Hand-held thoracic sonography for detecting post-traumatic pneumothoraces: the Extended Focused Assessment with Sonography for Trauma (EFAST)

An Experiential Learning Model Facilitates Learning of Bedside Ultrasound by Preclinical Medical Students

OBJECTIVE

To examine the effects of an experiential learning model of ultrasound training on preclinical medical students' knowledge and practice of Focused Assessment with Sonography for Trauma (FAST) examination.

METHODS

The study was conducted in 2 phases. In phase 1, first- and second-year medical students participated in a 45-minute didactic presentation and subsequent 1-hour hands-on practice followed by 3-5 precepted FAST examinations in the emergency department. A pretest or posttest design was used to examine the participants' knowledge interpreting ultrasound images of the FAST examination. In phase 2, students performed FAST scans on patients with abdominal complaints under the supervision of emergency ultrasound faculty over a 1-year period. The participants were scored based on window acquisition, quality of images, accuracy of FAST scan interpretation, confidence level rated by participant, and supervising attending physician.

RESULTS

In phase 1, 68 novice medical students participated in 11 training sessions offered over a 1-year period. Students showed significant improvement in basic ultrasound and abdominal anatomy knowledge. The mean score improved from a pretest score of 5.8 of 10 (95% CI: 5.3-6.2) to a posttest score of 7.3 of 10 (95% CI: 7-7.6). The students also demonstrated a significant improvement in FAST image interpretation (pretest of 6.2 [95% CI: 5.9-6.6] and posttest of 7.6 [95% CI: 7.1-7.9]). In phase 2, 22 students performed 304 FAST examinations on patients. At the beginning of their training when they performed less than 10 FAST scans, students were able to complete the right upper quadrant view in 88.9%, left upper quadrant view in 69.7%, subxiphoid in 64.7%, and pelvic view in 70% of scans. Across all views of the FAST examination, increasing level of practice was associated with improvement in successfully completing the examination. The absolute increase in the proportion experiencing success in the right upper quadrant view was 1.6%, 3.6%, and 6.2% for the 10-19, 20-29, and >30 groups, respectively, of which none were statistically significant. However, the improvements in the left upper quadrant view was 12.7%, 11.6%, 15.7% for the 10-19, 20-29, and >30 groups, respectively. In all views, performing >30 examinations more than doubled the odds of successfully completing the examination.

CONCLUSION

An experiential learning model of ultrasound training consisting of brief didactic presentation, practice FAST examinations on normal models, and proctored examinations on patients is an effective way to teach preclinical medical students basic ultrasound skills.

Diagnostic accuracy of oblique chest radiograph for occult pneumothorax: comparison with ultrasonography

Backgraound

An occult pneumothorax is a pneumothorax that is not seen on a supine chest X-ray but is detected by computed tomography scanning. However, critical patients are difficult to transport to the computed tomography suite. We previously reported a method to detect occult pneumothorax using oblique chest radiography (OXR). Several authors have also reported that ultrasonography is an effective technique for detecting occult pneumothorax. The aim of this study was to evaluate the usefulness of OXR in the diagnosis of the occult pneumothorax and to compare OXR with ultrasonography.

Methods

All consecutive blunt chest trauma patients with clinically suspected pneumothorax on arrival at the emergency department were prospectively included at our tertiary-care center. The patients underwent OXR and ultrasonography, and underwent computed tomography scans as the gold standard. Occult pneumothorax size on computed tomography was classified as minuscule, anterior, or anterolateral.

Results

One hundred and fifty-nine patients were enrolled. Of the 70 occult pneumothoraces found in the 318 thoraces, 19 were minuscule, 32 were anterior, and 19 were anterolateral. The sensitivity and specificity of OXR for detecting occult pneumothorax was 61.4 % and 99.2 %, respectively. The sensitivity and specificity of lung ultrasonography was 62.9 % and 98.8 %, respectively. Among 27 occult pneumothoraces that could not be detected by OXR, 16 were minuscule and 21 could be conservatively managed without thoracostomy.

Conclusion

OXR appears to be as good method as lung ultrasonography in the detection of large occult pneumothorax. In trauma patients who are difficult to transfer to computed tomography scan, OXR may be effective at detecting occult pneumothorax with a risk of progression.

Validation of hand motion analysis as an objective assessment tool for the Focused Assessment with Sonography for Trauma examination

BACKGROUND

Point-of-care ultrasonography is a standard part of trauma assessments, but there are no objective tools to assess proficiency and ensure high-quality examinations. Hand motion analysis (HMA) has been validated as a measure of surgical skill but has not previously been applied to ultrasonography. HMA was assessed for construct validity in Focused Assessment with Sonography for Trauma (FAST) performance.

METHODS

Two cohorts of 12 expert and 12 novice ultrasonographers performed a FAST examination on a healthy volunteer. Hand motions were recorded with the trakSTAR 3D electromagnetic motion-tracking device (Ascension Technology) and analyzed using our custom-designed Motion Analysis and Recording System (MARS) software. Data were recorded at 240 Hz. Outcomes included time of examination, number of movements, and path length.

RESULTS

Time of examination was not different between cohorts (expert, 345.9 seconds; novice, 475.7 seconds; p = 0.12). Total path length of travel was shorter, and the number of discreet movements was less in the expert cohort for the left-hand (18.52 m vs. 28.01 m, p = 0.03, and 109.5 vs. 193.9, p = 0.027, respectively) and the right-hand performance (14.25 m vs. 32.09 m, p < 0.01, and 153.5 vs. 258.5, p = 0.03, respectively) versus the novice cohort. Both total path length traveled and total number of discreet movements were associated with expertise level in logistic regression modeling with areas under the receiver operating characteristic curves of 0.8269 and 0.8205, respectively.

CONCLUSION

This is the first study in the medical literature showing HMA as an objective, valid measure of FAST imaging performance. These objective, automated metrics can function as an adjunct measure to assess FAST performance as well as follow progress of and provide feedback to learners to improve future performances.

