Tips and Tricks for Ultrasound Training in the Austere Environment

Sean E. Scott, MD, AEMUS-FPD
General Leonard Wood Army Community Hospital
Aicha Hull, MD, AEMUS-FPD
Madigan Army Medical Center

Point of care ultrasound (POCUS) has led to significant changes to patient care and outcomes in hospital environments and has since spread to pre-hospital and austere environments. Over the past several decades increased portability of ultrasound has allowed for its use and demonstrated efficacy in numerous resource-limited settings including low and middle income countries, the Iraq and Afghanistan wars, and natural disasters.^1,2,3 The introduction of handheld devices has further increased the portability and ease of use of POCUS with reliable diagnostic accuracy.^4,5 The intent of this document is to provide helpful advice to providers who will or are operating in austere environments in training others in POCUS.

For ease of reference, this document has been broken down into sections: Preparation, Training in Garrison (Pre-Mission), and Training in Austere Environments. A more in-depth resource for preparing and conducting non-military resource-limited US training may be found here: https://globalultrasound.wordpress.com/.

Preparation

Device Selection

In selecting an ultrasound device for austere environments, providers must carefully consider the specific conditions they will face, including environmental factors such as altitude, humidity, temperature extremes, and space limitations. Weight and size restrictions are also crucial factors, as devices should be portable and easy to deploy in field settings. Will you be working out of a single established location, where cart-based ultrasounds may afford you better image quality, or will you be working out of your own backpack and have to carry all of your own equipment, where a handheld device may better suit your needs?

Probe Selection

In austere environments, providers should have access to at least two types of probes: a high-frequency linear probe for superficial applications and a lower-frequency probe (either curvilinear or phased array) for deeper structures. The device's fragility, battery life, ease of recharging, and the need for system updates or technical support must be carefully evaluated. Given the often-remote nature of austere environments, providers should consider the availability of biomedical engineering support and plan accordingly.

Teaching Adjuncts

If you will be conducting training or teaching activities there are a few helpful tools which may enhance your teaching abilities.

Portable projectors have become much smaller, lighter, and battery-powered. Use of these along with a linen sheet, rope or a flat surface, and a laser pointer allow you to greatly expand your images, allowing learners better visualization of desired structures.

However, if you will be teaching outside in the daytime, projecting may not be as effective and your needs may better be suited by bringing a tablet device. It is the opinion of this author that the increase in size from a smartphone to a smart tablet can significantly improve learner visualization.

Additionally, having reference images or videos can be extremely helpful in teaching as pathology may not always be present in the training environment. This author has found thepocusatlas.com as an exceptional resource for reference materials, which may be downloaded in advance or used on-the-spot if you have internet connectivity.

If resources allow, premade medical models exist for a variety of procedures/simulated pathologies. Consider advocating for funding to provide a US compatible mannikin. If you are a 3D printer enthusiast or know of one, there are free medical simulation blueprints such as ribs for chest tube insertion which can be cheaply constructed and combined with on-hand materials during the mission to enhance your simulation training, potentially creating a pneumothorax or hemothorax model. Preparing in advance and thinking creatively can expand your down-range teaching ability.

Training in Garrison (Pre-Mission):

Familiarity with Equipment

Before your mission, it is essential to train with the ultrasound equipment that will be used in the austere environment. If small, portable devices are used at the point of care, operators should be familiar with the specific models they will use as the user interface, AI capabilities, and image quality varies for each model. For novice users, exposure to a variety of devices can help build confidence, as they may encounter different systems while on mission.

Curriculum Development

When developing a training curriculum, it is critical to consider the clinical needs of the forward provider, as well as the learners' baseline knowledge. A physician's training needs may differ significantly from those of a medic or other non-physician provider. Training should focus on practical, high-yield applications that are most relevant to the mission. Consider reaching out to colleagues in your local area to assist in either curriculum development or conducting hands-on training sessions.

