A novel use of ultrasound in pulseless electrical activity: the diagnosis of an acute abdominal aortic aneurysm rupture

Échographie et prise en charge de l’arrêt cardiaque

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.

Echocardiography in cardiac arrest: An emergency medicine review

INTRODUCTION

Cardiac arrest management primarily focuses on optimal chest compressions and early defibrillation for shockable cardiac rhythms. Non-shockable rhythms such as pulseless electrical activity (PEA) and asystole present challenges in management. Point-of-care ultrasound (POCUS) in cardiac arrest is promising.

OBJECTIVES

This review provides a focused assessment of POCUS in cardiac arrest, with an overview of transthoracic (TTE) and transesophageal echocardiogram (TEE), uses in arrest, and literature support.

DISCUSSION

Cardiac arrest can be distinguished between shockable and non-shockable rhythms, with management varying based on the rhythm. POCUS provides a diagnostic and prognostic tool in the emergency department (ED), which may improve accuracy in clinical decision-making. Several protocols incorporate POCUS based on different cardiac views. TTE includes parasternal long axis, parasternal short axis, apical 4-chamber, and subxiphoid views, which may be used in cardiac arrest for diagnosis of underlying cause and potential prognostication. TEE is conducted by inserting the probe into the esophagus of intubated patients, with several studies evaluating its use in cardiac arrest. It is associated with few adverse effects, while allowing continued compressions (and evaluation of those compressions) and not interrupting resuscitation efforts.

CONCLUSIONS

POCUS is a valuable diagnostic and prognostic tool in cardiac arrest, with recent literature supporting its diagnostic ability. TTE can guide resuscitation efforts dependent on the rhythm, though TTE should not interrupt other resuscitation measures. TEE can be useful during arrest, but further studies based in the ED are needed.

Accuracy of early rapid ultrasound in shock (RUSH) examination performed by emergency physician for diagnosis of shock etiology in critically ill patients

Background:

Rapid Ultrasound in Shock (RUSH) is a recently reported emergency ultrasound protocol designed to help clinicians better recognize distinctive shock etiologies in a short time. We tried to evaluate the accuracy of early RUSH protocol performed by emergency physicians to predict the shock type in critically ill patients.

Materials and Methods:

Our prospective study was approved by the ethics committee of trauma research center, Baqiyatallah University of Medical Science, Iran. We enrolled 52 patients with shock state in the emergency department from April 2013 to October 2013. We performed early bed-side sonographic examination for participants based on RUSH protocol. Patients received all needed standard therapeutic and diagnostic interventions without delay and were followed to document their final diagnosis. Agreement (Kappa index) of initial impression provided by RUSH with final diagnosis, and also sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of RUSH for diagnosis of each shock type were calculated.

Results:

Fifty-two patients were enrolled in our study. Kappa index was 0.7 (P value = 0.000), reflecting acceptable general agreement between initial impression and final diagnosis. For hypovolemic and obstructive shocks, the protocol had sensitivity of 100% but had lower PPV. For shocks with distributive or mixed etiology, RUSH showed PPV of 100% but had low sensitivity. For cardiogenic shocks, all reliability indices were above 90%.

Conclusion:

We highlight the role of RUSH examination in the hands of an emergency physician in making a rapid diagnosis of shock etiology, especially in ruling out obstructive, cardiogenic, and hypovolemic types.

Point-of-care multiorgan ultrasonography for the evaluation of undifferentiated hypotension in the emergency department

PURPOSE

We analyzed the efficacy of a point-of-care ultrasonographic protocol, based on a focused multiorgan examination, for the diagnostic process of symptomatic, non-traumatic hypotensive patients in the emergency department.

METHODS

We prospectively enrolled 108 adult patients complaining of non-traumatic symptomatic hypotension of uncertain etiology. Patients received immediate point-of-care ultrasonography to determine cardiac function and right/left ventricle diameter rate, inferior vena cava diameter and collapsibility, pulmonary congestion, consolidations and sliding, abdominal free fluid and aortic aneurysm, and leg vein thrombosis. The organ-oriented diagnoses were combined to formulate an ultrasonographic hypothesis of the cause of hemodynamic instability. The ultrasonographic diagnosis was then compared with a final clinical diagnosis obtained by agreement of three independent expert physicians who performed a retrospective hospital chart review of each case.

