Publications by authors named "John C Fox"

35 Publications

Point of Care Ultrasound in the Diagnosis of Necrotizing Fasciitis.

Am J Emerg Med 2022 Jan 29;51:397-400. Epub 2021 Oct 29.

University of California Irvine, Department of Emergency Medicine, United States.

Background: Necrotizing fasciitis (NF) is a severe, life-threatening soft tissue infection requiring prompt diagnosis and immediate surgical debridement. Imaging, including a computed tomography (CT) scan, can often aid in the diagnosis, though it can prolong time to treatment and diagnosis. Point-of-care ultrasound (POCUS) is often used in the ED to identify soft tissue infections. The objective of this study is to evaluate the use of POCUS to identify NF in patients presenting to the emergency department.

Methods: We prospectively enrolled patients who presented to the emergency department (ED) with suspected soft tissue infection who received a computed tomography and/or surgical consult. POCUS images of the suspected site of infection were obtained by the emergency medicine physician and interpreted based on sonographic findings of NF. These findings were compared with CT scan or surgical impression.

Results: We enrolled 64 patients in this study. Eight were determined to be at high risk of having NF based on CT scan and/or surgical impression. All of these patients also had POCUS images interpreted as concerning for NF. Furthermore, 56 patients were classified as being low risk for having NF based on CT scan and/or surgical impression. All but one of these patients had POCUS images interpreted as not concerning for NF.

Conclusions: Our data indicates that POCUS can be used to identify NF with a high sensitivity and specificity.
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http://dx.doi.org/10.1016/j.ajem.2021.10.033DOI Listing
January 2022

Role Of Point Of Care Ultrasound In The Diagnosis Of Retinal Detachment In The Emergency Department.

Open Access Emerg Med 2019 13;11:265-270. Epub 2019 Nov 13.

University of California, Irvine, Department of Emergency Medicine, Orange, CA 92868, USA.

Ocular complaints represent up to 3% of all emergency department (ED) visits. These presentations can result in permanent vision loss if not promptly diagnosed and treated. Recently, point of care ultrasound (POCUS) has been investigated for the evaluation of ocular pathology in the ED. Multiple studies have investigated the role that ultrasound may play in the early diagnosis of these patients. Ocular ultrasound can be used to visualize the structures of the eye and evaluate for pathology such as retinal detachment, vitreous hemorrhage and vitreous detachment. This comprehensive review aims to present current evidence for the efficacy and reliability of ED ocular ultrasound use in the detection of retinal detachment and additional ocular pathologies.
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http://dx.doi.org/10.2147/OAEM.S219333DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6859292PMC
November 2019

Tricuspid Annular Plane of Systolic Excursion (TAPSE) for the Evaluation of Patients with Severe Sepsis and Septic Shock.

West J Emerg Med 2020 Jan 13;21(2):348-352. Epub 2020 Jan 13.

University of California, Irvine; Department of Emergency Medicine, Orange, California.

Introduction: Sepsis is a systemic infection that can rapidly progress into multi organ failure and shock if left untreated. Previous studies have demonstrated the utility of point of care ultrasound (POCUS) in the evaluation of patients with sepsis. However, limited data exists on the evaluation of the tricuspid annular plane of systolic excursion (TAPSE) in patients with sepsis.

Methods: We prospectively enrolled patients who presented to the emergency department (ED) with concern for severe sepsis or septic shock in a pilot study. In patients that screened positive, the treating physician then performed POCUS to measure the TAPSE value. We compared the intensive care unit (ICU) admission rate, hospital length of stay, and morbidity with their respective TAPSE values.

Results: We enrolled 24 patients in the study. Eight patients had TAPSE values less than 16 millimeters (mm), two patients had TAPSE values between 16mm-20mm, and fourteen patients had TAPSE values greater than 20mm. There was no statistically significant association between TAPSE levels and ICU admission (p=0.16), or death (p=0.14). The difference of length of stay (LOS) was not statistically significant in case of hospital LOS (p= 0.72) or ICU LOS.

Conclusion: Our pilot data did not demonstrate a correlation between severe sepsis or septic shock and TAPSE values. This may be due to several factors including patient comorbidities, strict definitions of sepsis and septic shock, as well as the absence of septic cardiomyopathy (SCM) in patients with sepsis and septic shock. Future large-scale studies are needed to determine if TAPSE can be beneficial in the ED evaluation of patients with concern for SCM.
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http://dx.doi.org/10.5811/westjem.2019.11.44968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7081860PMC
January 2020

Retrospective analysis of eFAST ultrasounds performed on trauma activations at an academic level-1 trauma center.

World J Emerg Med 2020 ;11(1):12-17

Department of Emergency Medicine, University of California, Irvine, Orange, CA 92868, USA.

Background: Point-of-care ultrasound (POCUS) has become increasingly integrated into the practice of emergency medicine. A common application is the extended focused assessment with sonography in trauma (eFAST) exam. The American College of Emergency Physicians has guidelines regarding the scope of ultrasound in the emergency department and the appropriate documentation. The objective of this study was to conduct a review of performed, documented and billed eFAST ultrasounds on trauma activation patients.

Methods: This was a retrospective review of all trauma activation patients during a 10-month period at an academic level-one trauma center. A list comparing all trauma activations was cross-referenced with a list of all billed eFAST scans. Medical records were reviewed to determine whether an eFAST was indicated, performed, and appropriately documented.

Results: We found that 1,507 of 1,597 trauma patients had indications for eFAST, but 396 (27%) of these patients did not have a billed eFAST. Of these 396 patients, 87 (22%) had documentation in the provider note that an eFAST was performed but there was no separate procedure note. The remaining 309 (78%) did not have any documentation of the eFAST in the patient's chart although an eFAST was recorded and reviewed during ultrasound quality assurance.

