A novel method of assessing for lung sliding using Doppler imaging.

Ultrasound is an ideal modality in the emergency department (ED) to assess for pneumothorax given its rapid availability, portability, and repeatability to assess clinical status changes. Certain patient populations and clinical circumstances may present challenges to the performance of this examination. In this article, we review patterns of the presence or absence of lung sliding in the commonly utilized sonographic modes in the ED setting. We also describe a novel technique to evaluate lung sliding using tissue Doppler.

Air and its Sonographic Appearance: Understanding the Artifacts.

BACKGROUND: Although air has traditionally been considered a barrier to sonographic imaging, when encountered in unusual settings it can serve as an important indicator of various pathologic states as well. Clinician recognition and thorough understanding of the characteristic pattern of artifacts generated by air are critical for making a number of important diagnoses. CASE SERIES: We present five emergency department cases in which air was visualized in a pathologic location. Pneumothorax, pneumoperitoneum, necrotizing fasciitis, or Fournier's gangrene, and subcutaneous emphysema and pneumomediastinum, can be rapidly and easily identified on ultrasound by the presence of air artifacts. The relevant sonographic findings are described and discussed in this article. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Due to its inherent impedance mismatch with other human tissues, air has a characteristic appearance on ultrasound that includes irregular hyperechoic structures, "dirty shadowing," A-lines, and decreased visualization of deeper structures. Knowledge of the sonographic appearance of air artifacts can assist the physician in making a diagnosis, selecting appropriate additional imaging, and enlisting specialist consultation.

Reliability, Laterality and the Effect of Respiration on the Measured Corrected Flow Time of the Carotid Arteries.

BACKGROUND: Corrected flow time (FTc) measured via sonography of the carotid artery is a novel method that has shown promising results for predicting fluid responsiveness in shock states. It is a rapid and noninvasive examination that can be taught to emergency physicians with ease. However, its reliability has not been assessed, and the effects of several variables, including respiration and side of evaluation, are unclear. OBJECTIVES: The objectives were to compare carotid FTc during different phases of the respiratory cycle, (at end-inspiration and end-expiration), to compare FTc reproducibility among providers, and to compare FTc on the right and left sides in a given individual. METHODS: The FTc of both the right and left carotid arteries was measured in 16 healthy volunteers during an inspiratory hold and an expiratory hold. Examinations were completed by three sonographers blinded to previous results and were analyzed for reliability and reproducibility. RESULTS: Reliability and reproducibility were poor when comparing sonographers under all circumstances. No significant differences were found when comparing left vs. right sides of measurement regardless of respiratory phase. CONCLUSION: Although this method for predicting fluid responsiveness has many promising aspects, reproducibility between sonographers was found to be poor. No significant difference was found between the two sides of the body or respiratory phase.

Ultrasound-guided dorsal penile nerve block performed in a case of zipper entrapment injury.

Injury to the penis resulting from zipper entrapment is a painful condition that presents a unique anesthetic challenge to the emergency physician and may even require procedural sedation for removal. In this case report, we describe successful removal of zipper entrapment from the penis of a 34-year-old patient after the application of an ultrasound-guided dorsal penile nerve block. We discuss the anatomy, sonographic features, and steps required for the nerve block procedure. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:589-591, 2017.

Sonographer preference for Knox versus ballistic gelatin for the creation of deep venous thrombosis ultrasound phantoms.

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The Inter-rater Reliability of Echocardiographic Diastolic Function Evaluation Among Emergency Physician Sonographers.

STUDY OBJECTIVES: In a patient with dyspnea and suspected CHF, the evaluation of diastolic function involves: tissue Doppler of the mitral annulus and 2) pulsed wave Doppler of the mitral inflow. We aimed to 1) determine the inter-rater reliability for overall diastolic function and 2) evaluate the reliability of the individual Doppler measurements. METHODS: A convenience sample of adult emergency department patients was prospectively enrolled by 8 EPs who had participated in a 1-hour didactic session. Patients were selected if they had a history of CHF or suspected abnormal diastolic function due to chronic hypertension. Diastolic function was considered to be abnormal if Tissue Doppler of the septal e' was <8 cm/s and if the lateral e' was <10 cm/s. In cases of discordance, the E/e' ratio was calculated with ≤8 considered normal and >8 considered abnormal. A Kappa coefficient. Bland-Altman plot and a fixed effect regression model were used in the analysis. RESULTS: Thirty-two patients were enrolled, and 3 (9.4%) were excluded due to technical inadequacy. The inter-rater reliability among sonographers for overall interpretation was very good: κ = 0.86 (95% CL [0.67, 1.0]). Based on the Bland-Altman plot, was no consistent bias between readers. There was no evidence to conclude that the readings differed among sonographers: septal e' (p = 0.77), lateral e' (p = 0.89) and E (p = 0.15). CONCLUSION: EP sonographers obtained similar Doppler measurements for diastolic function evaluation with very good inter-rater reliability for the assessment of overall diastolic function.

