The technical errors of physicians learning to perform focused assessment with sonography in trauma

A quality assessment tool for focused abdominal sonography for trauma examinations using artificial intelligence

BACKGROUND

Current tools to review focused abdominal sonography for trauma (FAST) images for quality have poorly defined grading criteria or are developed to grade the skills of the sonographer and not the examination. The purpose of this study is to establish a grading system with substantial agreement among coders, thereby enabling the development of an automated assessment tool for FAST examinations using artificial intelligence (AI).

METHODS

Five coders labeled a set of FAST clips. Each coder was responsible for a different subset of clips (10% of the clips were labeled in triplicate to evaluate intercoder reliability). The clips were labeled with a quality score from 1 (lowest quality) to 5 (highest quality). Clips of 3 or greater were considered passing. An AI training model was developed to score the quality of the FAST examination. The clips were split into a training set, a validation set, and a test set. The predicted scores were rounded to the nearest quality level to distinguish passing from failing clips.

RESULTS

A total of 1,514 qualified clips (1,399 passing and 115 failing clips) were evaluated in the final data set. This final data set had a 94% agreement between pairs of coders on the pass/fail prediction, and the set had a Krippendorff α of 66%. The decision threshold can be tuned to achieve the desired tradeoff between precision and sensitivity. Without using the AI model, a reviewer would, on average, examine roughly 25 clips for every 1 failing clip identified. In contrast, using our model with a decision threshold of 0.015, a reviewer would examine roughly five clips for every one failing clip - a fivefold reduction in clips reviewed while still correctly identifying 85% of passing clips.

CONCLUSION

Integration of AI holds significant promise in improving the accurate evaluation of FAST images while simultaneously alleviating the workload burden on expert physicians.

LEVEL OF EVIDENCE

Diagnostic Test/Criteria; Level II.

Updates on the clinical integration of point-of-care ultrasound in pediatric emergency medicine

PURPOSE OF REVIEW

There is expanding evidence for point-of-care ultrasound (POCUS) use in pediatric emergency medicine - this review highlights the benefits and challenges in the clinical integration of high-yield POCUS applications. Specifically, it will delve into POCUS applications during resuscitations, controversies of Focused Assessment with Sonography for Trauma (FAST) in pediatric trauma, POCUS-guided procedures, and examples of clinical pathways where POCUS can expedite definitive care.

RECENT FINDINGS

POCUS can enhance diagnostic accuracy and aid in management of pediatric patients in shock and help identify reversible causes during cardiac arrest. The use of the FAST in pediatric blunt abdominal trauma remains nuanced - its proper use requires an integration with clinical findings and an appreciation of its limitations. POCUS has been shown to enhance safety and efficacy of procedures such as nerve blocks, incision & drainage, and intravenous access. Integrating POCUS into pathways for conditions such as intussusception and testicular torsion expedites downstream care.

SUMMARY

POCUS enhances diagnostic efficiency and management in pediatric patients arriving at the ED with undifferentiated shock, cardiac arrest, or trauma. Additionally, POCUS improves procedural success and safety, and is integral to clinical pathways for expediting definitive care for various pediatric emergencies. Future research should continue to focus on the impact of POCUS on patient outcomes, ensuring user competency, and the expansion of POCUS into diverse settings.

Evaluation of Focused Assessment With Sonography for Trauma Completeness of Children in the Clinical Setting

OBJECTIVES

We evaluated the completeness of real-world Focused Assessment with Sonography for Trauma (FAST) in children after blunt abdominal trauma by benchmarking against established expert guidelines.

METHODS

We conducted a retrospective cohort study, analyzing a random sample of FASTs from two urban pediatric emergency departments. Two experts reviewed and labeled all FASTs for completeness using a predefined guideline of 5 anatomic views and 30 landmarks. We compared frequencies of views and landmarks as medians with interquartile ranges.

RESULTS

We analyzed 200 FASTs, consisting of 1636 video clips, performed by 31 clinicians representing 198 children with a median age of 10 years (IQR 5,14). Over half of FASTs (52%) had all 5 views. The right upper quadrant view was most commonly visualized (96.5%), and suprapubic sagittal was least (65%). None of the FASTs included all 30 landmarks, ranging from 0 to 28 and median of 19 (IQR 15,23). The least visualized landmark of the right and left upper quadrants was caudal liver edge (60%) and splenic tip (64%), respectively. In the pericardial view, it was left atrium (45%). In both transverse and sagittal pelvic views, retro-uterine space was least visualized in girls, 21 and 29% respectively.

