A Potential Pitfall of Using Focused Assessment With Sonography for Trauma in Pediatric Trauma

Prospective studies have shown sensitivities of 73% to 88% and specificities of 98% to 100% for using the focused assessment with sonography for trauma (FAST) examination to identify free fluid in adult trauma patients. However, the efficacy of FAST examinations for pediatric trauma patients has not been well defined, and studies looking at diagnostic performance have had varied results. We describe 3 cases of the potential pitfalls of the pediatric FAST examination in pediatric trauma patients using an advanced‐processing ultrasound machine. We hypothesize several etiologies for these false‐positive findings in the setting of advanced image‐processing capabilities of point‐of‐care ultrasound. We also discuss the reevaluation of clinical algorithms and interpretation practices when using the FAST examination in pediatric trauma.     

FAST (Focused Assessment With Sonography in Trauma) Accurate for Cardiac and Intraperitoneal Injury in Penetrating Anterior Chest Trauma

Objective. To evaluate the FAST (focused assessment with sonography in trauma) examination for determining traumatic pericardial effusion and intraperitoneal fluid indicative of injury in patients with penetrating anterior chest trauma. Methods. An observational prospective study was conducted over a 30‐month period at an urban level I trauma center. FAST was performed in the emergency department by emergency physicians and trauma surgeons. FAST results were recorded before review of patient outcome as determined by 1 or more of the following: thoracotomy, laparotomy, pericardial window, cardiologic echocardiography, diagnostic peritoneal lavage, computed tomography, and serial examinations. Results. FAST was undertaken in 32 patients with penetrating anterior chest trauma: 20 (65%) had stab wounds, and 12 (35%) had gunshot wounds. Sensitivity of FAST for cardiac injury (n = 8) in patients with pericardial effusion was 100% (95% confidence interval, 63.1%–100%); specificity was 100% (95% confidence interval, 85.8%–100%). The presence of pericardial effusion determined by FAST correlated with the need for thoracotomy in 7 (87.5%) of 8 patients (95% confidence interval, 47.3%–99.7%). One patient with a pericardial blood clot on cardiologic echocardiography was treated nonsurgically. FAST had 100% sensitivity for intraperitoneal injury (95% confidence interval, 63.1%–100%) in 8 patients with views indicating intraperitoneal fluid but without pericardial effusion, again with no false‐positive results, giving a specificity of 100% (95% confidence interval, 85.8%–100%). This prompted necessary laparotomy in all 8. Conclusions. In this series of patients with penetrating anterior chest trauma, the FAST examination was sensitive and specific in the determination of both traumatic pericardial effusion and intraperitoneal fluid indicative of injury, thus effectively guiding emergent surgical decision making.     

Image Segmentation and Machine Learning for Detection of Abdominal Free Fluid in Focused Assessment With Sonography for Trauma Examinations

The objective of this pilot study was to test the feasibility of automating the detection of abdominal free fluid in focused assessment with sonography for trauma (FAST) examinations. Perihepatic views from 10 FAST examinations with positive results and 10 FAST examinations with negative results were used. The sensitivity and specificity compared to manual classification by trained physicians was evaluated. The sensitivity and specificity (95% confidence interval) were 100% (69.2%–100%) and 90.0% (55.5%–99.8%), respectively. These findings suggest that computerized detection of free fluid on abdominal ultrasound images may be sensitive and specific enough to aid clinicians in their interpretation of a FAST examination.     

The Focused Abdominal Sonography for Trauma (FAST) Examination: Considerations and Recommendations for Training Physicians in the Use of a New Clinical Tool

Focused abdominal sonography for trauma (FAST) is being used by growing numbers of emergency physicians and surgeons because it has proven to be an accurate, rapid, and repeatable bedside test for evaluating abdominal trauma victims. Controversy exists about the optimal means of FAST education and the number of examinations necessary to demonstrate competency. Most FAST educators agree that FAST education should consist of three phases: didactic, practical, and experiential. This article summarizes options and preliminary recommendations suitable for developing a FAST curriculum.     

The Double-Line Sign: A False Positive Finding on the Focused Assessment with Sonography for Trauma (FAST) Examination

Background: Emergency physicians commonly perform Focused Assessment with Sonography for Trauma (FAST) examinations to evaluate for free intraperitoneal fluid. Many ultrasound findings can be misinterpreted as free fluid, resulting in false-positive FAST examinations. Objectives: To describe a previously unreported ultrasound finding that can be misinterpreted as free intraperitoneal fluid. Case Report: A 32-year-old man was stabbed in the left upper abdomen. A FAST examination was performed and a right perinephric fat pad was interpreted as showing free fluid in Morison's pouch. After transfer to a trauma center, a repeat FAST examination revealed no signs of intraperitoneal free fluid. Wound exploration showed no signs of penetration into the peritoneal cavity. Conclusions: When performing a FAST examination, a wedge-shaped hypoechoic area in Morison's pouch that is bounded on both sides by echogenic lines (the “FAST Double-Line Sign”) is likely to represent perinephric fat and may result in a false-positive FAST examination.     

