Feasibility of bedside thoracic ultrasound in the helicopter emergency medical services setting

Prehospital Extended FAST Exams Improve Clinical Decision Making by Helicopter EMS Crews: A Retrospective Case Series

Point of Care Ultrasound (POCUS) has seen increasing use in the prehospital environment over the last decade, primarily with the extended focused assessment with sonography in trauma (eFAST) exam. Previous studies have shown prehospital eFAST exams are feasible in the helicopter transport environment but have yet to demonstrate effects on clinical care. This retrospective case series identified 655 patients with blunt thoraco-abdominal trauma or concern for pneumothorax due to penetrating injury transported by a single helicopter EMS (HEMS) program over a two-year period after introducing POCUS. Of those patients, 258 received prehospital ultrasound which was reported to change clinical care in seven cases (2.7%, 95%-CI [1.1-5.5]). This was primarily through preventing unnecessary needle thoracostomy and initiating blood transfusion for treatment of hemorrhagic shock in cases where the degree of shock was unclear due to inconsistent vital signs. This study highlights the improvements in clinical care that may result from the introduction of eFAST exams in the prehospital environment.

Is a Positive Prehospital FAST Associated with Severe Bleeding? A Multicenter Retrospective Study

INTRODUCTION

Severe hemorrhage is the leading cause of early preventable death in severe trauma patients. Delayed diagnosis is a poor prognostic factor, and severe hemorrhage prediction is essential. The aim of our study was to investigate if there was an association between the detection of peritoneal or pleural fluid on prehospital sonography for trauma and posttraumatic severe hemorrhage.

METHODS

We retrospectively studied data from records of thoracic or abdominal trauma patients managed in mobile intensive care units from January 2017 to December 2021 in four centers in France. Severe hemorrhage was defined as a condition necessitating transfusion of at least four packed red blood cells or surgical intervention/radioembolization for hemostasis within the first 24 h. Using a multivariate analysis, we investigated the predictive performance of focused assessment with sonography for trauma (FAST) alone or in combination with the five Red Flags criteria validated by Hamada et al.

RESULTS

Among the 527 patients analyzed, 371 (71%) were men, the mean age was 41 ± 19 years, and the Injury Severity Score was 11 (Interquartile range = [5; 22]). Seventy-three (14%) patients had severe hemorrhage - of whom 28 (38%) had a positive FAST, compared to 61 (13%) without severe hemorrhage (p < 0.01). For severe hemorrhage prediction, FAST had a sensitivity of 38% (95%CI = [27%; 50%]) and a specificity of 87% (95%CI = [83%; 90%]) (AUC = 0.62, 95%CI = [0.57; 0.68]). The comparison of the other outcomes between positive and negative FAST was: hemostatic procedure, 22 (25%) vs 28 (6%), p < 0.01; intensive care unit admission 71 (80%) vs 190 (43%), p < 0.01; mean length of hospital stay 11 [4; 27] vs 4 [0; 14] days, p = 0.02; 30-day mortality 13 (15%) vs 22 (5%), p < 0.01.

CONCLUSION

A positive FAST performed in the prehospital setting is associated with severe hemorrhage and all prognostic criteria we studied.

Impact of Point-of-Care Ultrasound on Prehospital Decision Making by HEMS Physicians in Critically Ill and Injured Patients: A Prospective Cohort Study

INTRODUCTION

Several studies have shown the additional benefit of point-of-care ultrasound (POCUS) by prehospital Emergency Medical Services (EMS). Since organization of EMS may vary significantly across countries, the value of POCUS likely depends on the prehospital system in which it is used. In order to be able to optimally implement POCUS and develop a tailored training curriculum, it is important to know how often POCUS is currently used, for which indications it is used, and how it affects decision making. The aims of this study were: (1) to determine the percentage of patients in whom POCUS was used by Dutch Helicopter Emergency Medical Services (HEMS) crews; (2) to determine how often POCUS findings led to changes in on-scene management; and (3) what these changes were.

METHODS

Patients who received prehospital care from December 1, 2020 through March 31, 2021 by a single HEMS crew were included in this prospective cohort study. Clinical data and specific data on POCUS examination, findings, and therapeutic consequences were collected and analyzed.

RESULTS

During the study period, on-scene HEMS care was provided to 612 patients, of which 211 (34.5%) patients underwent POCUS. Of these, 209 (34.2%) patients with a median age of 45 years were included. There were 131 (62.7%) trauma patients, and 70 (33.7%) of the included patients underwent cardiopulmonary resuscitation (CPR). The median reported time of POCUS examination was three (P25-P75 2-5) minutes. Median prolongation of on-scene time was zero (P25-P75 0-1) minutes. In 85 (40.7%) patients, POCUS examination had therapeutic consequence: POCUS was found to impact treatment decisions in 34 (26.0%) trauma patients and 51 (65.4%) non-trauma patients. In patients with cardiac arrest, POCUS was most often used to aid decision making with regard to terminating or continuing resuscitation (28 patients; 13.4%).

CONCLUSION

During the study period, POCUS examination was used in 34.5% of all prehospital HEMS patients and had a therapeutic consequence in 40.7% of patients. In trauma patients, POCUS seems to be most effective for patient triage and evaluation of treatment effectiveness. Moreover, POCUS can be of significant value in patients undergoing CPR. A tailored HEMS POCUS training curriculum should include ultrasound techniques for trauma and cardiac arrest.