CONCLUSIONS

In our study, most FAST views and landmarks were visualized. However, the pelvic sagittal view was the least frequently visualized view, and caudal liver edge was the least visualized landmark. Future research should evaluate if variability in visualizing FAST views and landmarks correlates with inconsistencies in diagnostic test performance.

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.

Exploring the use of knobology for image optimisation in final year sonography students

Introduction

Image optimisation is essential for acquisition of quality images in ultrasound and critical to the diagnostic ability of the examination. These skills are taught to sonography students early in their education, but research has found that retention of non-rehearsed knowledge decreases significantly after a year. The aim of this study was to determine which optimisation tools (knobology) final year sonography students use, how often and why they chose to adjust parameters and assess barriers to optimisation of knobology tools.

Methods

A prospective study using data from an anonymous online survey of 34 final year sonography students.

Results

Survey results showed that 19/34 (55%) of students "frequently" optimise all Doppler settings and 23/34 (67%) of students "frequently" optimise basic parameter settings (depth, focus, time gain compensation). Time constraints (24/34 (70%)) and loss of gained knowledge of sonography principles and instrumentation (17/34 (50%)) were the major barriers to the use of knobology. The majority 28/34 (82%) believed they would benefit from further training.

Conclusion

This study demonstrates that although most students are optimising settings to improve image quality, sonography principles and instrumentation knowledge loss and time constraints prevent students from maximising machine capabilities. This study supports the need for further training prior to final year clinical placement.

Development and Validation of a Deep Learning Strategy for Automated View Classification of Pediatric Focused Assessment With Sonography for Trauma

OBJECTIVE

Pediatric focused assessment with sonography for trauma (FAST) is a sequence of ultrasound views rapidly performed by clinicians to diagnose hemorrhage. A technical limitation of FAST is the lack of expertise to consistently acquire all required views. We sought to develop an accurate deep learning view classifier using a large heterogeneous dataset of clinician-performed pediatric FAST.

METHODS

We developed and conducted a retrospective cohort analysis of a deep learning view classifier on real-world FAST studies performed on injured children less than 18 years old in two pediatric emergency departments by 30 different clinicians. FAST was randomly distributed to training, validation, and test datasets, 70:20:10; each child was represented in only one dataset. The primary outcome was view classifier accuracy for video clips and still frames.

RESULTS

There were 699 FAST studies, representing 4925 video clips and 1,062,612 still frames, performed by 30 different clinicians. The overall classification accuracy was 97.8% (95% confidence interval [CI]: 96.0-99.0) for video clips and 93.4% (95% CI: 93.3-93.6) for still frames. Per view still frames were classified with an accuracy: 96.0% (95% CI: 95.9-96.1) cardiac, 99.8% (95% CI: 99.8-99.8) pleural, 95.2% (95% CI: 95.0-95.3) abdominal upper quadrants, and 95.9% (95% CI: 95.8-96.0) suprapubic.

CONCLUSION

A deep learning classifier can accurately predict pediatric FAST views. Accurate view classification is important for quality assurance and feasibility of a multi-stage deep learning FAST model to enhance the evaluation of injured children.

Development of a Consensus-Based Definition of Focused Assessment With Sonography for Trauma in Children

Importance

The wide variation in the accuracy and reliability of the Focused Assessment With Sonography for Trauma (FAST) and the extended FAST (E-FAST) for children after blunt abdominal trauma reflects user expertise. FAST and E-FAST that are performed by experts tend to be more complete, better quality, and more often clinically valuable.

Objective

To develop definitions of a complete, high-quality, and accurate interpretation for the FAST and E-FAST in children with injury using an expert, consensus-based modified Delphi technique.

Design, Setting, and Participants

This consensus-based qualitative study was conducted between May 1 to June 30, 2021. It used a scoping review and iterative Delphi technique and involved 2 rounds of online surveys and a live webinar to achieve consensus among a 26-member panel. This panel consisted of international experts in pediatric emergency point-of-care ultrasonography.

Main Outcomes and Measures

Definitions of complete, high-quality, and accurate FAST and E-FAST studies for children after injury.

