Ultrasound evaluation of blunt abdominal trauma: program implementation, initial experience, and learning curve

Artificial intelligence evaluation of focused assessment with sonography in trauma

BACKGROUND

The focused assessment with sonography in trauma (FAST) is a widely used imaging modality to identify the location of life-threatening hemorrhage in a hemodynamically unstable trauma patient. This study evaluates the role of artificial intelligence in interpretation of the FAST examination abdominal views, as it pertains to adequacy of the view and accuracy of fluid survey positivity.

METHODS

Focused assessment with sonography for trauma examination images from 2015 to 2022, from trauma activations, were acquired from a quaternary care level 1 trauma center with more than 3,500 adult trauma evaluations, annually. Images pertaining to the right upper quadrant and left upper quadrant views were obtained and read by a surgeon or radiologist. Positivity was defined as fluid present in the hepatorenal or splenorenal fossa, while adequacy was defined by the presence of both the liver and kidney or the spleen and kidney for the right upper quadrant or left upper quadrant views, respectively. Four convolutional neural network architecture models (DenseNet121, InceptionV3, ResNet50, Vgg11bn) were evaluated.

RESULTS

A total of 6,608 images, representing 109 cases were included for analysis within the "adequate" and "positive" data sets. The models relayed 88.7% accuracy, 83.3% sensitivity, and 93.6% specificity for the adequate test cohort, while the positive cohort conferred 98.0% accuracy, 89.6% sensitivity, and 100.0% specificity against similar models. Augmentation improved the accuracy and sensitivity of the positive models to 95.1% accurate and 94.0% sensitive. DenseNet121 demonstrated the best accuracy across tasks.

CONCLUSION

Artificial intelligence can detect positivity and adequacy of FAST examinations with 94% and 97% accuracy, aiding in the standardization of care delivery with minimal expert clinician input. Artificial intelligence is a feasible modality to improve patient care imaging interpretation accuracy and should be pursued as a point-of-care clinical decision-making tool.

LEVEL OF EVIDENCE

Diagnostic Test/Criteria; Level III.

Teaching point-of-care transfontanellar ultrasound for pediatricians and medical students

OBJECTIVES

The authors aim to evaluate the "point-of-care" transfontanellar ultrasound (TU) as an extension to pediatric physical examination and suggest a TU teaching protocol.

METHODS

The students were randomly divided into two groups, group A (12 participants) and group B (15 participants). The first group only received theoretical training, while the second group received theoretical and practical training. A third group, group C, included 15 pediatricians and interns who also received theoretical and practical training. All the participants underwent multiple-choice testing before and after a four-hour short course on TU. Six months later, another evaluation was performed to analyze the retained knowledge. Furthermore, a questionnaire based on the Likert scale was administered to evaluate satisfaction.

RESULTS

The cognitive evaluation (maximum score=10 points) before and after training increased in group A from 4,0±1,04 to 7,5±1,2 (p<0.001) and, 6 months later, to 6,5±1,16 (p<0.003); in group B from 3,8±1,24 to 8,8±1,01 (p<0.001) and, 6 months later, to 8,46±0,91 (p<0.001); and in group C from 6,0±0,75 to 9,0±0,75 (p<0.001) and, 6 months later, to 8,8±0,77 (p<0.001). The average satisfaction estimated by the Likert scale was over 80% for all questions.

CONCLUSION

Cognitive assessment before and after classes and training reveals progress in learning, with knowledge retention in 6 months. Theoretical-practical courses are well accepted.

Prehospital ABC Score Accurately Forecasts Patients Who Will Require Immediate Resource Utilization

OBJECTIVES

Scoring systems, such as the Assessment of Blood Consumption (ABC) Score, are used to identify patients at risk for massive transfusion (MT, ≥10 U red blood cells in 24 hours). Our aeromedical transport helicopter uses ultrasound to perform the Focused Assessment with Sonography for Trauma (FAST) examination. Our objective was to evaluate the ability of the Prehospital ABC (PhABC) Score to predict blood transfusions and the need for emergent laparotomy.

METHODS

Post hoc analysis of a prospective observational study of trauma patients who underwent an in-flight FAST during aeromedical transport during a 7-month period. PhABC Score was positive if ≥2 of the following were present in flight: penetrating trauma, heart rate >120 bpm, systolic blood pressure <90 mm Hg, or a positive abdominal FAST. The PhABC Score was evaluated by area under the receiver operating characteristic (AUROC) curves and logistic regression.

RESULTS

A total of 291 trauma patients met inclusion criteria, 23 underwent emergent laparotomy, and 12 received an MT. A positive PhABC Score predicted emergent laparotomy, with a positive predictive value of 48% and a negative predictive value of 95% (sensitivity 46%, specificity 96%, AUROC curve 0.83). A positive PhABC Score also predicted receipt of an MT with a positive predictive value of 28% and a negative predictive value of 94% (sensitivity 33%, specificity 93%, AUROC curve 0.77). Multiple logistic regression identified FAST as the most powerful contributor of the PhABC Score to the prediction of both emergent laparotomy (odds ratio 8.5, P < 0.001) and MT (odds ratio 5.9, P < 0.001).

CONCLUSIONS

The PhABC Score effectively predicts in-hospital resource utilization. It provides an outstanding undertriage rate from the prehospital setting, and it is helpful to improve trauma team activation, mobilize blood products, and prepare the operating room.

Ultrasound Training in Surgical Critical Care Fellowship: A Survey of Program Directors

OBJECTIVE

Surgical critical care (SCC) fellows are expected to receive training in critical care ultrasound (CCUS) but training is sporadic and there is no standardized curriculum to guide educators. Previous studies show wide variation in CCUS training during fellowship across specialties but SCC has been underrepresented. This study was performed to assess SCC program directors' views regarding CCUS during fellowship training.