Basic Ultrasound Skills

Every training session should include instruction on the basic functions of the ultrasound device, including how to use the various probes, adjust settings, and perform fundamental scanning techniques. Learners should also receive an introduction to ultrasound physics, which will help them understand the limitations of different probes and identify common artifacts. Consider conducting this education in a lecture format prior to hands-on training sessions, which may help achieve spaced-repetition learning.

To avoid overwhelming learners, the curriculum should focus on the specific clinical questions they are likely to encounter in austere settings. For example, while obstetric and biliary exams are important, they may not be critical in a combat or emergency care setting. In these environments, the curriculum should prioritize applications such as:

• eFAST (extended Focused Assessment with Sonography in Trauma)
• Ocular Nerve Sheath Diameter (ONSD) measurements for detecting elevated intracranial pressure
• Musculoskeletal ultrasound for trauma applications, including the identification of bone fractures, dislocations, hematomas, joint effusions, and tendon ruptures
• Basic soft tissue and foreign body identification for differentiating abscess, cellulitis, and lymphadenopathy or assisting in foreign body removal if needed

Real-Time Practice

All training should include hands-on practice, ideally on individuals with known pathology, simulation models, or virtual reality trainers. The more exposure to real-world applications, the better. Competency often requires multiple training sessions. If there is a delay between initial training and mission execution, additional practice should be arranged to ensure readiness.

Training in Austere Environments

In-Situ Training

Once in the field providers should revisit the training they received in the garrison or home environment. They should adapt to the challenges of scanning in austere settings, such as working with patients on litters or on the ground. It is essential to practice scanning in the types of environments providers will encounter during their mission to ensure they are comfortable with the logistics and physical limitations of performing ultrasound exams in these settings. Additionally, this training may reveal unanticipated effects of the environment on the US machine such as prolonged heat or cold exposure.

Identifying co-located medical assets can also provide you with additional resources, both in US devices and medical expertise. In the military setting, deployed Role 2 and above echelons of care may be co-located near other medical assets such as coalition (allied) forces or aeromedical assets which come with their own resources. Reaching out and building a relationship with these potential partners can both increase your capability to teach and increase your learner pool, allowing you to gain greater experience teaching providers of varying levels. Positively engaging with these co-located assets often has unanticipated downstream effects which can further enhance mission success for your larger group as well.

Many medical groups will conduct regular training, such as once weekly lectures. Consider using this lecture time to discuss basic US physics, knobology, and terminology in preparation for an upcoming class to both allow spaced-repetition learning and reduce the time needed to discuss this during hands-on sessions. Utilizing this time as well to frame POCUS as answering specific clinical questions rather than performing a comprehensive scan can help learners obtain the appropriate mindset for when they utilize POCUS themselves.

Careful consideration of your audience is crucial, as their ultrasound familiarity and needs will vary greatly. As an example, US Army Special Forces (SF) medics have ultrasound training integrated into their training pipeline, whereas Regular Army (RA) medics do not. Additionally, SF medics may have interest in pediatric and obstetric ultrasound in addition to trauma protocols to enhance building rapport with host nation or partner forces. RA medics also have variable job assignments and experience. Some may work exclusively in a clinical environment and not go into field environments whereas others may rarely work in a hardened structure. Keeping your training focused on their likely clinical scenarios and resources will improve the educational value of your training, save time, and build greater rapport.

Additionally, it is common practice for learners to serve as models themselves when learning US protocols. Informing groups of this in advance, especially when conducting thoracic protocols, can allow learners to better prepare and wear appropriate clothing to maintain personal dignity in training. Depending on where in the world training is being conducted, mixed-gender classes may not be a viable option and training may have to be conducted in either separate times or spaces. Anticipating and preparing for these scenarios can help create a safe space for education and avoid cultural faux pas.