Guiding Emergency Treatment With Extended Focused Assessment With Sonography in Trauma by Emergency Responders (GET eFASTER)

OBJECTIVE

Prehospital medicine has struggled to manage critical patients without the resources available to hospital-based teams. Point-of-care ultrasound could bridge this resource gap by providing critical insight into the pathology of trauma patients. This study aimed to determine if early positive extended focused assessment with sonography in trauma (eFAST) identification would lead to improved patient outcomes.

METHODS

This is a prospective observational trial that took place from February 1, 2019, to August 13, 2021. Paramedics, with no prior ultrasound experience, at a single ground ambulance agency were trained in obtaining and interpretating eFAST examinations.

RESULTS

Thirty-seven paramedics were trained and performed a total of 502 eFAST examinations with a total correct interpretation rate of 97.35%. There was a sensitivity of 30.0%/75.0%, specificity of 98.75%/94.05%, a positive predictive value of 33.33%/37.5%, a negative predictive value of 98.55%/98.75%, a positive likelihood ratio of 24.05/12.6, and a negative likelihood ratio of 0.71/0.27 for all exam/patient-only scans. The time spent on scene for eFAST and non-eFAST calls was not significantly different (F_{3, 2,512} = 2.59, P = .051, η² = .003).

CONCLUSION

Although we were able to show successful training and interpretation of eFAST with paramedics, given the low prevalence of disease, our study did not show eFAST use improving patient outcome. However, the large likelihood ratio suggests its benefit may lie with appropriate trauma resource utilization.

Prehospital Ultrasound: A Narrative Review

Background: Point-of-care ultrasound is rapidly becoming more prevalent in the prehospital environment. Though considered a relatively new intervention in this setting, there is growing literature that aims to explore the use of prehospital ultrasound by EMS personnel.Methods: To better understand and report the state of the science on prehospital ultrasound, we conducted a narrative review of the literature.Results: Following a keyword search of MEDLINE in Ovid from inception to August 2, 2022, 2,564 records were identified and screened. Based on review of abstracts and full texts, with addition of seven articles via bibliography review, 193 records were included. Many included studies detail usage in air medical and other critical care transport environments. Clinicians performing prehospital ultrasound are often physicians or other advanced practice personnel who have previous ultrasound experience, which facilitates implementation in the prehospital setting. Emerging literature details training programs for prehospital personnel who are novices to ultrasound, and implementation for some study types appears feasible without prior experience. Unique use scenarios that show promise include during critical care transport, for triage in austere settings, and for thoracic evaluation of patients at risk of life-threatening pathology.Conclusion: There is a growing mostly observational body of literature describing the use of ultrasound by prehospital personnel. Prehospital ultrasound has demonstrated feasibility for specific conditions, yet interventional studies evaluating benefit to patient outcomes are absent.

Use of Point-of-Care Ultrasound by Intensive Care Paramedics to Assess Respiratory Distress in the Out-of-Hospital Environment: A Pilot Study

BACKGROUND

Respiratory distress is a common presentation attended by paramedics. Chest auscultation has been shown to have low accuracy for diagnosing respiratory complaints, and this can lead to inaccurate patient assessment and potentially poor patient outcomes. Conversely, lung ultrasound is a relatively simple exam allowing for rapid differentiation of respiratory complaints with comparable accuracy to more advanced imaging modalities. Evidence suggests that lung ultrasound is easy to learn and apply and could be ideal for assessment of respiratory illness by paramedics.

OBJECTIVE

This study aimed to explore the utility of out-of-hospital lung ultrasound performed by intensive care paramedics (ICP) for patients with medical causes of respiratory distress, and explore whether the use of lung ultrasound affects the ICP's clinical impression or management.

METHODS

This was a prospective observational pilot study. After a training program, a sample of ICPs working in metropolitan and regional Victoria, Australia used ultrasound to assess adult patients with respiratory distress and/or dyspnea. ICPs used a handheld point-of-care ultrasound device to scan respiratory patients using a modified protocol, and completed a worksheet with their scan findings. The scans were then reviewed by a subject matter expert for quality and agreement.

RESULTS

Ninety-five patients were enrolled over the study period. The average image quality score was 2.68/5, and 56% of scans were of interpretable quality. Interrater agreement (between the ICPs and the subject matter expert) was reported using Cohen's kappa. Moderate overall agreement (0.44) was shown, with the highest reliability reported in A-profile and B-profile (0.49 and 0.57). In 42% of cases performance of the scan affected paramedic clinical impression and/or management.

CONCLUSION

ICPs can perform lung ultrasound with moderate accuracy for some respiratory conditions, and the scans may affect clinical impression and management. Future research should focus on enhanced education, expert feedback, and clinical outcomes.

Use of Point-of-Care Ultrasound by Non-Physicians to Assess Respiratory Distress in the Out-of-Hospital Environment: A Scoping Review

Background:

The use of ultrasound in the out-of-hospital environment is increasingly feasible. The potential uses for point-of-care ultrasound (POCUS) by paramedics are many, but have historically been limited to traumatic indications. This study utilized a scoping review methodology to map the evidence for the use of POCUS by paramedics to assess respiratory distress and to gain a broader understanding of the topic.

Methods:

Databases Ovid MEDLINE, EMBASE, CINAHL Plus, and PUBMED were searched from January 1, 1990 through April 14, 2021. Google Scholar was searched, and reference lists of relevant papers were examined to identify additional studies. Articles were included if they reported on out-of-hospital POCUS performed by non-physicians for non-traumatic respiratory distress.

