Ultrasound Use in the Prehospital Setting for Trauma: A Systematic Review

Variables for reporting studies on extended - focused assessment with sonography for trauma (E-FAST): An international delphi consensus study

BACKGROUND

The Extended Focused Assessment with Sonography for Trauma (E-FAST) is a diagnostic ultrasound technique used in hospital and pre-hospital settings for patients with torso trauma. While E-FAST is common in emergency departments, its pre-hospital use is less routine. This study aims to establish a set of variables for designing studies on pre-hospital E-FAST through a Delphi consensus process involving international experts.

METHODS

A Delphi consensus process was utilized, involving four rounds of e-mail to the experts. The experts proposed variables for each category, assessed them using a 5-point Likert scale, and voted on whether they should be included in the final template.

RESULTS

Out of 14 invited experts, 9 participated in the study. In total, the experts proposed 247 variables. After four rounds, a final list of 32 variables was approved by all experts. These variables related to the system, patient, process, training, imaging, outcome, and others.

CONCLUSIONS

This Delphi consensus study presents a list of 32 variables for future research studies concerning the use of E-FAST ultrasound in pre-hospital settings. The results of this study are significant as they provide a standardized set of variables that will facilitate the comparison of data obtained from various studies. This will ultimately contribute to the advancement of pre-hospital E-FAST research and practice.

Development and evaluation of a point-of-care ultrasound curriculum for paramedics in Germany - a prospective observational study and comparison

BACKGROUND

Point-of-care ultrasound (POCUS) is steadily growing in use in prehospital emergency medicine. While currently used primarily by emergency physicians, POCUS could also be employed by paramedics to support diagnosis and decision-making. Yet to date, no paramedicine-targeted POCUS curricula exist in Germany. Furthermore, given time and resource constraints in paramedic training, it is unclear whether paramedics could feasibly learn POCUS for prehospital deployment. Hence, this study outlines the development and implementation of a comprehensive POCUS curriculum for paramedics. Through this curriculum, we investigate whether paramedics can attain proficiency in POCUS comparable to other user groups.

METHODS

In this prospective observational study, we first developed a blended learning-based POCUS curriculum specifically for paramedics, focusing on basic principles, the RUSH-Protocol and ultrasound guided procedures. Participants underwent digital tests to measure their theoretical competence before (T1) and after the digital preparation phase (T2), as well as at the end of the on-site phase (T3). At time point T3, we additionally measured practical competence using healthy subjects and simulators. We compared the theoretical competence and the practical competence on a simulator with those of physicians and medical students who had also completed ultrasound training. Furthermore, we carried out self-assessment evaluations, as well as evaluations of motivation and curriculum satisfaction.

RESULTS

The paramedic study group comprised n = 72 participants. In the theoretical test, the group showed significant improvement between T1 and T2 (p < 0.001) and between T2 and T3 (p < 0.001). In the practical test on healthy subjects at T3, the group achieved high results (87.0% ± 5.6). In the practical test on a simulator at T3, paramedics (83.8% ± 6.6) achieved a lower result than physicians (p < 0.001), but a comparable result to medical students (p = 0.18). The results of the study group's theoretical tests (82.9% ± 9.2) at time point T3 were comparable to that of physicians (p = 0.18) and better than that of medical students (p < 0.01). The motivation and attitude of paramedics towards the prehospital use of POCUS as well as their self-assessment significantly improved from T1 to T3 (p < 0.001). The overall assessment of the curriculum was positive (92.1 ± 8.5).

CONCLUSION

With our tailored curriculum, German paramedics were able to develop skills in POCUS comparable to those of other POCUS learners. Integration of POCUS into paramedics' training curricula offers opportunities and should be further studied.