Tele-ultrasound and paramedics: real-time remote physician guidance of the Focused Assessment With Sonography for Trauma examination

Objectives

The aim of this study was to examine the capability of ultrasound-naïve paramedics to obtain interpretable Focused Assessment With Sonography for Trauma (FAST) images under the remote direction of emergency physicians (EPs).

Methods

Paramedics without experience using ultrasound participated in a 20-minute lecture covering orientation to the ultrasound machine and the FAST examination. The paramedics subsequently performed FAST examinations on a model patient, whereas the EP remained in another room, out of visual contact. The EP communicated with the paramedic via radio, viewing video from the ultrasound machine on a monitor and directing the probe movements to obtain the views of the FAST examination. We examined the success rate, time to complete the examinations, and adequacy of images from the paramedics' first FAST examination.

Results

Fifty-one paramedics performed their first FAST examinations and were able to successfully complete 100% of the views of the FAST. The median time from probe placement to examination completion was 262 seconds (interquartile range, 206-343 seconds). The median time to complete right upper quadrant (RUQ) versus left upper quadrant (LUQ) views was 39 and 50 seconds, respectively. The time to complete the LUQ scan took significantly longer than the RUQ (P < .01). Paramedics completed cardiac and pelvic view in a median time of 42 and 25 seconds, respectively.

Conclusions

The study demonstrated that paramedics with no prior ultrasound experience could obtain FAST images under remote guidance from experienced EPs in less than 5 minutes. Given rapidly evolving data transmission technology, this has applicability in battlefield, remote, and rural prehospital settings.     

Sonographic Detection of Pneumothorax by Radiology Residents as Part of Extended Focused Assessment With Sonography for Trauma

Objective. The purpose of this study was to assess the accuracy of sonographic pneumothorax detection by radiology residents as a part of extended focused assessment with sonography for trauma (eFAST). Methods. In a prospective study, a sonographic search for pneumothoraces was performed as part of a standard FAST examination by the on‐call resident. Each lung field was scanned at the second to fourth anterior intercostal spaces and the sixth to eighth midaxillary line intercostal spaces. A normal pleural interface was identified by the presence of parietal‐over‐visceral pleural sliding with “comet tail” artifacts behind. Absence of these normal features indicated a pneumothorax. The sonographic diagnosis was correlated with supine chest radiography and chest computed tomography (CT). Results. A total of 338 lung fields in 169 patients were included in the study. Patients underwent eFAST, chest radiography, and chest CT when clinically indicated. Chest CT was considered the reference standard examination. Computed tomography identified 43 pneumothoraces (13%): 34 small and 9 moderate. On chest radiography, 7 pneumothoraces (16%) were identified. Extended FAST identified 23 pneumothoraces (53%). Compared with CT, eFAST had sensitivity of 47%, specificity of 99%, a positive predictive value of 87%, and a negative predictive value of 93%. All of the moderate pneumothoraces were identified by eFAST. Twenty small pneumothoraces missed by eFAST did not require drainage during the hospitalization period. Conclusions. Extended FAST performed by residents is an accurate and efficient tool for early detection of clinically important pneumothoraces.     

Ultrasonographic Determination of Pubic Symphyseal Widening in Trauma: The FAST-PS Study

Background: The focused abdominal sonography in trauma (FAST) examination is a routine component of the initial work-up of trauma patients. However, it does not identify patients with retroperitoneal hemorrhage associated with significant pelvic trauma. A wide pubic symphysis (PS) is indicative of an open book pelvic fracture and a high risk of retroperitoneal bleeding. Study Objectives: We hypothesized that an ultrasound image of the PS as part of the FAST examination (FAST-PS) would be an accurate method to determine if pubic symphysis diastasis was present. Methods: This is a comparative study of a diagnostic test on a convenience sample of 23 trauma patients at a Level 1 Trauma Center. The PS was measured sonographically in the Emergency Department (ED) and post-mortem (PM) at the State Medical Examiner. The ultrasound (US) measurements were then compared with PS width on anterior-posterior pelvis radiograph. Results: Twenty-three trauma patients were evaluated with both plain radiographs and US (11 PM, 12 ED). Four patients had radiographic PS widening (3 PM, 1 ED) and 19 patients had radiographically normal PS width; all were correctly identified with US. US measurements were compared with plain X-ray study by Bland-Altman plot. With one exception, US measurements were within 2 standard deviations of the radiographic measurements and, therefore, have excellent agreement. The only exception was a patient with pubic symphysis wider than the US probe. Conclusion: Bedside ultrasound examination may be able to identify pubic symphysis widening in trauma patients. This potentially could lead to faster application of a pelvic binder and tamponade of bleeding.     