Results:

A total of 591 unique articles were identified, of which seven articles met the inclusion criteria. The articles reported various different scan protocols and, with one exception, suffered from low enrolments and low participation. Most articles reported that non-physician-performed ultrasound was feasible. Articles reported moderate to high levels of agreement between paramedics and expert reviewers for scan interpretation in most studies.

Conclusion:

Paramedics and emergency medical technicians (EMTs) have demonstrated the feasibility of lung ultrasound in the out-of-hospital environment. Further research should investigate the utility of standardized education and scanning protocols in paramedic-performed lung ultrasound for the differentiation of respiratory distress and the implications for patient outcomes.

Helicopter emergency medical services use of thoracic point of care ultrasound for pneumothorax: a systematic review and meta-analysis

Background

Auscultating for breath sounds to assess for pneumothorax in the helicopter emergency medical services (HEMS) settings can be extremely challenging. Thoracic point of care ultrasound (POCUS) offers a seemingly more useful visual (rather than audible) alternative. This review critically and quantitatively evaluates the use of thoracic POCUS for pneumothorax in the HEMS setting.

Methods

A systematic literature review with meta-analysis was conducted. Only papers reporting on patients undergoing POCUS for pneumothorax in the helicopter or pre-hospital setting were included. Primary outcome was accuracy, focusing on sensitivity and specificity. Secondary outcome was practicality. PubMed, Embase and the Cochrane Library were searched. The Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) was used to assess validity of studies.

Results

Twelve studies reporting on n = 1,936 images from medical and trauma patients were included in qualitative synthesis. Studies were nearly all observational designs. Most images were acquired by nurses or paramedics who were previously novices to ultrasound. The reference standard was predominantly CT. Specificity results were unanimously precise and very high, whereas sensitivity results were imprecise and extremely variable. Meta-analysis of eight studies involving n = 1,713 images yielded pooled sensitivity 61% (95% CI: 27–87%; I² = 94%) and pooled specificity 99% (95% CI: 98–100%; I² = 89%). Six studies involving n = 315 images reported practicality. The highest or second highest categorisation of image quality was reported in around half of those images.

Conclusion

Thoracic POCUS is highly specific but has extremely variable sensitivity for pneumothorax when performed in the HEMS setting. This is from purely a diagnostic (not clinical) perspective. Sensitivity increases when only clinically significant pneumothoraces are considered. Case reports reveal thoracic POCUS can appropriately alter treatment and triage decisions, but only for a small number of patients. It appears predominantly useful in mitigating against unnecessary interventions. More research reporting patient focused outcomes is required. In the meantime, thoracic POCUS appears to offer a more appropriate visual alternative to auscultation for breath sounds when assessing for pneumothorax in the HEMS setting.

Use of Point-of-Care Ultrasound in the Pediatric and Neonatal Emergency Transport Realm

Point-of-care ultrasound (POCUS) is a tool often used by clinical providers in the care of critically ill or acutely injured patients. POCUS can be used to evaluate for potentially harmful conditions during transport and to optimize downstream management. Although available literature primarily focuses on adults in the prehospital, critical care, and austere environment realm, more literature supporting POCUS use during pediatric and neonatal transport has emerged over the last few years. What is currently available is often from diverse operators and a wide variety of applications. The goal of this article is to describe current pediatric and neonatal POCUS applications and to identify its barriers and limitations in the transport realm. [Pediatr Ann. 2021;50(10):e432-e436.].

Quality of focused thoracic ultrasound performed by emergency medical technicians and paramedics in a prehospital setting: a feasibility study

BACKGROUND

In a prehospital setting, the severity of respiratory symptoms in patients calling for an ambulance differ. The initial evaluation, diagnosing, and thereby management can be challenging because respiratory symptoms can be caused by disease in many organs. Ultrasound examinations can contribute with important information and support the clinical decision-making. However, ultrasound is user-dependent and requires sufficient knowledge and training. The aim of this study was to explore the quality of thoracic ultrasound examinations performed on patients by emergency medical technicians and paramedics in a prehospital, clinical setting.

METHODS

From November 2018 - April 2020, Danish emergency medical technicians and paramedics (n = 100) performed thoracic ultrasound examinations on patients with respiratory symptoms using a portable ultrasound device. The ultrasound examinations were stored and retrospectively assessed by a reviewer blinded to the patients' symptoms and history, as well as the emergency medical technicians' and paramedics' findings. The image quality was scored from 1 to 5. The findings determined by the reviewer was then correlated with a questionnaire filled out by the emergency medical technicians and paramedics regarding ultrasonic findings and potential change in treatment or management of the patient. The agreement in percentage and as Cohen's kappa was explored.

RESULTS

A total of 590 ultrasound examinations were assessed, resulting in a median image quality score of 3 (IQ1 = 4, IQ3 = 3). The overall agreement in percentage between the emergency medical technicians and paramedics and reviewer was high (87.7% for a normal scan, 89.9% for interstitial syndrome, 97.3% for possible pneumothorax, and 96.3% for pleural effusion). Cohen's kappa varied from 0.01 for possible pneumothorax to 0.69 for pleural effusion. Based on the questionnaires (n = 406), the ultrasound examination entailed a change in treatment or visitation in 48 cases (11.7%) which in this study population encompasses a number-needed-to-scan of 8.5.

