Is pulmonary hypertension protective against cardiac tamponade? A systematic review

The presence of pulmonary hypertension (PH) may affect whether cardiac tamponade physiology develops from a pericardial effusion. Specifically, the increased intracardiac pressure and right ventricular hypertrophy associated with PH would seemingly increase the intrapericardial pressure threshold at which the right-sided chambers collapse. In this systematic review, we examined the impact of PH on the incidence, in-hospital and long-term mortality, and echocardiographic findings of patients with cardiac tamponade. Using the PRISMA guideline, a systematic search was conducted in PubMed, Academic Search Premier, Web of Science, Google Scholar, and the Cochrane Database for studies investigating PH and cardiac tamponade. The Newcastle-Ottawa Scale was used to analyze the quality of returned studies. Primary outcomes included the incidence of cardiac tamponade, as well as in-hospital and long-term mortality rates. Secondary outcomes were the presence or absence of echocardiographic findings of cardiac tamponade in patients with PH. Forty-three studies (9 cohort studies and 34 case reports) with 1054 patients were included. The incidence of cardiac tamponade was significantly higher in patients with PH compared to those without PH, 2.0% (95% CI 1.2-3.2%) vs. 0.05% (95% CI 0.05-0.05%), p < 0.0001, OR 40.76 (95% CI 24.8-66.9). The incidence of tamponade in patients with a known pericardial effusion was similar in those with and without PH, 20.3% (95% CI 12.0-32.3%) and 20.9% (95% CI 18.0-24.1%), p = 0.9267, OR 0.97 (95% CI 0.50-1.87). In patients with tamponade, those with PH demonstrated a significantly higher in-hospital mortality than those without PH, 38.8% (95% CI 26.4-52.8%) vs. 14.4% (95% CI 14.2-14.6%), p < 0.0001, OR 3.77 (95% CI 2.12-6.70). Long-term mortality in patients with tamponade was significantly lower in those with PH than in those without PH, 45.5% (95% CI 33.0-58.5%) vs. 59.1% (95% CI 54.7-63.4%), p = 0.0258, OR 0.576 (95% CI 0.33-1.01). However, after stratifying by non-malignant etiologies, the long-term mortality benefit for those with PH disappeared. In the studies that described specific echocardiographic findings of cardiac tamponade, only 10.5% of patients with PH and tamponade showed right atrial and right ventricular collapse. When evaluating patients with pericardial effusions, physicians must recognize the effects of underlying PH on the incidence, in-hospital and long-term mortality rates, and potentially atypical echocardiographic presentation of cardiac tamponade.

A Novel Tool for Predicting an Abnormal Echocardiogram in Patients with Pulmonary Embolism: The PEACE Score

BACKGROUND

Transthoracic echocardiography (TTE) is an essential tool for risk-stratifying patients with pulmonary embolism (PE), but its availability is limited, often requiring hospitalization. Minimal research exists evaluating clinical and laboratory criteria to predict lack of abnormal TTE findings.

OBJECTIVE

We aimed to identify predictors associated with abnormal TTE results in patients with PE to potentially identify those safe for early discharge.

METHODS

In this retrospective study, we analyzed an existing database of patients with venous thromboembolism (VTE) at two academic emergency departments, including adult patients with confirmed PE who underwent TTE. The primary goal was to develop and validate a score predicting abnormal TTE, defined as presence of one of the following: right ventricle (RV) dilatation or hypokinesis, septal flattening, right heart thrombus in transit, or ejection fraction < 50%. Variables were demographic characteristics, symptoms, computed tomography (CT) RV strain, troponin T, and N-terminal prohormone of brain natriuretic peptide (NTproBNP). Stepwise logistic regression was used to identify variables independently associated with abnormal TTE. Model discrimination was evaluated using area under the curve (AUC) of the receiver operating characteristic curve. A clinical prediction rule was developed.

RESULTS

530 of 2235 patients were included; 56% (297 of 530) had an abnormal TTE. The following six variables were independently associated with abnormal TTE: dyspnea, dizziness, troponin T ≥ 0.1 ng/mL, NTproBNP > 900 pg/mL, CT RV strain, and nonsubsegmental PE. A clinical prediction rule using these six criteria yielded scores between 0 and 7, performing well with AUC of 0.80 (95% CI 0.79-0.80). A score of 1 was 99.7% sensitive in identifying no abnormality. A score ≥ 5 was 98% specific for an abnormality.

CONCLUSIONS

The PEACE (Pulmonary Embolism and Abnormal Cardiac Echocardiogram) criteria, composed of six variables, is highly effective in predicting abnormal TTE in patients with PE, potentially identifying who is safe for early discharge from the hospital.