DESIGN

Adult SCC program directors were surveyed regarding the role of CCUS in fellowship training. This survey assessed how CCUS training was performed, perceived barriers to education, and importance of specific studies. Survey responses were measured using a Likert scale ranging from 5 (strongly agree) to 1 (strongly disagree).

SETTING

Web-based survey.

PARTICIPANTS

Adult Surgical Critical Care Fellowship Program Directors.

RESULTS

A total 67 of 108 (62%) SCC program directors responded to the survey. Over 75% felt that CCUS during training should be a priority. Fifteen (24.6%) programs required a specific number of ultrasounds to be performed. Five programs (7.5%) provided no CCUS training at all. Over 75% felt that training in FAST, transthoracic echocardiography, inferior vena cava assessment, and US for procedures (line placement, thoracentesis, and paracentesis) were either important or very important but experience in transesophageal echocardiography, assessment for deep vein thrombosis, and pulmonary US were not important. Lack of time (63.8%) and trained faculty (51.2%) were the most cited barriers to training.

CONCLUSIONS

There is a wide variation in how CCUS training is performed during SCC fellowship. SCC programs will need trained faculty, appropriate time allocation, and implementation of a standardized curriculum to provide consistent and high-quality CCUS education during fellowship.

Senior general surgery residents can be trained to perform focused assessment with sonography for trauma patients accurately

PURPOSES

Researchers studying trauma have found that physicians are able to perform a focused assessment with sonography for trauma (FAST) with minimal training and achieve ideal accuracy. However, there are currently no consensus or standard guidelines regarding the performance of this assessment. The aim of our study was to clarify the value of FAST performed by well-qualified senior general surgery residents in cases of suspected blunt abdominal trauma, which presents an important diagnostic problem in emergency departments.

METHODS

This was a retrospective study in the emergency department (ED) of our hospital performed from January 2011 to September 2013. Patients were included if they (1) had undergone a FAST examination performed by qualified residents and (2) had received subsequent formal radiographic or surgical evaluations. The results were compared against subsequent surgical findings or formal Department of Radiology reference standards.

RESULTS

Among the 438 patients enrolled, false-negative results were obtained in 8 and false-positive results in 5. Only one patient was missed and required laparotomy to repair a small intestine perforation. The sensitivity and specificity were 87 and 99%, respectively; the accuracy was 97%.

CONCLUSIONS

Senior general surgery residents can be trained to perform accurate FAST examinations on trauma patients.

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.

A Comparative Analysis of Diagnostic Accuracy of Focused Assessment With Sonography for Trauma Performed by Emergency Medicine and Radiology Residents

BACKGROUND

Focused assessment with sonography in trauma (FAST) is a method for prompt detection of the abdominal free fluid in patients with abdominal trauma.

OBJECTIVES

This study was conducted to compare the diagnostic accuracy of FAST performed by emergency medicine residents (EMR) and radiology residents (RRs) in detecting peritoneal free fluids.

PATIENTS AND METHODS

Patients triaged in the emergency department with blunt abdominal trauma, high energy trauma, and multiple traumas underwent a FAST examination by EMRs and RRs with the same techniques to obtain the standard views. Ultrasound findings for free fluid in peritoneal cavity for each patient (positive/negative) were compared with the results of computed tomography, operative exploration, or observation as the final outcome.

RESULTS

A total of 138 patients were included in the final analysis. Good diagnostic agreement was noted between the results of FAST scans performed by EMRs and RRs (κ = 0.701, P < 0.001), also between the results of EMRs-performed FAST and the final outcome (κ = 0.830, P < 0.0010), and finally between the results of RRs-performed FAST and final outcome (κ = 0.795, P < 0.001). No significant differences were noted between EMRs- and RRs-performed FASTs regarding sensitivity (84.6% vs 84.6%), specificity (98.4% vs 97.6%), positive predictive value (84.6% vs 84.6%), and negative predictive value (98.4% vs 98.4%).

CONCLUSIONS

Trained EMRs like their fellow RRs have the ability to perform FAST scan with high diagnostic value in patients with blunt abdominal trauma.

Focused abdominal sonography for trauma in the clinical evaluation of children with blunt abdominal trauma

Introduction

In pediatric care, the role of focused abdominal sonography in trauma (FAST) remains ill defined. The objective of this study was to assess the sensitivity and specificity of FAST for detecting free peritoneal fluid in children.

Methods

The trauma registry of a single level I pediatric trauma center was queried for the results of FAST examination of consecutive pediatric (<18 years) blunt trauma patients over a period of 36 months, from January 2010 to December 2012. Demographics, type of injuries, FAST results, computerized tomography (CT) results, and operative findings were reviewed.

Results

During the study period, 543 injured pediatric patients (mean age 8.2 ± 5 years) underwent FAST examinations. In 95 (17.5 %) FAST was positive for free peritoneal fluid. CT examination was performed in 219 (40.3 %) children. Positive FAST examination was confirmed by CT scan in 61/73 (83.6 %). CT detected intra-peritoneal fluid in 62/448 (13.8 %) of the patients with negative FAST results. These findings correspond to a sensitivity of 50 %, specificity of 88 %, positive predictive value (PPV) of 84 %, and a negative predictive value (NPV) of 58 %. In patients who had negative FAST results and no CT examination (302), no missed abdominal injury was detected on clinical ground. FAST examination in the young age group (<2 years) yielded lower sensitivity and specificity (36 and 78 % respectively) with a PPV of only 50 %.

