Ten Influential Point-of-Care Ultrasound Papers: 2022 in Review.

Keeping up with the latest developments in the point-of-care ultrasound (POCUS) literature is challenging, as with any area of medicine. Our group of POCUS experts has selected 10 influential papers from the past 12 months and provided a short summary of each. We hope to provide emergency physicians, intensivists, and other acute care providers with a succinct update concerning some key areas of ultrasound interest.

Ten Influential Point-of-Care Ultrasound Papers: 2021 in Review.

The ongoing rapid expansion of point-of-care ultrasound (POCUS) and its corresponding supporting literature leaves the frontline clinician in a difficult position when trying to keep abreast of the latest developments. Our group of POCUS experts has selected ten influential POCUS-related papers from the past twelve months and provided a short summary of each. Our aim is to give to emergency physicians, intensivists, and other acute care providers key information, helping them to keep up to date on rapidly evolving POCUS literature.

Stroke Volume Determination by Echocardiography.

Basic critical care echocardiography emphasizes two-dimensional (2D) findings, such as ventricular function, inferior vena cava size, and pericardial assessment, while generally excluding quantitative findings and Doppler-based techniques. Although this approach offers advantages, including efficiency and expedited training, it complicates attempts to understand the hemodynamic importance of any 2D abnormalities detected. Stroke volume (SV), as the summative event of the cardiac cycle, is the most pragmatic available indicator through which a clinician can rapidly determine, no matter the 2D findings, whether aberrant cardiac physiology is contributing to the state of shock. An estimate of SV allows 2D findings to be placed into better context in terms of both hemodynamic significance and acuity. This article describes the technique of SV determination, reviews common confounding factors and pitfalls, and suggests a systematic approach for using SV measurements to help integrate important 2D findings into the clinical context.

Basic ultrasound head-to-toe skills for intensivists in the general and neuro intensive care unit population: consensus and expert recommendations of the European Society of Intensive Care Medicine.

PURPOSE: To provide consensus, and a list of experts' recommendations regarding the basic skills for head-to-toe ultrasonography in the intensive care setting. METHODS: The Executive Committee of the European Society of Intensive Care (ESICM) commissioned the project and supervised the methodology and structure of the consensus. We selected an international panel of 19 expert clinicians-researchers in intensive care unit (ICU) with expertise in critical care ultrasonography (US), plus a non-voting methodologist. The panel was divided into five subgroups (brain, lung, heart, abdomen and vascular ultrasound) which identified the domains and generated a list of questions to be addressed by the panel. A Delphi process based on an iterative approach was used to obtain the final consensus statements. Statements were classified as a strong recommendation (84% of agreement), weak recommendation (74% of agreement), and no recommendation (less than 74%), in favor or against. RESULTS: This consensus produced a total of 74 statements (7 for brain, 20 for lung, 20 for heart, 20 for abdomen, 7 for vascular Ultrasound). We obtained strong agreement in favor for 49 statements (66.2%), 8 weak in favor (10.8%), 3 weak against (4.1%), and no consensus in 14 cases (19.9%). In most cases when consensus was not obtained, it was felt that the skills were considered as too advanced. A research agenda and discussion on training programs were implemented from the results of the consensus. CONCLUSIONS: This consensus provides guidance for the basic use of critical care US and paves the way for the development of training and research projects.

Assessing Competence in Critical Care Echocardiography: Development and Initial Results of an Examination and Certification Processes.