Conclusion: A significant proportion of trauma patients had eFAST exams performed but were not documented or billed. Lack of documentation was multifactorial. Emergency ultrasound programs require appropriate reimbursement to support training, credentialing, equipment, quality assurance, and device maintenance. Our study demonstrates a significant absence of adequate documentation leading to potential revenue loss for an emergency ultrasound program.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2020.01.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6885586PMC
January 2020

Evaluation of a point-of-care ultrasound curriculum taught by medical students for physicians, nurses, and midwives in rural Indonesia.

J Clin Ultrasound 2020 Mar 26;48(3):145-151. Epub 2019 Dec 26.

Department of Emergency Medicine, University of California, Irvine, California.

Purpose: In the Indonesian health-care system, nurses and midwives often serve as the primary health-care providers due to physician shortages. Seeking to address the need for medical care in resource-limited environments, some have advocated for portable equipment in the hands of health-care providers. We hypothesized that medical students are able to effectively teach point-of-care ultrasound (POCUS) to physicians, nurses, and midwives in rural Indonesia.

Methods: We conducted a prospective, observational study using health-care practitioners from a clinic and accredited school for nursing and midwifery in Mojokerto, East Java, Indonesia. Enrolled practitioners took part in a 4-week POCUS course followed by postinstructional testing.

Results: A total of 55 health-care practitioners completed the course. This included 19 physicians, 13 nurses, and 19 midwives. Of the 55 clinicians, 43 (72%) passed the course and 12 (28%) failed.

Conclusions: Physicians, nurses, and midwives in rural Indonesia showed significant acquisition of ultrasound (US) knowledge and skills following a 4-week US course. Following training, all three groups displayed skills in practical US use during a postcourse practical examination. This is one of the first studies to assess the efficacy of medical students teaching POCUS to midwives and nurses.
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http://dx.doi.org/10.1002/jcu.22809DOI Listing
March 2020

The association of smoking with ultrasound-measured kidney dimensions
.

Clin Nephrol 2020 Jan;93(1):9-16

Purpose: Ultrasound is considered a preferred first-line imaging technique for the assessment of kidney function. The potential relationship between tobacco smoke exposure and ultrasound-measured renal characteristics has yet to be explored. We hypothesized that exposure to tobacco smoke would be associated with reduced kidney dimensions.

Materials And Methods: This was a cross-sectional study that included all individuals over age 18 at a single site in Mojokerto, Indonesia. A questionnaire was used to assess prior history and environmental exposure, and blinded evaluators performed ultrasound assessments. Six kidney parameters (length, width, and parenchymal thickness of each kidney) were considered as dependent variables, and statistical relationships were assessed using multivariate analysis. Echogenicity was evaluated using a 5-point grading scale described previously.

Results: Of the 445 participants assessed, a total of 138 male and 269 female subjects were included in the final analysis. There was a statistically significant association between kidney measures and the following independent variables: pack years smoking (p < 0.001), height (p < 0.001), weight (p < 0.001), and beginning to smoke at the age of 25 or younger (p < 0.001). There was not a statistically significant association between kidney measures and hypertension (p > 0.05) or diabetes (p > 0.05). Echogenicity was similar among all smoking groups.

Conclusion: Kidney dimensions were decreased in individuals with increased smoking history. This association is notable, particularly given that statistically significant associations were not observed between renal dimensions and hypertension or diabetes. The null findings using echogenicity are consistent with previous studies.
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http://dx.doi.org/10.5414/CN109854DOI Listing
January 2020

A Prospective Evaluation of Point of Care Ultrasound Teaching in Switzerland.

J Med Ultrasound 2019 Apr-Jun;27(2):92-96. Epub 2019 Feb 26.

Department of Emergency Medicine, University of California Irvine, Irvine, California, USA.

Context: As the utility of point-of-care ultrasound (POCUS) continues to expand in the medical field, there is a need for effective educational methods. In Switzerland, medical education follows the European model and lasts 6 years, focusing on preclinical training during the first 2 years. No previous studies have evaluated the optimal time for teaching ultrasound in European medical education.

Aims: The aim of this study is to provide ultrasound training to medical students in Switzerland at varying times during their clinical training to determine if the level of training plays a role in their ability to comprehend and to apply basic POCUS skills.

Methods: We performed an observational study utilizing a convenience sample of Swiss medical students between July 11, 2016 and August 6, 2016. They were taught a 2-day POCUS course by five American-trained 1-year medical students. Following this course, students were evaluated with written and clinical examination.

Results: 100 Swiss medical students were enrolled in the study. A total of 59 of these students were early clinical students, and 41 students were late clinical students. A two-tailed -test was performed and demonstrated that the late clinical students performed better than the early clinical students on the written assessment; however, no difference was found in clinical skill.

Conclusion: Our data suggest that Swiss medical students can learn and perform POCUS after a 2-day instructional taught by trained 1-year American medical students. No difference was found between students in early clinical training and late clinical training for the ability to perform POCUS.
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http://dx.doi.org/10.4103/JMU.JMU_57_18DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6607874PMC
February 2019

A comparison of simulation versus didactics for teaching ultrasound to Swiss medical students.

World J Emerg Med 2019 ;10(3):169-176

Department of Emergency Medicine, University of California Irvine, Irvine, USA.

Background: Point-of-care ultrasound is an increasingly common imaging modality that is used in a variety of clinical settings. Understanding how to most effectively teach ultrasound is important to ensure that medical students learn pre-clinical content in a manner that promotes retention and clinical competence. We aim to assess the effectiveness of simulation-based ultrasound education in improving medical student competence in physiology in comparison to a traditional didactic ultrasound curriculum.

Methods: Subjects were given a pre and post-test of physiology questions. Subjects were taught various ultrasound techniques via 7 hours of lectures over two days. The control group received 2 additional hours of practice time while the experimental group received 2 hours of case-based simulations. A physiology post-test was administered to all students to complete the two-day course.

Results: Totally 115 Swiss medical students were enrolled in our study. The mean pre-course ultrasound exam score was 39.5% for the simulation group and 41.6% for the didactic group (>0.05). The mean pre-course physiology exam score was 54.1% for the simulation group and 59.3% for the didactic group (>0.05). The simulation group showed statistically significant improvement on the physiology exam, improving from 54.1% to 75.3% (<0.01). The didactic group also showed statistically significant improvement on the physiology exam, improving from 59.3% to 70.0% (<0.01).