Conclusions

This study shows that although a positive FAST evaluation does not necessarily correlate with an IAI, a negative one strongly suggests the absence of an IAI, with a high NPV. These findings are emphasized in the analysis of the subgroup of children less than 2 years of age. FAST examination tempered with sound clinical judgment seems to be an effective tool to discriminate injured children in need of further imaging evaluation.

Focused abdominal ultrasound for blunt trauma in an emergency department without advanced imaging or on-site surgical capability

Objectives:

To determine whether focused abdominal sonogram for trauma (FAST) in a rural hospital provides information that prompts immediate transfer to a tertiary care facility for patients with blunt abdominal trauma who would otherwise be discharged or held for observation.

Methods:

Prior to the study, participating emergency physicians underwent a minimum of 30 hours of ultrasound training. All patients who presented with blunt abdominal trauma to our rural hospital between Mar. 1, 2002, and Apr. 30, 2003, were eligible for study. Following a history and physical examination, the emergency physician documented his or her disposition decision. A FAST was then performed, and the disposition reconsidered in light of the FAST results.

Results:

Sixty-seven FAST exams were performed on 65 patients. Three examinations (4.5%) were true-positive (95% confidence interval [CI] 0.9%–12.5%); 60 (89.6%) were true-negative (95% CI 79.7%–95.7%), 4 (6%) were false-negative (95% CI 1.7%–14.6%) and none (0%) were false-positive (95% CI 0%–5.4%). These values reflect sensitivity, specificity, negative predictive value and positive predictive values of 43%, 100%, 94% and 100% respectively. FAST results did not alter the decision to transfer any patient (0%: 95% CI 0.0%–5.4%), although one positive FAST may have led to an expedited transfer. One of 38 patients who was discharged after a negative FAST study returned 24 hours later because of worsening symptoms, and was ultimately found to have splenic and pancreatic injuries.

Conclusions:

This study failed to demonstrate that FAST improves disposition decisions for patients with blunt abdominal trauma who are evaluated in a hospital without advanced imaging or on-site surgical capability. However, the study is not sufficiently powered to rule out a role for FAST in these circumstances, and our data suggest that up to 5.4% of transfer decisions could be influenced by FAST. Rural emergency physicians should not allow a negative FAST study to override a clinical indication for transfer to a trauma centre; however, positive FAST studies can be used to accelerate transfer for definitive treatment.

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.

Integrated medical school ultrasound: development of an ultrasound vertical curriculum

BACKGROUND

Physician-performed focused ultrasonography is a rapidly growing field with numerous clinical applications. Focused ultrasound is a clinically useful tool with relevant applications across most specialties. Ultrasound technology has outpaced the education, necessitating an early introduction to the technology within the medical education system. There are many challenges to integrating ultrasound into medical education including identifying appropriately trained faculty, access to adequate resources, and appropriate integration into existing medical education curricula. As focused ultrasonography increasingly penetrates academic and community practices, access to ultrasound equipment and trained faculty is improving. However, there has remained the major challenge of determining at which level is integrating ultrasound training within the medical training paradigm most appropriate.

METHODS

The Ohio State University College of Medicine has developed a novel vertical curriculum for focused ultrasonography which is concordant with the 4-year medical school curriculum. Given current evidenced-based practices, a curriculum was developed which provides medical students an exposure in focused ultrasonography. The curriculum utilizes focused ultrasonography as a teaching aid for students to gain a more thorough understanding of basic and clinical science within the medical school curriculum. The objectives of the course are to develop student understanding in indications for use, acquisition of images, interpretation of an ultrasound examination, and appropriate decision-making of ultrasound findings.

RESULTS

Preliminary data indicate that a vertical ultrasound curriculum is a feasible and effective means of teaching focused ultrasonography. The foreseeable limitations include faculty skill level and training, initial cost of equipment, and incorporating additional information into an already saturated medical school curriculum.

CONCLUSIONS

Focused ultrasonography is an evolving concept in medicine. It has been shown to improve education and patient care. The indications for and implementation of focused ultrasound is rapidly expanding in all levels of medicine. The ideal method for teaching ultrasound has yet to be established. The vertical curriculum in ultrasound at The Ohio State University College of Medicine is a novel evidenced-based training regimen at the medical school level which integrates ultrasound training into medical education and serves as a model for future integrated ultrasound curricula.

The role of focused abdominal sonography for trauma (FAST) in pediatric trauma evaluation

PURPOSE

With increasing concerns about radiation exposure, we questioned whether a structured program of FAST might decrease CT use.

METHODS

All pediatric trauma surgeons in our level 1 pediatric trauma center underwent formal FAST training. Children with potential abdominal trauma and no prior imaging were prospectively evaluated from 10/2/09 to 7/31/11. After physical exam and FAST, the surgeon declared whether the CT could be eliminated.

RESULTS

Of 536 children who arrived without imaging, 183 had potential abdominal trauma. FAST was performed in 128 cases and recorded completely in 88. In 48% (42/88) the surgeon would have elected to cancel the CT based on the FAST and physical exam. One of the 42 cases had a positive FAST and required emergent laparotomy; the others were negative. The sensitivity of FAST for injuries requiring operation or blood transfusion was 87.5%. The sensitivity, specificity, PPV, and NPV in detecting pathologic free fluid were 50%, 85%, 53.8%, and 87.9%.

CONCLUSIONS

True positive FAST exams are uncommon and would rarely direct management. While the negative FAST would have potentially reduced CT use due to practitioner reassurance, this reassurance may be unwarranted given the test's sensitivity.