Point-of-care AI-assisted stepwise ultrasound pneumothorax diagnosis

Objective. Ultrasound is extensively utilized as a convenient and cost-effective method in emergency situations. Unfortunately, the limited availability of skilled clinicians in emergency hinders the wider adoption of point-of-care ultrasound. To overcome this challenge, this paper aims to aid less experienced healthcare providers in emergency lung ultrasound scans.Approach. To assist healthcare providers, it is important to have a comprehensive model that can automatically guide the entire process of lung ultrasound based on the clinician's workflow. In this paper, we propose a framework for diagnosing pneumothorax using artificial intelligence (AI) assistance. Specifically, the proposed framework for lung ultrasound scan follows the steps taken by skilled physicians. It begins with finding the appropriate transducer position on the chest to locate the pleural line accurately in B-mode. The next step involves acquiring temporal M-mode data to determine the presence of lung sliding, a crucial indicator for pneumothorax. To mimic the sequential process of clinicians, two DL models were developed. The first model focuses on quality assurance (QA) and regression of the pleural line region-of-interest, while the second model classifies lung sliding. To achieve the inference on a mobile device, a size of EfficientNet-Lite0 model was further reduced to have fewer than 3 million parameters.Main results. The results showed that both the QA and lung sliding classification models achieved over 95% in area under the receiver operating characteristic (AUC), while the ROI performance reached 89% in the dice similarity coefficient. The entire stepwise pipeline was simulated using retrospective data, yielding an AUC of 89%.Significance. The step-wise AI framework for the pneumothorax diagnosis with QA offers an intelligible guide for each clinical workflow, which achieved significantly high precision and real-time inferences.

Point-of-Care Ultrasound in Children With Medical Complexity

BACKGROUND AND OBJECTIVES

Children with medical complexity (CMC) have significant chronic health conditions that involve congenital or acquired multisystem disease associated with medical fragility, functional limitations, dependence on technology, and high health care utilization. The objective of this study was to describe the indications, applications, and point-of-care ultrasound (POCUS) findings in this population.

METHODS

A descriptive study of POCUS scans performed for clinical purposes in CMC admitted to a single pediatric postacute care hospital. All children for whom a POCUS was requested by a medical team provider were eligible for inclusion.

RESULTS

One hundred and four POCUS evaluations were performed for 33 patients. Diagnostic groups for the 33 patients included multiple congenital anomalies (41%), neurologic or neuromuscular (31%), prematurity (25%) and cardiac (3%). Lung, cardiac, and diaphragmatic ultrasound accounted for 57% of POCUS requested. POCUS was abnormal in 82% of diaphragmatic, 73% of lung, and 11% of cardiac ultrasounds. Twenty-three percent of POCUS studies were requested to answer a specific clinical question, 56% for follow-up information, and 21% for baseline evaluation.

CONCLUSIONS

Lung, diaphragmatic, and cardiac ultrasound were the most prevalent POCUS studies requested in a postacute care hospital. POCUS may offer an expanded role in such patients and settings by answering clinical questions and by providing baseline and follow-up information.

Effect of the Extended Focused Assessment With Sonography for Trauma on the Screening Performance of the National Emergency X-Radiography Utilization Study Chest Decision Instrument

STUDY OBJECTIVE

Developed to decrease unnecessary thoracic computed tomography use in adult blunt trauma patients, the National Emergency X-Radiography Utilization Study (NEXUS) Chest clinical decision instrument does not include the extended Focused Assessment with Sonography in Trauma (eFAST). We assessed whether eFAST improves the NEXUS Chest clinical decision instrument's diagnostic performance and may replace the chest radiograph (CXR) as a predictor variable.

METHODS

We performed a secondary analysis of prospective data from 8 Level I trauma centers from 2011-2014. We compared performance of modified clinical decision instruments that (1) added eFAST as a predictor (eFAST-added clinical decision instrument), and (2) replaced CXR with eFAST (eFAST-replaced clinical decision instrument), in screening for blunt thoracic injuries.

RESULTS

One thousand nine hundred fifty-seven patients had documented computed tomography, CXR, clinical NEXUS criteria, and adequate eFAST; 624 (31.9%) patients had blunt thoracic injuries, and 126 (6.4%) had major injuries. Compared to the NEXUS Chest clinical decision instrument, the eFAST-added clinical decision instrument demonstrated unchanged screening performance for major injury (sensitivity 0.98 [0.94 to 1.00], specificity 0.28 [0.26 to 0.30]) or any injury (sensitivity 0.97 [0.95 to 0.98], specificity 0.21 [0.19 to 0.23]). The eFAST-replaced clinical decision instrument demonstrated unchanged sensitivity for major injury (sensitivity 0.93 [0.87 to 0.97], specificity 0.31 [0.29 to 0.34]) and decreased sensitivity for any injury (0.93 [0.91 to 0.951] versus 0.97 [0.953 to 0.98]).

CONCLUSION

In our secondary analysis, adding eFAST as a predictor variable did not improve the diagnostic screening performance of the original NEXUS Chest clinical decision instrument; eFAST cannot replace the CXR criterion of the NEXUS Chest clinical decision instrument.

Deoxycholic Acid for Dercum Disease: Repurposing a Cosmetic Agent to Treat a Rare Disease

Dercum disease is a rare condition characterized by multiple painful fatty tumors distributed throughout the body. There currently are no US Food and Drug Administration-approved treatments for Dercum disease, and the treatments tried have shown little to no efficacy, leaving many patients with a profoundly negative impact on quality of life. We present a case series of 3 patients who were diagnosed with Dercum disease and were treated with deoxycholic acid (DCA), a therapy approved for adipolysis of submental fat. The patients experienced a reduction in tumor size with radiographic evidence as well as a notable reduction in symptoms.