Ultrasound for the evaluation of soft tissue foreign bodies before and after the addition of fluid to the surrounding interstitial space in a cadaveric model.

BACKGROUND: Point-of-care ultrasound may be used to facilitate foreign body (FB) localization and removal. We hypothesized that injection of normal saline adjacent to an FB may make it easier to detect. METHODS: The study was performed on one embalmed human cadaver. Potential FB sites were created of wood (24), metal (24), and null (24). Two sonographers evaluated each of the 72 sites both before and after a 25-gauge needle was inserted into each incision and 3 cc of normal saline was injected. Accuracy, sensitivity, and specificity were calculated both before and after injection of normal saline. Binomial tests were used to determine the statistical significance of FB detection before and after injection. A 2-tailed Student's t test was used to determine if there was a statistically significant difference between the 2 methods. RESULTS: Preinjection, 116 (81%) of the 144 interpretations (P≤ .001) were correct in their assessment of whether or not an FB was present, with a sensitivity of 81% (95% confidence interval [CI], 72%-88%) and a specificity of 79% (95% CI, 65%-90%). Postinjection, 119 (83%) of these 144 interpretations (P≤ .001) were correct in their assessment of whether or not an FB was present, with a sensitivity of 85% (95% CI, 77%-92%) and a specificity of 77% (95% CI, 63%-88%). This difference was not significant (P=.08; 95% CI, -0.04 to 0.01). DISCUSSION: Ultrasound was reasonably accurate, sensitive, and specific in identifying 1-cm metal and wood FBs. Although accuracy and sensitivity did improve after normal saline injection, this difference was not significant.

A workflow task force affects emergency physician compliance for point-of-care ultrasound documentation and billing.

BACKGROUND: Emergency point-of-care ultrasound (POC u/s) is an example of a health information technology that improves patient care and time to correct diagnosis. POC u/s examinations should be documented, as they comprise an integral component of physician decision making. Incomplete documentation prevents coding, billing and physician group compensation for ultrasound-guided procedures and patient care. We aimed to assess the effect of directed education and personal feedback through a task force driven initiative to increase the number of POC u/s examinations documented and transferred to medical coders by emergency medicine physicians. METHODS: Three months before a chosen go-live date, departmental leadership, the ultrasound division, and residents formed a task force. Barriers to documentation were identified through brain storming and email solicitation. The total number and application-specific POC u/s examinations performed and transferred to the healthcare record and medical coders were compared for the pre- and post-task force intervention periods. Chi square analysis was used to determine the difference between the number of POC u/s examinations reported before and after the intervention. RESULTS: A total of 1652 POC u/s examinations were reported during the study period. Successful reporting to the patient care chart and medical coders increased from 41 % pre-task force intervention to 63 % post-intervention (p value 0.000). The number of scans performed during the 3-month periods (pre-intervetion, post-intervention 0-3 months, post-intervention 3-6 months) was similar (521, 594 and 537). When analyzed by specific application, the majority showed a statistically significant increase in the percentage of examinations reported, including those most critical for patient care decision making: (EFAST (41 vs. 64 %), vascular access (26 vs. 61 %), and cardiac (43 vs. 72 %); and those most commonly performed: biliary (44 vs. 61 %) and pelvic (60 vs. 66 %). Of the POC u/s studies coded and reported for reimbursement, 15.9 % were billed before intervention and 32 % were billed after intervention (p value: 0.000). CONCLUSIONS: The formation of a workflow solution task force positively affected emergency physician compliance with POC u/s documentation for coding and billing over a 6-month period. Further investigation should assess the long-term effect of the intervention and whether this translates into increased revenue to the department.

Hand dominance in intravenous drug using patients does not affect peripheral venous access sites identified by ultrasound.