To determine the accuracy of focused assessment with sonography for trauma done by nonradiologists and its comparative analysis with radiologists in emergency department of a level 1 trauma center of India

Background:

Focused assessment with sonography for trauma (FAST) is an important skill during trauma resuscitation. Use of point of care ultrasound among the trauma team working in emergency care settings is lacking in India.

Objective:

To determine the accuracy of FAST done by nonradiologists (NR) when compared to radiologists during primary survey of trauma victims in the emergency department of a level 1 trauma center in India.

Materials and Methods:

A prospective study was done during primary survey of resuscitation of nonconsecutive patients in the resuscitation bay. The study subjects included NR such as one consultant emergency medicine, two medicine residents, one orthopedic resident and one surgery resident working as trauma team. These subjects underwent training at 3-day workshop on emergency sonography and performed 20 supervised positive and negative scans for free fluid. The FAST scans were first performed by NR and then by radiology residents (RR). The performers were blinded to each other's sonography findings. Computed tomography (CT) and laparotomy findings were used as gold standard whichever was feasible. Results were compared between both the groups. Intraobserver variability among NR and RR were noted.

Results:

Out of 150 scans 144 scans were analyzed. Mean age of the patients was 28 [1-70] years. Out of 24 true positive patients 18 underwent CT scan and exploratory laparotomies were done in six patients. Sensitivity of FAST done by NR and RR were 100% and 95.6% and specificity was 97.5% in both groups. Positive predictive value among NR and RR were 88.8%, 88.46% and negative predictive value were 97.5% and 99.15%. Intraobserver performance variation ranged from 87 to 97%.

Conclusion:

FAST performed by NRs is accurate during initial trauma resuscitation in the emergency department of a level 1 trauma center in India.

Development and evaluation of a novel, real time mobile telesonography system in management of patients with abdominal trauma: study protocol

BACKGROUND

Despite the use of e-FAST in management of patients with abdominal trauma, its utility in prehospital setting is not widely adopted. The goal of this study is to develop a novel portable telesonography (TS) system and evaluate the comparability of the quality of images obtained via this system among healthy volunteers who undergo e-FAST abdominal examination in a moving ambulance and at the ED. We hypothesize that: (1) real-time ultrasound images of acute trauma patients in the pre-hospital setting can be obtained and transmitted to the ED via the novel TS system; and (2) Ultrasound images transmitted to the hospital from the real-time TS system will be comparable in quality to those obtained in the ED.

METHODS

Study participants are three healthy volunteers (one each with normal, overweight and obese BMI category). The ultrasound images will be obtained by two ultrasound-trained physicians The TS is a portable sonogram (by Sonosite) interfaced with a portable broadcast unit (by Live-U). Two UTPs will conduct e-FAST examinations on healthy volunteers in moving ambulances and transmit the images via cellular network to the hospital server, where they are stored. Upon arrival in the ED, the same UTPs will obtain another set of images from the volunteers, which are then compared to those obtained in the moving ambulances by another set of blinded UTPs (evaluators) using a validated image quality scale, the Questionnaire for User Interaction Satisfaction (QUIS).

DISCUSSION

Findings from this study will provide needed data on the validity of the novel TS in transmitting live images from moving ambulances to images obtained in the ED thus providing opportunity to facilitate medical care of a patient located in a remote or austere setting.

Use of ultrasonography by veterinary surgeons in small animal clinical emergencies

Computed tomography may be the imaging modality of choice for diagnosing haemorrhage after trauma; however, it has limited availability in veterinary medicine, requires sedation or anaesthesia to restrain the animal, and is expensive. Ultrasound, in many situations, offers a portable, rapid and economic alternative. This article reviews the use of ultrasound by veterinary surgeons in the emergency setting. Both thoracic and abdominal applications are described.

Diagnostic accuracy of focused assessment with sonography for trauma (FAST) examinations performed by emergency medical technicians

OBJECTIVE

We aimed to assess the diagnostic accuracy of focused assessment with sonography for trauma (FAST) examinations when used by emergency medical technicians (EMTs) to detect the presence of free abdominal fluid.

METHODS

Six level 1 EMTs (similar to intermediate EMTs in the United States) who worked at a tertiary emergency department in Korea underwent an educational program consisting of two one-hour didactic lectures that included the principles of ultrasonography, the anatomy of the abdomen, and two hours of hands-on practice. After this educational session, the EMTs performed FAST examinations on a convenience sample of patients from July 1 to October 5, 2009. These patients also received an abdominal computed tomography (CT) scan regardless of their chief complaints. The CT findings served as the definitive standard and were interpreted routinely and independently by emergency radiologists who were blinded to the study protocol. In addition, the EMTs were blinded to the CT findings. A positive CT finding was defined as the presence of free fluid, as interpreted by the radiologist. The sensitivity, specificity, predictive values, and their 95% confidence intervals (CIs) were calculated. Informed consent was obtained from all participating patients.

RESULTS

Among the 1,060 eligible patients with abdominal CT scans, 403 patients were asked to participate in the study, and 240 patients agreed. Of these 240 patients, 80 (33.3%) had results showing the presence of free fluid. Fourteen patients had a significant amount of peritoneal cavity fluid, 15 had a moderate amount of peritoneal cavity fluid, and 51 had a minimal amount of peritoneal cavity fluid. Compared with the CT findings, the diagnostic performance of the FAST examination had a sensitivity of 61.3% (95% CI, 50.3%-71.2%), specificity of 96.3% (95% CI, 92.1%-98.3%), positive predictive value of 89.1% (95% CI, 77.0%-95.4%), and negative predictive value of 83.2% (95% CI, 76.9%-88.2%). For a significant or moderate amount of peritoneal cavity fluid, the sensitivity was considerably higher (86.2%).