Results

Of the 29 invited pediatric FAST experts, 26 (15 men [58%]) agreed to participate in the panel. All 26 panelists completed the 2 rounds of surveys, and 24 (92%) participated in the live and asynchronous online discussions. Consensus was reached on FAST and E-FAST study definitions, and the panelists rated these 5 anatomic views as important and appropriate for a complete FAST: right upper-quadrant abdominal view, left upper-quadrant abdominal view, suprapubic views (transverse and sagittal), and subxiphoid cardiac view. For E-FAST, the same FAST anatomic views with the addition of the lung or pneumothorax view were deemed appropriate and important. In addition, the panelists rated a total of 32 landmarks as important for assessing completeness. Similarly, the panelists rated 14 statements on quality and 20 statements on accurate interpretation as appropriate.

Conclusions and Relevance

This qualitative study generated definitions for complete FAST and E-FAST studies with high image quality and accurate interpretation in children with injury. These definitions are similar to those in adults with injury and may be used for future education, quality assurance, and research. Future research may focus on interpretation of trace volumes of abdominal free fluid and the use of serial FAST.

Deep Learning Assisted Detection of Abdominal Free Fluid in Morison's Pouch During Focused Assessment With Sonography in Trauma

Background: The use of focused assessment with sonography in trauma (FAST) enables clinicians to rapidly screen for injury at the bedsides of patients. Pre-hospital FAST improves diagnostic accuracy and streamlines patient care, leading to dispositions to appropriate treatment centers. In this study, we determine the accuracy of artificial intelligence model-assisted free-fluid detection in FAST examinations, and subsequently establish an automated feedback system, which can help inexperienced sonographers improve their interpretation ability and image acquisition skills.

Methods: This is a single-center study of patients admitted to the emergency room from January 2020 to March 2021. We collected 324 patient records for the training model, 36 patient records for validation, and another 36 patient records for testing. We balanced positive and negative Morison's pouch free-fluid detection groups in a 1:1 ratio. The deep learning (DL) model Residual Networks 50-Version 2 (ResNet50-V2) was used for training and validation.

Results: The accuracy, sensitivity, and specificity of the model performance for ascites prediction were 0.961, 0.976, and 0.947, respectively, in the validation set and 0.967, 0.985, and 0.913, respectively, in the test set. Regarding feedback prediction, the model correctly classified qualified and non-qualified images with an accuracy of 0.941 in both the validation and test sets.

Conclusions: The DL algorithm in ResNet50-V2 is able to detect free fluid in Morison's pouch with high accuracy. The automated feedback and instruction system could help inexperienced sonographers improve their interpretation ability and image acquisition skills.

eFAST exam errors at a level 1 trauma center: A retrospective cohort study

OBJECTIVES

Extended Focused Assessment with Sonography for Trauma (eFAST) ultrasound exams are central to the care of the unstable trauma patient. We examined six years of eFAST quality assurance data to identify the most common reasons for false positive and false negative eFAST exams.

METHODS

This was an observational, retrospective cohort study of trauma activation patients evaluated in an urban, academic Level 1 trauma center. All eFAST exams that were identified as false positive or false negative exams compared with computed tomography (CT) imaging were included.

RESULTS

4860 eFAST exams were performed on trauma patients. 1450 (29.8%) were undocumented, technically limited, or incomplete (missing images). Of the 3410 remaining exams, 180 (5.27%) were true positive and 3128 (91.7%) were true negative. 27 (0.79%) exams were identified as false positive and 75 (2.19%) were identified as false negative. Of the false positive scans, 7 had no CT scan and 8 had correct real-time trauma paper documentation of eFAST exam results when compared to CT and were excluded, leaving 12 false positive scans. Of the false negative scans, 11 were excluded for concordant documentation in real-time trauma room paper documentation, 20 were excluded for no CT scan, and 2 were excluded as incomplete, leaving 42 false negative scans. Pelvic fluid, double-line sign, pericardial fat pad, and the thoracic portion of the eFAST exam were the most common source of errors.

CONCLUSION

The eFAST exams in trauma activation patients are highly accurate. Unfortunately poor documentation and technically limited/incomplete studies represent 29.8% of our eFAST exams. Pelvic fluid, double-line sign, pericardial fat pad, and the thoracic portion of the eFAST exam are the most common source of errors.

