in …
Part 7: Adult advanced cardiovascular life support: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care.
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