LEVEL OF EVIDENCE

A "diagnostic criteria"-style test where the "diagnosis" is a determination of competence in a care provider, level II.

"Anterior convergent" chest probing in rapid ultrasound transducer positioning versus formal chest ultrasonography to detect pneumothorax during the primary survey of hospital trauma patients: a diagnostic accuracy study

Background

Occult pneumothorax represents a diagnostic pitfall during the primary survey of trauma patients, particularly if these patients require early positive pressure ventilation. This study investigated the accuracy of our proposed rapid model of ultrasound transducer positioning during the primary survey of trauma patients after their arrival at the hospital.

Methods

This diagnostic trial was conducted over 12 months and was based on the results of 84 ultrasound (US) exams performed on patients with severe multiple trauma. Our index test (US) was used to detect pneumothorax in four pre-defined locations on the anterior of each hemi-thorax using the “Anterior Convergent” approach, and its performance was limited to the primary survey. Consecutively, patients underwent chest-computed tomography (CT) with or without chest radiography. The diagnostic findings of both chest radiography and chest ultrasounds were compared to the gold-standard test (CT).

Results

The diagnostic sensitivity was 78 % for US and 36.4 % for chest radiography (p < 0.001); the specificity was 92 % for US and 98 % for chest radiography (not significant); the positive predictive values were 74 % for US and 80 % for chest radiography (not significant); the negative predictive values were 94 % for US and 87 % for chest radiography (not significant); the positive likelihood ratio was 10 for US and 18 for chest radiography (p = 0.007); and the negative likelihood ratio was 0.25 for US and 0.65 for chest radiography (p = 0.001). The mean required time for performing the new method was 64 ± 10 s. An absence of the expected diffused dynamic view among ultrasound images obtained from patients with pneumothorax was also observed. We designated this phenomenon “Gestalt Lung Recession.”

Conclusions

“Anterior convergent” chest US probing represents a brief but efficient model that provides clinicians a safe and accurate exam and adequate resuscitation during critical minutes of the primary survey without interrupting other medical staff activities taking place around the trauma patient. The use of the new concept of “Gestalt Lung Recession” instead of the absence of “lung sliding” might improve the specificity of US in detecting pneumothorax.

Chest Abdominal-Focused Assessment Sonography for Trauma during the primary survey in the Emergency Department: the CA-FAST protocol

PURPOSE

To evaluate the feasibility of a new protocol, Chest Abdominal-Focused Assessment Sonography for Trauma (CA-FAST), during the primary survey and to estimate its diagnostic accuracy when compared with thoracoabdominal computed tomography (CT) scan.

METHODS

A prospective accuracy study was performed from November 2012 to November 2013 at the Emergency Department. Only adult trauma patients who underwent a CA-FAST examination prior to a thoracoabdominal CT scan were enrolled. In addition to standard patterns detected by Extended-FAST (E-FAST) such as pneumothorax (PTX), hemothorax (HTX), pericardial and intraabdominal effusion, CA-FAST protocol also included the research of lung contusions (LCs).

RESULTS

Six hundred and one patients were enrolled. The mean time for protocol execution was 7 ± 3 min. Chest ultrasonography showed the following results (all p < 0.001): LCs sensitivity 59 %, specificity 98 %, positive predictive value (PPV) 92 %, negative predictive value (NPV) 86 %, accuracy 87 %; PTX sensitivity 84 %, specificity 98 %, PPV 93 %, NPV 95 %, accuracy 95 %; HTX sensitivity 82 %, specificity 97 %, PPV 87 %, NPV 95 %, accuracy 94 %. The standard 4-views FAST examination showed a diagnostic accuracy of 91 % with a sensitivity of 75 %, specificity of 96 %, PPV of 81 % and NPV of 94 %.

CONCLUSION

According to our results CA-FAST protocol proved to be a rapid bedside method, with good accuracy and high NPV in detection of ultrasonographic patterns suggestive of serious injury in trauma patients; moreover, the additional research of LCs did not cause a delay in the diagnosis. Ultrasonography should be used as initial investigation during the primary survey, sending to further diagnostic studies (CT scan) only those patients not clearly classified.

BRIPPED scan for evaluation of ED patients with shortness of breath

OBJECTIVE

The BRIPPED scan is an ultrasound evaluation of pulmonary B-lines, right ventricle size, inferior vena cava collapsibility, pleural and pericardial effusion, pneumothorax, left ventricle ejection fraction, and lower extremity deep venous thrombosis. The primary goal was to evaluate the effect of the BRIPPED scan on the physician's list of differential diagnoses for patients presenting with shortness of breath.

METHODS

This prospective randomized control trial was performed on patients presenting to the emergency department with shortness of breath. Primary data analysis was performed using an ordinal quasi-symmetry model to compare the magnitude of change in the differential diagnoses between 2 groups. Secondary outcome measures included changes in physician orders or interventions, time to disposition, time to perform the BRIPPED scan, and the interrater reliability of the interpretation of the scan.

RESULTS

A total of 104 patients and 24 physicians were enrolled in this study. Fifty-two patients were randomly assigned to each cohort. Among the BRIPPED cohort, there was significant movement of likelihood for several etiologies of shortness of breath on the physician differential. There was no significance in the change of differential diagnosis between the BRIPPED and control cohorts. The average (SD) time to perform the scan was 5.7 (1.3) minutes (95% confidence interval, 5.4-6 minutes).

CONCLUSION

The BRIPPED scan is a rapid ultrasound evaluation of shortness of breath in the emergency department. BRIPPED influenced physician differential diagnoses to the same degree as laboratory and radiographic testing. BRIPPED did not alter the final diagnosis in this patient population.