Point-of Care Ultrasound in Stratifying Clinically Evolving Inguinal and Femoral Hernias

BACKGROUND

Point-of-care ultrasound (POCUS) is an optimal imaging modality for the risk stratification of patients presenting to the emergency department (ED) with inguinal and femoral hernias, allowing for better evaluation of clinical presentations and guiding appropriate treatment. The lack of ultrasound classification for inguinal and femoral hernias has led to inconsistent use and often underuse of POCUS in this patient population. Several groin hernia classifications are available, but most are complex and often targeted toward surgical management.

OBJECTIVES

The objective of this study is to review the use of POCUS in the diagnosis of inguinal and femoral hernias, providing a synopsis of critical ultrasound findings in determining signs of incarceration, strangulation, and small bowel obstruction, and suggesting a simple and educative sonographic classification for inguinal or femoral hernias.

DISCUSSION

POCUS can reliably confirm the presence of groin hernias and can uniquely identify specific ultrasound findings predictive of complications, such as aperistaltic nonreducible bowel loops, free fluid in the hernia sac, and lack of color doppler in the entrapped mesentery and bowel walls. POCUS can also aid in determining the presence of small bowel obstruction by detecting dilated loops of bowel >25 mm adjacent and proximal to the hernia site.

CONCLUSIONS

In the ED, POCUS can confirm the presence of a hernia sac and identify and predict surgical emergencies, such as bowel incarceration or strangulation, which are the most important elements in the management of patients presenting with possible inguinal or femoral hernias.

Advanced practice providers proficiency-based model of ultrasound training and practice in the ED

Competency in the application of point-of-care ultrasound (POCUS) has come to be an expected fundamental skill set for advanced practice providers (APPs) in the emergency department. Both American College of Emergency Physicians and the Society of Emergency Medicine Physician Assistants approve of and endorse POCUS use by APPs. However, clinical exposure to and practice of ultrasound in this setting is often variable and without structure. POCUS training must be evolved into a system where developed skills are compatible with clinical need and expectations of APPs. At our institution, we developed a formal, structured POCUS training program for emergency medicine (EM) APPs (including physician assistants and nurse practitioners) and evaluated its efficacy quantitatively by means of a proficiency index. This report examines the EM POCUS training most common to physician assistants and nurse practitioners before practicing at our institution and explores the components of our POCUS training program that have affected program development.

Point-of-Care Lung Ultrasound for Differentiating COVID-19 From Influenza

Background and objectives

Patients infected with influenza and COVID-19 exhibit similar clinical presentations; thus, a point-of-care test to differentiate between the diseases is needed. Here, we sought to identify features of point-of-care lung ultrasound (LUS) that can discriminate between influenza and COVID-19.

Methods

In this prospective, cross-sectional study, LUS clips of patients presenting to the emergency department (ED) with viral-like symptoms were collected via a 10-zone scanning protocol. Deidentified clips were interpreted by emergency ultrasound fellows blinded to patients’ clinical context and influenza or COVID-19 diagnosis. Modified Soldati scores were calculated for each lung zone. Logistic regression identified the association of pulmonary pathologies with each disease.

Results

Ultrasound fellows reviewed LUS clips from 165 patients, of which 30.9% (51/165) had confirmed influenza, 33.9% (56/165) had confirmed COVID-19, and 35.1% (58/165) had neither disease. Patients with COVID-19 were more likely to have irregular pleura and B-lines in all lung zones (p<0.01). The median-modified Soldati score for influenza patients was 0/20 (IQR 0-2), 9/20 (IQR 2.5-15.5) for COVID-19 patients, and 2/20 (IQR 0-8) for patients with neither disease (p<0.0001). In multivariate regression analysis adjusted for age, sex, and congestive heart failure (CHF), the presence of B-lines (OR = 1.29, 95% CI 1.09-1.53) was independently associated with COVID-19 diagnosis. The presence of pleural effusion was inversely associated with COVID-19 (OR = 0.09, 95% CI 0.01-0.65).

Conclusions

LUS may help providers preferentially identify the presence of influenza versus COVID-19 infection both visually and by calculating a modified Soldati score. Further studies assessing the utility of LUS in differentiating viral illnesses in patients with variable illness patterns and those with variable illness severity are warranted.

Sonographic Assessment of the Effects of Mechanical Ventilation on Carotid Flow Time and Volume

Background

Corrected carotid flow time (CFTc) and carotid blood flow (CBF) are sonographic measurements used to assess fluid responsiveness in hypotension. We investigated the impacts of mechanical ventilation on CFTc and CBF.

Materials and methods

Normotensive patients undergoing cardiac surgery were prospectively enrolled. Carotid ultrasound (US) was performed pre and post-intubation. Post-intubation measurements took place after the initiation of mechanical ventilation. To measure CFTc and CBF, a sagittal carotid view was obtained with pulse wave-Doppler (maximum angle 60°). CFTc was calculated with the Bazett formula (CFTc = systolic time/√cycle time). CBF was calculated using CBF (mL/min) = area (cm ² ) x time average mean velocity (TAMEAN) (cm/sec) x 60 (sec/min). The maximum carotid diameter was measured at the level of the thyroid.