Prehospital Trauma Care

Prehospital trauma evaluation begins with the primary assessment of airway, breathing, circulation, disability, and exposure. This is closely followed by vital signs and a secondary assessment. Key prehospital interventions include management and resuscitation according to the aforementioned principles with a focus on major hemorrhage control, airway compromise, and invasive management of tension pneumothorax. Determining the appropriate time and method for transportation (eg, ground ambulance, helicopter, police, private vehicle) to the hospital or when to terminate resuscitation are also important decisions to be made by emergency medical services clinicians.

Prehospital ultrasound scanning for abdominal free fluid detection in trauma patients: a systematic review and meta-analysis

INTRODUCTION

Focused assessment with sonography for trauma helps detect abdominal free fluid. Prehospital ultrasound scanning is also important because the early diagnosis of hemoperitoneum may reduce the time to definitive treatment in the hospital. This study investigated whether prehospital ultrasound scanning can help detect abdominal free fluid.

MATERIALS AND METHODS

In this systematic review, relevant databases were searched for studies investigating prehospital ultrasound examinations for abdominal free fluid in trauma patients. The prehospital ultrasound results were compared with computed tomography, surgery, or hospital ultrasound examination data. The pooled sensitivity and specificity values were analyzed using forest plots. The overall predictive power was calculated by the summary receiver operating characteristic curve. The quality of the included studies was assessed using the quality assessment of diagnostic accuracy studies tool. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) was performed to assess the certainty of evidence.

RESULT

This meta-analysis comprised six studies that included 1356 patients. The pooled sensitivity and specificity values were 0.596 (95% confidence interval [CI] = 0.345-0.822) and 0.970 (95% CI = 0.953-0.983), respectively. The pooled area under the summary receiver operating characteristic curve was 0.998. The quality assessment tool showed favorable results. In the GRADE analysis, the quality of evidence was very low for sensitivity and high for specificity when prehospital ultrasound was used for hemoperitoneum diagnosis.

CONCLUSION

The specificity of abdominal free fluid detection using prehospital ultrasound examinations in trauma patients was very high.

Guidance for clinical practice using emergency and point-of-care ultrasonography

Owing to the miniaturization of diagnostic ultrasound scanners and their spread of their bedside use, ultrasonography has been actively utilized in emergency situations. Ultrasonography performed by medical personnel with focused approaches at the bedside for clinical decision-making and improving the quality of invasive procedures is now called point-of-care ultrasonography (POCUS). The concept of POCUS has spread worldwide; however, in Japan, formal clinical guidance concerning POCUS is lacking, except for the application of focused assessment with sonography for trauma (FAST) and ultrasound-guided central venous cannulation. The Committee for the Promotion of POCUS in the Japanese Association for Acute Medicine (JAAM) has often discussed improving the quality of acute care using POCUS, and the "Clinical Guidance for Emergency and Point-of-Care Ultrasonography" was finally established with the endorsement of JAAM. The background, targets for acute care physicians, rationale based on published articles, and integrated application were mentioned in this guidance. The core points include the fundamental principles of ultrasound, airway, chest, cardiac, abdominal, and deep venous ultrasound, ultrasound-guided procedures, and the usage of ultrasound based on symptoms. Additional points, which are currently being considered as potential core points in the future, have also been widely mentioned. This guidance describes the overview and future direction of ultrasonography for acute care physicians and can be utilized for emergency ultrasound education. We hope this guidance will contribute to the effective use of ultrasonography in acute care settings in Japan.

[The correct way to deal with the definitive surgical airway]