RESULTS

Considering the whole population, concordance between the point-of-care ultrasonography diagnosis and the final clinical diagnosis was interpreted as good, with Cohen's k = 0.710 (95 % CI, 0.614-0.806), p < 0.0001 and raw agreement (Ra) = 0.768. By eliminating the 13 cases where the final clinical diagnosis was not agreed upon (indefinite), the concordance increased to almost perfect, with k = 0.971 (95 % CI, 0.932-1.000), p < 0.0001 and Ra = 0.978.

CONCLUSIONS

Emergency diagnostic judgments guided by point-of-care multiorgan ultrasonography in patients presenting with undifferentiated hypotension significantly agreed with a final clinical diagnosis obtained by retrospective chart review. The integration of an ultrasonographic multiorgan protocol in the diagnostic process of undifferentiated hypotension has great potential in guiding the first-line therapeutic approach.

Cardiac movement identified on prehospital echocardiography predicts outcome in cardiac arrest patients

INTRODUCTION

The prognostic value of emergency echocardiography (EE) in the management of cardiac arrest patients has previously been studied in an in-hospital setting. These studies mainly included patients who underwent cardiopulmonary resuscitation (CPR) by emergency medicine technicians at the scene and who arrived at the emergency department (ED) still in a state of cardiac arrest. In most European countries, cardiac arrest patients are normally treated by physician-staffed emergency medical services (EMS) teams on scene. Transportation to the ED while undergoing CPR is uncommon.

OBJECTIVE

To evaluate the ability of EE to predict outcome in cardiac arrest patients when it is performed by ultrasound-inexperienced emergency physicians on scene.

METHODS

We performed a prospective, observational study of nonconsecutive, nontrauma, adult cardiac arrest patients who were treated by physician-staffed urban EMS teams on scene. Participating emergency physicians (EPs) received a two-hour course in EE during CPR. After initial procedures were accomplished, EE was performed during a rhythm and pulse check. A single subxiphoid, four-chamber view was required for study enrollment. We defined sonographic evidence of cardiac kinetic activity as any detected motion of the myocardium, ranging from visible ventricular fibrillation to coordinated ventricular contractions. The CPR had to be continued for at least 15 minutes after the initial echocardiography. No clinical decisions were made based on the results of EE.

RESULTS

Forty-two patients were enrolled in the study. The heart could be visualized successfully in all patients. Five (11.9%) patients survived to hospital admission. Of the 32 patients who had cardiac standstill on initial EE, only one (3.1%) survived to hospital admission, whereas four out of 10 (40%) patients with cardiac movement on initial EE survived to hospital admission (p = 0.008). Neither asystole on initial electrocardiogram nor peak capnography value, age, bystander CPR, or downtime was a significant predictor of survival. Only cardiac movement was associated with survival, and cardiac standstill at any time during CPR resulted in a positive predictive value of 97.1% for death at the scene.

CONCLUSION

Our results support the idea of focused echocardiography as an additional criterion in the evaluation of outcome in CPR patients and demonstrate its feasibility in the prehospital setting.

Usefulness of emergency ultrasound in nontraumatic cardiac arrest

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.

The RUSH exam: Rapid Ultrasound in SHock in the evaluation of the critically lll

The RUSH exam (Rapid Ultrasound in SHock examination), presented in this article, represents a comprehensive algorithm for the integration of bedside ultrasound into the care of the patient in shock. By focusing on a stepwise evaluation of the shock patient defined here as "Pump, Tank, and Pipes," clinicians will gain crucial anatomic and physiologic data to better care for these patients.