Results

Twenty patients were enrolled. Mean CFTc pre-intubation was 328 ms (SD 43.9 ms) compared to CFTc post-intubation 336 ms (SD 36 ms). There was no significant difference between pre and post-intubation CFTc (mean differences=-0.008; t(19)=-0.71, p=.49). Mean CBF pre-intubation was 487 mL/min (SD 176 mL/min) compared to CBF post-intubation 447 mL/min (SD 187 mL/min). There was no significant difference between pre and post-intubation CBF (mean differences= 40; t(19)=1.24, p=.23).

Conclusions

In this study of normotensive patients, there were no detected differences in CFTc or CBF pre and post-intubation with mechanical ventilation.

The Use of Angle-Independent M-Mode in the Evaluation of Diaphragmatic Excursion: Towards Improved Accuracy

Assessment of diaphragmatic function has been well described in the intensive care setting as well as in emergency medicine and pediatrics. Conventional M-mode evaluation of diaphragmatic excursion is frequently associated with over and under-estimations of diaphragmatic excursion. Angle-independent M-mode allows free rotation and movement of the analysis line to obtain M-mode images in a direction that more accurately reflects diaphragmatic excursion. In order to provide a standardized approach to the evaluation of diaphragmatic excursion with angle-independent M-mode, we propose a landmark-based approach utilizing the spine in order to target the same diaphragmatic segment consistently throughout the diaphragmatic analysis. While the proposed approach is not intended to replace current methods, it may improve accuracy and inter-rater reliability. The relevant background, as well as three patient cases, are presented demonstrating the use of a landmark-based approach in the emergency department. Angle-independent M-mode may provide a more accurate and consistent evaluation of diaphragmatic excursion, an examination that can be used to guide clinical care and anticipate outcomes.

Detecting Ventilator-Induced Diaphragmatic Dysfunction Using Point-of-Care Ultrasound in Children With Long-term Mechanical Ventilation

Long-term mechanical ventilation (MV) is defined as the use of MV for more than 6 hours per day for at least 3 weeks. Children requiring long-term MV include those with neuromuscular disease, central dysregulation, or lung dysfunction. Such children with medical complexity may be at risk for ventilator-induced diaphragmatic dysfunction. Ventilator-induced diaphragmatic dysfunction has been described in adult patients requiring acute MV with ultrasound (US). At this time, diaphragmatic US has not been evaluated in the pediatric post-acute care setting or incorporated into weaning strategies. We present 24 cases of children requiring long-term MV who underwent diaphragmatic US examinations to evaluate for ventilator-induced diaphragmatic dysfunction.

Point-of-care Ultrasound in Morbidity and Mortality Cases in Emergency Medicine: Who Benefits the Most?

Introduction

Point-of-care ultrasound (POCUS) is an essential tool in the timely evaluation of an undifferentiated patient in the emergency department (ED). Our primary objective in this study was to determine the perceived impact of POCUS in high-risk cases presented at emergency medicine (EM) morbidity and mortality (M&M) conferences. Additionally, we sought to identify in which types of patients POCUS might be most useful, and which POCUS applications were considered to be highest yield.

Methods

This was a retrospective survey of cases submitted to M&M at an EM residency program that spans two academic EDs, over one academic year. Postgraduate year 4 (PGY) residents who presented M&M cases at departmental sessions were surveyed on perceived impacts of POCUS on individual patient outcomes. We evaluated POCUS use and indications while the POCUS was used.

Results

Over the 12-month period, we reviewed 667 cases from 18 M&M sessions by 15 PGY-4 residents and a supervising EM attending physician who chairs the M&M committee. Of these cases, 75 were selected by the M&M committee for review and presentation. POCUS was used in 27% (20/75) of the cases and not used in 73% (55/75). In cases where POCUS was not used, retrospective review determined that if POCUS had been used it would have “likely prevented the M&M” in 45% (25/55). Of these 25 cases, the majority of POCUS applications that could have helped were cardiac (32%, 8/25) and lung (32%, 8/25) ultrasound. POCUS was felt to have greatest potential in identifying missed diagnoses (92%, 23/25), and decreasing the time to diagnosis (92%, 23/25). Patients with cardiopulmonary chief complaints and abnormal vital signs were most likely to benefit. There were seven cases (35%, 7/20, 95% CI 15–59%) in which POCUS was performed and thought to have possibly adversely affected the outcome of the M&M.

Conclusion

POCUS was felt to have the potential to reduce or prevent M&M in 45% of cases in which it was not used. Cardiac and lung POCUS were among the most useful applications, especially in patients with cardiopulmonary complaints and in those with abnormal vital signs.