OBJECTIVES: To describe the development and initial results of an examination and certification process assessing competence in critical care echocardiography. DESIGN: A test writing committee of content experts from eight professional societies invested in critical care echocardiography was convened, with the Executive Director representing the National Board of Echocardiography. Using an examination content outline, the writing committee was assigned topics relevant to their areas of expertise. The examination items underwent extensive review, editing, and discussion in several face-to-face meetings supervised by National Board of Medical Examiners editors and psychometricians. A separate certification committee was tasked with establishing criteria required to achieve National Board of Echocardiography certification in critical care echocardiography through detailed review of required supporting material submitted by candidates seeking to fulfill these criteria. SETTING: The writing committee met twice a year in person at the National Board of Medical Examiner office in Philadelphia, PA. SUBJECTS: Physicians enrolled in the examination of Special Competence in Critical Care Electrocardiography (CCEeXAM). MEASUREMENTS AND MAIN RESULTS: A total of 524 physicians sat for the examination, and 426 (81.3%) achieved a passing score. Of the examinees, 41% were anesthesiology trained, 33.2% had pulmonary/critical care background, and the majority had graduated training within the 10 years (91.6%). Most candidates work full-time at an academic hospital (46.9%). CONCLUSIONS: The CCEeXAM is designed to assess a knowledge base that is shared with echocardiologists in addition to that which is unique to critical care. The National Board of Echocardiography certification establishes that the physician has achieved the ability to independently perform and interpret critical care echocardiography at a standard recognized by critical care professional societies encompassing a wide spectrum of backgrounds. The interest shown and the success achieved on the CCEeXAM by practitioners of critical care echocardiography support the standards set by the National Board of Echocardiography for testamur status and certification in this imaging specialty area.

Focused Transesophageal Echocardiography During Cardiac Arrest Resuscitation: JACC Review Topic of the Week.

Focused transthoracic echocardiography (TTE) during cardiac arrest resuscitation can enable the characterization of myocardial activity, identify potentially treatable pathologies, assist with rhythm interpretation, and provide prognostic information. However, an important limitation of TTE is the difficulty obtaining interpretable images due to external and patient-related limiting factors. Over the last decade, focused transesophageal echocardiography (TEE) has been proposed as a tool that is ideally suited to image patients in extremis-those in cardiac arrest and periarrest states. In addition to the same diagnostic and prognostic role provided by TTE images, TEE provides unique advantages including the potential to optimize the quality of chest compressions, shorten cardiopulmonary resuscitation interruptions, guide resuscitative procedures, and provides a continuous image of myocardial activity. This review discusses the rationale, supporting evidence, opportunities, and challenges, and proposes a research agenda for the use of focused TEE in cardiac arrest with the goal to improve resuscitation outcomes.

Better With Ultrasound: Transcranial Doppler.

Transcranial Doppler (TCD) ultrasound is a noninvasive method of obtaining bedside neurologic information that can supplement the physical examination. In critical care, this can be of particular value in patients who are unconscious with an equivocal neurologic examination because TCD findings can help the physician in decisions related to more definitive imaging studies and potential clinical interventions. Although TCD is traditionally the domain of sonographers and radiologists, there is increasing adoption of goal-directed TCD at the bedside in the critical care environment. The value of this approach includes round-the-clock availability and a goal-directed approach allowing for repeatability, immediate interpretation, and quick clinical integration. This paper presents a systematic approach to incorporating the highest yield TCD techniques into critical care bedside practice, and includes a series of illustrative figures and narrated video presentations to demonstrate the techniques described.

Better With Ultrasound: Transesophageal Echocardiography.

Transesophageal echocardiography (TEE) is a safe and minimally invasive tool that can routinely provide high-quality anatomic and hemodynamic information in the severely ill. Despite its potential for frontline acute care clinicians, TEE use has typically been reserved for diagnostic experts in the cardiac-surgical milieu. With the continued evolution of point-of-care ultrasound into increasingly sophisticated domains, TEE has gained steady uptake in many nontraditional environments for both advanced echocardiographic assessment as well as answering more goal directed, fundamental questions. This article introduces the workings of the TEE transducer, presents a systematic approach to a goal-directed hemodynamic assessment, and includes a series of illustrative figures and narrated video presentations to demonstrate the techniques described.

Expert Agreement in the Interpretation of Lung Ultrasound Studies Performed on Mechanically Ventilated Patients.