CONCLUSION

Emergency medical technicians and paramedics perform focused thoracic ultrasound examinations with adequate image quality sufficient to determine if pathology is present or not. The emergency medical technicians' and paramedics' assessment correlates to some extent with an experienced reviewer and their findings are most reliable for the inclusion of a normal scan or inclusion of pleural effusion. Implementation could possibly impact the number of patients receiving correct prehospital treatment and optimal choice of receiving facility.

Utility of Different Lung Ultrasound Simulation Modalities Used by Paramedics during Varied Ambulance Driving Conditions

INTRODUCTION

Prehospital use of lung ultrasound (LUS) by paramedics to guide the diagnoses and treatment of patients has expanded over the past several years. However, almost all of this education has occurred in a classroom or hospital setting. No published prehospital use of LUS simulation software within an ambulance currently exists.

STUDY OBJECTIVE

The objective of this study was to determine if various ambulance driving conditions (stationary, constant acceleration, serpentine, and start-stop) would impact paramedics' abilities to perform LUS on a standardized patient (SP) using breath-holding to simulate lung pathology, or to perform LUS using ultrasound (US) simulation software. Primary endpoints included the participating paramedics': (1) time to acquiring a satisfactory simulated LUS image; and (2) accuracy of image recognition and interpretation. Secondary endpoints for the breath-holding portion included: (1) the agreement between image interpretation by paramedic versus blinded expert reviewers; and (2) the quality of captured LUS image as determined by two blinded expert reviewers. Finally, a paramedic LUS training session was evaluated by comparing pre-test to post-test scores on a 25-item assessment requiring the recognition of a clinical interpretation of prerecorded LUS images.

METHODS

Seventeen paramedics received a 45-minute LUS lecture. They then performed 25 LUS exams on both SPs and using simulation software, in each case looking for lung sliding, A and B lines, and seashore or barcode signs. Pre- and post-training, they completed a 25-question test consisting of still images and videos requiring pathology recognition and formulation of a clinical diagnosis. Sixteen paramedics performed the same exams in an ambulance during different driving conditions (stationary, constant acceleration, serpentines, and abrupt start-stops). Lung pathology was block randomized based on driving condition.

RESULTS

Paramedics demonstrated improved post-test scores compared to pre-test scores (P <.001). No significant difference existed across driving conditions for: time needed to obtain a simulated image; clinical interpretation of simulated LUS images; quality of saved images; or agreement of image interpretation between paramedics and blinded emergency physicians (EPs). Image acquisition time while parked was significantly greater than while the ambulance was driving in serpentines (Z = -2.898; P = .008). Technical challenges for both simulation techniques were noted.

CONCLUSION

Paramedics can correctly acquire and interpret simulated LUS images during different ambulance driving conditions. However, simulation techniques better adapted to this unique work environment are needed.

Can non-physician advanced retrieval practitioners (ARP) acquire and interpret diagnostic views of the lungs with sufficient quality to aid in the diagnosis of pneumothorax in the pre-hospital and retrieval environment?

Background

As an adjunct to physical examination, ultrasound is a potentially attractive option for diagnosing pneumothoraces in the pre-hospital and retrieval environment – and could confer a benefit to patient safety. However, the published evidence supporting non-physicians use of ultrasound in this setting is limited.

Aim

We aimed to establish if Advanced Retrieval Practitioners (non-physicians) could acquire ultrasound views of the lungs and interpret them with sufficient quality to diagnose pneumothorax in the pre-hospital and retrieval environment when compared to expert review.

Method

The study consisted of an observational trial from April 2017 to April 2018. Twelve (12) patients bilateral lung ultrasound images (24 images) were randomly selected from 87 patients assessed using Point of Care Ultrasound (POCUS) by three Advanced Retrieval Practitioners in the Pre-hospital and Retrieval environment. Two expert reviewers’ evaluated these images to determine ARPs ability to acquire diagnostic quality images and interpret them correctly. CXR results of patients in whom lung ultrasound was undertaken were recorded as the reference standard investigation.

Results

Within the 22 images considered adequate by the Advanced Retrieval Practitioners, 19 (86.4%, one-tailed McNemar test p = 0.125) were considered adequate on expert review. Of the 19 images mutually considered as adequate, both the Advanced Retrieval Practitioners and the reviewers identified two pneumothoraces which were subsequently confirmed on chest x-ray (Sensitivity 100% and Specificity 100% in technically adequate images). One pneumothorax was detected on CXR in a patient with inadequate ultrasound images. Advanced Retrieval Practitioners were therefore able to both obtain adequate images and correctly diagnose pneumothorax in the pre-hospital environment with 66.6% sensitivity (95%CI 66.6–100%) and 100% specificity (95%CI 81.0–100%) compared to expert review.

Conclusion

Advanced Retrieval Practitioners (non-physicians) can obtain diagnostic views of the lungs of sufficient quality to diagnose the presence, or particularly the absence, of pneumothorax in the pre-hospital and retrieval environment. Although Advanced Retrieval Practitioners were less accurate than the expert reviewers at interpreting the quality of the ultrasound images, the result was not statistically significant, despite the ARPs possibly having been at a methodological disadvantage.

