Aarti Sarwal1, Sahil Kapoor1, Austin Offnick2, Ralph D’Agostino Jr.1, Pamela Duncan1, James E Winslow1, Stacey Quintero Wolfe3, Casey Glass4, Charles Tegeler1, Jason Stopyra4, Kara Clarke5, Brian Emory6, Zach Stutts7, Justin Moore2, Andrew W. Asimos7.
Affiliations: 1Atrium Health Wake Forest Baptist Medical Center, Department of Neurology, Division of Neurocritical Care, Winston-Salem, NC; 2Wake Forest University School of Medicine, Winston-Salem, NC; 3Atrium Health Wake Forest Baptist Medical Center, Department of Neurosurgery, Winston-Salem, NC; 4Atrium Health Wake Forest Baptist Medical Center, Department of Emergency Medicine, Winston-Salem, NC; 5Cabarrus County EMS Agency, Cabarrus, NC; 6Iredell EMS Agency, Iredell, NC; 7Cherokee Tribal EMS Agency, Cherokee, NC; 7Atrium Health Carolinas Medical Center, Department of Emergency Medicine, Charlotte, NC.
Introduction: We evaluated the feasibility of teaching cranial ultrasound skills to emergency medical technicians (EMTs) and paramedics as part of a research project evaluating the feasibility of performing cranial ultrasound in a moving ambulance.
Methods: EMTs and paramedics from 4 rural counties were trained on a standardized education module that included teaching on brain anatomy, ultrasound topography of the brain, and research workflows. The training included an in-person didactic session followed by hands-on training using hand-held ultrasound machines.
Results: 362 personnel in 4 EMS agencies attended training sessions. 65.1% reported no prior ultrasound training, and only 16% had some cranial ultrasound knowledge. After training, attendees reported higher confidence in performing cranial ultrasound and identifying relevant brain structures. We noted moderate to high performance in answering imaging-based and research protocol-based questions on the post-training questionnaire.
Conclusion: Teaching paramedics cranial ultrasound performed as part of a research study is feasible despite lack of prior ultrasound or neuroanatomy knowledge.
Keywords: cranial ultrasound, neuro-ultrasound, hemorrhagic stroke
Introduction
Early prehospital diagnosis of spontaneous intracranial hemorrhage (ICH) could facilitate interventions that reduce hematoma expansion in the first 1-3 hours after onset.1–4 Importantly, prehospital detection of ICH may impact decisions related to blood pressure goals or whether transport to a specialized facility (i.e., stroke center) is preferable.5 Clinical stroke scores to predict ICH have low accuracy and mobile stroke units are cost-prohibitive for many rural settings.6,7 Cost-effective diagnostic modalities to allow pre-hospital distinction of hemorrhage from ischemic stroke are urgently needed.
Prior studies have documented the feasibility and validity of ultrasound performed by emergency medical services (EMS) personnel in various clinical applications.8–11 Because of recent advances in ultrasound technology, EMS personnel now have access to relatively inexpensive hand-held devices connected to an encrypted HIPAA-compliant cloud-based platform. This allows physicians to remotely access images for interpretation in real-time, facilitating incorporation of ultrasound within the EMS scope of practice.12 EMS providers have been trained to use ultrasound for lung, heart, and abdominal examinations.13 14 15 With the increasing use of ultrasound in clinical resuscitation algorithms in the pre-hospital, emergency, and critical care settings, it is a natural next step for ultrasound to be implemented in neurologic emergencies.1 2 In the present study, we explored the feasibility of training EMS personnel to use cranial ultrasound in the field.
Methods
We recruited four EMS agencies from rural regions in North Carolina without direct first access to Comprehensive Stroke Centers. After obtaining IRB approval, additional regulatory approvals were obtained from EMS compliance officers and medical directors to train the EMS personnel for participating in the study. Data use agreements were created between these agencies and our academic medical center.
Each EMS agency partnering in this study hosted 2-4 sessions to include all paramedics and EMTs at their agency who respond to stroke calls. Attendance was mandatory for all EMTs and paramedics at these agencies to encourage their engagement in research. Data were included in the study only if pretest questionnaires were completed through a REDCap®-based electronic data capture tools hosted at Wake Forest School of Medicine.16 Some attendees were called away to duty before their session was finished, so fewer individuals completed the post-session questionnaire.