CONCLUSION

EMTs in Korea showed a high diagnostic performance that was comparable to that of surgeons and physicians when detecting peritoneal cavity free fluid in a Korean emergency department setting. The validity of FAST examinations in prehospital care situations should be investigated further.

Review article: Use of ultrasound in the developing world

As portability and durability improve, bedside, clinician-performed ultrasound is seeing increasing use in rural, underdeveloped parts of the world. Physicians, nurses and medical officers have demonstrated the ability to perform and interpret a large variety of ultrasound exams, and a growing body of literature supports the use of point-of-care ultrasound in developing nations. We review, by region, the existing literature in support of ultrasound use in the developing world and training guidelines currently in use, and highlight indications for emergency ultrasound in the developing world. We suggest future directions for bedside ultrasound use and research to improve diagnostic capacity and patient care in the most remote areas of the globe.

Comparison of a multimedia simulator to a human model for teaching FAST exam image interpretation and image acquisition

OBJECTIVES

This study compared the effectiveness of a multimedia ultrasound (US) simulator to normal human models during the practical portion of a course designed to teach the skills of both image acquisition and image interpretation for the Focused Assessment with Sonography for Trauma (FAST) exam.

METHODS

This was a prospective, blinded, controlled education study using medical students as an US-naïve population. After a standardized didactic lecture on the FAST exam, trainees were separated into two groups to practice image acquisition on either a multimedia simulator or a normal human model. Four outcome measures were then assessed: image interpretation of prerecorded FAST exams, adequacy of image acquisition on a standardized normal patient, perceived confidence of image adequacy, and time to image acquisition.

RESULTS

Ninety-two students were enrolled and separated into two groups, a multimedia simulator group (n = 44), and a human model group (n = 48). Bonferroni adjustment factor determined the level of significance to be p = 0.0125. There was no difference between those trained on the multimedia simulator and those trained on a human model in image interpretation (median 80 of 100 points, interquartile range [IQR] 71-87, vs. median 78, IQR 62-86; p = 0.16), image acquisition (median 18 of 24 points, IQR 12-18 points, vs. median 16, IQR 14-20; p = 0.95), trainee's confidence in obtaining images on a 1-10 visual analog scale (median 5, IQR 4.1-6.5, vs. median 5, IQR 3.7-6.0; p = 0.36), or time to acquire images (median 3.8 minutes, IQR 2.7-5.4 minutes, vs. median = 4.5 minutes, IQR = 3.4-5.9 minutes; p = 0.044).

CONCLUSIONS

There was no difference in teaching the skills of image acquisition and interpretation to novice FAST examiners using the multimedia simulator or normal human models. These data suggest that practical image acquisition skills learned during simulated training can be directly applied to human models.

Assessment of a training curriculum for emergency ultrasound for pediatric soft tissue infections

OBJECTIVES

The objective was to evaluate a training protocol for pediatric emergency physicians (EPs) learning emergency ultrasound (EUS) for the evaluation of skin and soft tissue infections (SSTIs) by assessing technical ability and interrater reliability.

METHODS

Pediatric emergency medicine (EM) fellows and attending physicians completed a 1-day training course taught by an expert emergency sonologist. After the course, EPs performed proctored examinations on patients with SSTIs until they reached predefined performance criteria, after which they performed independent EUS examinations. All EUS examinations were recorded using still images and video clips that were reviewed and rated by the expert sonologist on four technical measures and combined into a composite score. The expert's opinion regarding the presence or absence of an abscess was also compared to the study sonologist's opinion and analyzed for interrater reliability.

RESULTS

Seven EPs performed 107 EUS examinations. The mean (±SD) composite score for the evaluation of technical ability for the first EUS was 3.3 ± 0.14 (on a 4-point scale), indicating a high level of quality following the training course. There was a small amount of improvement in the quality score (0.015, 95% confidence interval [CI] = 0.0003 to 0.03) with each consecutive EUS examination. The interrater reliability between the sonologist and the expert for the presence of an abscess as measured by the kappa statistic was 0.80 (95% CI = 0.63 to 0.97), indicating substantial agreement.

CONCLUSIONS

After a brief training program, pediatric EPs can perform technically successful emergency EUS examination of SSTIs, with excellent agreement with an expert sonologist.

Potential role of ultrasound in anesthesia and intensive care

One of the most exiting recent technological advances in the field of anesthesia to track the region of interest is the introduction of anatomical evaluation by ultrasound imaging. Widespread use of this modality depends on its proven clinical efficacy, cost effectiveness, and practicality as it allows anesthesiologist to evaluate complex and varied anatomy prior to needle insertion. Sound used in medicine is not significantly transmitted by air or bone but through fluids which make up the larger part of soft tissues in the body. Ultrasound has been shown to offer excellent guidance for difficult venous access, epidural space identification in cases of difficult anatomy, delineating nerve plexuses for chronic nerve blocks, for regional anesthesia, and in transesophageal echocardiography for cardiac imaging with blood flows or in an otherwise high-risk patient where interventional procedure is required. It has special application to assess the narrowest diameter of the subglottic upper airway. A systemic literature search was performed in PubMed and the Cochrane library. The search strategy was set up using either single text word or combinations. We also included the studies where in these techniques were compared with conventional methods . Despite the initial excitement of this technique, ultrasound visualization is still indirect and images are subject to individual interpretation. It is gradually becoming routine in daily practice at our institution due to its reliability and safety. Though ultrasound is much safer, exposure in terms of intensity and time should be limited as far as possible, as high-energy ultrasound can cause heating and damage to tissues. In this review, we discuss established and future areas of ultrasound imaging and emphasize the use of B-mode ultrasound to improve the efficacy of interventional techniques. We have also illustrated potential uses with reference to cross-sectional B-mode images which visually represent a slice of tissues and are the easiest images for interpretation by clinicians.