Conclusion: Our data indicates that both simulation curriculum and standard didactic curriculum can be used to teach ultrasound. Simulation based training showed statistically significant improvement in physiology learning when compared to standard didactic curriculum.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2019.03.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6545372PMC
January 2019

Point-of-Care Ultrasonography in the Diagnosis of Retinal Detachment, Vitreous Hemorrhage, and Vitreous Detachment in the Emergency Department.

JAMA Netw Open 2019 04 5;2(4):e192162. Epub 2019 Apr 5.

Department of Emergency Medicine, University of California, Irvine.

Importance: Ocular symptoms represent approximately 2% to 3% of all emergency department (ED) visits. These disease processes may progress to permanent vision loss if not diagnosed and treated quickly. Use of ocular point-of-care ultrasonography (POCUS) may be effective for early and accurate detection of ocular disease.

Objective: To perform a large-scale, multicenter study to determine the utility of POCUS for diagnosing retinal detachment, vitreous hemorrhage, and vitreous detachment in the ED.

Design, Setting, And Participants: A prospective diagnostic study was conducted at 2 academic EDs and 2 county hospital EDs from February 3, 2016, to April 30, 2018. Patients who were eligible for inclusion were older than 18 years; were English- or Spanish-speaking; presented to the ED with ocular symptoms with concern for retinal detachment, vitreous hemorrhage, or vitreous detachment; and underwent an ophthalmologic consultation that included POCUS. Patients with ocular trauma or suspicion for globe rupture were excluded. The accuracy of the ultrasonographic diagnosis was compared with the criterion standard of the final diagnosis of an ophthalmologist who was masked to the POCUS findings. Seventy-five unique emergency medicine attending physicians, resident physicians, and physician assistants performed ocular ultrasonography.

Exposure: Point-of-care ultrasonography performed by an emergency medicine attending physician, resident physician, or physician assistant.

Main Outcomes And Measures: Sensitivity and specificity of POCUS in identifying retinal detachment, vitreous hemorrhage, and vitreous detachment in patients presenting to the ED with ocular symptoms.

Results: Two hundred twenty-five patients were enrolled. Of these, the mean age was 51 years (range, 18-91 years) and 135 (60.0%) were men; ophthalmologists diagnosed 47 (20.8%) with retinal detachment, 54 (24.0%) with vitreous hemorrhage, and 34 (15.1%) with vitreous detachment. Point-of-care ultrasonography had an overall sensitivity of 96.9% (95% CI, 80.6%-99.6%) and specificity of 88.1% (95% CI, 81.8%-92.4%) for diagnosis of retinal detachment. For diagnosis of vitreous hemorrhage, the sensitivity of POCUS was 81.9% (95% CI, 63.0%-92.4%) and specificity was 82.3% (95% CI, 75.4%-87.5%). For vitreous detachment, the sensitivity was 42.5% (95% CI, 24.7%-62.4%) and specificity was 96.0% (95% CI, 91.2%-98.2%).

Conclusions And Relevance: These findings suggest that emergency medicine practitioners can use POCUS to accurately identify retinal detachment, vitreous hemorrhage, and vitreous detachment. Point-of-care ultrasonography is not intended to replace the role of the ophthalmologist for definitive diagnosis of these conditions, but it may serve as an adjunct to help emergency medicine practitioners improve care for patients with ocular symptoms.
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http://dx.doi.org/10.1001/jamanetworkopen.2019.2162DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6481597PMC
April 2019

A Prospective, Multicenter Evaluation of Point-of-care Ultrasound for Small-bowel Obstruction in the Emergency Department.

Acad Emerg Med 2019 08 12;26(8):921-930. Epub 2019 Mar 12.

Department of Emergency Medicine, Wellspan York Hospital, York, PA.

Objective: The main objective of this study was to evaluate the accuracy of emergency physician-performed point-of-care ultrasound (POCUS) for the diagnosis of small-bowel obstruction (SBO) compared to computed tomography (CT).

Methods: We performed a prospective, multicenter, observational study examining a convenience sample of adult patients with potential SBO presenting to the emergency department (ED) between July 2014 and May 2017. Each POCUS was interpreted at the bedside by the performing emergency physician and retrospectively by an expert reviewer. Test characteristics were calculated for POCUS, blinded expert interpretation, and specific POCUS parameters.

Results: A total of 217 subjects were included in the primary analysis with an overall SBO prevalence of 42.9%. For the diagnosis of SBO, POCUS demonstrated an overall sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of 0.88 (95% confidence interval [CI] = 0.80 to 0.94), 0.54 (95% CI = 0.45 to 0.63), 1.92 (95% CI = 1.56 to 2.35), and 0.22 (95% CI = 0.12 to 0.39), respectively. Expert review yielded a similar sensitivity (0.89 [95% CI = 0.81 to 0.95]) with a significantly higher specificity (0.82 [95% CI = 0.74 to 0.88]). The more sensitive sonographic parameters for both POC sonographers and expert reviewers were small-bowel dilation ≥ 25 mm (0.87 [95% CI = 0.79 to 0.93], 0.87 [95% CI = 0.79 to 0.93]) and abnormal peristalsis (0.82 [95% CI = 0.72 to 0.89], 0.85 [95% CI = 0.76 to 0.87]). The more specific parameters for both groups were transition point (0.82 [95% CI = 0.74 to 0.89], 0.98 [95% CI = 0.94 to 1.00]), intraperitoneal free fluid (0.82 [95% CI = 0.74 to 0.89], 0.93 [95% CI = 0.87 to 0.97]), and bowel wall edema (0.76 [95% CI = 0.67 to 0.83], 0.93 [95% CI = 0.87 to 0.97]).

Conclusion: POCUS is moderately sensitive for SBO, although less specific, when performed by a diverse group of emergency physicians across multiple EDs. Interpretation of acquired POCUS images is significantly more accurate when performed by physicians with prior emergency ultrasound fellowship training and familiarity with the sonographic appearance of SBO.
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http://dx.doi.org/10.1111/acem.13713DOI Listing
August 2019

Can an 8 grade student learn point of care ultrasound?