We created a didactic module to teach learners to distinguish between ischemic and hemorrhagic stroke, and provided details of brain topography visualized on cranial ultrasound using an image library.8 Cranial ultrasound involved B mode imaging of the cranium using the temporal windows to evaluate the brain parenchyma as opposed to Transcranial Doppler that utilizes Doppler to assess for cerebral blood flow. We only included cranial ultrasound in this project. We applied the SQUIRE-EDUguidelines, the Guideline for Reporting Evidence-based practice educational interventions and Teaching (GREET) checklist, Walter Barbe’s model focusing on visual, auditory, and kinesthetic channels of learning, and adult learning models specific to EMS.17–20 21
Based on the Kolb Learning Style Model described in the EMS literature, sessions considered all four learning modes (Concrete Experience, Reflective Observation, Abstract Conceptualization, and Active Experimentation).22 23 Learning objectives related to identification of relevant neuroanatomy, ultrasound image acquisition, recognition of cranial topography and artifacts on ultrasound, and research ethics relevant to the study workflow. The content of the didactic module was reviewed and edited based on feedback from several EMS, Emergency Medicine, and radiology professionals. After an initial pilot training session including 22 EMS providers who are stroke supervisors at one EMS agency, we modified the didactic module based on attendees’ suggestions. Subsequent training sessions resulted in no further updates. The didactic module was then delivered over 1 to 1.5 hours, including a pre- and post-questionnaire on ultrasound background and neuroanatomy knowledge (Figure 1).
The didactic module was immediately followed by a hands-on session. During the hands-on sessions lasting 1.5 to 2 hours, cranial ultrasound was first demonstrated by instructors. Each attendee then performed cranial ultrasounds on other attendees and on standardized patients with active supervision from instructors. Active discussion over cranial topography was encouraged and workflow was re-visualized multiple times during the training sessions.
In addition to a PowerPoint-based didactic tutorial largely incorporating images and videos and hands-on scanning, we used a plastic skull model and an ultrasound device to teach relevant anatomy during the lecture. Attendees were encouraged throughout the sessions to ask questions and provide feedback on the delivery framework. All attendees received a handout summarizing the didactic module and laminated QR codes for surveys as part of the study. Learners received no incentives or reimbursements except for meals after the sessions. The didactic tutorial was made available to EMS leaders both in PowerPoint and voice-over recorded formats for reference.
All training was provided by the study principal investigator (AS), a neurologist with certification as a registered physician in neurovascular interpretation and extensive experience in CME training related to point-of-care ultrasound and neuro-ultrasound.8,24–26 Hands-on instruction was supported by another instructor (SK) after undergoing 50 hours of cranial ultrasound training involving standardized patients, critically ill patients, and direct comparison of ultrasound images with brain CT.
All questionnaires were administered via REDCap®.16 Pre-didactic questions investigated preexisting familiarity with ultrasound and cranial structures. The post-intervention questionnaires solicited feedback on familiarity/comfort with the content taught and feedback on the intervention itself. After the didactic and hands-on training, attendees completed a 10-question quiz testing responses on 6 images and 4 workflow-related research questions. These questions were chosen based on competencies expected as part of the field implementation of this modality. All answers were reviewed at the end of each session to ensure an appropriate understanding of the correct answers.
Results
Personnel from four EMS agencies (N=362) participated in 11 sessions over 6 months (Table 1). Over 65% of attendees had no prior ultrasound training of any kind, but the proportion varied by site (EMS 1, 52.78%; EMS 2, 93.75%; EMS 3, 75.19%, and EMS 4, 75.27%). The site with the largest proportion of trained EMS staff (EMS 2) also had the fewest numbers of attendees. A total of 323 EMTs completed both pre and post-test questionnaires. Because they were called to service in between sessions, 39 EMTs did not complete post-session tests.
| County | EMS 1 | EMS 2 | EMS 3 | EMS 4 | TOTALS |
| Training days | July 19 & 26, 2022 | Aug 2-3, 2022 | Aug 24, Dec 2-3, 2022 | Jan 3-4 &10-11, 2023 | |
| N of trainees N who completed: | 108 | 32 | 129 | 93 | 362 |
| Pre-session questionnaire | 108 | 32 | 129 | 93 | 362 |
| Didactic training | 92 | 25 | 113 | 88 | 318 |
| Hands-on session | 100 | 27 | 115 | 87 | 329 |
| Post-session questionnaire completed | 96 | 26 | 111 | 90 | 323 |
Before training, 36.6% of trainees reported they could identify normal anatomic brain structures with a moderate or higher level of comfort; this proportion increased to 73.6% after the training. After training, only 0.7% of participants reported no familiarity with anatomic brain structures, compared to 19% before the training (Figure 2). Attendees reported a high degree of familiarity with bony structures at baseline, but familiarity with naming individual intracranial structures increased after training (Figure 3).