BACKGROUND: The peripheral veins in the arms and forearms of patients with a history of intravenous (IV) drug use may be sclerosed, calcified, or collapsed due to damage from previous injections. These patients may consequently require alternative, more invasive types of vascular access including central venous or intraosseous catheters. We investigated the relationship between hand dominance and the presence of patent upper extremity (UE) veins specifically in patients with a history of IV drug-use. We predicted that injection into the non-dominant UE would occur with a higher frequency than the dominant UE, leading to fewer damaged veins in the dominant UE. If hand dominance affects which upper extremity has more patent veins, providers could focus their first vascular access attempt on the dominant upper extremity. METHODS: Adult patients were approached for enrollment if they provided a history of IV drug use into one of their upper extremities. Each upper extremity was examined with a high frequency linear transducer in 3 areas: the antecubital crease, forearm and the proximal arm. The number of fully compressible veins ≥1.8 mm in diameter was recorded for each location. RESULTS: The mean vein difference between the numbers of veins in the dominant versus the non-dominant UE was -1.5789. At a .05 significance level, there was insufficient evidence to suggest the number of compressible veins between patients' dominant and non-dominant arms was significantly different (P = .0872.) CONCLUSIONS: The number of compressible veins visualized with ultrasound was not greater in the dominant upper extremity as expected. Practitioners may gain more information about potential peripheral venous access sites by asking patients their previous injection practice patterns.

High Body Mass Index is Strongly Correlated with Decreased Image Quality in Focused Bedside Echocardiography.

BACKGROUND: There is a well-established relationship between obesity, as measured by body mass index (BMI), and overall health risk. The presence of body fat is a known limitation to ultrasound, but it is unknown whether any decrease in quality due to obesity limits the interpretability of focused bedside echocardiography (FBE). OBJECTIVES: To correlate obesity, as measured by BMI, with image quality and interpretability of (FBE) performed by an emergency physician. METHODS: We conducted a prospective observational study in a convenience sample of adults presenting to two academic emergency departments (EDs) and a bariatric surgery outpatient clinic. Twenty patients were enrolled in each of three BMI categories, <30, 30-39, and ≥40 kg/m(2). FBE was performed in multiple views in two positions. Images were rated for ability to discern the pericardial myocardial interface (PMI) and the endocardial border of the left ventricle (ELV). RESULTS: There were 23 males and 37 females enrolled. The median age was 49 years and the median BMI was 35.6 kg/m(2). There was a significant difference in the percentage of technically limited examinations between BMI categories for both PMI and ELV. There was an overall negative linear correlation between BMI and image quality for both PMI and ELV. CONCLUSION: There is an overall decrease in the quality of focused bedside echocardiographic images as BMI increases. This relationship exists for visualization of both the PMI and the ELV. Emergency physicians should be aware of the potential limitations of focused bedside echocardiography in this patient population.

Ultrasound in the evaluation of penetrating thoraco-abdominal trauma: a review of the literature.

The use of ultrasound in the evaluation of blunt thoraco-abdominal trauma is well described. Evidence for the use of ultrasound in the evaluation of penetrating cardio-thoracic and abdominal trauma, however, is more limited and varied. Current literature demonstrates that ultrasound is an excellent screening tool for penetrating thoracic and cardiac injuries with a high sensitivity for detecting injury requiring acute intervention. For abdominal injuries, however, the sensitivity for detection of injury is low and thus the utility of ultrasound as a screening tool is limited. This review summarizes the existing literature addressing the clinical utility of ultrasound for penetrating trauma to the pericardium, thorax and abdomen.

M-Mode Ultrasound Applications for the Emergency Medicine Physician.

BACKGROUND: M-mode or "motion" mode is a form of ultrasound imaging that is of high clinical utility in the emergency department. It can be used in a variety of situations to evaluate motion and timing, and can document tissue movement in a still image when the recording of a video clip is not feasible. OBJECTIVES: In this article we describe several straightforward and easily performed applications for the emergency physician to incorporate M-mode into his or her practice, including the evaluation for: 1) pneumothorax, 2) left ventricular systolic function, 3) cardiac tamponade, and 4) hypertrophic cardiomyopathy. DISCUSSION: The emergency physician and other point-of-care ultrasound providers can use this versatile function in the evaluation of patients for a number of critical cardiopulmonary diagnoses. CONCLUSION: A great deal of important information may be obtained with M-mode imaging through views and measurements that are relatively easy to obtain.

Preferences of air-blood-saline sonographic microbubble contrast agents among emergency medicine resident physicians.