Focused assessment with sonography in nontraumatized dogs and cats in the emergency and critical care setting

OBJECTIVE

To evaluate the use of abdominal- and thoracic-focused assessment with sonography for trauma (AFAST and TFAST) in nontraumatized dogs and cats in the emergency and critical care setting and to compare prevalence of free fluid identified via these techniques between stable and unstable patients.

DESIGN

Prospective observational study.

SETTING

University Distributed Veterinary Learning Community.

ANIMALS

One hundred client-owned dogs and cats presenting to an emergency service with no evidence of trauma.

INTERVENTIONS

AFAST and TFAST performed within 12 hours of presentation.

MEASUREMENT AND MAIN RESULTS

Free fluid was identified on AFAST or TFAST in 33% of dogs and cats in this study. Free fluid was identified in 27 of 36 (75%) cardiovascularly unstable or dyspneic patients, compared to 6 of 64 (9%) stable patients. A significantly greater proportion of unstable patients had free fluid compared to stable patients (P < 0.0001).

CONCLUSIONS

Results of this study support the use of AFAST and TFAST to detect free fluid in nontraumatized dogs and cats in the emergency and critical care setting, particularly patients that are unstable on presentation.

In-flight ultrasound identification of pneumothorax

Ultrasound is a standard adjunct to the initial evaluation of injured patients in the emergency department. We sought to evaluate the ability of prehospital, in-flight thoracic ultrasound to identify pneumothorax. Non-physician aeromedical providers were trained to perform and interpret thoracic ultrasound. All adult trauma patients and adult medical patients requiring endotracheal intubation underwent both in-flight and emergency department ultrasound evaluations. Findings were documented independently and reviewed to ensure quality and accuracy. Results were compared to chest X-ray and computed tomography (CT). One hundred forty-nine patients (136 trauma/13 medical) met inclusion criteria. Mean age was 44.4 (18-94) years; 69 % were male. Mean injury severity score was 17.68 (1-75), and mean chest injury score was 2.93 (0-6) in the injured group. Twenty pneumothoraces and one mainstem intubation were identified. Sixteen pneumothoraces were correctly identified in the field. A mainstem intubation was misinterpreted. When compared to chest CT (n = 116), prehospital ultrasound had a sensitivity of 68 % (95 % confidence interval (CI) 46-85 %), a specificity of 96 % (95 % CI 90-98 %), and an overall accuracy of 91 % (95 % CI 85-95 %). In comparison, emergency department (ED) ultrasound had a sensitivity of 84 % (95 % CI 62-94 %), specificity of 98 % (95 % CI 93-99 %), and an accuracy of 96 % (95 % CI 90-98 %). The unique characteristics of the aeromedical environment render the auditory element of a reliable physical exam impractical. Thoracic ultrasonography should be utilized to augment the diagnostic capabilities of prehospital aeromedical providers.

[Diagnostic ultrasound in pneumothorax]

For a long time the lung has been regarded as inaccessible to ultrasound. However, recent clinical studies have shown that this organ can be examined by this technique, which appears, in some situations, to be superior to thoracic radiography. The examination does not require special equipment and is possible using a combination of simple qualitative signs: lung sliding, the presence of B lines and the demonstration of the lung point. The lung sliding corresponds to the artefact produced by the movement of the two pleural layers, one against the other. The B lines indicate the presence of an interstitial syndrome. The presence of lung sliding and/or B lines has a negative predictive value of 100% and formally excludes a pneumothorax in the area where the probe has been applied. The presence of the lung point is pathognomonic of pneumothorax but the sensitivity is no more than 60%. Ultrasound is therefore a rapid and simple means of excluding a pneumothorax (lung sliding or B lines) and of confirming a pneumothorax when the lung point is visible. The question that remains is whether ultrasound can totally replace radiography in the management of this disorder.

BLUE-protocol and FALLS-protocol: two applications of lung ultrasound in the critically ill

This review article describes two protocols adapted from lung ultrasound: the bedside lung ultrasound in emergency (BLUE)-protocol for the immediate diagnosis of acute respiratory failure and the fluid administration limited by lung sonography (FALLS)-protocol for the management of acute circulatory failure. These applications require the mastery of 10 signs indicating normal lung surface (bat sign, lung sliding, A-lines), pleural effusions (quad and sinusoid sign), lung consolidations (fractal and tissue-like sign), interstitial syndrome (lung rockets), and pneumothorax (stratosphere sign and the lung point). These signs have been assessed in adults, with diagnostic accuracies ranging from 90% to 100%, allowing consideration of ultrasound as a reasonable bedside gold standard. In the BLUE-protocol, profiles have been designed for the main diseases (pneumonia, congestive heart failure, COPD, asthma, pulmonary embolism, pneumothorax), with an accuracy &gt; 90%. In the FALLS-protocol, the change from A-lines to lung rockets appears at a threshold of 18 mm Hg of pulmonary artery occlusion pressure, providing a direct biomarker of clinical volemia. The FALLS-protocol sequentially rules out obstructive, then cardiogenic, then hypovolemic shock for expediting the diagnosis of distributive (usually septic) shock. These applications can be done using simple grayscale machines and one microconvex probe suitable for the whole body. Lung ultrasound is a multifaceted tool also useful for decreasing radiation doses (of interest in neonates where the lung signatures are similar to those in adults), from ARDS to trauma management, and from ICUs to points of care. If done in suitable centers, training is the least of the limitations for making use of this kind of visual medicine.

Impact of a 2-Day Critical Care Ultrasound Course during Fellowship Training: A Pilot Study

Objectives. Despite the increasing utilization of point-of-care critical care ultrasonography (CCUS), standards establishing competency for its use are lacking. The purpose of this study was to evaluate the effectiveness of a 2-day CCUS course implementation on ultrasound-naïve critical care medicine (CCM) fellows. Methods. Prospective evaluation of the impact of a two-day CCUS course on eight CCM fellows' attitudes, proficiency, and use of CCUS. Ultrasound competency on multiple organ systems was assessed including abdominal, pulmonary, vascular, and cardiac systems. Subjects served as self-controls and were assessed just prior to, within 1 week after, and 3 months after the course. Results. There was a significant improvement in CCM fellows' written test scores, image acquisition ability, and pathologic image interpretation 1 week after the course and it was retained 3 months after the course. Fellows also had self-reported increased confidence and usage of CCUS applications after the course. Conclusions. Implementation of a 2-day critical care ultrasound course covering general CCUS and basic critical care echocardiography using a combination of didactics, live models, and ultrasound simulators is effective in improving critical care fellows' proficiency and confidence with ultrasound use in both the short- and long-term settings.