Model Construction

In austere environments where access to clinical models may be limited, providers can create basic musculoskeletal and soft tissue models using readily available materials. Examples include:

• Chicken bones in Jello molds to simulate bone fractures.
• Spam or tofu to represent soft tissue structures and simulate foreign body identification and abscess identification and drainage.
• Tendon or joint injuries can be mimicked using bone models inside simple materials like ballistic gel or agar to enhance the learning experience.
• Fluid filled gloves to allow simple and procedural recreation of pericardial effusion/pericardiocentesis.⁶
• Pork belly, chest tubes, and chest seals filled with saline and food dye can be utilized to create vascular models which would allow practice with central lines or rapid infusion catheters.

These models help learners visualize and practice key applications, improving their competence and confidence in the field.

Teaching the Class

Maintaining a lower ratio of instructors to learners is critical for hands-on US training. Though having 1:1 is ideal, this is not commonly practical. This author recommends a minimum goal of 1 instructor for every 5 learners if possible. For simpler protocols such as the FAST exam and when sufficient US devices are present you may consider increasing your instructor numbers by conducting train-the-trainer sessions or by teaching other providers the basics of your chosen US protocol and having those providers run students through hands-on training. As an example, if you have 20 learners, you may teach 4 providers the basics of the exam, split the learners into 4 groups, and you move between these groups supervising and teaching the finer points of the protocol. This way you can maximize the hands-on time each learner experiences.

After the Class

Process improvement is a critical aspect of teaching. Conducting an After Action Review (AAR) or feedback session can provide helpful information from multiple perspectives to enhance your future education. Proximity in time to the teaching event helps enhance this feedback, so collect this information as soon as possible after your class. For larger classes or when time-constrained, consider having someone from each group collect feedback points and summarize these for you. As well, do not forget to collect feedback from your fellow instructors or colleagues. Challenge yourself to find one sustain and one improve after your teaching sessions to allow yourself the time and mental space to reflect. Build time for this into your curricula so that you can make meaningful improvements from your experience.

Image Storage and Interpretation

If image storage is necessary, it is important to establish a process for secure storage, labeling, and interpretation of ultrasound images. Providers should be trained on how to capture quality images, as well as the specific protocols for labeling and archiving those images in their operational environment.

Device Accessibility and Maintenance

Ultrasound machines should remain easily accessible in the field to encourage frequent use. A system for recharging devices, including backup power solutions, should be established to ensure the equipment remains operational throughout the mission. Testing this plan in advance is highly recommended.

Conclusion

By thoroughly preparing both at home and in the field, providers can be more confident in their ability to use and teach ultrasound effectively in austere environments, ultimately improving patient care in challenging conditions.

Disclaimer

The views expressed are those of the author(s) and do not reflect the official policy of the Department of the Army, the Department of Defense, or the U.S. Government.

References

1. Ferre, R. MD, et al. Prehospital, austere and tactical ultrasound. ACEP: Prehospital, Austere, and Tactical Ultrasound Subcommittee. https://www.acep.org/emultrasound/subcommittees/prehospital-austere-tactical-ultrasound
2. El Zahran T, El Sayed MJ. Prehospital Ultrasound in Trauma: A Review of Current and Potential Future Clinical Applications. J Emerg Trauma Shock. 2018;11(1):4-9.
3. Anderson A, Theophanous RG. Point-of-care ultrasound use in austere environments: A scoping review. PLoS One. 2024;19(12):e0312017.
4. Kodaira Y, Pisani L, Boyle S, Olumide S, Orsi M, Adeniji AO, et al. Reliability of ultrasound findings acquired with handheld apparatuses to inform urgent obstetric diagnosis in a high-volume resource-limited setting. Int J Gynaecol Obstet. 2021;153(2):280-6.
5. Gibbons RC, Jaeger DJ, Berger M, Magee M, Shaffer C, Costantino TG. Diagnostic Accuracy of a Handheld Ultrasound vs a Cart-based Model: A Randomized Clinical Trial. West J Emerg Med. 2024;25(2):268-274.
6. Angert R, Rosen O. Pericardiocentesis Simulation Model: Low Cost, Easy to Assemble, Effective Task Trainer. Cureus. 2021;13(4):e14475.