INTRODUCTION: The placement of a central venous catheter (CVC) remains an important intervention in the care of critically ill patients in the emergency department, and bedside ultrasound can be used for procedural guidance as well as conformation of placement. Microbubble contrast-enhanced ultrasound may facilitate CVC tip position localization, and the addition of autologous blood can significantly increase its echogenicity. The purpose of this study was to describe the preferences of a group of resident physicians regarding the performance of various concentrations of air-blood-saline sonographic microbubble contrast agents. METHODS: Institutional Animal Care and Use Committee approved prospective study. A CVC was inserted into the right internal jugular vein of a 20-kg Yorkshire swine under general anesthesia. Contrast mixtures were created with air, saline, and varying amounts of blood and were injected while echocardiographic video clips were recorded and reviewed by 25 physician sonographers. RESULTS: All reading physicians reported increased overall echogenicity, a higher peak echogenicity, and greater personal preference for blood containing solutions. Nearly all reading physicians preferred the lower percentage blood containing mixtures over the higher percentage blood containing mixture. CONCLUSION: The inclusion of 1 to 3 parts of 10 of the patient's blood in the preparation of a sonographic contrast mixture increased the echogenicity of the contrast, resulted in better visualization of both the contrast and the endocardial border and was the preferred mixture among the resident physicians studied.

Ultrasound accurately identifies soft tissue foreign bodies in a live anesthetized porcine model.

BACKGROUND: Some subcutaneous foreign bodies (FBs) are not easily visualized during physical examination and may not be detected on radiographic evaluation. Ultrasound (US) is capable of visualizing FBs of varying compositions. Previous studies have examined the use of US to detect FBs in deceased animal or human tissue. This study used live anesthetized porcine tissue to more closely model clinical conditions. OBJECTIVES: The objectives were to examine the test characteristics of US in the evaluation of FBs in living tissue and to evaluate if secondary findings such as surrounding edema and hematoma improve diagnostic accuracy. METHODS: Institutional Animal Care and Use Committee (IACUC) approval was obtained. FBs 1 cm in length and 1 to 3 mm in width were created from toothpicks (wood), 21-gauge needles (metal), and a broken ampule (glass) and inserted subcutaneously into an anesthetized 20-kg Yorkshire swine. There were 72 sites implanted with equal proportions of each FB type and null sites. Half of the FBs were inserted at time 0 and half were inserted after 2 hours. Immediately after placement, four blinded physicians performed US evaluations of the first 36 sites. At 2 hours after placement, they evaluated each of the original 36 sites and the 36 new sites. They documented the presence or absence of FBs and surrounding edema. RESULTS: After initial FB placement, 122 of the 144 interpretations (85%) were correct, with a sensitivity of 85% (95% confidence interval [CI] = 79% to 92%) and a specificity of 86% (95% CI = 76% to 98%). No sites demonstrated surrounding edema. At 2 hours after placement, 127 of 144 interpretations (88%) for these same sites were correct, with a sensitivity of 87% (95% CI = 82% to 93%) and a specificity of 89% (95% CI = 81% to 97%). Of the 108 observations (27 sites that contained FBs), eight of the 108 (7%) observations had surrounding edema (four glass, three wood, one metal). For the 36 new sites with FBs placed 2 hours later, 126 of the 144 interpretations (83%) were correct, with a sensitivity of 88% (95% CI = 82% to 94%) and a specificity of 83% (95% CI = 73% to 95%). No sites had surrounding edema present. CONCLUSIONS: Ultrasound was sensitive, specific, and accurate in identifying FBs in live anesthetized porcine tissue. Surrounding edema or hematoma 2 hours after placement was so infrequently observed that it was not possible to determine its influence on the test characteristics.

The Ultrasound-Only Central Venous Catheter Placement and Confirmation Procedure.

The placement of a central venous catheter remains an important intervention in the care of critically ill patients in the emergency department. We propose an ultrasound-first protocol for 3 aspects of central venous catheter placement above the diaphragm: dynamic procedural guidance, evaluation for pneumothorax, and confirmation of the catheter tip location.

Foot pain and swelling after minor traumatic injury.

Necrotizing fasciitis is a rare bacterial infection of the fascia and surrounding soft tissue, which carries a mortality rate as high as 20%, even in well-appearing patients [1]. Classically, this diagnosis must be made with computed tomography or magnetic resonance,but recent literature shows that ultrasonography, readily available in the emergency department, may be adequate for diagnosis [2]. We present a case of a 48-year-old man who presented with a painful rash. We used his clinical presentation and ultrasound to make the diagnosis,which was later corroborated with plain radiograph findings. He was taken immediately to the operating room for extensive debridement.He was discharged 8 days later in good condition.