Utility of extended FAST in blunt chest trauma: is it the time to be used in the ATLS algorithm?

INTRODUCTION

The clinical significance of extended Focused Assessment with Sonography for Trauma (EFAST) for diagnosis of pneumothorax is not well defined.

OBJECTIVES

To investigate the utility of EFAST in blunt chest trauma (BCT) patients.

STUDY DESIGN

A single blinded, prospective study.

PARTICIPANTS

All patients admitted with BCT (2011-2013).

SETTINGS

Level 1 trauma center in Qatar.

PROCEDURES AND OUTCOME MEASURES

Patients were screened by EFAST and results were compared to the clinical examination (CE) and chest X-ray (CXR). Chest-computed tomography (CT) scoring system was used to confirm and measure the pneumothorax. Diagnostic accuracy of diagnostic modalities of pneumothorax was measured using sensitivity, specificity, predictive values (PVs), and likelihood ratio.

RESULTS

A total of 305 BCT patients were included with median age of 34 (18-75). Chest CT was positive for pneumothorax in 75 (24.6 %) cases; of which 11 % had bilateral pneumothorax. Chest CT confirmed the diagnosis of pneumothorax in 43, 41, and 11 % of those who were initially diagnosed by EFAST, CE, and CXR, respectively. EFAST was positive in 42 hemithoraces and its sensitivity (43 %) was higher in comparison to CXR (11 %). Positive and negative PVs of EFAST were 76 and 92 %, respectively. The frequency of missed cases by CXR was higher in comparison to EFAST and CE. The lowest median score of missed pneumothorax was observed by EFAST.

CONCLUSION

EFAST can be used as an efficient triaging tool in BCT patients to rule out pneumothorax. Based on our analysis, we would recommend EFAST as an adjunct in ATLS algorithm.

ERS task force statement: diagnosis and treatment of primary spontaneous pneumothorax

Primary spontaneous pneumothorax (PSP) affects young healthy people with a significant recurrence rate. Recent advances in treatment have been variably implemented in clinical practice. This statement reviews the latest developments and concepts to improve clinical management and stimulate further research.The European Respiratory Society's Scientific Committee established a multidisciplinary team of pulmonologists and surgeons to produce a comprehensive review of available scientific evidence.Smoking remains the main risk factor of PSP. Routine smoking cessation is advised. More prospective data are required to better define the PSP population and incidence of recurrence. In first episodes of PSP, treatment approach is driven by symptoms rather than PSP size. The role of bullae rupture as the cause of air leakage remains unclear, implying that any treatment of PSP recurrence includes pleurodesis. Talc poudrage pleurodesis by thoracoscopy is safe, provided calibrated talc is available. Video-assisted thoracic surgery is preferred to thoracotomy as a surgical approach.In first episodes of PSP, aspiration is required only in symptomatic patients. After a persistent or recurrent PSP, definitive treatment including pleurodesis is undertaken. Future randomised controlled trials comparing different strategies are required.

Incidental Findings on Bedside Ultrasonography: Detection Rate and Accuracy of Resident-Performed Examinations in the Acute Setting

Background

Bedside ultrasonography has become a valuable tool in the emergent care setting for triage and rapid evaluation of patients who are acutely ill. Given the cross-sectional nature of ultrasound technology, incidental findings are frequently encountered during imaging. These can impact clinical management and can pose a diagnostic dilemma for emergency medicine (EM) physicians and EM residents.

Purpose

Our retrospective study was designed to evaluate the prevalence and detection rate of incidental findings on bedside ultrasound examinations performed by EM residents. We also sought to identify types of incidental findings encountered and the diagnostic accuracy of those findings.

Materials and Methods

Board-certified radiologists retrospectively reviewed bedside ultrasonography examinations performed and interpreted by EM residents at a large urban academic hospital. Our sample included patients who presented with traumatic and nontraumatic symptoms in the acute setting. Findings were defined as incidental only if they were previously unknown and not related to a patients presenting symptoms. The results were corroborated with electronic medical records and additional pertinent imaging when available.

Results

Of 196 examinations analysed, EM residents identified incidental findings on 26% of the studies, which mostly involved the renal and biliary system. Radiologist review detected incidental findings in 20.9% but was more accurate when supplemental imaging was available. EM residents detected incidental findings at rates similar to that published previously and had moderate interobserver agreement with radiologist review. Worrisome and indeterminate findings were confirmed by additional work-up and further imaging.

Conclusion

Incidental findings are frequently encountered on bedside ultrasonography and have the potential to alter clinical management. Expertise in detection and knowledge of the presence and spectrum of these incidental findings is essential for appropriate triage, patient management, and follow-up.

Point-of-care ultrasonography by pediatric emergency medicine physicians

Emergency physicians have used point-of-care ultrasonography since the 1990 s. Pediatric emergency medicine physicians have more recently adopted this technology. Point-of-care ultrasonography is used for various scenarios, particularly the evaluation of soft tissue infections or blunt abdominal trauma and procedural guidance. To date, there are no published statements from national organizations specifically for pediatric emergency physicians describing the incorporation of point-of-care ultrasonography into their practice. This document outlines how pediatric emergency departments may establish a formal point-of-care ultrasonography program. This task includes appointing leaders with expertise in point-of-care ultrasonography, effectively training and credentialing physicians in the department, and providing ongoing quality assurance reviews.