The Association of Prehospital Intravenous Fluids and Mortality in Patients with Penetrating Trauma

Background

The optimal approach to prehospital care of trauma patients is controversial, and thought to require balancing advanced field interventions with rapid transport to definitive care.

Systematic Sonography for Detection of Occult Wounds in Trauma

Treating victims of penetrating trauma is challenging, especially in a mass‐casualty or resource‐limited setting. The traditional focused assessment with sonography for trauma examination is a well‐established clinical tool in the initial evaluation of trauma victims. This article describes a novel technique of systematic sonography of the abdomen to look for occult wounds, which is used in conjunction with the focused assessment with sonography for trauma examination to evaluate occult intraperitoneal injury and improve patient treatment and use of resources. The technique is highlighted in a case of a child injured in a conflict zone in northern Iraq.     

Use of Targeted Neonatal Echocardiography and Focused Cardiac Sonography in Tertiary Neonatal Intensive Care Units

Focused cardiac sonography and targeted neonatal echocardiography refer to goal‐directed cardiac imaging using ultrasound, typically by noncardiologic specialists. Although the former consists of a rapid qualitative assessment of cardiac function, which is usually performed by acute care practitioners, the latter refers to detailed functional echocardiography to obtain quantitative and qualitative indexes of pulmonary and systemic hemodynamics in sick neonates and is typically performed by neonatologists. Although the use of these modalities is increasing, they still remain unavailable in most North American centers providing acute care to neonates, partly because of limited data regarding their direct impact on patient care. Here we present a series of 5 cases from a large perinatal unit in which immediate availability of relevant expertise led to important and arguably life‐saving clinical interventions. In 4 of these cases, focused cardiac sonography was sufficient to make the diagnosis, whereas in 1 case, clinical integration of detailed systemic hemodynamics measured on target neonatal echocardiography was required.     

Comparison of the Accuracy and Reproducibility of Focused Abdominal Sonography for Trauma Performed by Emergency Medicine and Radiology Residents

We compared the diagnostic accuracy of emergency medicine residents (EMRs) and radiology residents (RRs) in performing focused abdominal sonography for trauma (FAST). The cohort in this prospective study comprised 200 unstable patients (163 males and 37 females; mean ± standard deviation of age, 34.3 ± 16.4 y) who presented with trauma. These patients were evaluated using FAST, first by EMRs and subsequently by RRs. Patients with positive FAST results underwent further diagnostic procedures such as computed tomography, diagnostic peritoneal lavage and laparotomy. Those with negative FAST results underwent clinical follow-up for 72 h until their condition deteriorated or they were discharged. Sensitivity, specificity, positive and negative predictive values and accuracy in evaluating free intraperitoneal fluid were 80%, 95%, 57%, 98% and 94% when FAST was performed by EMRs and 86%, 95%, 59%, 98% and 94% when FAST was performed by RRs. The level of agreement between EMRs and RRs was moderate (κ = 0.525). FAST is a useful screening tool for initial assessment of free abdominal fluid in patients with trauma. Our results indicate that EMRs can perform sonography on trauma patients as successfully as RRs.     

高强度聚焦超声治疗子宫肌瘤疗效研究

目的探讨高强度聚焦超声治疗子宫肌瘤的有效性,评价超声造影对HIFU治疗的疗效判断。方法选择HIFU治疗的子宫肌瘤患者88例,共检出肌瘤138枚,于治疗前和治疗后彩色多普勒血流显像及超声造影检查,观察瘤体大小、内部及周边组织回声和血流灌注对比变化。结果治疗2~5d后肌瘤内部回声不均匀性增强,血流信号减少,肌瘤内无造影剂显示,肌瘤内时间强度曲线幅度减低。治疗3个月后肌瘤缩小,平均有效率52%,肌瘤内部回声均发生变化,血流信号消失,临床症状改善。结论HIFU治疗子宫肌瘤有效。超声造影可早期客观评估子宫肌瘤血流灌注状态,有效评价HIFU治疗的效果,作为治疗后判断疗效是一项较好的检测指标。