How long does it take to perform emergency ultrasound for the primary indications?

Purpose

Although emergency ultrasound (EU) is gaining popularity, EU is performed in a minority of emergency departments (EDs). The perception may exist that EU is too time-consuming. This study sought to determine the duration of EUs performed for the primary indications by staff emergency physicians (EPs).

Methods

A prospective, time–motion study was conducted on a convenience sample of EUs at the Sudbury Regional Hospital ED from June to August 2006. All EPs had Canadian EU certification. A research assistant timed EUs. Primary EU indications in Canada are: cardiac arrest evaluation, rule-out pericardial effusion, rule-out intraperitoneal free fluid in trauma, rule-out abdominal aortic aneurysm, and rule-in intrauterine pregnancy. Descriptive statistics are reported.

Results

Eleven EPs performed 66 EUs for the primary indications on 51 patients. The mean EU duration was 137.8 s (range 11–465; CI 123.0–162.6). There was no difference in the duration of EUs performed by the two most experienced EPs (n = 37; duration = 129.4; CI = 96.4–162.4) compared to the other EPs (n = 29; duration = 148.4; CI = 110.6–186.2). Although subgroups were small, positive (n = 8; duration = 199.4; CI = 97.4–301.4), negative (n = 49; duration = 123.3; CI = 97.9–148.7), and indeterminate (n = 9; duration = 161.6; CI = 91.5–231.7) EUs did not differ in duration. There is some suggestion of differences in duration between types of EU, although again the subgroups were small: cardiac (n = 21; duration = 90.3; CI = 62.6–118.0), abdominal (n = 22; duration = 157.1; CI = 111.9–202.3), aneurysm (n = 15; duration = 170.1; CI = 117.5–222.7), transabdominal pelvic (n = 5; duration = 89.8; CI = 40.3–139.1), transvaginal (n = 3; duration = 246.0; CI = 30.6–461.4).

Conclusion

When performed by staff EPs with EU certification, mean EU duration for the primary indications was brief regardless of EP’s experience, EU type, or results.

Improved patient management with point-of-care ultrasound

Point-of-care ultrasound (PoCUS) is an examination often performed at the bedside that can assist in patient assessment and answer focused questions. It is increasingly used by a number of specialties to aid invasive procedures and for clinical evaluation, with the ultimate aim of improving patient management. Although there is a paucity of robust evidence supporting some applications, it is gaining popularity and has been termed the ‘new stethoscope’. Good clinical governance arrangements, especially with regard to training and competency, are key to this modality developing further and safely.

An Evidence-Based Approach for Integrating Bedside Ultrasound Into Routine Practice in the Assessment of Undifferentiated Shock

Undifferentiated hypotension remains a central diagnostic and therapeutic challenge in emergency and critical care medicine. Increasingly, bedside ultrasound conducted by intensivists and emergency medicine providers is assuming a central role in diagnosis and resuscitation of hypotension. This review discusses sample algorithms for the bedside ultrasonographic assessment of undifferentiated shock and outlines an evidence-based framework for the intensivist seeking to incorporate bedside ultrasound into daily clinical practice. The literature regarding specific applications including cardiac, thoracic, pulmonary, and vascular assessment is briefly reviewed, as is the evidence pertaining to effective implementation, training, credentialing, and ongoing quality assurance.

Ultrasound in trauma

Point-of-care ultrasound is well suited for use in the emergency setting for assessment of the trauma patient. Currently, portable ultrasound machines with high-resolution imaging capability allow trauma patients to be imaged in the pre-hospital setting, emergency departments and operating theatres. In major trauma, ultrasound is used to diagnose life-threatening conditions and to prioritise and guide appropriate interventions. Assessment of the basic haemodynamic state is a very important part of ultrasound use in trauma, but is discussed in more detail elsewhere. Focussed assessment with sonography for Trauma (FAST) rapidly assesses for haemoperitoneum and haemopericardium, and the Extended FAST examination (EFAST) explores for haemothorax, pneumothorax and intravascular filling status. In regional trauma, ultrasound can be used to detect fractures, many vascular injuries, musculoskeletal injuries, testicular injuries and can assess foetal viability in pregnant trauma patients. Ultrasound can also be used at the bedside to guide procedures in trauma, including nerve blocks and vascular access. Importantly, these examinations are being performed by the treating physician in real time, allowing for immediate changes to management of the patient. Controversy remains in determining the best training to ensure competence in this user-dependent imaging modality.

Establishing the evidence base for trauma quality improvement: a collaborative WHO-IATSIC review

BACKGROUND

Quality improvement (QI) programs are an integral part of well-developed trauma systems. However, they have not been extensively implemented globally. To promote greater use of effective QI programs, the World Health Organization (WHO) and the International Association for Trauma Surgery and Intensive Care (IATSIC) have been collaboratively developing the upcoming Guidelines for Trauma Quality Improvement Programmes. As part of the development of this publication and to satisfy global demands for WHO guidelines to be evidence based, we conducted a thorough literature search on the effectiveness of trauma QI programs.

METHODS

The review was based on a PubMed search of all articles reporting an outcome from a trauma QI program.