Can Routine Trauma Bay Chest X-ray be Bypassed with an Extended Focused Assessment with Sonography for Trauma Examination?

The objective of this study was to investigate the feasibility of using ultrasound (US) in place of portable chest x-ray (CXR) for the rapid detection of a traumatic pneumothorax (PTX) requiring urgent decompression in the trauma bay. All patients who presented as a trauma alert to a single institution from August 2011 to May 2012 underwent an extended focused assessment with sonography for trauma (FAST). The thoracic cavity was examined using four-view US imaging and were interpreted by a chief resident (Postgraduate Year 4) or attending staff. US results were compared with CXR and chest computed tomography (CT) scans, when obtained. The average age was 37.8 years and 68 per cent of the patients were male. Blunt injury occurred in 87 per cent and penetrating injury in 12 per cent of activations. US was able to predict the absence of PTX on CXR with a sensitivity of 93.8 per cent, specificity of 98 per cent, and a negative predictive value of 99.9 per cent compared with CXR. The only missed PTX seen on CXR was a small, low anterior, loculated PTX that was stable for transport to CT. The use of thoracic US during the FAST can rapidly and safely detect the absence of a clinically significant PTX. US can replace routine CXR obtained in the trauma bay and allow more rapid initiation of definitive imaging studies.

From FAST to E-FAST: an overview of the evolution of ultrasound-based traumatic injury assessment

Ultrasound is a ubiquitous and versatile diagnostic tool. In the setting of acute injury, ultrasound enhances the basic trauma evaluation, influences bedside decision-making, and helps determine whether or not an unstable patient requires emergent procedural intervention. Consequently, continued education of surgeons and other acute care practitioners in performing focused emergency ultrasound is of great importance. This article provides a synopsis of focused assessment with sonography for trauma (FAST) and the extended FAST (E-FAST) that incorporates basic thoracic injury assessment. The authors also review key pitfalls, limitations, controversies, and advances related to FAST, E-FAST, and ultrasound education.

Portable ultrasound in disaster triage: a focused review

Ultrasound technology has become ubiquitous in modern medicine. Its applications span the assessment of life-threatening trauma or hemodynamic conditions, to elective procedures such as image-guided peripheral nerve blocks. Sonographers have utilized ultrasound techniques in the pre-hospital setting, emergency departments, operating rooms, intensive care units, outpatient clinics, as well as during mass casualty and disaster management. Currently available ultrasound devices are more affordable, portable, and feature user-friendly interfaces, making them well suited for use in the demanding situation of a mass casualty incident (MCI) or disaster triage. We have reviewed the existing literature regarding the application of sonology in MCI and disaster scenarios, focusing on the most promising and practical ultrasound-based paradigms applicable in these settings.

Out of hospital point of care ultrasound: current use models and future directions

INTRODUCTION

Ultrasound has evolved from a modality that was once exclusively reserved to certain specialities of its current state, in which its portability and durability lend to its broadly increasing applications.

OBJECTIVES

This review describes portable ultrasound in the hospital setting and its comparison to gold standard imaging modalities. Also, this review summarizes current literature describing portable ultrasound use in prehospital, austere and remote environments, highlighting successes and barriers to use in these environments.

DISCUSSION

Prehospital ultrasound has the ability to increase diagnostic ability and allow for therapeutic intervention in the field. In austere environments, ultrasound may be the only available imaging modality and thus can guide diagnosis, therapeutics and determine which patients may need emergent transfer to a healthcare facility. The most cutting edge applications of portable ultrasound employ telemedicine to obtain and transmit ultrasound images. This technology and ability to transmit images via satellite and cellular transmission can allow for even novice users to obtain interpretable images in austere environments. Portable ultrasound uses have steadily grown and will continue to do so with the introduction of more portable and durable technologies. As applications continue to grow, certain technologic considerations and future directions are explored.

Model Point-of-Care Ultrasound Curriculum in an Intensive Care Unit Fellowship Program and Its Impact on Patient Management

Objectives. This study was designed to assess the clinical applicability of a Point-of-Care (POC) ultrasound curriculum into an intensive care unit (ICU) fellowship program and its impact on patient care. Methods. A POC ultrasound curriculum for the surgical ICU (SICU) fellowship was designed and implemented in an urban, academic tertiary care center. It included 30 hours of didactics and hands-on training on models. Minimum requirement for each ICU fellow was to perform 25–50 exams on respective systems or organs for a total not less than 125 studies on ICU. The ICU fellows implemented the POC ultrasound curriculum into their daily practice in managing ICU patients, under supervision from ICU staff physicians, who were instructors in POC ultrasound. Impact on patient care including finding a new diagnosis or change in patient management was reviewed over a period of one academic year. Results. 873 POC ultrasound studies in 203 patients admitted to the surgical ICU were reviewed for analysis. All studies included were done through the POC ultrasound curriculum training. The most common exams performed were 379 lung/pleural exams, 239 focused echocardiography and hemodynamic exams, and 237 abdominal exams. New diagnosis was found in 65.52% of cases (95% CI 0.590, 0.720). Changes in patient management were found in 36.95% of cases (95% CI 0.303, 0.435). Conclusions. Implementation of POC ultrasound in the ICU with a structured fellowship curriculum was associated with an increase in new diagnosis in about 2/3 and change in management in over 1/3 of ICU patients studied.

The use of FAST scan by paramedics in mass-casualty incidents: a simulation study

INTRODUCTION

The Focused Abdominal Sonography in Trauma (FAST) scan is used to detect free fluid in the peritoneal cavity, or pericardium, to quickly assess for injuries needing immediate surgical intervention. Mass-casualty incidents (MCIs) are settings where paramedics must make triage decisions in minutes. The Simple Triage and Rapid Transport (START) system is used to prioritize transport. The FAST scan can be added to the triage of critical patients, and may aid in triage.