World J Emerg Med 2019 ;10(2):109-113

Department of Emergency Medicine, UC Irvine Medical Center, UC Irvine School of Medicine, Irvine, Orange, California 92868, USA.

Background: Point-of-care ultrasound has gained widespread use in developing countries due to decreased cost and improved telemedicine capabilities. Ultrasound training, specifically image acquisition skills, is occurring with more frequency in non-medical personnel with varying educational levels in these underdeveloped areas. This study evaluates if students without a high school education can be trained to acquire useful FAST images, and to determine if an 8 grade student can teach peers these skills.

Methods: The 8 grade students at a small middle school were divided into two groups. One group received training by a certified medical sonographer, while the other group received training by a peer 8 grade student trainer who had previously received training by the sonographer. After training, each student was independently tested by scanning the four FAST locations. A blinded ultrasound expert evaluated these images and deemed each image adequate or inadequate for clinical use.

Results: Eighty video image clips were obtained. The overall image adequacy rate was 74%. The splenorenal window had the highest rate at 95%, followed by retrovesical at 90%, hepatorenal at 75%, and subxiphoid cardiac at 35%. The adequacy rate of the sonographer-trained group was 78%, while the adequacy rate of the student-trained group was 70%. The difference in image adequacy rate between the two groups was not significant (P-value 0.459).

Conclusion: The majority of 8 graders obtained clinically adequate FAST images after minimal training. Additionally, the student-trained group performed as well as the sonographer-trained group.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2019.02.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6340824PMC
January 2019

Tricuspid annular plane of systolic excursion to prognosticate acute pulmonary symptomatic embolism (TAPSEPAPSE study).

J Ultrasound Med 2019 Mar 4;38(3):695-702. Epub 2018 Sep 4.

Department of Emergency Medicine, University of California, Irvine, Orange, California, USA.

Introduction: The imaging standard for evaluation of acute pulmonary embolism (PE) includes a computed tomography pulmonary angiogram. Ultrasonography has shown promise in obtaining the tricuspid annular plane systolic excursion (TAPSE) measurements, which may be of clinical importance in patients with acute PE. The objective of this study is to evaluate the diagnostic capability of TAPSE measurements for patients with suspicion for acute PE.

Methods: We prospectively enrolled patients who came to the emergency department with suspicion of acute PE. Each patient underwent a point-of-care sonogram where a TAPSE measurement was obtained, followed by computed tomography pulmonary angiogram. Based on the computed tomography pulmonary angiogram findings, patients were grouped into 3 categories: no acute PE, clinically insignificant acute PE, or clinically significant acute PE.

Results: We enrolled 87 patients in this study. Twenty-three (26.4%) of these patients were diagnosed with PE. Of patients with PE, 15 (65%) were found to have a clinically significant acute PE. Analysis of mean TAPSE measurements between patients with clinically significant acute PE and those with insignificant or no PE was 15.2 mm and 22.7 mm, respectively (P ≤ .0001). Following receiver operating characteristic curve analysis, optimum TAPSE measurement to identify clinically significant acute PE is 18.2 mm. A cutoff TAPSE measurement of 15.2 mm shows a sensitivity of 53.3% (95% confidence interval, 26.7%-80%) and a specificity of 100% (95% confidence interval, 100%-100%) for the diagnosis of a clinically significant PE.

Conclusions: Our data suggest that TAPSE measurements less than 15.2 mm have a high specificity for identifying clinically significant acute PE.
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http://dx.doi.org/10.1002/jum.14753DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6628892PMC
March 2019

Ultrasound curriculum taught by first-year medical students: A four-year experience in Tanzania.

World J Emerg Med 2018 ;9(1):33-40

Department of Emergency Medicine, University of California Irvine, Orange, California 92868, USA.

Background: Diagnostic imaging is an integral aspect of care that is often insufficient, if not altogether absent, in rural and remote regions of low to middle income countries (LMICs) such as Tanzania. The introduction of ultrasound can significantly impact treatment in these countries due to its portability, low cost, safety, and usefulness in various medical assessments. This study reviews the implementation of a four-week ultrasound course administered annually from 2013-2016 in a healthcare professional school in Mwanza, Tanzania by first-year allopathic US medical students.

Methods: Participants (=582, over 4 years) were recruited from the Tandabui Institute of Health Sciences and Technology to take the ultrasound course. Subjects were predominantly clinical officer students, but other participants included other healthcare professional students, practicing healthcare professionals, and school employees. Data collected includes pre-course examination scores, post-course examination scores, course quiz scores, demographic surveys, and post-course feedback surveys. Data was analyzed using two-tailed -tests and the single factor analysis of variance (ANOVA).

Results: For all participants who completed both the pre- and post-course examinations (=229, 39.1% of the total recruited), there was a significant mean improvement in their ultrasound knowledge of 42.5%, <0.01.

Conclusion: Our data suggests that trained first-year medical students can effectively teach a point of care ultrasound course to healthcare professional students within four weeks in Tanzania. Future investigation into the level of long-term knowledge retention, impact of ultrasound training on knowledge of human anatomy and diagnostic capabilities, and how expansion of an ultrasound curriculum has impacted access to care in rural Tanzania is warranted.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2018.01.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5717373PMC
January 2018

Utility of common bile duct measurement in ED point of care ultrasound: A prospective study.

Am J Emerg Med 2018 Jun 20;36(6):962-966. Epub 2017 Nov 20.

University of California, Irvine, Department of Emergency Medicine, 333 The City Boulevard West Suite 640, Orange 92868, CA, USA.

Background: Measurement of the common bile duct (CBD) is considered a fundamental component of biliary point-of-care ultrasound (POCUS), but can be technically challenging.

Objective: The primary objective of this study was to determine whether CBD diameter contributes to the diagnosis of complicated biliary pathology in emergency department (ED) patients with normal laboratory values and no abnormal biliary POCUS findings aside from cholelithiasis.