Frequency-Dependent Spatial Coherence in Conventional and Chirp Transmissions

The development of adaptive imaging techniques is contingent on the accurate and repeatable characterization of ultrasonic image quality. Adaptive transmit frequency selection, filtering, and frequency compounding all offer the ability to improve target conspicuity by balancing the effects of imaging resolution, the signal-to-clutter ratio, and speckle texture, but these strategies rely on the ability to capture image quality at each desired frequency. We investigate the use of broadband linear frequency-modulated transmissions, also known as chirps, to expedite the interrogation of frequency-dependent tissue spatial coherence for real-time implementations of frequency-based adaptive imaging strategies. Chirp-collected measurements of coherence are compared to those acquired by individually transmitted conventional pulses over a range of fundamental and harmonic frequencies, in order to evaluate the ability of chirps to recreate conventionally acquired coherence. Simulation and measurements in a uniform phantom free of acoustic clutter indicate that chirps replicate not only the mean coherence in a region-of-interest but also the distribution of coherence values over frequency. Results from acquisitions in porcine abdominal and human liver models show that prediction accuracy improves with chirp length. Chirps are also able to predict frequency-dependent decreases in coherence in both porcine abdominal and human liver models for fundamental and pulse inversion harmonic imaging. This work indicates that the use of chirps is a viable strategy to improve the efficiency of variable frequency coherence mapping, thus presenting an avenue for real-time implementations for frequency-based adaptive strategies.

Efficacy of a certified modular ultrasound curriculum

Background

In recent years, ultrasound (US) has become more incorporated into anesthesia and intensive care medicine. The German Anesthesia Society established a modular curriculum to teach US skills. Until now, the efficacy of this modular curriculum has not been validated.

Objective

The main objective of this study was to determine whether there is an increase of knowledge and of psychomotor skills for the trainees in this curriculum.

Material and methods

After ethical committee approval, 41 anesthesia physicians were enrolled. To determine the increase of knowledge and of practical skills theoretical and practical tests performed were evaluated before and after two different US courses.

Results

Comparing before and after course tests, the participants showed significant improvement in theoretical multiple choice tests (p = 0.008). Regarding psychomotor skills following course 1, the trainees improved significantly in the time needed to perform the two practical tests (p = 0.03), but not in the performance of the test. Better needle visualization during simulated US-guided vessel puncture (p = 0.52) and better identification of the anatomical structures in the axillary region (p = 0.56) could not be achieved.

Conclusion

This study shows that although this US course curriculum has positively enhanced the trainees’ theoretical knowledge of US practice, it does not enhance the practical application of that theoretical knowledge. To improve this curriculum, a supervised clinically practical training should follow the course.

Electronic supplementary material

The online version of this article (10.1007/s00101-020-00730-9) provides the two questionnaires in German. The article and additional material are available at www.springermedizin.de. Please enter the title of the article in the search field, the additional material can be found under “Ergänzende Inhalte”.

Assessing how emergency and trauma ultrasonography is taught to medical students

Objective

To evaluate a method aimed at teaching ultrasound techniques to medical students in emergency settings.

Methods

A prospective study conducted with 66 sixth-year undergraduate medical students. Students participated in theory and practicing sessions with a 5-hour load; knowledge acquisition was assessed through pre- and post-course and 90-day tests. A questionnaire were distributed to the students after course completion for theoretical and practical knowledge assessment.

Results

Average pre-test grade in theoretical content evaluation was 4.9, compared to 7.6 right after course completion, and 5.9 within 90 days (p<0.001). Questions addressing technical aspects and image acquisition were mostly answered correctly; in contrast, questions related to clinical management of patients tended to be answered incorrectly. In practical evaluation, 54 students (81.8%) were able to correctly interpret images.

Conclusion

Ultrasound applicability and image acquisition techniques can be taught to medical students in emergency settings. However, teaching should be focused on technical aspects rather than clinical management of patients.

Interobserver Agreement on Focused Assessment with Sonography for Trauma in Blunt Abdominal Injury

Introduction

Trauma constitutes a major public health problem. Ninty percent of world's fatalities on road occur in low and middle-income countries. Focused assessment with sonography in trauma (FAST) has a key role in trauma investigation, altering subsequent management in a significant number of patients. There is a rising trend of introducing FAST examination to non-radiologists and junior members of healthcare team to hasten triage of trauma patients.

Objective

To determine interobserver agreement on focused assessment with sonography for trauma in blunt abdominal injury between senior and junior residents.