METHODS

This was a single-blinded, randomized control trial. Ten paramedics with field experience were trained with an ultrasound machine in the performance of the FAST scan. Two weeks were allowed to pass before testing to simulate the time between training of standard procedures and their implementation. On test day, five peritoneal dialysis patients with instilled dialysis fluid and five matched control patients were placed in a room in a random order where the paramedics performed FAST scans on each patient. The paramedics were assessed by declaring positive or negative for each evaluation, as well as being timed for the total exercise.

RESULTS

Of the ninety tests (one paramedic dropped out due to family emergency), the paramedics had a mean accuracy of 60% and median of 62% (range 40%-80%). There was a statistically significant higher false-positive rate of 59% than false-negative rate of 41% (P < .01). Sensitivity was 67% with a specificity of 56%. Average time taken was 1,218 seconds (121.8 seconds per patient) with a range of 735-1,701 seconds and a median of 1,108 seconds.

CONCLUSION

In this simulation study, paramedics had difficulty performing FAST scans with a high degree of accuracy. However, they were more apt to call a patient positive, limiting the likelihood for false-negative triage.

Sports medicine ultrasound (US) beyond the musculoskeletal system: use in the abdomen, solid organs, lung, heart and eye

The use of point-of-care ultrasound (US) by non-radiologists is not new and the expansion into sports medicine practice is relatively young. US has been used extensively to evaluate the musculoskeletal system including the diagnosis of muscle, tendon and bone injuries. However, as sports medicine practitioners we are responsible for the care of the entire athlete. There are many other non-musculoskeletal applications of US in the evaluation and treatment of the athlete. This paper highlights the use of US in the athlete to diagnose pulmonary, cardiac, solid organ, intra-abdominal and eye injuries.

The peril of thoracoabdominal firearm trauma: 984 civilian injuries reviewed

BACKGROUND

Thoracoabdominal firearm injuries present major diagnostic and therapeutic challenges because of the risk for potential injury in multiple anatomic cavities and the attendant dilemma of determining the need for and correct sequencing of cavitary intervention. Injury patterns, management strategies, and outcomes of thoracoabdominal firearm trauma remain undescribed across a large population.

METHODS

All patients with thoracoabdominal firearm injury admitted to a major Level I trauma center during a 16-year period were reviewed.

RESULTS

The 984 study patients experienced severe injury burden; 25% (243 of 984) presented in cardiac arrest, and 75% (741 of 984) had an Abbreviated Injury Scale (AIS) score of 3 or greater in both the chest and the abdomen. Operative management occurred in 86% (638 of 741). Of the patients arriving alive, 68% (507 of 741) underwent laparotomy alone, 4% (27 of 741) underwent thoracotomy alone, and 14% (104 of 741) underwent dual-cavitary intervention. Negative laparotomy occurred in 3%. Diaphragmatic injury (DI) occurred in 63%. Seventy-five percent had either DI or hollow viscus injury. Cardiac injury was present in 33 patients arriving alive. Despite the use of trauma bay ultrasound, 44% of the patients with cardiac injury underwent initial laparotomy. In half of this group, ultrasound did not detect pericardial blood. The need for thoracotomy, either alone or as part of dual-cavitary intervention, was the strongest independent risk factor for mortality in those arriving alive.

CONCLUSION

Greater kinetic destructive potential drives the peril of thoracoabdominal firearm trauma, producing clinical challenges qualitatively and quantitatively different from nonfirearm injuries. Severe injury, on both sides of the diaphragm, generates high operative need with low rates of negative exploration. The need for emergent intervention and a high incidence of DI or hollow viscus injury limit opportunity for nonoperative management. Even with ultrasound, emergent preoperative diagnosis remains challenging, as the complex combination of intra-abdominal, thoracic, and diaphragmatic injuries can provoke misinterpretation of both radiologic and clinical data. Successful emergent management requires thorough assessment of all anatomic spaces, integrating ultrasonographic, radiologic, and clinical findings.

LEVEL OF EVIDENCE

Epidemiologic study, level III.

Year in review 2013: Critical Care--respirology

This review documents important progress made in 2013 in the field of critical care respirology, in particular with regard to acute respiratory failure and acute respiratory distress syndrome. Twenty-five original articles published in the respirology and critical care sections of Critical Care are discussed in the following categories: pre-clinical studies, protective lung ventilation – how low can we go, non-invasive ventilation for respiratory failure, diagnosis and prognosis in acute respiratory distress syndrome and respiratory failure, and promising interventions for acute respiratory distress syndrome.

Prospective evaluation of prehospital trauma ultrasound during aeromedical transport

BACKGROUND

Ultrasound is widely considered the initial diagnostic imaging modality for trauma. Preliminary studies have explored the use of trauma ultrasound in the prehospital setting, but the accuracy and potential utility is not well understood.

OBJECTIVE

We sought to determine the accuracy of trauma ultrasound performed by helicopter emergency medical service (HEMS) providers.

METHODS

Trauma ultrasound was performed in flight on adult patients during a 7-month period. Accuracy of the abdominal, cardiac, and lung components was determined by comparison to the presence of injury, primarily determined by computed tomography, and to required interventions.

RESULTS

HEMS providers performed ultrasound on 293 patients during a 7-month period, completing 211 full extended Focused Assessment with Sonography for Trauma (EFAST) studies. HEMS providers interpreted 11% of studies as indeterminate. Sensitivity and specificity for hemoperitoneum was 46% (95% confidence interval [CI] 27.1%-94.1%) and 94.1% (95% CI 89.2%-97%), and for laparotomy 64.7% (95% CI 38.6%-84.7%) and 94% (95% CI 89.2%-96.8%), respectively. Sensitivity and specificity for pneumothorax were 18.7% (95% CI 8.9%-33.9%) and 99.5% (95% CI 98.2%-99.9%), and for thoracostomy were 50% (95% CI 22.3%-58.7%) and 99.8% (98.6%-100%), respectively. The positive likelihood ratio for laparotomy was 10.7 (95% CI 5.5-21) and for thoracostomy 235 (95% CI 31-1758), and the negative likelihood ratios were 0.4 (95% CI 0.2-0.7) and 0.5 (95% CI 0.3-0.8), respectively. Of 240 cardiac studies, there was one false-positive and three false-negative interpretations (none requiring intervention).