Dealing with a difficult airway is familiar to emergency care providers in both the prehospital and clinical settings. In anesthesiology and emergency medical care different algorithms almost equal in their wording have been introduced, indicating that an emergency front of neck airway access (eFONA) has to be established in the case of a cannot ventilate-cannot oxygenate situation. In a survey (Surveymonkey®) data concerning the level of experience with eFONA, devices required, previous training and complications were allocated among acute and emergency care providers of different backgrounds (doctors and paramedics). Furthermore, we asked about individual attitudes to and frequency of previous situations, in which an eFONA was not established despite strong indications. Of the respondents 15% (n = 63) answered that they had experienced this type of situation. eFONA had been performed by 28% of the interviewed (n = 117), reflecting the high number of military and EMT (emergency medical team) physicians participating in the survey. The number of experiences are rarely representative for the civilian setting. Different adjuncts may be helpful to detect the cricothyroid ligament. To use ultrasound seems obvious but it doubles the time for the detection of the cricothyroid ligament. Laryngeal masks can be employed as a supraglottic airway device (SAD) during "plan B". Stabilizing the airway with a SAD almost doubles the success of identifying laryngeal landmarks in females. The crew resource management (CRM) guidelines are more than essential in threatening situations demanding measures like eFONA. Providers should anticipate emerging problems and whenever feasible call for help and finally speak up. Naming a failed airway should be avoided as it implies a failure of the provider or of the entire airway team. In fact, the term non-accessible airway should be introduced. This might help to avoid the implication of a major failure. So far, an ideal simulator to train eFONA has not been introduced but it is mandatory to train procedures and algorithms on different types of simulators and manikins to achieve mastery.

The European guideline on management of major bleeding and coagulopathy following trauma: sixth edition

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Detection of pneumothorax on ultrasound using artificial intelligence

BACKGROUND

Ultrasound (US) for the detection of pneumothorax shows excellent sensitivity in the hands of skilled providers. Artificial intelligence may facilitate the movement of US for pneumothorax into the prehospital setting. The large amount of training data required for conventional neural network methodologies has limited their use in US so far.

METHODS

A limited training database was supplied by Defense Advanced Research Projects Agency of 30 patients, 15 cases with pneumothorax and 15 cases without. There were two US videos per patient, of which we were allowed to choose one to train on, so that a limited set of 30 videos were used. Images were annotated for ribs and pleural interface. The software performed anatomic reconstruction to identify the region of interest bounding the pleura. Three neural networks were created to analyze images on a pixel-by-pixel fashion with direct voting determining the outcome. Independent verification and validation was performed on a data set gathered by the Department of Defense.

RESULTS

Anatomic reconstruction with the identification of ribs and pleura was able to be accomplished on all images. On independent verification and validation against the Department of Defense testing data, our program concurred with the SME 80% of the time and achieved a 86% sensitivity (18/21) for pneumothorax and a 75% specificity for the absence of pneumothorax (18/24). Some of the mistakes by our artificial intelligence can be explained by chest wall motion, hepatization of the underlying lung, or being equivocal cases.

CONCLUSION

Using learning with limited labeling techniques, pneumothorax was identified on US with an accuracy of 80%. Several potential improvements are controlling for chest wall motion and the use of longer videos.

LEVEL OF EVIDENCE

Diagnostic Tests; Level III.

The Impact of Prehospital Point of Care Ultrasounds on Emergency Patients Length of Stay in Thailand

Purpose

Globally, emergency departments (ED) are faced with an overcrowding problem. This issue is further compounded due to the multitude of contributing factors. Point of Care ultrasound (POCUS), especially when performed in prehospital care, that is before the patient is admitted to the ED has a high potential to reduce time of diagnosis and time of investigation which leads to shorter ED length of stay (LOS). The primary focus was on variances in ED LOS between the prehospital POCUS group and the standard care group.

Patients and Methods

A cross-sectional study was conducted on prehospital patients who were admitted to the ED at Srinagarind Hospital, Thailand, from January to December 2021. We divided patients into two groups including patients who obtained prehospital POCUS (the prehospital POCUS group) and patients who received standard care treatment in which there was no prehospital POCUS performed (the standard care group). POCUS and ED medical records were documented and submitted for analysis.

Results

Of 1348 prehospital patients, 840 were enrolled in this study: 169 with prehospital POCUS and 671 with standard care. Median LOS in the prehospital POCUS group was 159 min (IQR 89,289) versus 165 (IQR 102,330) in the standard care group (p = 0.125). Further imaging diagnostic test which affected ED LOS more than four hours was lower in the prehospital POCUS group (adjusted odds ratio [OR], 0.92; 95% confidence intervals [CI], 0.729-1.666) than in the standard care group. The factor associated with increased odds of ED LOS more than four hour in the prehospital POCUS group was admission to hospital (adjusted OR 1.88; 95% CI, 1.230-2.239).