Methods: We performed a prospective, observational study of adult ED patients undergoing POCUS of the right upper quadrant (RUQ) and serum laboratory studies for suspected biliary pathology. The primary outcome was complicated biliary pathology occurring in the setting of normal laboratory values and a POCUS demonstrating the absence of gallbladder wall thickening (GWT), pericholecystic fluid (PCF) and sonographic Murphy's sign (SMS). The association between CBD dilation and complicated biliary pathology was assessed using logistic regression to control for other factors, including laboratory findings, cholelithiasis and other sonographic abnormalities.

Results: A total of 158 patients were included in the study. 76 (48.1%) received non-biliary diagnoses and 82 (51.9%) were diagnosed with biliary pathology. Complicated biliary pathology was diagnosed in 39 patients. Sensitivity of CBD dilation for complicated biliary pathology was 23.7% and specificity was 77.9%.

Conclusion: Of patients diagnosed with biliary pathology, none had isolated CBD dilatation. In the absence of abnormal laboratory values and GWT, PCF or SMS on POCUS, obtaining a CBD measurement is unlikely to contribute to the evaluation of this patient population.
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http://dx.doi.org/10.1016/j.ajem.2017.10.064DOI Listing
June 2018

Procedural simulation: medical student preference and value of three task trainers for ultrasound guided regional anesthesia.

World J Emerg Med 2017 ;8(4):287-291

Department of Emergency Medicine, University of California, Irvine, Orange, California 92868, USA.

Background: Ultrasound guided regional anesthesia is widely taught using task trainer models. Commercially available models are often used; however, they can be cost prohibitive. Therefore, alternative "homemade" models with similar fidelity are often used. We hypothesize that professional task trainers will be preferred over homemade models. The purpose of this study is to determine realism, durability and cleanliness of three different task trainers for ultrasound guided nerve blocks.

Methods: This was a prospective observational study using a convenience sample of medical student participants in an ultrasound guided nerve block training session on January 24th, 2015. Participants were asked to perform simulated nerve blocks on three different task trainers including, 1 commercial and 2 homemade. A questionnaire was then given to all participants to rate their experiences both with and without the knowledge on the cost of the simulator device.

Results: Data was collected from 25 participants. The Blue Phantom model was found to have the highest fidelity. Initially, 10 (40%) of the participants preferred the Blue Phantom model, while 10 (40%) preferred the homemade gelatin model and 5 (20%) preferred the homemade tofu model. After cost awareness, the majority, 18 (72%) preferred the gelatin model.

Conclusion: The Blue Phantom model was thought to have the highest fidelity, but after cost consideration the homemade gelatin model was preferred.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2017.04.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5675970PMC
January 2017

Evaluation of a point of care ultrasound curriculum for Indonesian physicians taught by first-year medical students.

World J Emerg Med 2017 ;8(4):281-286

School of Medicine, University of California, Irvine, USA.

Background: The purpose of this study was to assess the short-term efficacy of a 4-week ultrasound curriculum taught by American first-year medical students to general practitioners working in public health care clinics, or puskesmas, in Bandung, Indonesia.

Methods: We performed a prospective, observational study of Indonesian health care practitioners from public clinics in Bandung, Indonesia. These practitioners were enrolled in a 4-week ultrasound training course taught by first-year American medical students. A total of six sessions were held comprising of 38 ultrasound milestones. A pre-course and post-course written exam and practical exam was taken by each participant.

Results: We enrolled 41 clinicians in the course. The average pre-course exam score was 35.2% with a 2.4% pass rate, whereas the average post-course exam score was 82.0% with a 92.7% pass rate. The average practical score at the completion of the course was 83.2% (=0.145) with 82.9% of the class passing (score above 75.0%).

Conclusion: Our data suggests that first-year medical students can effectively teach ultrasound to physicians in Indonesia using a 4-week intensive ultrasound training course. Future studies are needed to determine the amount of training required for proficiency and to evaluate the physicians' perceptions of the student-instructors' depth of knowledge and skill in point of care ultrasound.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2017.04.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5675969PMC
January 2017

Reply.

J Ultrasound Med 2018 06 9;37(6):1576. Epub 2017 Oct 9.

Department of Emergency Medicine, Newport Harbor Cardiology, Newport Beach, California, USA.

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http://dx.doi.org/10.1002/jum.14441DOI Listing
June 2018

A Prospective Evaluation of Transverse Tracheal Sonography During Emergent Intubation by Emergency Medicine Resident Physicians.

J Ultrasound Med 2017 Oct 15;36(10):2079-2085. Epub 2017 May 15.

Department of Emergency Medicine, University of Nevada School of Medicine, Las Vegas, Nevada, USA.

Objectives: Establishing a definitive airway is often the first step in emergency department treatment of critically ill patients. Currently, there is no agreed upon consensus as to the most efficacious method of airway confirmation. Our objective was to determine the diagnostic accuracy of real-time sonography performed by resident physicians to confirm placement of the endotracheal tube during emergent intubation.

Methods: We performed a prospective cohort study of adult patients in the emergency department undergoing emergent endotracheal intubation. Thirty emergency medicine residents, who were blinded to end-tidal carbon dioxide detection results, performed real-time transverse tracheal sonography during intubation to evaluate correct endotracheal tube placement.

Results: Seventy-two patients were enrolled in the study. Sixty-eight instances (94.4%) were interpreted as correct placement in the trachea; 4 (5.6%) were interpreted as esophageal, of which 1 was a false-negative finding, therefore conferring sensitivity of 98.5% (95% confidence interval, 92.1%-99.9%) and specificity of 75.0% (95% confidence interval, 19.4%-99.4%) for correct placement. There was no significant difference in accuracy among resident sonographers with different levels of residency training.

Conclusions: A simple transverse tracheal sonographic examination performed by emergency medicine resident physicians can be used as an adjunct to help confirm correct endotracheal tube placement during intubation. In our cohort, the level of training did not appear to affect the ability of residents to correctly identify the endotracheal tube position.
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http://dx.doi.org/10.1002/jum.14231DOI Listing
October 2017

Simplified point-of-care ultrasound protocol to confirm central venous catheter placement: A prospective study.