CONCLUSIONS

HEMS providers performed EFAST with moderate accuracy. Specificity was high and positive interpretations raised the probability of injury requiring intervention. Negative interpretations were predictive, but sensitivity was not sufficient for ruling out injury.

Thoracic ultrasound can predict safe removal of thoracostomy tubes

BACKGROUND

Chest x-rays (CXRs) have been the mainstay for the management of thoracostomy tubes (TTs), but reports that ultrasound (US) may be more sensitive for detection of pneumothorax (PTX) continue to increase. The objective of this study was to determine if US is safe and effective for the detection of PTX following TT removal.

METHODS

This was a retrospectively reviewed, prospective process improvement project involving patients who had a TT managed by the surgical team. Bedside US was performed by experienced surgeon sonographers before and after TT removal. Initially, a CXR was obtained before and after TT removal, with sonographers blinded to CXR findings. Subsequently, routine CXR was no longer obtained, and TT removal was determined by US.

RESULTS

One hundred twenty-nine TTs were placed during the study. Initially, water seal and postpull US were performed on 49 TTs, with 6 tubes having only postpull imaging. US was able to detect all significant PTXs seen on CXR but identified one false-positive. Subsequently, 74 TTs had US imaging on water seal and after pull. Water seal US allowed the safe removal of 70% of the TTs. Twenty patients had no slide on water seal US and required follow-up CXR. Most importantly, US had a 100% negative predictive value for PTX during TT removal.

CONCLUSION

US is safe and effective for the rapid diagnosis of PTX. This has allowed the discontinuation of routine CXR for the evaluation of PTX during TT removal for patients with adequate lung slide seen on thoracic US lung windows.

LEVEL OF EVIDENCE

Diagnostic test, level II. Therapeutic study, level IV.

Bedside ultrasonography-Applications in critical care: Part II

Point of care ultrasonography, performed by acute care physicians, has developed into an invaluable bedside tool providing important clinical information with a major impact on patient care. In Part II of this narrative review, we describe ultrasound guided central venous cannulation, which has become standard of care with internal jugular vein cannulation. Besides improving success rates, real-time guidance also significantly reduces the incidence of complications. We also discuss compression ultrasonography - a quick and effective bedside screening tool for deep vein thrombosis of the lower extremity. Abdominal ultrasound offers vital clues in the emergency setting; in the unstable trauma victim, a focused examination may provide immediate answers and has largely superseded diagnostic peritoneal lavage in diagnosing intraperitoneal bleed. From estimation of intracranial pressure to transcranial Doppler studies, ultrasound is becoming increasingly relevant to neurocritical care. Ultrasound may also help with airway management in several situations, including percutaneous tracheostomy. Clearly, bedside ultrasonography has become an indispensable part of intensive care practice – in the rapid assessment of critically ill-patients as well as in enhancing the safety of invasive procedures.

Integrated cardiopulmonary sonography: a useful tool for assessment of acute pulmonary edema in the intensive care unit

OBJECTIVES

Bedside sonography has become a popular method of assessment of critically ill patients with shock and dyspnea. This study evaluated the usefulness of integrated cardiopulmonary sonography for assessment of acute pulmonary edema.

METHODS

A total of 128 intensive care unit (ICU) patients with acute pulmonary edema were randomly divided into 2 groups: a sonography group, which received standard treatment as well as cardiopulmonary sonography, and a control group, which received standard treatment only. All patients were treated according to the same therapeutic strategies and underwent chest radiography and central venous catheter placement. Serum myocardial injury marker levels and central venous/arterial blood gas parameters were measured 0, 24, and 72 hours after enrollment. The cumulative fluid infusion volume at 6, 12, 24, and 72 hours, the time to diagnosis of the pulmonary edema etiology by the attending physician, the lengths of ICU and hospital stays, and ICU mortality were recorded.

RESULTS

The sonography group had a shorter time to diagnosis and received a smaller fluid infusion volume than the control group. There were no significant differences in ICU mortality and lengths of ICU and hospital stays between the sonography and control groups. In patients with cardiogenic pulmonary edema, the sonography group had a significantly shorter ICU stay and a faster return to normal myocardial injury marker levels and perfusion parameters than the control group (P < .05).

CONCLUSIONS

Integrated cardiopulmonary sonography resulted in faster and better-informed clinical decision making, shortened the time to diagnosis of the pulmonary edema etiology, and decreased fluid use. However, the impact of this examination on prognoses requires further study. We propose that integrated cardiopulmonary sonography may be a useful bedside tool for treatment of ICU patients with acute pulmonary edema.

Bedside ultrasonography: Applications in critical care: Part I

There is increasing interest in the use of ultrasound to assess and guide the management of critically ill patients. The ability to carry out quick examinations by the bedside to answer specific clinical queries as well as repeatability are clear advantages in an acute care setting. In addition, delays associated with transfer of patients out of the Intensive Care Unit (ICU) and exposure to ionizing radiation may also be avoided. Ultrasonographic imaging looks set to evolve and complement clinical examination of acutely ill patients, offering quick answers by the bedside. In this two-part narrative review, we describe the applications of ultrasonography with a special focus on the management of the critically ill. Part I explores the utility of echocardiography in the ICU, with emphasis on its usefulness in the management of hemodynamically unstable patients. We also discuss lung ultrasonography - a vastly underutilized technology for several years, until intensivists began to realize its usefulness, and obvious advantages over chest radiography. Ultrasonography is rapidly emerging as an important tool in the hands of intensive care physicians.