Point-of-Care Teleultrasound: A Systematic Review

Background: Telemedicine and point-of-care ultrasound have merged to create a field known as teleultrasound (TUS). Real-time TUS involves the transmission of bedside ultrasound (US) images with direct feedback from an US expert. In this review, we summarize the current uses of real-time TUS and discuss its potential future uses. Methods: We performed a literature search (PubMed and EMBase) to assess articles related to real-time TUS. Data were extracted using a standardized collection form, and relevant articles were separated into feasibility or clinical studies. Results: Our search yielded 45 articles, with most of the reports taking place in resource-constrained settings. A large portion of the studies discussed the use of the focused assessment with sonography in trauma exam. Others included musculoskeletal, vascular, and echocardiography. Conclusion: Real-time TUS allows for rapid access to diagnostic imaging in various clinical settings. This technology is poised to expand with many uses on the horizon.

A Blended Prehospital Ultrasound Curriculum for Critical Care Paramedics

OBJECTIVE

Point-of-care ultrasound is a nascent and growing area of prehospital care. Most previously described ultrasound curricula for paramedics examine a single type of ultrasound scan. Here, we describe the implementation and evaluation of a prehospital ultrasound curriculum using a blended model of traditional didactics and hands-on experience with online prereading.

METHODS

We recruited a prospective convenience sample of critical care paramedics without prior ultrasound experience to take part in a 2-day ultrasound course. All participants completed prereading modules built from online resources followed by a didactic review of the material and hands-on practice. Ultrasound examinations included extended focused abdominal sonography in trauma, cardiac ultrasound, thoracic ultrasound, and vascular ultrasound. A written examination evaluated ultrasound theory and image interpretation, and a practical examination evaluated image acquisition.

RESULTS

Seventeen critical care paramedics completed the course with a mean grade on the written examination of 76%, with 76% of paramedics achieving the predetermined passing mark of 70% or greater. All paramedics passed the practical examination.

CONCLUSION

The implementation of a prehospital critical care ultrasound program is feasible in our provincial emergency medical services system. Further assessment is necessary to determine future knowledge and skill retention as well as clinical application and utility in real-world settings.

Defining a Theory-Driven Ultrasound Curriculum for Prehospital Providers

Advances in point-of-care ultrasound technology have allowed for the extension of emergency medicine ultrasound beyond the walls of the emergency department. Emergency medical system providers may benefit from the use of ultrasound. It has previously been shown that with a brief introductory course, novices can obtain and correctly interpret focused ultrasound examinations. The purpose of this study was to design a theory-driven point-of-care ultrasound curriculum to assess and develop ultrasound skill in prehospital providers. The resultant curriculum outlined in this paper encompasses a large array of skills that may be useful for different prehospital services to use to develop curriculum for their own needs.

Which ultrasound transducer type is best for diagnosing pneumothorax?

Background

An accurate physical examination is essential in the care of critically ill and injured patients. However, to diagnose or exclude a pneumothorax, chest auscultation is unreliable compared to lung ultrasonography. In the dynamic prehospital environment, it is desirable to have the best possible ultrasound transducer readily available. The objective is to assess the difference between a linear-array, curved-array, and phased-array ultrasound transducer in the assessment for pneumothorax and to determine which is best.

Methods

In this double-blinded, cross-sectional, observational study, 15 observers, experienced in lung ultrasonography, each assessed 66 blinded ultrasound video clips of either normal ventilation or pneumothorax that were recorded with three types of ultrasound transducers. The clips were recorded in 11 adult patients that underwent thoracoscopic lung surgery immediately before and after the surgeon opened the thorax. The diagnostic accuracy of the three transducers, elapsed time until a diagnosis was made, and the perceived image quality was recorded.

Results

In total, 15 observers assessed 990 ultrasound video clips. The overall sensitivity and specificity were 98.2% and 97.2%, relatively. No significant difference was found in the diagnostic performance between transducers. A diagnosis was made slightly faster in the linear-array transducer clips, compared to the phased-array transducer (p = .031). For the linear-, curved-, and phased-array transducer, the image quality was rated at a median (interquartile range [IQR]) of 4 (IQR 3–4), 3 (IQR 2–4), and 2 (IQR 1–2), relatively. Between the transducers, the difference in image quality was significant (p < .0001).

Conclusions

There was no difference in diagnostic performance of the three transducers. Based on image quality, the linear-array transducer might be preferred for (prehospital) lung ultrasonography for the diagnosis of pneumothorax.

Quality And Feasibility of Sonographic Measurement of the Optic Nerve Sheath Diameter to Estimate the Risk of Raised Intracranial Pressure After Traumatic Brain Injury in Prehospital Setting

OBJECTIVE

In patients with traumatic brain injury (TBI), early detection and subsequent prompt treatment of elevated intracranial pressure (ICP) is a challenge in the prehospital setting, because physical examination is limited in comatose patients and invasive device placement is not possible. The aim of this study was to evaluate the quality and feasibility of optic nerve sheath diameter (ONSD) measurements obtained during the prehospital management of patients with TBI.

METHODS

This study was a prospective, observational study of 23 patients with moderate and severe TBI during prehospital medical care. The primary endpoint was the quality of ONSD measurements expressed as the percentage of ONSD validated by the experts. Secondary endpoints included the feasibility of ONSD measurements as the percentage of ONSD performed and assessment by operators of ease and duration to perform.