As shown in Figure 4, 34.9% of attendees reported some degree of prior ultrasound training. This included 16.6% who reported some cranial ultrasound and/or transcranial Doppler knowledge, mostly acquired through informal training and hands-on workshops led by other EMS staff (23.33%) or educational hands-on workshops only (8.9%). However, 64.5% reported never performing any type of ultrasound on a patient. After the training, 72.2% of attendees reported they had to a moderate or higher level of confidence performing cranial ultrasound, and only 2.3% of attendees reported no such confidence. After training, 60% of attendees reported confidence in identifying normal from abnormal brain anatomy on cranial ultrasound to a moderate, very, or extreme degree; only 3% reported no such confidence.
On post-didactic tests, questions identifying normal structures in the brain and distinguishing artifacts from normal brain structures on cranial ultrasound had the lowest number of correct responses (41.86%-68.75%). There was a high correct response rate for identifying the absence of temporal windows (75%-95.7%; Figure 5). Correct responses were more likely for questions based on research protocols, such as eligibility for a study, consent procedures, and standard of care practices.
Participants reported that the training was of an appropriate length (82.8%), had informative content representative of the protocol and intervention (99.4%), and increased their skills and knowledge about brain anatomy (98.2%). Over 93% rated the training as good to excellent. Attendees also provided 60 free text comments. The most common requests were for more hands-on time, more machines for hands-on training, and more images and context for neuroanatomy. Specific positive feedback was given by 13 attendees, including on content and teaching methods.
Discussion
EMS competencies in point-of-care ultrasound have been tested for evaluation of the lung, heart, inferior vena cava, and abdomen for detecting pathologies such as pneumothorax, pericardial effusion, cardiac arrest, and free intra-abdominal fluid 13–15. However, few studies have evaluated the effects of ultrasound education on ability to learn cranial ultrasound modality in the field. A recent systematic review of 14 papers included 4 studies that assessed lecture and hands-on-based training lasting 1-4 hours; 4 that involved a 1- to 2-day course utilizing simulators, and 3 studies that assessed longer programs; 3 studies were of low quality and not described further in the review 9.
Two studies reported the use of neuro-ultrasound in pre-hospital settings, but ultrasound was performed by a neurologist accompanying emergency crews.27 28 All these studies were based on a transcranial Doppler protocol performed by a physician, which also requires a higher degree of knowledge of cerebrovascular hemodynamics and greater training to establish competency. We found no reports in the literature on cranial ultrasound or neuro-ultrasound directly performed by EMTs in the field.
This report describes our experience in teaching cranial ultrasound to EMS personnel. Current ultrasound technology using handheld devices makes this modality cost-effective for staffing ambulances with real-time physician interpretation through HIPAA-compliant cloud-based platforms. Thus, the existing framework can allow broader scalability of ultrasound-based resuscitation protocols, including those in neuro-emergencies.
Despite showing the feasibility of training EMTs in cranial ultrasound, our pilot study has several limitations. We did not collect data on individual learning styles for attendees. We also did not perform any OSCE-based assessment of competency in performing ultrasound acquired after training, or increases in pass rates after debriefing questions for the quiz.29 Finally, limited resources did not allow us to include other sites. Thus, our report from 4 rural EMS agencies may not be generalizable to others.
Conclusions
We demonstrated feasibility of teaching cranial ultrasound with in-person sessions attended by 343 mostly ultrasound-naïve EMS personnel. Once EMS personnel are trained, cranial ultrasound is a low-cost modality that could increase access to specialized stroke care, especially in rural or lower-resource settings.
Funding: This study was sponsored by an intramural grant through the Clinical and Translational Science Institute supported by the National Center for Advancing Translational Sciences (NCATS) (UL1TR001420). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. We also received a device loan from Butterfly Inc. under a research contract agreement to support the study of prehospital detection of intracranial hemorrhage using ultrasound.
Acknowledgments: We thank the staff and leaders from the Iredell, Cherokee, Cabarrus, and Catawba EMS agencies for their willingness to participate in this study. We also thank the following individuals:
Wake Forest University School of Medicine: Cheryl Bushnell, MD, Neurology; Metin Gurcan, Ph.D., Director, Wake Forest Center of Biomedical Informatics; Darrell Nelson, MD, Emergency Medicine; Patrick A. Brown, MD, Radiology & Neurosurgery; Jeffrey R. Sachs, MD, and Tatum Johnson, MD, Radiology; Joshua Tan, Translational Imaging Program; Cara Everhart, research program manager, Yash Patel, visiting research student, Neurology and Sheila Marie Lennen, Neurology; Bridget Francis, Ian Saunders, and Janae Joyner, Center for Experiential Learning.
Others: Jeremiah Underwood, Guilford County Community College; Raymond Samuel, Ph.D., North Carolina Agricultural & Technical University. We would like to acknowledge the support of Karen Potvin Klein, MA, ELS, MWC, for revising the manuscript prior to journal submission.
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