OBJECTIVES: Although lung ultrasound (US) has been shown to have high diagnostic accuracy in patients presenting with acute dyspnea, its precision in critically ill patients is unknown. We investigated common areas of agreement and disagreement by studying 6 experts as they interpreted lung US studies in a cohort of intensive care unit (ICU) patients. METHODS: A previous study by our group asked experts to rate the quality of 150 lung US studies performed by 10 novices in a population of mechanically ventilated patients. For this study, experts were asked to interpret them without the clinical context, reporting the presence of pneumothorax, interstitial syndrome, consolidation, atelectasis, or pleural effusion. RESULTS: The rate of expert agreement depended on how it was defined, ranging from 51% (with a strict definition of agreement) to 57% (with a more liberal definition). Removing cases involving lung consolidation (the most common source of disagreement) improved the rates of agreement to 69% and 86%, respectively. CONCLUSIONS: The frequency of agreement was lower than might have been expected in this study. Several potential reasons are identified, chief among them the fact that ICU patients often develop multiple pulmonary insults, making agreement on a specific primary diagnosis challenging. This finding suggests that the utility of lung US in identifying the main contributing lung condition in ICU patients may be lower than in dyspneic patients encountered in the emergency department. It also raises the possibility that the clinical context is more important for lung US than other imaging modalities.

The Assessment of Competency in Thoracic Sonography (ACTS) scale: validation of a tool for point-of-care ultrasound.

BACKGROUND: The rapid adoption of point-of-care ultrasound (POCUS) has created a need to develop assessment tools to ensure that learners can competently use these technologies. In this study, the authors developed and tested a rating scale to assess the quality of point-of-care thoracic ultrasound studies performed by novices. In Phase 1, the Assessment of Competency in Thoracic Sonography (ACTS) scale was developed based on structured interviews with subject matter experts. The tool was then piloted on a small series of ultrasound studies in Phase 2. In Phase 3 the tool was applied to a sample of 150 POCUS studies performed by ten learners; performance was then assessed by two independent raters. RESULTS: Evidence for the content validity of the ACTS scale was provided by a consensus exercise wherein experts agreed on the general principles and specific items that make up the scale. The tool demonstrated reasonable inter-rater reliability despite minimal requirements for evaluator training and displayed evidence of good internal structure, with related scale items correlating well with each other. Analysis of the aggregate learning curves suggested a rapid early improvement in learner performance with slower improvement after approximately 25-30 studies. CONCLUSIONS: The ACTS scale provides a straightforward means to assess learner performance. Our results support the conclusion that the tool is an effective means of making valid judgments regarding competency in point-of-care thoracic ultrasound, and that the majority of learner improvement occurs during their first 25-30 practice studies.

Outcomes from extensive training in critical care echocardiography: Identifying the optimal number of practice studies required to achieve competency.

PURPOSE: Optimal instruction and assessment of critical care ultrasound (CCUS) skills requires an assessment tool to measure learner competency and changes over time. In this study, a previously published tool was used to monitor the development of critical care echocardiography (CCE) competencies, the attainment of performance plateaus, and the extent to which previous experience influenced learning. MATERIALS AND METHODS: A group of experts used the Rapid Assessment of Competency in Echocardiography (RACE) scale to rate a large pool of CCE studies performed by novices in a longitudinal design. A total of 380 studies performed by twelve learners were assessed; each study was independently rated by two experts. RESULTS: Learners demonstrated improvement in mean RACE scores over time, with peak performance occurring early in training and a performance plateau thereafter. Learners with little experience received the greatest benefit from training, with an average performance plateau reached at the twentieth study. CONCLUSIONS: Supporting earlier results, the RACE scale provided a straightforward means to assess learner performance with minimal requirements for evaluator training. The results of the present study suggest that novices experience the greatest gains in competency during their first twenty practice studies, a threshold which should serve to guide training initiatives.

The Rapid Assessment of Competency in Echocardiography Scale: Validation of a Tool for Point-of-Care Ultrasound.