RESULTS

Ultrasound ONSD was performed in 19 (82%) patients and 80% of ONSD measurements were validated by the experts. The ONSD measurements were possible in 15 (79%) cases. The physicians have assessed the ease of use at 8 (interquartile range [IQR] = 2.5-8) on 10 for and the median time to obtain ONSD measurement was 4 min (IQR = 3-5). ONSD measurement was performed in 12 (63%) cases during the transport and in 7 (37%) cases on scene, with 58% (n = 7) and 71% (n = 5) validated ONSD, respectively. The success rate in the helicopter was 43% compared to 80% in the ambulance.

CONCLUSION

This study shows that it is feasible to obtain high-quality ONSD measurements in the management of patients with TBI in a prehospital setting. A randomized study evaluating the usefulness of ONSD to guide management of TBI in the prehospital phase may be of great interest.

ABCDE of prehospital ultrasonography: a narrative review

Prehospital point-of-care ultrasound used by nonradiologists in emergency medicine is gaining ground. It is feasible on-scene and during aeromedical transport and allows health-care professionals to detect or rule out potential harmful conditions. Consequently, it impacts decision-making in prioritizing care, selecting the best treatment, and the most suitable transport mode and destination. This increasing relevance of prehospital ultrasonography is due to advancements in ultrasound devices and related technology, and to a growing number of applications. This narrative review aims to present an overview of prehospital ultrasonography literature. The focus is on civilian emergency (trauma and non-trauma) setting. Current and potential future applications are discussed, structured according to the airway, breathing, circulation, disability, and environment/exposure (ABCDE) approach. Aside from diagnostic implementation and specific protocols, procedural guidance, therapeutic ultrasound, and challenges are reviewed.

The role of point of care ultrasound in prehospital critical care: a systematic review

Background

In 2011, the role of Point of Care Ultrasound (POCUS) was defined as one of the top five research priorities in physician-provided prehospital critical care and future research topics were proposed; the feasibility of prehospital POCUS, changes in patient management induced by POCUS and education of providers. This systematic review aimed to assess these three topics by including studies examining all kinds of prehospital patients undergoing all kinds of prehospital POCUS examinations and studies examining any kind of POCUS education in prehospital critical care providers.

Methods and results

By a systematic literature search in MEDLINE, EMBASE, and Cochrane databases, we identified and screened titles and abstracts of 3264 studies published from 2012 to 2017. Of these, 65 studies were read in full-text for assessment of eligibility and 27 studies were ultimately included and assessed for quality by SIGN-50 checklists. No studies compared patient outcome with and without prehospital POCUS. Four studies of acceptable quality demonstrated feasibility and changes in patient management in trauma. Two studies of acceptable quality demonstrated feasibility and changes in patient management in breathing difficulties. Four studies of acceptable quality demonstrated feasibility, outcome prediction and changes in patient management in cardiac arrest, but also that POCUS may prolong pauses in compressions. Two studies of acceptable quality demonstrated that short (few hours) teaching sessions are sufficient for obtaining simple interpretation skills, but not image acquisition skills. Three studies of acceptable quality demonstrated that longer one- or two-day courses including hands-on training are sufficient for learning simple, but not advanced, image acquisition skills. Three studies of acceptable quality demonstrated that systematic educational programs including supervised examinations are sufficient for learning advanced image acquisition skills in healthy volunteers, but that more than 50 clinical examinations are required for expertise in a clinical setting.

Conclusion

Prehospital POCUS is feasible and changes patient management in trauma, breathing difficulties and cardiac arrest, but it is unknown if this improves outcome. Expertise in POCUS requires extensive training by a combination of theory, hands-on training and a substantial amount of clinical examinations – a large part of these needs to be supervised.

Electronic supplementary material

The online version of this article (10.1186/s13049-018-0518-x) contains supplementary material, which is available to authorized users.

Prehospital Ultrasound in Trauma: A Review of Current and Potential Future Clinical Applications

Ultrasound (US) is an essential tool for evaluating trauma patients in the hospital setting. Many previous in-hospital studies have been extrapolated to out of hospital setting to improve diagnostic accuracy in prehospital and austere environments. This review article presents the role of prehospital US in blunt and penetrating trauma management with emphasis on its current clinical applications, challenges, and future implications of such use.

Educational standards for training paramedics in ultrasound: a scoping review

BACKGROUND

Paramedic-performed out-of-hospital ultrasound is a novel skill that has gained popularity in some services in recent years. In this setting point-of care ultrasound (POCUS) can provide additional information that can assist with management and guide transport to the most appropriate facility. We sought to explore the different educational approaches used for training paramedics in ultrasound in the out-of-hospital setting.

METHODS

Ovid MEDLINE, EMBASE, EBM Reviews, The Cochrane Library, CINAHL plus, The Monash University Research Repository and the British Thesis Library were searched from the 1^st of January 1990 to the 6^th of April 2016. Google Scholar was searched and reference lists of relevant papers were examined to identify additional studies. Articles were included if they reported on out-of-hospital and POCUS educational approaches for paramedics.

RESULTS

A total of 2002 unique articles were identified of which 18 articles met the inclusion criteria. Most articles reported combined cohorts of emergency providers with varying years of experience though most operators were POCUS naïve. The most common clinical assessment for which paramedic POCUS curricula was described was the focused assessment sonography for trauma (FAST) examination. Education programs varied from two-minutes to two-days with all studies including both didactic and practical training.

CONCLUSION

Education programs for POCUS for paramedics vary considerably, and do not appear to align with qualification level or clinical experience. Further research investigating education and subsequent clinical application of POCUS by paramedics is required, as well as prospective, outcome based studies in order to measure the clinical utility of out-of-hospital POCUS.