Nuking the radiation: minimizing radiation exposure in the evaluation of pediatric blunt trauma

PURPOSE OF REVIEW

Our objective is to highlight recent literature investigating low-radiation diagnostic strategies in the evaluation of pediatric trauma.

RECENT FINDINGS

In the area of minor head injury, research has focused on implementation of validated clinical decision rules into practice to reduce unnecessary computed tomography scans. Clinical observation may also serve as an adjunct to initial assessment and a potential substitute for computed tomography imaging. Subgroups of children with special needs or severe injury mechanisms may also be safely characterized by the clinical decision rule and spared radiation exposure. Physical examination techniques may be useful in diagnosing mandibular fractures. In addition, evidence suggests that plain radiography for evaluation of blunt thoracic trauma may be sufficient in many cases, and computed tomography could be reserved for those with abnormal radiographs, high-risk mechanisms, or abnormal physical findings. Clinical decision rules are able to predict intra-abdominal injury with high sensitivity. Data suggest that skeletal surveys may be modified to limit radiation exposure in the case of suspected nonaccidental trauma.

SUMMARY

More research is needed in development of pediatric-specific clinical decision rules and risk stratification and in testing low-radiation diagnostic modalities in the pediatric trauma population.

Making the financial case for a surgeon-directed critical care ultrasound program

BACKGROUND

We sought to demonstrate that a well-staffed, surgeon-directed, critical care ultrasound program (CCUP) is financially sustainable and provides administrative and educational support for point-of-care ultrasound.

METHODS

The CCUP provides a clinical service and training as well as conducts research. Initial costs, annual costs (C), revenue (R), and savings (S) were prospectively recorded. Using data from the first 3 years, we calculated the projected C, R, and S at 5 years. We determined CCUP sustainability by C < R and C < R + S at 3 years and 5 years.

RESULTS

During 36 months, the CCUP covered four surgical intensive care units (55 beds). Start-up costs included one basic and one cardiovascular device per 25 beds and a data storage system linking reports and images to the electronic medical record ($203,650). Billing increased threefold from Years 1 to 3, with a 21% increase between Years 2 to 3. Yearly costs included 0.5 full-time equivalent (FTE) sonographer and 0.2 FTE surgeon ($106,025); this was increased to 1 FTE and 0.25 FTE, respectively, for Years 4 and 5. The total 3-year cost was $521,725 and projected to be $863,325 by Year 5. The total 3-year revenue was $290,775 and projected to be $891,600 at 5 years. The total 3-year savings associated with the CCUP was $600,035 and is projected to be $1,194,220. With the use of the C < R, the CCUP meets operating expenses at Year 3 and covers overall cost at 5 years. If savings are included, then the CCUP is sustainable by its third year and is potentially profitable by Year 5.

CONCLUSION

A surgeon-directed CCUP is financially sustainable, addresses administrative issues, and provides valuable training in point-of-care ultrasound.

Ultrasonography for clinical decision-making and intervention in airway management: from the mouth to the lungs and pleurae

OBJECTIVES

To create a state-of-the-art overview of the new and expanding role of ultrasonography in clinical decision-making, intervention and management of the upper and lower airways, that is clinically relevant, up-to-date and practically useful for clinicians.

METHODS

This is a narrative review combined with a structured Medline literature search.

RESULTS

Ultrasonography can be utilised to predict airway difficulty during induction of anaesthesia, evaluate if the stomach is empty or possesses gastric content that poses an aspiration risk, localise the essential cricothyroid membrane prior to difficult airway management, perform nerve blocks for awake intubation, confirm tracheal or oesophageal intubation and facilitate localisation of tracheal rings for tracheostomy. Ultrasonography is an excellent diagnostic tool in intraoperative and emergency diagnosis of pneumothorax. It also enables diagnosis and treatment of interstitial syndrome, lung consolidation, atelectasis, pleural effusion and differentiates causes of acute breathlessness during pregnancy. Patient safety can be enhanced by performing procedures under ultrasound guidance, e.g. thoracocentesis, vascular line access and help guide timing of removal of chest tubes by quantification of residual pneumothorax size.

CONCLUSIONS

Ultrasonography used in conjunction with hands-on management of the upper and lower airways has multiple advantages. There is a rapidly growing body of evidence showing its benefits.

TEACHING POINTS

• Ultrasonography is becoming essential in management of the upper and lower airways. • The tracheal structures can be identified by ultrasonography, even when unidentifiable by palpation. • Ultrasonography is the primary diagnostic approach in suspicion of intraoperative pneumothorax. • Point-of-care ultrasonography of the airways has a steep learning curve. • Lung ultrasonography allows treatment of interstitial syndrome, consolidation, atelectasis and effusion.

Assessment of a human cadaver model for training emergency medicine residents in the ultrasound diagnosis of pneumothorax

Objectives. To assess a human cadaver model for training emergency medicine residents in the ultrasound diagnosis of pneumothorax. Methods. Single-blinded observational study using a human cadaveric model at an academic medical center. Three lightly embalmed cadavers were used to create three “normal lungs” and three lungs modeling a “pneumothorax.” The residents were blinded to the side and number of pneumothoraces, as well as to each other's findings. Each resident performed an ultrasound examination on all six lung models during ventilation of cadavers. They were evaluated on their ability to identify the presence or absence of the sliding-lung sign and seashore sign. Results. A total of 84 ultrasound examinations (42-“normal lung,” 42-“pneumothorax”) were performed. A sliding-lung sign was accurately identified in 39 scans, and the seashore sign was accurately identified in 34 scans. The sensitivity and specificity for the sliding-lung sign were 93% (95% CI, 85–100%) and 90% (95% CI, 81–99%), respectively. The sensitivity and specificity for the seashore sign were 80% (95% CI, 68–92%) and 83% (95% CI, 72–94%), respectively. Conclusions. Lightly embalmed human cadavers may provide an excellent model for mimicking the sonographic appearance of pneumothorax.