Utility of point-of-care ultrasound in patients with suspected diverticulitis in the emergency department

In emergency department (ED) cases with clinically suspected diverticulitis, diagnostic imaging is often needed for diagnostic confirmation, to exclude complications, and to direct patient management. Patients typically undergo a CT scan in the ED; however, in a subset of cases with suspected diverticulitis, point-of-care ultrasound (POCUS) may provide sufficient data to confirm the diagnosis and ascertain a safe plan for outpatient management.We review the main sonographic features of diverticulitis and discuss the diagnostic accuracy and potential benefits of a POCUS First model.

Ultrasound Measurement of Carotid Intima-Media Thickness and Plaques in Predicting Coronary Artery Disease

Ultrasound measurement of carotid intima-media thickness (CIMT) and plaque thickness (PT) may be an additional tool for risk stratification of patients with suspected acute coronary syndrome (ACS) in the emergency department (ED). The aim of this study was to evaluate the correlation of CIMT and PT with coronary artery disease (CAD) in risk stratification tests.This prospective observational study was conducted in an academic tertiary care ED. Carotid ultrasound measurements were obtained for emergency patients with suspected ACS. Carotid measurements included PT, mean CIMT and maximum CIMT. The correlations between carotid ultrasound and the results of coronary catheter angiography (CA), coronary computed tomography angiography (CCTA) and stress tests were identified. The convenience sample included 58 patients comprising 39 men and 19 women with a mean age of 60 ± 12 y. Twenty-two percent (13/58) of patients were positive for CAD, as indicated by results of the cardiac risk stratification tests. Presence of plaque correlated with CCTA findings, with a high specificity (92.8%) for a positive test. Max CIMT predicted abnormal CCTA (area under the curve [AUC] = 0.93, 95% confidence interval: 0.80-1). The correlations with stress test (0.78, 0.46-1) and CA (0.55, 0.28-0.82) were weaker. Presence of carotid plaque correlated significantly with findings of CAD on all risk stratification tests, but especially with CCTA. Carotid ultrasound could have a role in risk stratification in the ED, though more research is needed.

A Novel Application of Ultrasound-Guided Interscalene Anesthesia for Proximal Humeral Fractures

BACKGROUND

Proximal humeral fractures are commonly encountered in the emergency department (ED). These injuries are often associated with significant pain, with patients often receiving multiple doses of opiate medications while awaiting definitive management. The interscalene nerve block has been efficacious as perioperative analgesia for patients undergoing operative shoulder repair. The utilization of the interscalene nerve block in the ED for proximal humeral fractures is largely unexplored.

DISCUSSION

We report the use of an ultrasound-guided interscalene nerve block in the ED for a patient presenting with significant pain from a proximal humerus fracture. The procedure provided excellent regional anesthesia with no additional need for intravenous or oral opiates during the rest of her ED course. With the significant risks associated with pain medication, particularly opiates, regional anesthesia may be an excellent option for the appropriate patient in the ED.

CONCLUSIONS

As documented in this report, the ultrasound-guided interscalene block, in particular, may be utilized as a means to provide adequate pain control for patients with proximal humerus fractures in the ED.

Barriers to learning and using point-of-care ultrasound: a survey of practicing internists in six North American institutions

Background

Point-of-care ultrasound (POCUS) is increasingly used in internal medicine, but a lack of trained faculty continues to limit the spread of POCUS education. Using a framework based on organizational change theories, this study sought to identify barriers and enablers for hospital-based practicing internists to learn and use POCUS in clinical practice.

Methods

We invited practicing internists at six North American institutions to participate in an electronic survey on their opinions regarding 39 barriers and enablers.

Results

Of the 342 participants invited, 170 participated (response rate 49.3%). The top barriers were lack of training (79%), lack of handheld ultrasound devices (78%), lack of direct supervision (65%), lack of time to perform POCUS during rounds (65%), and lack of quality assurance processes (53%). The majority of participants (55%) disagreed or strongly disagreed with the statement “My institution provides funding for POCUS training.” In general, participants’ attitudes towards POCUS were favourable, and future career opportunities and the potential for billing were not considered significant factors by our participants in the decision to learn or use POCUS.

Conclusions

This survey confirms the perceived importance of POCUS to practicing internists. To assist in closing faculty development gap, interventions should address training, supervision, quality assurance processes, availability of handheld devices, as well as dedicated time to perform POCUS during clinical care.

Enhanced Point-of-Care Ultrasound Applications by Integrating Automated Feature-Learning Systems Using Deep Learning

Recent applications of artificial intelligence (AI) and deep learning (DL) in health care include enhanced diagnostic imaging modalities to support clinical decisions and improve patients' outcomes. Focused on using automated DL-based systems to improve point-of-care ultrasound (POCUS), we look at DL-based automation as a key field in expanding and improving POCUS applications in various clinical settings. A promising additional value would be the ability to automate training model selections for teaching POCUS to medical trainees and novice sonologists. The diversity of POCUS applications and ultrasound equipment, each requiring specialized AI models and domain expertise, limits the use of DL as a generic solution. In this article, we highlight the most advanced potential applications of AI in POCUS tailored to high-yield models in automated image interpretations, with the premise of improving the accuracy and efficacy of POCUS scans.