Assessment of Paramedic Ultrasound Curricula: A Systematic Review

OBJECTIVE

Prehospital ultrasound is being applied in the field. The purpose of this systematic review is to describe evidence pertaining to ultrasound curricula for paramedics specifically, including content, duration, setting, design, evaluation, and application.

METHODS

Electronic searches of MEDLINE, Embase, CINAHL, and the Cochrane Center Register of Controlled Trials were conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Primary literature describing acute care ultrasound curricula for paramedics were included. Two authors independently extracted data and assessed quality using 2 validated tools.

RESULTS

Twelve studies with 187 paramedics were included. Curricula duration varied, with effective curricula teaching focused assessment with sonography for trauma (FAST) in 6 to 8 hours and pleural ultrasound in 25 minutes. FAST, pleural, and fracture-detection ultrasound are being applied in the field by paramedics; however, no literature exists describing application to detect cardiac standstill. Curricula combined didactic and hands-on components including simulation and evaluated competency using sensitivity and specificity of paramedic-performed ultrasound.

CONCLUSIONS

Paramedic ultrasound curricula in FAST and pleural ultrasound is feasible and time effective with successful application. Although fracture detection ultrasound is being used by the special operations forces, no comprehensive curriculum was described. Curricula designed to detect cardiac standstill have been too short, and successful application by paramedics has not been shown.

Thoracic ultrasound: An adjunctive and valuable imaging tool in emergency, resource-limited settings and for a sustainable monitoring of patients

Imaging workup of patients referred for elective assessment of chest disease requires an articulated approach: Imaging is asked for achieving timely diagnosis. The concurrent or subsequent use of thoracic ultrasound (TUS) with conventional (chest X-rays-) and more advanced imaging procedures (computed tomography and magnetic resonance imaging) implies advantages, limitations and actual problems. Indeed, despite TUS may provide useful imaging of pleura, lung and heart disease, emergency scenarios are currently the most warranted field of application of TUS: Pleural effusion, pneumothorax, lung consolidation. This stems from its role in limited resources subsets; actually, ultrasound is an excellent risk reducing tool, which acts by: (1) increasing diagnostic certainty; (2) shortening time to definitive therapy; and (3) decreasing problems from blind procedures that carry an inherent level of complications. In addition, paediatric and newborn disease are particularly suitable for TUS investigation, aimed at the detection of congenital or acquired chest disease avoiding, limiting or postponing radiological exposure. TUS improves the effectiveness of elective medical practice, in resource-limited settings, in small point of care facilities and particularly in poorer countries. Quality and information provided by the procedure are increased avoiding whenever possible artefacts that can prevent or mislead the achievement of the correct diagnosis. Reliable monitoring of patients is possible, taking into consideration that appropriate expertise, knowledge, skills, training, and even adequate equipment’s suitability are not always and everywhere affordable or accessible. TUS is complementary imaging procedure for the radiologist and an excellent basic diagnostic tool suitable to be shared with pneumologists, cardiologists and emergency physicians.

Effect of ultrasound training of physicians working in the prehospital setting

BACKGROUND

Advances in technology have made ultrasound (US) devices smaller and portable, hence accessible for prehospital care providers. This study aims to evaluate the effect of a four-hour, hands-on US training course for physicians working in the prehospital setting. The primary outcome measure was US performance assessed by the total score in a modified version of the Objective Structured Assessment of Ultrasound Skills scale (mOSAUS).

METHODS

Prehospital physicians participated in a four-hour US course consisting of both hands-on training and e-learning including a pre- and a post-learning test. Prior to the hands-on training a pre-training test was applied comprising of five videos in which the participants should identify pathology and a five-minute US examination of a healthy volunteer portraying to be a shocked patient after a blunt torso trauma. Following the pre-training test, the participants received a four-hour, hands-on US training course which was concluded with a post-training test. The US examinations and screen output from the US equipment were recorded for subsequent assessment. Two blinded raters assessed the videos using the mOSAUS.

RESULTS

Forty participants completed the study. A significant improvement was identified in e-learning performance and US performance, (37.5 (SD: 10.0)) vs. (51.3 (SD: 5.9) p = < 0.0001), total US performance score (15.3 (IQR: 12.0-17.5) vs. 17.5 (IQR: 14.5-21.0), p = < 0.0001) and in each of the five assessment elements of the mOSAUS.

CONCLUSION

In the prehospital physicians assessed, we found significant improvements in the ability to perform US examinations after completing a four-hour, hands-on US training course.

Five-year Retrospective Review of Physician and Non-physician Performed Ultrasound in a Canadian Critical Care Helicopter Emergency Medical Service

OBJECTIVE

To describe the use of prehospital ultrasonography (PHUS) to support interventions, when used by physician and non-physician air medical crew (AMC), in a Canadian helicopter emergency medical service (HEMS).

METHODS

A retrospective review was conducted of consecutive patients who underwent ultrasound examination during HEMS care from January 1, 2009 through March 10, 2014. An a priori created data form was used to record patient demographics, type of ultrasound scan performed, ultrasound findings, location of scan, type of interventions supported by PHUS, factors that affected PHUS completion, and quality indicator(s). Data analysis was performed through descriptive statistics, Student's t-test for continuous variables, Z-test for proportions, and Mann-Whitney U Test for nonparametric data. Outcomes included interventions supported by PHUS, factors associated with incomplete scans, and quality indicators associated with PHUS use. Differences between physician and AMC groups were also assessed.