Conclusion

Patients evaluated with prehospital POCUS had a shorter LOS than the only standard care treatment without statistical significance.

Prehospital FAST reduces time to admission and operative treatment: a prospective, randomized, multicenter trial

BACKGROUND

The focused assessment with sonography in trauma (FAST) exam is an established trauma care diagnostic procedure. Ultrasound performed during prehospital care can improve early treatment and management of the patients. In this prospective randomized clinical trial, we wanted to assess whether a pre-hospital FAST (p-FAST) influences pre-hospital strategy and the time to operative treatment.

METHODS

We studied 296 trauma victims in a prehospital setting. Inclusion criteria were potential abdominal injuries identified either by clinical examination or suggested by the mechanism of injury. Physician-staffed helicopters and emergency ambulances were equipped with portable ultrasound devices. According to a scheme related to calendar weeks, a clinical exam only (CEX) or a clinical exam together with a p-FAST (CEX-p-FAST) was conducted. Outcome variables were prehospital diagnosis and strategy, the time to admission to the trauma room and to operation theater. The study was approved by the university ethical committee (REB#: 46/06).

RESULTS

CEX-p-FAST showed a high sensitivity (94.7%) and specificity (97.6%) in detection of free fluid compared to CEX-only (80.0%, 84.4%). The median time to admission was reduced significantly by 13 min and to operative treatment by 15 min after CEX-p-FAST. We observed a cross-over rate of 30.8% of p-FAST (n = 36) to CEX-p-FAST during the CEX-only weeks.

CONCLUSION

According to the experience of the principal investigators, CEX-p-FAST was superior to CEX-only. Despite the time needed for p-FAST, the relevant admission time was significantly shorter. Thus, p-FAST is recommended in addition to CEX if possible for decision-making in prehospital trauma care.

TRIAL REGISTRATION

German Clinical Trials Register #DRKS00022117-Registered 10 July 2020-Retrospectively registered, https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00022117 .

The Utilization of Handheld Ultrasound Devices in a Prehospital Setting

INTRODUCTION

Prehospital ultrasounds can be considered a new form of diagnostic tool when taking into account their small structure and due to the fact that nowadays, they are used in the care of emergency patients. However, at present, there is no study regarding the advantage of ultrasound usage in prehospital settings in Thailand.

STUDY OBJECTIVE

This study aims to determine the sonographic characteristics recorded by handheld ultrasounds used in prehospital care and the diagnostic accuracy of ultrasounds for prehospital patients.

METHODS

A cross-sectional study was conducted on prehospital patients who underwent point-of-care ultrasound (POCUS) examination on Emergency Medical Service (EMS) operations at Srinagarind Hospital, Thailand from January 2021 through December 2021. The ultrasound images, the electronic emergency department medical records, and the EMS database were recorded and reviewed by a team of emergency physicians. The quality of prehospital ultrasound examinations was assessed by comparing the diagnoses at the scene with those taken at the hospital.

RESULTS

One hundred sixty-nine prehospital patients who received POCUS examinations were examined over a one-year period. All (100.0%) of the scans were for medical cases. No ultrasound protocol was used in the prehospital care. Two hundred eight POCUS examinations were performed in this study. The most common POCUS indication was dyspnea (45.6%), followed by hypotension/shock (30.1%), and finally syncope (8.2%). The most common area where POCUS was performed was on the lung (37.0%), followed by the inferior vena cava (30.8%), and finally for cardiac cases (26.4%). This study found that 34.9% of sonographic findings could be considered abnormal. The diagnoses of prehospital patients were confirmed by using POCUS in 66 cases (39.1%) with the accuracy of prehospital diagnosis reaching a peak of 75.8%.