Transesophageal echocardiography during cardiopulmonary arrest in the emergency department

Management of patients in cardiopulmonary arrest is challenging and can be resource consuming. Outcomes continue to be poor and physicians may feel a sense of futility when running a resuscitation. Bedside ultrasound has been utilized to guide resuscitations, diagnose correctable cardiac pathology leading to an arrest and has proved to have a prognostic value when utilized in the initial stages of resuscitation. Bedside emergency ultrasound is limited by inability to scan during chest compression and poor image quality in obese patients and those with emphysema. During cardiopulmonary resuscitation pulse checks need to be rapid and leave little time for transducer manipulation during image acquisition. Recent American Heart Association guidelines further stress the need for quality chest compressions and minimizing intervals with no compressions. Transesophageal echocardiography offers high resolution and clarity of images in the vast majority of patients. It allows for constant visualization of the heart, even during chest compressions, cardioversion and other procedures. This case series describes the use of transesophageal echocardiography (TEE) during cardiac arrest by emergency physicians. The cases illustrate some of the potential benefits of TEE during cardiopulmonary arrest.

The dead continue to teach the living: examining the role of computed tomography and magnetic resonance imaging in the setting of postmortem examinations

High-resolution imaging methods are used more frequently in the setting of postmortem investigation. Used for some time in forensics, computed tomography (CT) and magnetic resonance imaging (MRI) are now being evaluated as complementary or even as alternative means of postmortem examination. We review briefly the history of autopsy and the reasons for the gradual decrease in autopsy rates. An overview of advantages and limitations of modern imaging autopsy techniques is then presented, which includes a discussion of the potential role of imaging autopsy in medical and surgical education. Potential future applications of this technology in postmortem analysis, which includes the incorporation of ultrasound technology, are then discussed.

C.A.U.S.E.: Cardiac arrest ultra-sound exam—A better approach to managing patients in primary non-arrhythmogenic cardiac arrest

Cardiac arrest is a condition frequently encountered by physicians in the hospital setting including the Emergency Department, Intensive Care Unit and medical/surgical wards. This paper reviews the current literature involving the use of ultrasound in resuscitation and proposes an algorithmic approach for the use of ultrasound during cardiac arrest. At present there is the need for a means of differentiating between various causes of cardiac arrest, which are not a direct result of a primary ventricular arrhythmia. Identifying the cause of pulseless electrical activity or asystole is important as the underlying cause is what guides management in such cases. This approach, incorporating ultrasound to manage cardiac arrest aids in the diagnosis of the most common and easily reversible causes of cardiac arrest not caused by primary ventricular arrhythmia, namely; severe hypovolemia, tension pneumothorax, cardiac tamponade, and massive pulmonary embolus. These four conditions are addressed in this paper using four accepted emergency ultrasound applications to be performed during resuscitation of a cardiac arrest patient with the aim of determining the underlying cause of a cardiac arrest. Identifying the underlying cause of cardiac arrest represents the one of the greatest challenges of managing patients with asystole or PEA and accurate determination has the potential to improve management by guiding therapeutic decisions. We include several clinical images demonstrating examples of cardiac tamponade, massive pulmonary embolus, and severe hypovolemia secondary to abdominal aortic aneurysm. In conclusion, this protocol has the potential to reduce the time required to determine the etiology of a cardiac arrest and thus decrease the time between arrest and appropriate therapy.

Imaging of aortic abnormalities with contrast-enhanced ultrasound. A pictorial comparison with CT

Aortic abnormalities are commonly encountered and may represent a diagnostic challenge in patients with acute or chronic clinical symptoms. Contrast-enhanced ultrasound (CEUS) with low mechanical index (low MI) is a new promising method in the diagnosis and follow-up of pathological aortic lesions. CEUS with SonoVue allows a more rapid and noninvasive diagnosis, especially in critical patients because of its bedside availability. This review compares CEUS findings with those documented on computed tomography angiography (CTA), allowing the reader to appreciate the usefulness of CEUS in this clinical situation.

Ruptured abdominal aortic aneurysm: categorization of sonographic findings and report of 3 new signs

OBJECTIVE

The purpose of this study was to categorize the sonographic findings seen in patients with a ruptured abdominal aortic aneurysm (AAA) and to describe 3 previously undescribed sonographic findings.