Pilot Point-of-Care Ultrasound Curriculum at Harvard Medical School: Early Experience

INTRODUCTION

Point-of-care ultrasound (POCUS) is expanding across all medical specialties. As the benefits of US technology are becoming apparent, efforts to integrate US into pre-clinical medical education are growing. Our objective was to describe our process of integrating POCUS as an educational tool into the medical school curriculum and how such efforts are perceived by students.

METHODS

This was a pilot study to introduce ultrasonography into the Harvard Medical School curriculum to first- and second-year medical students. Didactic and hands-on sessions were introduced to first-year students during gross anatomy and to second-year students in the physical exam course. Student-perceived attitudes, understanding, and knowledge of US, and its applications to learning the physical exam, were measured by a post-assessment survey.

RESULTS

All first-year anatomy students (n=176) participated in small group hands-on US sessions. In the second-year physical diagnosis course, 38 students participated in four sessions. All students (91%) agreed or strongly agreed that additional US teaching should be incorporated throughout the four-year medical school curriculum.

CONCLUSION

POCUS can effectively be integrated into the existing medical school curriculum by using didactic and small group hands-on sessions. Medical students perceived US training as valuable in understanding human anatomy and in learning physical exam skills. This innovative program demonstrates US as an additional learning modality. Future goals include expanding on this work to incorporate US education into all four years of medical school.

The Massachusetts abscess rule: a clinical decision rule using ultrasound to identify methicillin-resistant Staphylococcus aureus in skin abscesses

OBJECTIVES

Treatment failure rates for incision and drainage (I&D) of skin abscesses have increased in recent years and may be attributable to an increased prevalence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA). Previous authors have described sonographic features of abscesses, such as the presence of interstitial fluid, characteristics of abscess debris, and depth of abscess cavity. It is possible that the sonographic features are associated with MRSA and can be used to predict the presence of MRSA. The authors describe a potential clinical decision rule (CDR) using sonographic images to predict the presence of CA-MRSA.

METHODS

This was a pilot CDR derivation study using databases from two emergency departments (EDs) of patients presenting to the ED with uncomplicated skin abscesses who underwent I&D and culture of the abscess contents. Patients underwent ultrasound (US) imaging of the abscesses prior to I&D. Abscess contents were sent for culture and sensitivity. Two independent physicians experienced in soft tissue US blinded to the culture results and clinical data reviewed the images in a standardized fashion for the presence or absence of the predetermined image characteristics. In the instance of a disagreement between the initial two investigators, a third reviewer adjudicated the findings prior to analysis. The association between the primary outcome (presence of MRSA) and each sonographic feature was assessed using univariate and multivariate analysis. The reliability of each sonographic feature was measured by calculating the kappa (κ) coefficient of interobserver agreement. The decision tree model for the CDR was created with recursive partitioning using variables that were both reliable and strongly associated with MRSA.

RESULTS

Of the total of 2,167 patients who presented with skin and soft tissue infections during the study period, 605 patients met inclusion criteria with US imaging and culture and sensitivity of purulence. Among the pathogenic organisms, MRSA was the most frequently isolated, representing 50.1% of all patients. Six of the sonographic features were associated with the presence of MRSA, but only four of these features were reliable using the kappa analysis. Recursive partitioning identified three independent variables that were both associated with MRSA and reliable: 1) the lack of a well-defined edge, 2) small volume, and 3) irregular or indistinct shape. This decision rule demonstrates a sensitivity of 89.2% (95% confidence interval [CI] = 84.7% to 92.7%), a specificity of 44.7% (95% CI = 40.9% to 47.8%), a positive predictive value of 57.9 (95% CI = 55.0 to 60.2), a negative predictive value of 82.9 (95% CI = 75.9 to 88.5), and an odds ratio (OR) of 7.0 (95% CI = 4.0 to 12.2).

CONCLUSIONS

According to our putative CDR, patients with skin abscesses that are small, irregularly shaped, or indistinct, with ill-defined edges, are seven times more likely to demonstrate MRSA on culture.

International evidence-based recommendations for point-of-care lung ultrasound

BACKGROUND

The purpose of this study is to provide evidence-based and expert consensus recommendations for lung ultrasound with focus on emergency and critical care settings.

METHODS

A multidisciplinary panel of 28 experts from eight countries was involved. Literature was reviewed from January 1966 to June 2011. Consensus members searched multiple databases including Pubmed, Medline, OVID, Embase, and others. The process used to develop these evidence-based recommendations involved two phases: determining the level of quality of evidence and developing the recommendation. The quality of evidence is assessed by the grading of recommendation, assessment, development, and evaluation (GRADE) method. However, the GRADE system does not enforce a specific method on how the panel should reach decisions during the consensus process. Our methodology committee decided to utilize the RAND appropriateness method for panel judgment and decisions/consensus.

RESULTS

Seventy-three proposed statements were examined and discussed in three conferences held in Bologna, Pisa, and Rome. Each conference included two rounds of face-to-face modified Delphi technique. Anonymous panel voting followed each round. The panel did not reach an agreement and therefore did not adopt any recommendations for six statements. Weak/conditional recommendations were made for 2 statements, and strong recommendations were made for the remaining 65 statements. The statements were then recategorized and grouped to their current format. Internal and external peer-review processes took place before submission of the recommendations. Updates will occur at least every 4 years or whenever significant major changes in evidence appear.