Methods

This cross-sectional study was conducted at Aga Khan University Hospital. Three hundred patients with blunt abdominal trauma meeting inclusion criteria were enrolled. FAST was performed using standard curvilinear 3.5-5 MHz transducer. Agreement between junior and senior residents was measured and Kappa statistic was calculated.

Results

Mean age of the patients included in the study was 30.04 ± 18.09 years. Among these 237 (79%) were male and 63 (21%) were female. Sixteen (5.3%) were positive for intraperitoneal free fluid while the remaining 284 (94.7%) were negative. A total of 19 FAST examinations were reported positive by junior residents, of which 15 (78.9%) were confirmed by a senior resident to be correct, while four (21.05%) were falsely labeled positive by a junior resident. A total of 281 negative FAST examinations were reported by junior residents, of which 280 (99.6%) were confirmed by a senior resident, while only one (0.003%) was falsely labeled negative. Kappa statistic was calculated for inter-observer agreement on FAST examination findings, which showed a kappa value of 0.84 (very good agreement), with a p-value of <0.001.

Conclusion

Our study suggests very good interobserver agreement on FAST examination between senior and junior resident in patients with blunt trauma to the abdomen. Results suggest that FAST can be easily learnt with minimal radiology training and may have greater applicability in trauma.

Basic ultrasound training assessment in the initial abdominal trauma screening

OBJECTIVE

to verify the efficiency and usefulness of basic ultrasound training in trauma (FAST - Focused Assessment with Sonography in Trauma) for emergency physicians in the primary evaluation of abdominal trauma.

METHODS

a longitudinal and observational study was carried out from 2015 to 2017, with 11 emergency physicians from Hospital Universitário do Oeste do Paraná, submitted to ultrasound training in emergency and trauma (USET® - SBAIT). FAST results started to be collected two months after the course. These were compared with a composite score of complementary exams and surgical findings. Information was stored in a Microsoft Excel program database and submitted to statistical analysis.

RESULTS

FAST was performed in 120 patients. In the study, 38.4% of the assessed patients had a shock index ≥0.9. The composite score detected 40 patients with free peritoneal fluid, whereas FAST detected 27 cases. The method sensitivity was 67.5%, specificity was 98.7%, the positive predictive value was 96.4%, the negative predictive value was 85.39% and accuracy was 88%. All those with a positive FAST had a shock index ≥0.9. Fifteen patients with positive FAST and signs of instability were immediately submitted to surgery.

CONCLUSIONS

the basic training of emergency physicians in FAST showed efficiency and usefulness in abdominal trauma assessment. Due to its low cost and easy implementation, this modality should be considered as a screening strategy for patients with abdominal trauma in health systems.

The Dangers of Equivocal FAST in Trauma Resuscitation

Equivocal focused abdominal sonography for trauma (FAST) examinations confound decision-making for trauma surgeons. We sought to determine whether the equivocal FAST (defined as any nonconcordant result) has a deleterious effect on trauma outcomes. A 2-year review (2014–2015) of all trauma activations at our Level I trauma center was performed. Patients were matched at baseline and FAST results were compared. Outcomes included resuscitation time (h), ventilation days (d), hospital length of stay (HLOS-d), ICU length-of-stay, and survival (%). In addition, skill level of the sonographer was stratified by novice (postgraduate year (PGY) years 1–3) or expert skill levels (PGY-4/fellow or attending). A total of 1,027 patients were included. Compared with concordant FAST examinations, equivocal FASTs were associated with increased HLOS (14.1 vs 10.6, P = 0.05), higher mortality (9.8 vs 3.7%, P = 0.02), decreased positive predictive value in the right upper quadrant (RUQ) (55 vs 79%, P = 0.02) and left upper quadrant (LUQ) (50 vs 83%, P < 0.01) and significantly decreased specificity in the thoracic (83 vs 98%), RUQ (80 vs 98%), LUQ (86 vs 99%), and pelvic (88 vs 98%) windows (P < 0.01 for all). A trend of greater positive predictive value in the thoracic window (100 vs 81%, P = 0.09) among PGY-4/fellow and attending providers compared with PGY levels 1–3 was observed. Equivocal FASTs portend worse outcomes than concordant FASTs because of high false-negative rates, specifically in the thoracic region and the upper quadrants. Lower thresholds for intervention are recommended.