OBJECTIVES: Increased use of point-of-care ultrasound (US) requires the development of assessment tools that measure the competency of learners. In this study, we developed and tested a tool to assess the quality of point-of-care cardiac US studies performed by novices. METHODS: In phase 1, the Rapid Assessment of Competency in Echocardiography (RACE) scale was developed on the basis of structured interviews with subject matter experts; the tool was then piloted on a small series of US studies in phase 2. In phase 3, the tool was applied to a sample of 154 point-of-care US studies performed by 12 learners; each study was independently rated by 2 experts, with quantitative analysis subsequently performed. RESULTS: Evidence of the content validity of the RACE scale was supported by a consensus exercise, wherein experts agreed on the assessment dimensions and specific items that made up the RACE scale. The tool showed good inter-rater reliability. An analysis of inter-item correlations provided support for the internal structure of the scale, and the tool was able to discriminate between learners early in their point-of-care US learning and those who were more advanced in their training. CONCLUSIONS: The RACE scale provides a straightforward means to assess learner performance with minimal requirements for evaluator training. Our results support the conclusion that the tool is an effective means of making valid judgments regarding competency in point-of-care cardiac US.

Development of a fluid resuscitation protocol using inferior vena cava and lung ultrasound.

Appropriate fluid resuscitation has been a major focus of critical care medicine since its inception. Currently, the most accurate method to guide fluid administration decisions uses "dynamic" measures that estimate the change in cardiac output that would occur in response to a fluid bolus. Unfortunately, their use remains limited due to required technical expertise, costly equipment, or applicability in only a subset of patients. Alternatively, point-of-care ultrasound (POCUS) has become widely used as a tool to help clinicians prescribe fluid therapy. Common POCUS applications that serve as guides to fluid administration rely on assessments of the inferior vena cava to estimate preload and lung ultrasound to identify the early presence of extravascular lung water and avoid fluid overresuscitation. Although application of these POCUS measures has multiple limitations that are commonly misunderstood, current evidence suggests that they can be used in combination to sort patients among 3 fluid management categories: (1) fluid resuscitate, (2) fluid test, and (3) fluid restrict. This article reviews the pertinent literature describing the use of inferior vena cava and lung ultrasound for fluid responsiveness and presents an evidence-informed algorithm using these measures to guide fluid resuscitation decisions in the critically ill.

The utility of remote supervision with feedback as a method to deliver high-volume critical care ultrasound training.

OBJECTIVE: Despite international agreement that critical care ultrasound (CCUS) is an essential skill for intensive care providers, CCUS training and dissemination is complicated by a shortage of educators. Newer technology now permits remote, offline supervision as a method of overseeing trainees undergoing CCUS instruction. DESIGN: This was a retrospective, descriptive report of a CCUS curriculum and its output of clinical ultrasound examinations at an academic critical care training program over a 1-year period. The curriculum consisted of typical didactic and hands-on training as well as wireless archiving of examinations with remote, offline oversight and feedback provided by the director using ultrasound management software. SETTING: A tertiary-care, academic critical care training program. MEASUREMENTS AND MAIN RESULTS: Twenty-nine trainees acquired and archived a total of 2531 CCUS studies (average 76 studies per trainee) for 1 year. Of these, 1807 (71%) examinations had a typewritten report generated by the operator, and 1788 of these examinations were overread and subjected to feedback from the curriculum director. The predominant application of CCUS was for cardiac (62%), thoracic (32%), and abdominal (5%) assessment. CONCLUSIONS: This study suggests that the use of wireless archiving and offline oversight in a CCUS curriculum is a feasible and highly-efficient strategy permitting a small number of faculty to supervise a large number of trainees. This approach provides an efficient method to address unmet demand for CCUS education.

Critical care ultrasonography.

Resuscitative ultrasonography provides rapid, repeatable, and multisystem assessment to guide diagnosis and management of critically ill patients in the emergency department (ED). Cardiac ultrasonography offers new anatomic and hemodynamic information, previously unavailable in an ED setting, whereas other applications match or exceed the speed and utility of existing tests such as chest radiograph (thoracic ultrasonography) or central venous pressure determination (inferior vena cava ultrasonography). Evolving areas of resuscitative ultrasonography include neurologic applications and transesophageal echocardiography, which promise to further enhance the role of ultrasonography in managing critical illness in the ED.