CONCLUSION

This study shows POCUS examinations can be effectively used in prehospital care. The prehospital diagnosis given by physicians administering treatment who used POCUS examinations correlated with the in-hospital diagnosis.

The role of prehospital ultrasound in reducing time to definitive care in abdominal trauma patients with moderate to severe liver and spleen injuries

BACKGROUND

The role of prehospital focused assessment sonography for trauma (FAST) is still under debate and no definitive recommendations are available in actual guidelines, moreover, the availability of ultrasound machines in emergency medical services (EMS) is still inhomogeneous. On the other hand, time to definitive care is strictly related to survival in bleeding trauma patients. This study aimed at investigating if a positive prehospital FAST in abdominal trauma patients could have a role in reducing door-to-CT scan or door-to-operating room (OR) time.

METHODS

This retrospective observational study included all the patients affected by an abdominal trauma with an abdominal abbreviated injury score ≥ 2 and a spleen or liver injury admitted to Maggiore Hospital Carlo Alberto Pizzardi, a level 1 trauma centre between 2014 and 2019. Prehospital and emergency department (ED) clinical and laboratory variables were collected, as well as in-hospital times during the diagnostic and therapeutic pathways of these patients.

RESULTS

199 patients were included in the final analysis. Of these, 44 had a prehospital FAST performed and in 27 of them, peritoneal free fluid was detected in the prehospital setting, while 128 out of 199 patients had a positive ED-FAST. Sensitivity was 62.9% (95% CI: 42.4%-80.6%) and specificity 100% (95% CI: 80.5% - 100%). Patients with a positive prehospital FAST reported a significantly lower door-to-CT or door-to-OR median time (46 vs 69 min, p < 0.001). Prehospital hypotension and Glasgow coma scale, first arterial blood lactate, ISS, age, positive prehospital and ED FAST were inserted in a stepwise selection for a multivariable Cox proportional regression hazards model. Only ISS and prehospital FAST resulted significantly associated with a reduction in the door-to-CT scan or door-to-operating theatre time in the multivariable model.

CONCLUSION

Prehospital FAST information of intraperitoneal free fluid could significantly hasten door-to-CT scan or door-to-operating theatre time in abdominal trauma patients if established hospital response protocols are available.

LEVEL OF EVIDENCE

III, (Therapeutic / Care Management).

A multicenter evaluation of the accuracy of prehospital eFAST by a physician-staffed helicopter emergency medical service

PURPOSE

The purpose of this study is to report the relative accuracy of prehospital extended focused assessment with sonography in trauma (eFAST) examinations performed by HEMS physicians.

METHODS

Trauma patients who received prehospital eFAST by HEMS clinicians between January 2013 and December 2017 were reviewed. The clinician's interpretations of these ultrasounds were compared to gold standard references of CT imaging or operating room findings. The outcomes measured include the calculated accuracy of eFAST for detecting intraperitoneal free fluid (IPFF), pneumothorax, hemothorax, and pericardial fluid compared to available gold standard results.

RESULTS

Of the 411 patients with adequate data for comparison, the median age was 39.5 years with 73% male and 98% sustaining blunt force trauma. For the detection of IPFF, eFAST had a sensitivity of 25% (95% CI 16-36%) and specificity of 96% (95% CI 93-98%). Sensitivities and specificities were calculated for pneumothorax (38% and 96% respectively), hemothorax (17% and 97% respectively), and pericardial effusion (17% and 100% respectively). These results did not change significantly when reassessed with several sensitivity analyses.

CONCLUSION

Prehospital eFAST is reliable for detecting the presence of intraperitoneal free fluid. This finding should inform receiving trauma teams to prepare for early definitive care in these patients. The low sensitivities across all components of the eFAST highlight the importance of cautiously interpreting negative studies while prompting the need for further studies.

TRIAL REGISTRATION

ACTRN12618001973202 (Registered on 06/12/2018).