Focused assessment with sonography for trauma: current perspectives

Focused assessment with sonography for trauma (FAST) is a part of resuscitation of trauma patients recommended by international panel consensus. The purpose of FAST is to identify free fluid, which necessarily means blood in acute trauma patients. In this article, the authors focused on various aspects of FAST in the emergency department, prehospital care, pediatric setting, training and general pearls/pitfalls. Detailed techniques and interpretation of FAST are beyond the scope of this article.

A unique method for estimating the reliability learning curve of optic nerve sheath diameter ultrasound measurement

Background

Optic nerve sheath diameter (ONSD) measurement using ultrasound has been proposed as a rapid, non-invasive, point of care technique to estimate intra-cranial pressure (ICP). Ultrasonic measurement of the optic nerve sheath can be quite challenging and there is limited literature surrounding learning curves for this technique. We attempted to develop a method to estimate the reliability learning curve for ONSD measurement utilizing a unique definition of reliability: a plateau in within-subject variability with unchanged between-subject variability.

Methods

As part of a previously published study, a single operator measured the ONSD in 120 healthy volunteers over a 6-month period. Utilizing the assumption that the four measurements made on each subject during this study should be equal, the relationship of within-subject variance was described using a quadratic-plateau model as assessed by segmental polynomial (knot) regression.

Results

Segmental polynomial (knot) regression revealed a plateau in within-subject variance after the 21st subject. However, there was no difference in overall mean values [3.69 vs 3.68 mm (p = 0.884)] or between-subject variance [14.49 vs 11.92 (p = 0.54)] above or below this cutoff.

Conclusions

This study suggests a significant finite learning curve associated with ONSD measurements. It also offers a unique method of calculating the learning curve associated with ONSD measurement.

Do we really rely on fast for decision-making in the management of blunt abdominal trauma?

INTRODUCTION

The Focused Assessment with Sonography in Trauma examination (FAST) is currently taught and recommended in the ATLS(®), often as an addendum to the primary survey for patients with blunt abdominal trauma. Although it is non-invasive and rapidly performed at bedside, the utility of FAST in blunt abdominal trauma has been questioned. We designed this study to examine our hypothesis that FAST is not an efficacious screening tool for identifying intra-abdominal injuries.

METHODS

We performed a retrospective chart review of all patients with confirmatory diagnosis of blunt abdominal injuries with CT and/or laparotomy for a period of 1.5 years (from 7/2009 to 11/2010). FAST was performed by ED residents and considered positive when free intra-abdominal fluid was visualized. Abdominal CT, or exploratory laparotomy findings were used as confirmation of intra-abdominal injury.

RESULTS

A total of 1671 blunt trauma patients were admitted to and evaluated in the Emergency Department during a 1½ year period and 146 patients were confirmed intra-abdominal injuries by CT and/or laparotomy. Intraoperative findings include injuries to the liver, spleen, kidneys, and bowels. In 114 hemodynamically stable patients, FAST was positive in 25 patients, with a sensitivity of 22%. In 32 hemodynamically unstable patients, FAST was positive in 9 patients, with a sensitivity of 28%. A free peritoneal fluid and splenic injury are associated with a positive FAST on univariate analysis, and are the independent predictors for a positive FAST on multiple logistic regression.

CONCLUSION

FAST has a very low sensitivity in detecting blunt intraabdominal injury. In hemodynamically stable patients, a negative FAST without a CT may result in missed intra-abdominal injuries. In hemodynamically unstable blunt trauma patients, with clear physical findings on examination, the decision for exploratory laparotomy should not be distracted by a negative FAST.

Learning curves in emergency ultrasound education

OBJECTIVES

Proficiency in the use of bedside ultrasound (US) has become standard in emergency medicine residency training. While milestones have been established for this training, supporting data for minimum standard experience are lacking. The objective of this study was to characterize US learning curves to identify performance plateaus for both image acquisition and interpretation, as well as compare performance characteristics of learners to those of expert sonographers.

METHODS

A retrospective review of an US database was conducted at a single academic institution. Each examination was scored for agreement between the learner and expert reviewer interpretation and given a score for image quality. A locally weighted scatterplot smoothing method was used to generate a model of predicted performance for each individual examination type. Performance characteristics for expert sonographers at the site were also tracked and used in addition to performance plateaus as benchmarks for learning curve analysis.

RESULTS

There were 52,408 US examinations performed between May 2007 and January 2013 and included for analysis. Performance plateaus occurred at different points for different US protocols, from 18 examinations for soft tissue image quality to 90 examinations for right upper quadrant image interpretation. For the majority of examination types, a range of 50 to 75 examinations resulted in both excellent interpretation (sensitivity > 84% and specificity > 90%) and good image quality (90% the image quality benchmark of expert sonographers).