RESULTS

Thirty-six articles were identified that reported results of evaluations of a trauma QI program or in which the trauma QI program was integrally related to identification and correction of specific problems. Thirteen of these articles reported on mortality as their main outcome; 12 reported on changes in morbidity (infection rates, complications), patient satisfaction, costs, or other outcomes of tangible patient benefit; and 11 reported on changes in process of care. Thirty articles addressed hospital-based care; four system-wide care; and two prehospital care. Thirty-four articles reported an improvement in the outcome assessed; two reported no change; and none reported worsening of the outcome. Five articles also reported cost savings.

CONCLUSIONS

Trauma QI programs are consistently shown to improve the process of care, decrease mortality, and decrease costs. Further efforts to promote trauma QI globally are warranted. These findings support the further development and promulgation of the WHO-IATSIC Guidelines for Trauma QI Programmes.

[The value of sonography in traumatology and orthopedics : Part 2: emergency diagnostics in blunt abdominal and thoracic trauma]

Ultrasound examinations in trauma patients should be done in the emergency department using curved-array (3.5-7.5 MHz) probes. Blunt trauma of the abdomen and thorax must be regarded as a single organ injury. Sonography is the imaging technique of first choice and has completely replaced peritoneal lavage. Paramount advantages are its ability to provide rapid information and reproducible results at short intervals and in a noninvasive manner. The sensitivity and specificity of sonography in detecting intraabdominal fluid are 97-100% and 80-90%, respectively. To achieve such good results, though, adequate education in ultrasound and state-of-the-art devices is crucial. Clinical experiences prove that standardized sonography must be part of polytrauma management and should be integrated in advanced trauma life support courses. Technical improvements with better image quality and miniaturization of hardware will contribute to increase the use of this technique. However, ultrasound does not replace computed tomography for follow-up in answering more sophisticated questions in multiple injured patients.

Focussed Assessment Sonograph Trauma (FAST) and CT scan in blunt abdominal trauma: surgeon's perspective

BACKGROUND

Diagnosis of blunt abdominal trauma is a real challenge even for experienced trauma surgeons. Diagnostic tools that help the treating doctor in optimum management of blunt abdominal trauma include; Focussed Assessment Sonography for Trauma (FAST), Diagnostic peritoneal lavage (DPL) and CT scan.

OBJECTIVES

the aim of this communication is to define the recent role of FAST and CT scan of the abdomen in the diagnosis of blunt abdominal trauma.

FINDINGS AND CONCLUSIONS

FAST is useful as the initial diagnostic tool for abdominal trauma to detect intraabdominal fluid. With proper training and understanding the limitations of ultrasound, the results of FAST can be optimized. DPL is indicated to diagnose suspected internal abdominal injury when ultrasound machine is not available, there is no trained person to perform FAST, or the results of FAST are equivocal or difficult to interpret in a haemodynamically unstable patient. In contrast, in haemodynamically stable patients the diagnostic modality of choice is CT with intravenous contrast. It is useful to detect free air and intraperitoneal fluid, delineate the extent of solid organ injury, detect retroperitoneal injuries, and help in the decision for conservative treatment. Helical CT is done rapidly which reduces the time the patient stays in the CT scan room. Furthermore, this improves sagittal and coronal reconstruction images which are useful for detecting ruptured diaphragm.

Focused bedside ultrasonography by clinicians: experiences with a basic introductory course

OBJECTIVE

Ultrasonography (US) performed by clinicians might shorten workout time and diminish the workload of simple diagnostic procedures for physicians specialized in US. The purpose of this follow-up study was to evaluate the effect of an introductory course in US on participants' clinical behaviour and course compliance.

MATERIAL AND METHODS

The course consisted of a combined didactic, hands-on, one-day course including a skills test and a review of 20 still-pictures of pathological findings for final authorization. A questionnaire focusing on pre- and post-course activity and its impact on clinical behaviour was sent to 162 participants.

RESULTS

The response rate was 64% (103). Forty-eight (47%) participants changed their clinical approach, 45 (44%) their workout programme and 25 (24%) the pattern of referral. Eleven (10%) sent in the required pathological findings for final authorization. Thirty-four (33%) participants did not carry out US after the course; 19 did not have access to US apparatus, 7 claimed that they lacked the time, 6 lacked supervision and 1 participant cited insufficiency of the course. Clinical approach was changed by 48 (47%), acute workout by 45 (44%) and pattern of referral by 24 (23%).

CONCLUSIONS

Clinicians appear to be ready to change the patterns of their workout programmes and clinical approach after a combined didactic and hands-on introduction to US, but only 10% produced the recommended documentation for authorization. National guidelines need to be introduced for gastroenterologists and surgeons or the European Federation of Societies for Ultrasound in Medicine and Biology Guidelines should be implemented.

Current Role of Emergency US in Patients with Major Trauma

In patients with major trauma, focused abdominal ultrasonography (US) often is the initial imaging examination. US is readily available, requires minimal preparation time, and may be performed with mobile equipment that allows greater flexibility in patient positioning than is possible with other modalities. It also is effective in depicting abnormally large intraperitoneal collections of free fluid, which are indirect evidence of a solid organ injury that requires immediate surgery. However, because US has poor sensitivity for the detection of most solid organ injuries, an initial survey with US often is followed by a more thorough examination with multidetector computed tomography (CT). The initial US examination is generally performed with a FAST (focused assessment with sonography in trauma) protocol. Speed is important because if intraabdominal bleeding is present, the probability of death increases by about 1% for every 3 minutes that elapses before intervention. Typical sites of fluid accumulation in the presence of a solid organ injury are the Morison pouch (liver laceration), the pouch of Douglas (intraperitoneal rupture of the urinary bladder), and the splenorenal fossa (splenic and renal injuries). FAST may be used also to exclude injuries to the heart and pericardium but not those to the bowel, mesentery, and urinary bladder, a purpose for which multidetector CT is better suited. If there is time after the initial FAST survey, the US examination may be extended to extra-abdominal regions to rule out pneumothorax or to guide endotracheal intubation, vascular puncture, or other interventional procedures.

