Beatrice Hoffmann

Seventy-two-hour Returns May Not be a Good Indicator of Safety in the Emergency Department: A National Study

OBJECTIVES The objective was to measure the association between returns to an emergency department (ED) within 72 hours and resource utilization, severity of illness, mortality, and admission rate. METHODS This was a retrospective, cross-sectional analysis of ED visits using data from the National Hospital Ambulatory Medical Care Survey (NHAMCS) from 1998 to 2006. Cohorts were patients who had been seen in the ED within the past 72 hours versus those without the prior visit. A multivariate model was created to predict adjusted-resource utilization and mortality or admission rate. RESULTS During the study period, there were 218,179 ED patient visits and a 3.2% 72-hour return rate. Patients with Medicare (3.5%) and without insurance (3.5%) were more likely to return within 72 hours. Visits associated with alcohol (4.1%), low triage acuity (4.0%), or dermatologic conditions (5.9%) were more likely to return. Seventy-two-hour return visits used fewer resources (5.0 [±0.1] vs. 5.5 [±0.1] tests, medications, procedures), were less likely to be Level I triage acuity (17% vs. 20%), and had a similar admission rate (13% vs. 13%) as those not seen within 72 hours. The sample size was too small to evaluate mortality. CONCLUSIONS Patients who return to the ED within 72 hours do not use more resources, are not more severely ill, and do not have a higher hospital admission rate than those who had not been previously seen. These findings do not support the use of 72-hour returns as a quality or safety indicator. A more refined variation such as 72-hour returns resulting in admission may have more value.

Point-of-care ultrasound education: the increasing role of simulation and multimedia resources.

This article reviews the current technology, literature, teaching models, and methods associated with simulation‐based point‐of‐care ultrasound training. Patient simulation appears particularly well suited for learning point‐of‐care ultrasound, which is a required core competency for emergency medicine and other specialties. Work hour limitations have reduced the opportunities for clinical practice, and simulation enables practicing a skill multiple times before it may be used on patients. Ultrasound simulators can be categorized into 2 groups: low and high fidelity. Low‐fidelity simulators are usually static simulators, meaning that they have nonchanging anatomic examples for sonographic practice. Advantages are that the model may be reused over time, and some simulators can be homemade. High‐fidelity simulators are usually high‐tech and frequently consist of many computer‐generated cases of virtual sonographic anatomy that can be scanned with a mock probe. This type of equipment is produced commercially and is more expensive. High‐fidelity simulators provide students with an active and safe learning environment and make a reproducible standardized assessment of many different ultrasound cases possible. The advantages and disadvantages of using low‐ versus high‐fidelity simulators are reviewed. An additional concept used in simulation‐based ultrasound training is blended learning. Blended learning may include face‐to‐face or online learning often in combination with a learning management system. Increasingly, with simulation and Web‐based learning technologies, tools are now available to medical educators for the standardization of both ultrasound skills training and competency assessment.

Focus on abnormal air: diagnostic ultrasonography for the acute abdomen.

Emergency ultrasonography is a frequently used imaging tool in the bedside diagnosis of the acute abdomen. Classic indications include imaging for acute abdominal aneurysm, acute cholecystitis, hydronephrosis, and free intra-abdominal fluid in patients with trauma or suspected vascular or ectopic pregnancy rupture. Point-of-care sonographic imaging often emphasizes the diagnostic utility of fluid and edema, both as a significant finding and as a desirable adjunct for improved imaging. Conversely, the finding of sonographic intra-abdominal air is commonly ‘tolerated’ as a necessary evil that can foil image acquisition. This is in stark contrast to the accepted diagnostic utility of air in other imaging modalities for the acute abdomen, such as computed tomography and conventional radiography. Countering the bias against air as a deterrent for diagnostic ultrasound’s accuracy are several published studies suggesting that abnormal air patterns can be used with high precision to diagnose pneumoperitoneum. These studies advocate that sonographic findings of abnormal air can be straightforward and can become crucial for increasing the diagnostic yield of bedside ultrasound of the acute abdomen. They suggest that practitioners should familiarize themselves with the findings and techniques to gain the experience required to make the diagnosis with confidence. This article will discuss four groups of abnormal air patterns found in the abdomen and the retroperitoneum and the respective scanning techniques, with a focus on the use of ultrasound for diagnosing pneumoperitoneum and a suggested scanning approach in the emergency setting.

Real-time optic nerve sheath diameter reduction measured with bedside ultrasound after therapeutic lumbar puncture in a patient with idiopathic intracranial hypertension

Idiopathic intracranial hypertension (IIH), also referred to as pseudotumor cerebri, is a condition of raised intracranial pressure (ICP) with unknown etiology. Sonographic measurement of optic nerve sheath diameter (ONSD) has been shown to be a reliable, noninvasive method to characterize elevated ICP in a variety of settings. However, little is known about the immediate response of ONSD to an acute reduction in ICP after lumbar puncture. We describe a case of an emergency department patient with IIH in whom we identified real-time change in ONSD correlated with a decrease in cerebrospinal fluid pressure after a therapeutic lumbar puncture. Ocular ultrasound and ONSD measurements were performed by a trained provider using a 9- to 13-MHz linear transducer and an ultrasound machine with ocular software package and low mechanical index settings for data collection (MTurbo; SonoSite Inc, Bothell, WA). The ONSD was measured 30 minutes prior to and 30 minutes after a therapeutic lumbar puncture. Opening and closing pressures were recorded. Optic nerve sheath diameter measurements correlated with ICP as measured by opening and closing lumbar puncture pressures and showed an acute reduction in ONSD within 30 minutes after lumbar puncture. Sonographic measurement of ONSD reduction may be a novel, noninvasive and convenient way to follow acute reductions in ICP. Further investigation is necessary in order to validate this finding.