CONCLUSIONS

This document reflects the overall results of the first consensus conference on "point-of-care" lung ultrasound. Statements were discussed and elaborated by experts who published the vast majority of papers on clinical use of lung ultrasound in the last 20 years. Recommendations were produced to guide implementation, development, and standardization of lung ultrasound in all relevant settings.

My patient has no blood pressure: point-of-care ultrasound in the hypotensive patient – FAST and RELIABLE

There is perhaps no greater challenge to the emergency and critical care physician than management of the hypotensive patient. A rapid, yet accurate, assessment is essential in this clinical setting. Point-of-care ultrasound (PoCUS) has evolved to become an indispensable test in the critical care and emergency setting. This article addresses the use of ultrasound in the evaluation of the hypotensive patient and reviews some of the scanning protocols and algorithms that have been described. We use the mnemonic FAST and RELIABLE to describe key aspects of PoCUS for undifferentiated hypotension.

Focused maternal ultrasound by midwives in rural Zambia

Point-of-care ultrasound is being increasingly implemented in resource-poor settings in an ad hoc fashion. We developed a focused maternal ultrasound-training program for midwives in a rural health district in Zambia. Four hundred forty-one scans were recorded by 21 midwives during the 6-month study period. In 74 scans (17%), the ultrasound findings prompted a change in clinical decision-making. Eight of the midwives were evaluated with a 14-question observed structured clinical examination (OSCE) and demonstrated a slight overall improvement with mean scores at 2 and 6 months of 10.0/14 (71%) and 11.6/14 (83%), respectively. Our pilot project demonstrates that midwives in rural Zambia can be trained to perform basic obstetric ultrasound and that it impacts clinical decision-making. Ultrasound skills were retained over the study period. More data is necessary to determine whether the introduction of ultrasound ultimately improves outcomes of pregnant women in rural Zambia.

Decreased sensitivity of lung ultrasound limited to the anterior chest in emergency department diagnosis of cardiogenic pulmonary edema: a retrospective analysis

Purposes

B-lines are vertical echogenic artifacts seen on lung ultrasound that allow bedside diagnosis of pulmonary edema. The BLUE protocol, published by Lichtenstein and Mezière, suggests that cardiogenic pulmonary edema is sufficiently ruled out in the ICU setting when B-lines are not predominant in the anterior chest (the B-profile). Our analysis sought to evaluate the sensitivity of the B-profile for ruling out pulmonary edema in the ED patient population.

Methods

The ultrasound lung scans of patients with confirmed official diagnoses of acute decompensated heart failure (ADHF) from two ED databases were retrospectively analyzed. 170 acutely dyspneic patients had complete studies (130 from one database and 40 from the other). The scans were reviewed using the B-profile definition for ruling out pulmonary edema and comparing that to an alternate scanning protocol that includes ultrasound evaluation of the lateral and anterior chest.

Results

Of the 170 ED patients with ADHF diagnoses, the B-profile missed 16.5% (n = 28) for a sensitivity of 83.5% (95% CI 77–89%). These 28 patients did not show anterior bilateral B-lines that fit the criteria for positive under the BLUE protocol. Moreover, 25% (7/28) of these missed patients had only lateral B-lines on their lung scans and B-lines would have been detected only by including scans of the lateral zones.

Conclusions

Limiting the sonographic lung examination to the anterior chest areas only will miss cases of ADHF in the dyspneic ED patients. The BLUE protocol (B-profile) may need to be modified to include examination of the lateral chest as necessary for ED patients with ADHF.

Are live instructors replaceable? Computer vs. classroom lectures for EFAST training

BACKGROUND

The EFAST (extended focused assessment with sonography for trauma) is part of the recommended curriculum for Emergency Medicine and Surgery residents. Computer-based lectures may represent a time-efficient alternative to traditional lectures.

OBJECTIVES

Our hypothesis was that computer lectures in basic ultrasound and the EFAST are not inferior to classroom lectures in test score improvement for residents with or without prior training.

METHODS

First-year Emergency Medicine and Surgery residents were enrolled and completed a pre-test. Subjects were then randomized into a classroom group, which attended traditional lectures, and a computer group, which listened to narrated lectures on computers. After the didactic training, all subjects completed a post-test.

RESULTS

Forty-four subjects completed the study: 64% were General Surgery residents, 66% were male. Overall, mean test score improvements were higher in the classroom than in the computer group (28.0% vs. 18.4%). In 25 residents without prior training, mean improvements in the computer and classroom groups were 25% and 27%, respectively. The 95% confidence limit around the difference was 9%, falling within the a priori non-inferiority range of 10%, and consistent with non-inferiority of computer-based lectures. In 19 residents with prior training, mean test score improvements for the computer and classroom groups were 13% and 29%, respectively. The 95% confidence limit of 24% exceeded the non-inferiority range, consistent with inferiority of computer-based lectures.