RESULTS

PHUS was used in 455 missions, 318 by AMC and 137 by physicians. In combined trauma and medical patients, in the AMC group interventions were supported by PHUS in 26% of cases (95% CI 18-34). For transport physicians the percentage support was found to be significantly greater at 45% of cases (95% CI 34-56) p = < 0.006. Incomplete PHUS scans were common and reasons included patient obesity, lack of time, patient access, and clinical reasons. Quality indicators associated with PHUS were rarely identified.

CONCLUSIONS

The use of PHUS by both physicians and non-physicians was found to support interventions in select trauma and medical patients. Key words: emergency medical services; aircraft; helicopter; air ambulance; ultrasonography; emergency care, prehospital; prehospital emergency care.

Prehospital ultrasound of the abdomen and thorax changes trauma patient management: A systematic review

BACKGROUND

Ultrasound examination of trauma patients is increasingly performed in prehospital services. It is unclear if prehospital sonographic assessments change patient management: providing prehospital diagnosis and treatment, determining choice of destination hospital, or treatment at the receiving hospital.

OBJECTIVE

This review aims to assess and grade the evidence that specifically examines whether prehospital ultrasound (PHUS) of the thorax and/or abdomen changes management of the trauma patient.

METHODS

A systematic review was conducted of trauma patients who had an ultrasound of the thorax or abdomen performed in the prehospital setting. PubMed, MEDLINE, Web of Science (CINAHL, EMBASE, Cochrane Central Register of Controlled Trials) and the reference lists of included studies were searched. Methodological quality was checked and risk of bias analysis performed, a level of evidence grade was assigned, and descriptive data analysis performed.

RESULTS

992 unique citations were identified, which included eight studies that met inclusion criteria with a total of 925 patients. There are no reports of randomised controlled trials. Heterogeneity exists between the included studies which ranged from a case series to retrospective and prospective non-randomised observational studies. Three studies achieved a 2+ Scottish Intercollegiate Guidelines Networks grade for quality of evidence and the remainder demonstrated a high risk of bias. The three best studies each provided examples of prehospital ultrasound positively changing patient management.

CONCLUSION

There is moderate evidence that supports prehospital physician use of ultrasound for trauma patients. For some patients, management was changed based on the results of the PHUS. The benefit of ultrasound use in non-physician services is unclear.

Prehospital Evaluation of Effusion, Pneumothorax, and Standstill (PEEPS): Point-of-care Ultrasound in Emergency Medical Services

Introduction

In the United States, there are limited studies regarding use of prehospital ultrasound (US) by emergency medical service (EMS) providers. Field diagnosis of life-threatening conditions using US could be of great utility. This study assesses the ability of EMS providers and students to accurately interpret heart and lung US images.

Methods

We tested certified emergency medical technicians (EMT-B) and paramedics (EMT-P) as well as EMT-B and EMT-P students enrolled in prehospital training programs within two California counties. Participants completed a pre-test of sonographic imaging of normal findings and three pathologic findings: pericardial effusion, pneumothorax, and cardiac standstill. A focused one-hour lecture on emergency US imaging followed. Post-tests were given to all EMS providers immediately following the lecture and to a subgroup one week later.

Results

We enrolled 57 prehospital providers (19 EMT-B students, 16 EMT-P students, 18 certified EMT-B, and 4 certified EMT-P). The mean pre-test score was 65.2%±12.7% with mean immediate post-test score of 91.1%±7.9% (95% CI [22%–30%], p<0.001). Scores significantly improved for all three pathologic findings. Nineteen subjects took the one-week post-test. Their mean score remained significantly higher: pre-test 65.8%±10.7%; immediate post-test 90.5%±7.0% (95% CI [19%–31%], p<0.001), one-week post-test 93.1%±8.3% (95% CI [21%–34%], p<0.001).

Conclusion

Using a small sample of EMS providers and students, this study shows the potential feasibility for educating prehospital providers to accurately identify images of pericardial effusion, pneumothorax, and cardiac standstill after a focused lecture.

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.

Point-of-care ultrasonography during rescue operations on board a Polish Medical Air Rescue helicopter

Point-of-care ultrasound examination has been increasingly widely used in pre-hospital care. The use of ultrasound in rescue medicine allows for a quick differential diagnosis, identification of the most important medical emergencies and immediate introduction of targeted treatment. Performing and interpreting a pre-hospital ultrasound examination can improve the accuracy of diagnosis and thus reduce mortality. The authors' own experiences are presented in this paper, which consist in using a portable, hand-held ultrasound apparatus during rescue operations on board a Polish Medical Air Rescue helicopter. The possibility of using an ultrasound apparatus during helicopter rescue service allows for a full professional evaluation of the patient's health condition and enables the patient to be brought to a center with the most appropriate facilities for their condition.

Prehospital emergency ultrasound: a review of current clinical applications, challenges, and future implications

Imaging modalities in the prehospital setting are helpful in the evaluation and management of time-sensitive emergency conditions. Ultrasound is the main modality that has been applied by emergency medical services (EMS) providers in the field. This paper examines the clinical applications of ultrasound in the prehospital setting. Specific focus is on applications that provide essential information to guide triage and management of critical patients. Challenges of this modality are also described in terms of cost impact on EMS agencies, provider training, and skill maintenance in addition to challenges related to the technical aspect of ultrasound.