METHODS

From January 1997 to December 2003, we evaluated 388 consecutive patients with an AAA (transverse aortic diameter >30 mm). Among these patients, 29 had surgical or computed tomographic demonstration of aneurysm rupture. The remaining 359 were asymptomatic and had no evidence of AAA rupture at follow-up.

RESULTS

Findings recognized among 29 positive cases included AAA deformation (n = 12), luminal thrombus inhomogeneity (n = 20), clear interruption of a luminal thrombus (n = 5), retroperitoneal hematoma (n = 22), and hemoperitoneum (n = 11). In addition, 3 previously unreported findings were noted: an intraluminal floating thrombus layer (n = 8), a parietal hypoechoic focus due to aneurysm wall interruption (n = 3), and a para-aortic hypoechoic area adjacent to the bleeding side (n = 4). Aside from AAA deformation and thrombus heterogeneity, no other signs were recognized among subjects with a nonruptured aneurysm.

CONCLUSIONS

In the past, sonography has been used mainly to rapidly confirm aneurysm presence in the clinical setting of a patient with a suspected rupture. Instead, this retrospective series shows how this imaging technique can frequently identify several direct and indirect signs of aneurysm rupture itself. Moreover, 3 new indicators of AAA rupture have been observed.

Contrast-enhanced sonography for diagnosis of ruptured abdominal aortic aneurysm

OBJECTIVE

We describe the contrast-specific sonography features of ruptured abdominal aortic aneurysm, and we hypothesize that this technique would be useful for emergency imaging of patients with suspected aneurysm rupture.

CONCLUSION

We used contrast-specific sonography to assess eight patients with ruptured abdominal aortic aneurysm. Five of these cases were correlated with CT findings. We found that contrast-enhanced sonography can reveal features specific for ruptured aortic aneurysm without causing a significant delay in surgery. This technique may be as effective as CT but may allow a more rapid and noninvasive diagnosis, especially when sonography can be performed bedside.

Ultrasound detection of abdominal aortic aneurysm

US is becoming a widely used diagnostic and therapeutic tool in emergency medicine training and practice. Its use in detecting an AAA is efficient and practical and can occur concurrently with resuscitation. US of the abdominal aorta has been shown to be highly accurate for the detection of AAA and to decrease the time to operative repair of ruptured AAA. The emergency physician should consider using US to search for an AAA in any patient presenting with abdominal or back pain or with shock of unknown etiology.

Emergency echocardiography to detect pericardial effusion in patients in PEA and near-PEA states

OBJECTIVES

Emergency echocardiography (EM echo) has been proposed to assist in decision-making in patients with pulseless electric activity (PEA) or PEA-like states. We observed the value of EM echo by emergency physicians in detecting pericardial effusion in patients in PEA and near PEA states.

MATERIALS AND METHODS

Observational, prospective series at a Level 1 urban ED of patients with non-traumatic PEA or near PEA states who had EM echoes performed by emergency physicians during an 18-month period. Outcomes of patients with EM echoes were established by review of clinical course, formal echocardiography, radiography, operation or autopsy.

RESULTS

Twenty patients had EM echo for non-traumatic hemodynamic collapse. Eight of 20 patients (40%) were without cardiac ventricular motion and were refractory to ACLS measures. Twelve of 20 (60%) patients had cardiac kinetic motion observed on echo. Eight of the 12 (67%) patients with cardiac motion had a pericardial effusion observed on EM echo. Formal echocardiography or other imaging studies confirmed all pericardial effusion cases. The following diagnoses were subsequently confirmed in patients with pericardial effusion: one aortic aneurysm, two aortic dissections, two metastatic cancers, one post-dialysis effusion, two minimal effusions. Three patients had tamponade with emergency pericardial drainage or surgery. In two of four patients with cardiac activity without pericardial effusion, EM echo was useful by detecting pacer capture and ROSC, respectively.

CONCLUSIONS

Emergency echocardiography performed by emergency physicians in patients in PEA or near PEA states can detect pericardial effusions with correctable etiologies versus true PEA with ventricular standstill.