World J Emerg Med 2017 ;8(1):25-28

Department of Emergency Medicine, University of California, Irvine, Orange, California 92868, USA.

Background: The current standard for confirmation of correct supra-diaphragmatic central venous catheter (CVC) placement is with plain film chest radiography (CXR). We hypothesized that a simple point-of-care ultrasound (POCUS) protocol could effectively confirm placement and reduce time to confirmation.

Methods: We prospectively enrolled a convenience sample of patients in the emergency department and intensive care unit who required CVC placement. Correct positioning was considered if turbulent flow was visualized in the right atrium on sub-xiphoid, parasternal or apical cardiac ultrasound after injecting 5 cc of sterile, non-agitated, normal saline through the CVC.

Results: Seventy-eight patients were enrolled. POCUS had a sensitivity of 86.8% (95% 77.1%-93.5%) and specificity of 100% (95% 15.8%-100.0%) for identifying correct central venous catheter placement. Median POCUS and CXR completion were 16 minutes (IQR 10-29) and 32 minutes (IQR 19-45), respectively.

Conclusion: Ultrasound may be an effective tool to confirm central venous catheter placement in instances where there is a delay in obtaining a confirmatory CXR.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2017.01.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263031PMC
January 2017

Implementation of a 4-Year Point-of-Care Ultrasound Curriculum in a Liaison Committee on Medical Education-Accredited US Medical School.

J Ultrasound Med 2017 02 10;36(2):321-325. Epub 2016 Dec 10.

Department of Emergency Medicine, University of California, Irvine, Orange, California, USA.

Objectives: The established benefits of point-of-care ultrasound have given rise to multiple new and innovative curriculums to incorporate ultrasound teaching into medical education. This study sought to measure the educational success of a comprehensive and integrated 4-year point-of-care ultrasound curriculum.

Methods: We integrated a curriculum consisting of traditional didactics combined with asynchronous learning modules and hands-on practice on live models with skilled sonographers into all 4 years of education at a Liaison Committee on Medical Education-accredited US Medical School. Each graduating student was administered an exit examination with 48 questions that corresponded to ultrasound milestones.

Results: Ninety-five percent (n = 84) of fourth-year medical students completed the exit examination. The mean score was 79.5% (SD, 10.2%), with mean scores on the ultrasound physics and anatomy subsections being 77.1% (SD, 11.0%) and 85.9% (SD, 21.0%), respectively.

Conclusions: A comprehensive 4-year point-of-care ultrasound curriculum integrated into medical school may successfully equip graduating medical students with a fundamental understanding of ultrasound physics, anatomy, and disease recognition.
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http://dx.doi.org/10.7863/ultra.16.03068DOI Listing
February 2017

Point-of-care ultrasound versus radiology department pelvic ultrasound on emergency department length of stay.

World J Emerg Med 2016 ;7(3):178-82

Department of Emergency Medicine, University of California Irvine, Irvine, California 92697, USA.

Background: The study aimed to compare the time to overall length of stay (LOS) for patients who underwent point-of-care ultrasound (POCUS) versus radiology department ultrasound (RDUS).

Methods: This was a prospective study on a convenience sample of patients who required pelvic ultrasound imaging as part of their emergency department (ED) assessment.

Results: We enrolled a total of 194 patients who were on average 32 years-old. Ninety-eight (51%) patients were pregnant (<20 weeks). Time to completion of RDUS was 66 minutes longer than POCUS (95%CI 60-73, P<0.01). Patients randomized to the RDUS arm experienced a 120 minute longer ED length of stay (LOS) (95%CI 66-173, P<0.01).

Conclusion: In patients who require pelvic ultrasound as part of their diagnostic evaluation, POCUS resulted in a significant decrease in time to ultrasound and ED LOS.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2016.03.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4988106PMC
August 2016

Prospective evaluation of point-of-care ultrasound for pre-procedure identification of landmarks versus traditional palpation for lumbar puncture.

World J Emerg Med 2016 ;7(3):173-7

Emergency Medicine, University of California, Irvine, Orange, California 92868, USA.

Background: The objective of this study is to determine if point-of-care ultrasound (POCUS) pre-procedure identification of landmarks can decrease failure rate, reduce procedural time, and decrease the number of needle redirections and reinsertions when performing a lumbar puncture (LP).

Methods: This was a prospective, randomized controlled trial comparing POCUS pre-procedure identification of landmarks versus traditional palpation for LP in a cohort of patients in the emergency department and intensive care unit.

Results: A total of 158 patients were enrolled. No significant difference was found in time to completion, needle re-direction, or needle re-insertion when using POCUS when compared to the traditional method of palpation.

Conclusion: Consistent with findings of previous studies, our data indicate that there was no observed benefit of using POCUS to identify pre-procedure landmarks when performing an LP.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2016.03.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4988105PMC
August 2016

Pilot Study to Determine Accuracy of Posterior Approach Ultrasound for Shoulder Dislocation by Novice Sonographers.

West J Emerg Med 2016 May 26;17(3):377-82. Epub 2016 Apr 26.

University of California Irvine, Department of Emergency Medicine, Orange, California.

Introduction: The goal of this study was to investigate the efficacy of diagnosing shoulder dislocation using a single-view, posterior approach point-of-care ultrasound (POCUS) performed by undergraduate research students, and to establish the range of measured distance that discriminates dislocated shoulder from normal.

Methods: We enrolled a prospective, convenience sample of adult patients presenting to the emergency department with acute shoulder pain following injury. Patients underwent ultrasonographic evaluation of possible shoulder dislocation comprising a single transverse view of the posterior shoulder and assessment of the relative positioning of the glenoid fossa and the humeral head. The sonographic measurement of the distance between these two anatomic structures was termed the Glenohumeral Separation Distance (GhSD). A positive GhSD represented a posterior position of the glenoid rim relative to the humeral head and a negative GhSD value represented an anterior position of the glenoid rim relative to the humeral head. We compared ultrasound (US) findings to conventional radiography to determine the optimum GhSD cutoff for the diagnosis of shoulder dislocation. Sensitivity, specificity, positive predictive value, and negative predictive value of the derived US method were calculated.