CONCLUSIONS

Educational performance benchmarks occur at variable points for image interpretation and image quality for different examination types. These data should be considered when developing training standards for US education as well as experience requirements for US credentialing.

Focused Assessment Sonography for Trauma (FAST) training: a systematic review

BACKGROUND

The aim of this study was to systematically review the different methods for training Focused Assessment Sonography for Trauma (FAST), course design, and requirements for hospital credentialing.

METHODS

We searched MEDLINE/PubMed, EMBASE, and the Cochrane database and performed a manual search of selected papers. All papers and abstracts written in English that studied training and education of FAST were included. Papers were critically evaluated, looking into training methods and models of FAST, their advantages and disadvantages, number and type of training hours, practice exams in the course, and number of cases advised to achieve hospital credentialing.

RESULTS

A total of 52 studies were critically analyzed. The theoretical part of the courses lasted over a median (range) of 4 (1-16) h (n = 35 studies), while the practical part lasted over a median (range) of 4 (1-32) h (n = 34 studies). The participants performed a median (range) of 10 (3-20) FAST exams during the courses (n = 13 studies). The most commonly used model was the normal human model (65 %), followed by peritoneal dialysis patients (27 %). The least used models were animal (4 %) and cadaveric models (2 %). Each of these models had their advantages and disadvantages. The median number (range) of FAST exams needed for credentialing was 50 (10-200) (n = 19 studies).

CONCLUSION

Standardization of FAST training is important to improving the clinical impact of FAST. Different models used in FAST training are complementary; each has its own advantages and disadvantages. It is recommended that FAST courses be at least 2 days (16 h) long. The first day should include 4 h of theory and 4 h of training on normal human models. The second day should enforce learning using animal models, case scenarios including video clips, or simulators.

The FAST and E-FAST in 2013: trauma ultrasonography: overview, practical techniques, controversies, and new frontiers

This article reviews important literature on the FAST and E-FAST examinations in adults. It also reviews key pitfalls, limitations, and controversies. A practical "how-to" guide is presented. Lastly, new frontiers are explored.

Personalized peer-comparison feedback and its effect on emergency medicine resident ultrasound scan numbers

Background

Clinician-performed ultrasound has become a widely utilized tool in emergency medicine and is a mandatory component of the residency curricula. We aimed to assess the effect of personalized peer-comparison feedback on the number of ultrasound scans performed by emergency medicine residents.

Findings

A personalized peer-comparison feedback was performed by sending 44 emergency medicine residents a document including personally identified scan numbers and class averages. The number of ultrasound scans per clinical shift for a 3-month period before and after the feedback intervention was calculated. The average number of ultrasound exams per shift improved from 0.39 scans/shift before to 0.61 scans/shift after feedback (p = 0.04). Among the second year residents, the scans/shift ratio improved from 0.35 to 0.87 (p = 0.07); for third year residents, from 0.51 to 0.58 (p = 0.46); and from 0.33 to 0.41 (p = 0.21) for the fourth year residents before and after the intervention, respectively.

Conclusions

A personalized peer-comparison feedback provided to emergency medicine residents resulted in increased ultrasound scan numbers per clinical shift. Incorporating this method of feedback may help encourage residents to scan more frequently.

Body Mass Index and Abdominal Ultrasound Image Quality

The objective was to assess the consensus among sonographers that the quality of abdominal ultrasound (US) images is related to the patient’s body mass index (BMI). Fourteen sonographers completed a 12-item questionnaire to evaluate their experience with abdominal US imaging with respect to image quality in correlation with the patient’s adipose tissue. Of the sonographers sampled, 85.7% agreed that there is an association between the amount of adipose tissue on a patient’s abdomen and the quality of US image obtained; 85.7% also agreed that a normal BMI of 18.5 to 24.9 provides the best US image. However, only 28.6% agreed that normal amounts of adipose tissue produce poor image quality. There appears to be agreement among sonographers that BMI is a factor in obtaining good quality abdominal US images. The general consensus was that the best abdominal US images were obtained in patients with normal BMI, whereas images obtained from patients with BMI 30.0 to 34.9 and to a lesser extent BMI 25.0 to 29.9 were limited in quality.