Ultrasound-Guided Internal Jugular Access

In 2001, the Agency for Healthcare Research and Quality recommended the use of ultrasound for the placement of central venous catheters (CVCs) as one of their 11 practices to improve patient care. These recommendations were based on the results of several randomized clinical trials showing significantly improved overall success as well as reductions in complications. This article will describe the practical aspects of using ultrasound to guide placement of CVCs in the internal jugular vein in a "how I do it" approach, as well as review the practice management and training aspects related to incorporating ultrasound into daily practice.

Focused ultrasound training for clinicians

Clinician use of diagnostic ultrasound, particularly at point of care and in emergency situations, is well established. The standard of training courses and of postcourse supervision and accreditation is variable, and international standards are required to maintain safety, accuracy, and credibility of the technique. The accuracy of the technique by trained personnel has been well documented. There is evidence that prereading, a course involving theoretical and practical training, and ongoing mentoring (proctoring) provides high standards of practice. Regular accreditation and continuous comparison with gold standards is required to maintain this level. Most areas of the body are now accessible to clinicians of varied specialties, even those previously thought impossible for ultrasound examination, such as the chest and bone. Training and supervision in rural, remote, and austere environments provides added challenges.

Abdominal injuries

This article will give an overview of abdominal trauma and provide a broad framework for the initial management of injuries to the abdomen. Abdominal injury carries a high morbidity and mortality in all age groups, therefore a sound understanding of the patterns of injury, examination, investigations and resuscitation procedures is vital to the trauma surgeon's armamentarium.

A bedside ultrasound curriculum for medical students: prospective evaluation of skill acquisition

OBJECTIVE

We conducted a study to evaluate the efficacy of an introductory ultrasound (US) curriculum for medical students rotating through our emergency department.

MATERIALS AND METHODS

Third- and 4th-year medical students indicated their previous US experience and were given a pretest consisting of static US images to assess baseline interpretation skills. They participated in a 45-min interactive didactic session followed by a 45-min session of hands-on experience practicing real-time US image acquisition on a normal model. After this session, we tested the timing and quality of their image acquisition skills on a separate normal model. Quality of images was based on a point value from 0 to 2 per image. This was followed by a posttest of static US images, which was graded in the same manner as the pretest.

RESULTS

Thirty-one students participated in the study. Median time to acquire 2 images was 112.5 sec (range = 15420 sec). Acquisition time was unaffected by previous experience (p = .97). The mean score on the quality of 2 images (maximum score = 4) was 3.84; median was 4 (range = 14). Image quality was significantly better in participants with previous US experience (p = .014). Scores on interpretation of static images improved significantly from pretest to posttest by a median of 8.25 points (p = .0001).

CONCLUSION

Our introductory US course is effective at significantly improving medical students' interpretation of static US images. The majority of students were able to acquire high quality images in a short period of time after this session.

The accuracy of focused assessment with sonography in trauma (FAST) in blunt trauma patients: experience of an Australian major trauma service

Focused assessment with sonography for trauma (FAST) is a method for detecting haemoperitoneum in trauma patients on initial assessment in the Emergency Department. The aim of this paper is to present an Australian trauma centre's experience with FAST as a tool to screen for intraabdominal free fluid in patient's sustaining blunt truncal trauma.

METHOD

Over a 63-month period, FAST scans were prospectively studied and compared with findings from a gold-standard investigation, either computed tomography (CT) or laparotomy.

RESULTS

463 FAST results were collected prospectively from 463 patients. 53 scans were excluded due to lack of a corresponding confirmatory gold-standard test. Overall sensitivity, specificity, positive and negative predictive values for FAST in detecting free fluid were 78%, 97%, 91%, 93%, respectively. Analysis of the credentialed operators demonstrated an improvement in accuracy (sensitivity 80%, specificity 100%, positive predictive value 100%, negative predictive value 94%). These findings are comparable with documented international experience.

CONCLUSION

The study demonstrates that the use of non-radiologist performed FAST in the detection of free fluid is safe and accurate within an Australian Trauma Centre.

Physical examination as a reliable tool to predict intra-abdominal injuries in brain-injured children

BACKGROUND

Brain-injured children have been thought to have an unreliable abdominal examination. This study evaluates the reliability of physical examination in the prediction of intra-abdominal injury in brain-injured children.

METHODS

Pediatric patients with a traumatic brain injury or Glasgow Coma Scale (GCS) <15 and intra-abdominal organ injuries were selected. Admission data were reviewed, and findings were tabulated.

RESULTS

Fifty patients had an abnormal abdominal examination. Nineteen of 71 patients with head injury and intra-abdominal organ injuries required laparotomy. These 19 patients had abdominal tenderness, distention, abrasions, and/or a positive focused abdominal sonography for trauma (FAST) scan. Seven of 19 patients had a GCS of 3. Of the 12 patients requiring surgery with GSC 4 to 14, all patients had abnormal physical examinations.

CONCLUSIONS

Patients who required an operation presented with an abnormal examination and/or a positive FAST. These data suggest that examination and/or FAST may reliably identify patients with intra-abdominal organ injuries in need of an operation.

[Medical imaging in the management of abdominal trauma]

There is a marked trend toward nonoperative management of abdominal trauma. This has been possible thanks to the advances in imaging and interventional techniques. Computed tomography (CT), angiography, and endoscopic retrograde cholangiopancreatography (ERCP) can guide the nonoperative management of abdominal trauma.