Automatic segmentation of the left-ventricular cavity and atrium in 3D ultrasound using graph cuts and the radial symmetry transform

In this paper, we propose a graph-based method for fullyautomatic segmentation of the left ventricle and atrium in 3D ultrasound (3DUS) volumes. Our method requires no user input and can segment volumes with open and closed mitral valves. We utilize the radial symmetry transform to determine a central axis along which the 3D volume is warped into a cylindrical coordinate space. A graph is constructed for the volume in this space and a min-cut algorithm is applied to segment the left ventricle and atrium from the background. Since segmentation in the cylindrical coordinate space is defined as finding a boundary between the left (interior) and right (exterior) sides, we obviate the need for user specified seeds. The segmented results are transformed back to the Cartesian coordinate space. Experiments using intraoperative 3D ultrasound data show promising results.

The Core Content of Clinical Ultrasonography Fellowship Training

The purpose of developing a core content for subspecialty training in clinical ultrasonography (US) is to standardize the education and qualifications required to provide oversight of US training, clinical use, and administration to improve patient care. This core content would be mastered by a fellow as a separate and unique postgraduate training, beyond that obtained during an emergency medicine (EM) residency or during medical school. The core content defines the training parameters, resources, and knowledge of clinical US necessary to direct clinical US divisions within medical specialties. Additionally, it is intended to inform fellowship directors and candidates for certification of the full range of content that might appear in future examinations. This article describes the development of the core content and presents the core content in its entirety.

Bedside ocular ultrasound in the emergency department.

The use of point-of-care ultrasound in the emergency department has expanded considerably in recent years, allowing enhanced evaluation of the patient with an emergent eye or vision complaint. The technique is simple and quick to perform, and can yield clinical information that may not be readily obtainable through physical or slit-lamp exams. Ocular bedside sonography can aid in the diagnosis of retinal and vitreous hemorrhage, retinal and vitreous detachments, ocular infections, foreign bodies, retrobulbar hematoma, or ocular vascular pathology. Optic nerve sheath diameter can be measured in patients with a suspected intracranial process as a surrogate for intracranial pressure, and may aid emergency diagnosis and management. This article reviews common emergency ophthalmic pathologies diagnosed with ultrasound in the emergency setting and a mnemonic for the use of bedside ocular ultrasound is proposed to aid in thoroughly scanning the eye and its surrounding structures.

Peripheral fields of sympathetic vasoconstrictor neurons in guinea pigs

We have combined retrograde axonal tracing using Fast Blue and Dil, with immunohistochemistry, to estimate the maximum size of peripheral fields of identified sympathetic vasoconstrictor neurons projecting to guinea-pig ear tips. Many neurons in the superior cervical ganglia were labelled with both Fast Blue and Dil after dye injections up to 7 mm apart. Few neurons were labelled when dye injections were 8-10 mm apart. Neurons labelled with both Dil and Fast Blue after dye injections 5-7 mm apart had, on average, larger somata (436 +/- 84 microm2, mean +/- SEM, n = 47) than neurons labelled with Dil only (388 +/- 11 microm2, n = 147). Typically, 50-100 neurons innervated a region of vasculature 1 mm in diameter. We conclude that sympathetic vasoconstrictor neurons branch widely before converging on to their target blood vessels. Progressive recruitment of vasoconstrictor neurons with increasing field size would provide an efficient mechanism for graded neural control of the circulation.

Myocardial motion computation in 4D ultrasound

This paper presents a method for the computation of 3D flow in 4D (3D spatial+time) Transesophageal Echocardiography (4D TEE). 4D echocardiography is the only modality that allows real-time 3D imaging of the heart, at rates that are sufficiently high to characterize the very fast motion of key anatomical structures, such as the mitral and aortic valves or the left ventricle. The method described in this paper relies on a recently introduced variational optical flow approach. We applied the method to estimate the velocity field of myocardium in the left heart. Real intraoperative 4D TEE data was used and the method yielded good quantitative and qualitative preliminary results. This method has many applications, including elastography, biomechanical modeling, and automated diagnostics.

Emergency ultrasound of acute scrotal pain.

Patients presenting with acute scrotal pain to the emergency department require a timely diagnosis. Although the differential diagnosis can be extensive and varies with age, there are a few conditions that are considered true surgical emergencies. These include torsion of the spermatic cord, incarcerated hernia with strangulation, testicular trauma leading to rupture or organ-threatening hematomas, and Fournier’s gangrene. These are conditions that need to be kept in mind by the physician when approaching such patients. Other causes such as epididymitis or orchitis need to be distinguished, and although not requiring emergency surgery, still require urgent diagnosis and treatment. Diagnostic ultrasound can accurately diagnose many acute conditions of the scrotum, and emergency physicians have come to utilize it to advance their diagnostic acumen. This educational review article discusses the current literature and the use of emergency ultrasound in patients presenting with scrotal pain as well as scanning approaches and common sonographic findings.