CONCLUSIONS

Computer-based lectures are not inferior to classroom lectures and may represent a worthwhile substitution in subjects without prior ultrasound education. Our data suggest that didactic ultrasound training through classroom lectures is more effective than computer-based lectures in individuals with prior training.

Ultrasound assessment for extravascular lung water in patients undergoing hemodialysis. Time course for resolution

BACKGROUND

Sonographic B-lines, also known as lung comets, have been shown to correlate with the presence of extravascular lung water (EVLW). Absent in normal lungs, these sonographic findings become prominent as interstitia and alveoli fill with fluid. Characterization of the dynamics of B-lines, specifically their rate of disappearance as volume is removed, has not been previously described. In this study, we describe the dynamics of B-line resolution in patients undergoing hemodialysis.

METHODS

Patients undergoing hemodialysis underwent three chest ultrasound examinations: before, at the midpoint, and after dialysis. We followed a previously described chest ultrasound protocol that counts the number of B-lines visualized in 28 lung zones. Baseline demographics, assessment of ejection fraction, time elapsed, net volume of fluid removed, and subjective degree of shortness of breath were recorded for each patient.

RESULTS

Forty of 45 patients completed full dialysis runs and had all three lung scans performed; 6 of 40 patients had zero or one B-line predialysis, and none of these 6 patients gained B-lines during dialysis. Thirty-four of 40 patients had statistically significant reductions in the number of B-lines from predialysis to the midpoint scan and from predialysis to postdialysis with a p value < 0.001. There was no association between subjective dyspnea scores and number of B-lines removed.

CONCLUSIONS

B-line resolution appears to occur real-time as fluid is removed from the body, and this change was statistically significant. These data support thoracic ultrasound as a useful method for evaluating real-time changes in EVLW and in assessing a patient's physiologic response to the removal of fluid.

TRIAL REGISTRATION

Massachusetts General Hospital trial registration protocol No. 2007P 002226.

Evaluation of a thoracic ultrasound training module for the detection of pneumothorax and pulmonary edema by prehospital physician care providers

BACKGROUND

While ultrasound (US) has continued to expedite diagnosis and therapy for critical care physicians inside the hospital system, the technology has been slow to diffuse into the pre-hospital system. Given the diagnostic benefits of thoracic ultrasound (TUS), we sought to evaluate image recognition skills for two important TUS applications; the identification of B-lines (used in the US diagnosis of pulmonary edema) and the identification of lung sliding and comet tails (used in the US diagnosis of pneumothorax). In particular we evaluated the impact of a focused training module in a pre-hospital system that utilizes physicians as pre-hospital providers.

METHODS

27 Paris Service D'Aide Médicale Urgente (SAMU) physicians at the Hôpital Necker with varying levels of US experience were given two twenty-five image recognition pre-tests; the first test had examples of both normal and pneumothorax lung US and the second had examples of both normal and pulmonary edema lung US. All 27 physicians then underwent the same didactic training modules. A post-test was administered upon completing the training module and results were recorded.

RESULTS

Pre and post-test scores were compared for both the pneumothorax and the pulmonary edema modules. For the pneumothorax module, mean test scores increased from 10.3 +/- 4.1 before the training to 20.1 +/- 3.5 after (p < 0.0001), out of 25 possible points. The standard deviation decreased as well, indicating a collective improvement. For the pulmonary edema module, mean test scores increased from 14.1 +/- 5.2 before the training to 20.9 +/- 2.4 after (p < 0.0001), out of 25 possible points. The standard deviation decreased again by more than half, indicating a collective improvement.

CONCLUSION

This brief training module resulted in significant improvement of image recognition skills for physicians both with and without previous ultrasound experience. Given that rapid diagnosis of these conditions in the pre-hospital system can change therapy, especially in systems where physicians can integrate this information into treatment decisions, the further diffusion of this technology would seem to be beneficial and deserves further study.

Ultrasound diagnosis of type a aortic dissection

BACKGROUND

An aortic dissection is a life-threatening process that must be diagnosed and treated expeditiously. Imaging modalities used for diagnosis in the emergency department include computed tomography, magnetic resonance imaging, and trans-esophageal echocardiography. There are significant limitations to these studies, including patient contraindications (intravenous contrast dye allergies, renal insufficiency, metal-containing implants, hemodynamic instability) and the length of time required for study completion and interpretation by a radiologist or cardiologist.

OBJECTIVES

A case is presented that demonstrates how emergency physicians can use trans-thoracic and abdominal bedside ultrasound to diagnose a type A aortic dissection.

CASE REPORT

A 72-year-old woman presented with chest pain radiating to her neck and back that was concerning for aortic dissection. This was subsequently confirmed and further classified as a type A dissection by bedside emergency physician-performed ultrasound. The images showed a clear intimal flap in the abdominal aorta, a dilatated aortic root, and extension of the intimal flap into the left common carotid artery. With prompt diagnosis, the patient was able to have emergent surgical consultation, confirmatory imaging, and intervention before further complication occurred.

CONCLUSION

This case provides an example of how emergency trans-thoracic and abdominal ultrasound can be used to promptly diagnose a type A aortic dissection and expedite further consultation and prompt management.