Results: A total of 84 patients were enrolled and 19 (22.6%) demonstrated shoulder dislocation on conventional radiography, all of which were anterior. All confirmed dislocations had a negative measurement of the GhSD, while all patients with normal anatomic position had GhSD>0. This value represents an optimum GhSD cutoff of 0 for the diagnosis of (anterior) shoulder dislocation. This method demonstrated a sensitivity of 100% (95% CI [82.4-100]), specificity of 100% (95% CI [94.5-100]), positive predictive value of 100% (95% CI [82.4-100]), and negative predictive value of 100% (95% CI [94.5-100]).

Conclusion: Our study suggests that a single, posterior-approach POCUS can diagnose anterior shoulder dislocation, and that this method can be employed by novice ultrasonographers, such as non-medical trainees, after a brief educational session. Further validation studies are necessary to confirm these findings.
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http://dx.doi.org/10.5811/westjem.2016.2.29290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4899074PMC
May 2016

Ultrasound-guided central venous access: which probe is preferred for viewing the subclavian vein using a supraclavicular approach?

Am J Emerg Med 2016 Sep 7;34(9):1761-4. Epub 2016 Jun 7.

Department of Emergency Medicine, University of California Irvine, Irvine, California.

Background: Point-of-care ultrasound guidance using a linear probe is well established as a tool to increase safety when performing a supradiaphragmatic cannulation of the internal jugular central vein. However, little data exist on which probe is best for performing a supradiaphragmatic cannulation of the subclavian vein.

Methods: This was a prospective, observational study at a single-site emergency department, where 5 different physician sonologists evaluate individual practice preference for visualization of the subclavian vein using a supraclavicular approach with 2 different linear probes and 1 endocavitary probe.

Results: Of 155 patients enrolled, there was no clear preference any of the probes (P= .03). After pooling linear probe preference, there was a preference for either linear probe over the alternative endocavitary probe (76.8% vs 23.1%, P< .05).

Conclusion: We observed a preference for a linear probe over an endocavitary probe. Further investigation is necessary to determine which probe is optimal for this application.
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http://dx.doi.org/10.1016/j.ajem.2016.06.013DOI Listing
September 2016

Pre-hospital assessment with ultrasound in emergencies: implementation in the field.

World J Emerg Med 2016 ;7(2):117-23

Emergency Medicine, University of California, Irvine, Orange, California 92868, USA.

Background: Point-of-care ultrasound (US) is a proven diagnostic imaging tool in the emergency department (ED). Modern US devices are now more compact, affordable and portable, which has led to increased usage in austere environments. However, studies supporting the use of US in the prehospital setting are limited. The primary outcome of this pilot study was to determine if paramedics could perform cardiac ultrasound in the field and obtain images that were adequate for interpretation. A secondary outcome was whether paramedics could correctly identify cardiac activity or the lack thereof in cardiac arrest patients.

Methods: We performed a prospective educational study using a convenience sample of professional paramedics without ultrasound experience. Eligible paramedics participated in a 3-hour session on point-of-care US. The paramedics then used US during emergency calls and saved the scans for possible cardiac complaints including: chest pain, dyspnea, loss of consciousness, trauma, or cardiac arrest.

Results: Four paramedics from two distinct fire stations enrolled a total of 19 unique patients, of whom 17 were deemed adequate for clinical decision making (89%, 95%CI 67%-99%). Paramedics accurately recorded 17 cases of cardiac activity (100%, 95%CI 84%-100%) and 2 cases of cardiac standstill (100%, 95%CI 22%-100%).

Conclusion: Our pilot study suggests that with minimal training, paramedics can use US to obtain cardiac images that are adequate for interpretation and diagnose cardiac standstill. Further large-scale clinical trials are needed to determine if prehospital US can be used to guide care for patients with cardiac complaints.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2016.02.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4905867PMC
June 2016

Retrospective Review of Ocular Point-of-Care Ultrasound for Detection of Retinal Detachment.

West J Emerg Med 2016 Mar 2;17(2):196-200. Epub 2016 Mar 2.

University of California Irvine Medical Center, Department of Emergency Medicine, Orange, California.

Introduction: Retinal detachment is an ocular emergency that commonly presents to the emergency department (ED). Ophthalmologists are able to accurately make this diagnosis with a dilated fundoscopic exam, scleral depression or ophthalmic ultrasound when a view to the retina is obstructed. Emergency physicians (EPs) are not trained to examine the peripheral retina, and thus ophthalmic ultrasound can be used to aid in diagnosis. We assessed the accuracy of ocular point-of-care ultrasound (POCUS) in diagnosing retinal detachment.

Methods: We retrospectively reviewed charts of ED patients with suspected retinal detachment who underwent ocular POCUS between July 2012 and May 2015. Charts were reviewed for patients presenting to the ED with ocular complaints and clinical concern for retinal detachment. We compared ocular POCUS performed by EPs against the criterion reference of the consulting ophthalmologist's diagnosis.

Results: We enrolled a total of 109 patients. Of the 34 patients diagnosed with retinal detachment by the ophthalmologists, 31 were correctly identified as having retinal detachment by the EP using ocular POCUS. Of the 75 patients who did not have retinal detachment, 72 were ruled out by ocular POCUS by the EP. This resulted in a POCUS sensitivity of 91% (95% CI [76-98]) and specificity of 96% (95% CI [89-99]).

Conclusion: This retrospective study suggests that ocular POCUS performed by EPs can aid in the diagnosis of retinal detachment in ED.
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http://dx.doi.org/10.5811/westjem.2015.12.28711DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786246PMC
March 2016

A feasibility study to determine if minimally trained medical students can identify markers of chronic parasitic infection using bedside ultrasound in rural Tanzania.

World J Emerg Med 2015 ;6(4):293-8

UC Irvine Health, Department of Emergency Medicine, Orange, California 92868, USA.

Background: Parasitic infections pose a significant health risk in developing nations and are a major cause of morbidity and mortality worldwide. In the Republic of Tanzania, the CDC estimates that 51.5% of the population is infected with one or more intestinal parasites. If diagnosed early, the consequences of chronic parasitic infection can potentially be avoided.

Methods: Six first-year medical students were recruited to enroll patients in the study. They underwent ten hours of formal, hands-on, ultrasound which included basic cardiac, hepatobiliary, renal, pulmonary and FAST scan ultrasound. A World Health Organization protocol with published grading scales was adapted and used to assess for pathology in each patient's liver, bladder, kidneys, and spleen.

Results: A total of 59 patients were enrolled in the study. Students reported a sensitivity of 96% and specificity of 100% for the presence of a dome shaped bladder, a sensitivity and specificity of 100% for bladder thickening, a sensitivity and specificity of 100% for portal hypertension and ascites. The sensitivity was 81% with a specificity of 100% for presence of portal vein distention. The sensitivity was 100% with a specificity of 90% for dilated bowel.

Conclusions: Ultrasound has shown a promise at helping to identify pathology in rural communities with limited resources such as Tanzania. Our data suggest that minimally trained first year medical students are able to perform basic ultrasound scans that can identify ultrasonographic markers of parasitic infections.
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http://dx.doi.org/10.5847/wjem.j.1920-8642.2015.04.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4677073PMC
December 2015

Ultrafest: a novel approach to ultrasound in medical education leads to improvement in written and clinical examinations.

West J Emerg Med 2015 Jan 15;16(1):143-8. Epub 2014 Dec 15.

University of California, Irvine, School of Medicine, Irvine, California.

Introduction: Our objective was to evaluate the effectiveness of hands-on training at a bedside ultrasound (US) symposium ("Ultrafest") to improve both clinical knowledge and image acquisition skills of medical students. Primary outcome measure was improvement in multiple choice questions on pulmonary or Focused Assessment with Sonography in Trauma (FAST) US knowledge. Secondary outcome was improvement in image acquisition for either pulmonary or FAST.

Methods: Prospective cohort study of 48 volunteers at "Ultrafest," a free symposium where students received five contact training hours. Students were evaluated before and after training for proficiency in either pulmonary US or FAST. Proficiency was assessed by clinical knowledge through written multiple-choice exam, and clinical skills through accuracy of image acquisition. We used paired sample t-tests with students as their own controls.

Results: Pulmonary knowledge scores increased by a mean of 10.1 points (95% CI [8.9-11.3], p<0.00005), from 8.4 to a posttest average of 18.5/21 possible points. The FAST knowledge scores increased by a mean of 7.5 points (95% CI [6.3-8.7] p<0.00005), from 8.1 to a posttest average of 15.6/21. We analyzed clinical skills data on 32 students. The mean score was 1.7 pretest and 4.7 posttest of 12 possible points. Mean improvement was 3.0 points (p<0.00005) overall, 3.3 (p=0.0001) for FAST, and 2.6 (p=0.003) for the pulmonary US exam.

Conclusion: This study suggests that a symposium on US can improve clinical knowledge, but is limited in achieving image acquisition for pulmonary and FAST US assessments. US training external to official medical school curriculum may augment students' education.
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http://dx.doi.org/10.5811/westjem.2014.11.23746DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4307699PMC
January 2015

The role of ultrasound in the management and diagnosis of infectious mononucleosis.

Crit Ultrasound J 2014 Feb 28;6(1). Epub 2014 Feb 28.

University of California, Irvine School of Medicine, 101 The City Drive South, Orange, CA 92688, USA.

Currently, infectious mononucleosis (IM) is a clinically diagnosed condition. According to the American Family Physician criteria for IM, splenomegaly is the key factor that distinguishes IM from other causes of sore throat. Though heterophile antibody tests are often ordered to confirm diagnosis of IM, this test has a high false-negative rate early in the course of the disease. This case report provides an example of how the use of ultrasound to diagnose splenomegaly and subsequently mononucleosis increases diagnostic accuracy.
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http://dx.doi.org/10.1186/2036-7902-6-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3942514PMC
February 2014

Suction-modified needle biopsy technique for the human soleus muscle.

Aviat Space Environ Med 2013 Oct;84(10):1066-73

University of California, Irvine, CA 92697, USA.

Introduction: The needle biopsy technique for the soleus muscle is of particular interest because of the muscle's unique fiber type distribution, contractile properties, and sensitivity to unloading. Unlike other commonly biopsied muscles, the soleus is not fully superficial and is in close proximity to neurovascular structures, resulting in a more challenging biopsy. Because of this, a standardized protocol for performing needle biopsies on the human soleus muscle that is safe, reliable, and repeatable is presented.

Methods: Ultrasonography was used on an initial set of 12 subjects to determine the optimal biopsy zone, thereby guiding the location of the incision site. There were 45 subjects recruited who attended 2 separate biopsy sessions. Each biopsy session incorporated 3 passes of the biopsy needle proximal, posterior, and distal using suction from a portable vacuum source producing 3 separate muscle specimens.

Results: There were 84 soleus muscle biopsy procedures which were successfully conducted yielding 252 total samples without complication. Ultrasonography was used to confirm biopsy needle infiltration of the soleus muscle. Average sample weight obtained per pass was 61.5 +/- 15.7 mg. Histochemistry and molecular analyses demonstrated a considerably higher amount of slow type I MHC in comparison to the vastus lateralis, providing verification for the successful sampling of the soleus muscle.

Discussion: The procedure presented consists of a detailed protocol to accurately and consistently obtain muscle biopsy samples from the human soleus muscle. We have demonstrated that the human soleus biopsy is a safe, reliable, and repeatable procedure providing ample tissue for multiple types of analyses.
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http://dx.doi.org/10.3357/asem.3632.2013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4050078PMC
October 2013
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