Shadow Boxing in EMS
Point-of-care ultrasound (POCUS) has been widely adopted for emergency department care as a versatile tool to reduce diagnostic time and guide interventions for both adult and pediatric cases. Uses have ranged from rapidly detecting intra-abdominal hemorrhage, assessing heart contractions when pulses are not detectable, or demonstrating gallstones in those with right upper quadrant pain. It can facilitate intravenous access, identify retinal detachments or diagnose ectopic pregnancies—just to name a few key indications.
Likewise, POCUS can facilitate similar patient care enhancements in the often austere prehospital environment.1–3 Evolving data already indicate that POCUS can reduce morbidity and mortality in the EMS setting.1–3 Among advantageous prehospital uses, POCUS has clinical benefit in trauma care. The extended Focused Assessment with Sonography for Trauma (eFAST) exam works well to detect pneumothorax, as well as free fluid in the abdominal or pericardial spaces.
Not only can POCUS findings alter EMS transport and on-scene treatment decisions, but such far-forward knowledge can be objectively communicated to trauma centers and expedite time-dependent in-hospital care.2 It can also significantly mitigate risk for treatment complications. For example, POCUS can diminish the risk of unintentional penetration of vital organs during needle thoracostomy as compared to use of a landmark technique.4
Other advantageous applications in trauma care include the identification of fractures.3,5 This application can be particularly useful for triaging in certain athletic settings or in situations in which patients may be reluctant, on first encounter, to go to the hospital. It can also guide paramedics’ decisions to proceed to a higher level trauma center, despite lengthier transport, because of those findings.
Likewise, POCUS can assist in nontraumatic cases, given its ability to differentiate causes of respiratory distress such as delineating pulmonary edema from chronic emphysema. This allows for more appropriate treatment choices.5 Similarly, in cases of out-of-hospital cardiac arrest, POCUS can play a crucial role in identifying reversible conditions or in assessing for active cardiac activity when one cannot palpate pulses. Among all EMS POCUS uses to date, this technology has been applied most often in patients who are found without palpable pulses but are still having residual electrocardiographic activity (PEA) in both post-traumatic and nontraumatic cases.1
Accordingly, this important application has been quite pivotal in decisions to either terminate or continue resuscitation efforts.3,5 Studies have now shown that imaging of visible cardiac activity (i.e., ventricular contractions) with POCUS has been associated with improved surivial to hospital admission in cardiac arrest cases.1,2 Similar applications are now being considered to help delineate whether hemorrhaging patients in extremis should be viable candidates for prehospital blood transfusion or terminated on scene if there is no active ventricular contraction, considering that such asystolic patients predictably have futile outcomes.
Despite these cited rationales and benefits for incorporating POCUS into EMS patient care, a recent evaluation of National Emergency Medical Services Information System (NEMSIS) records demonstrated an overall low frequency of prehospital POCUS application across the U.S.1,3 Prehospital POCUS use did increase nearly eight-fold between 2018 and 2021, but it still was only implemented in 0.002% (1 in 50,000) of all patient encounters.
This low frequency of use is largely associated with infrequent adoption by individual agencies. At the time of study, only 0.5% of EMS agencies (1 in 200) had incorporated POCUS into their prehospital care protocols.1 In contrast to the U.S., increased adoption has been observed in Europe’s mostly physican-staffed medical helicopter agencies among which 75% utilize POCUS. As a result, POCUS is applied in 15% of their patient encounters.2,6
However, other factors limiting use involve training standards, regulatory bodies and general misperceptions. The National EMS Scope of Practice Model doesn't provide clear guidance or training standards for EMS POCUS use. This defers credentialing of ultrasound application to local medical directors.2,7 Ultrasound training is not part of the typical intitial EMS educational curricula, creating heterogeneity in any described training.2,5
Moreover, the majority of U.S. states don't include POCUS in their respective scopes of practice for EMS. The classic fear of the unknown (lack of familiarity) usually sparks concerns that prehospital POCUS can delay patient care without adding demonstrable patient benefit. Last, but not least, is the usual major obstacle—the added expense of equipment, related training, and quality assurance, even when medical directors and EMS crews ethusiasticlly embrace implementation.
Fortunately, there are now advances in technology and training that may offer opportunities to expand the adoption and routine use of POCUS in EMS, for both traumatic and non-traumtic medical conditions.
Very portable, compact (and affordable) ultrasound device systems are now available, which allow for confidential recording, transmission and archiving of images, serving both diagnostic and quality assurance functions.2,8 Model curricula, with well-defined competencies, have now been developed. These may better guide EMS systems in a more standardized fashion.9
Another subtle factor is the the growing number of EMS fellows and newer generations of EMS medical directors for whom POCUS had been a routine part of daily care in their emergency medicine training programs. Most are quite facile in POCUS, making training, implementation and quality assurance more concrete, practical and experience based.
Not surpisingly, the latest training programs are simpler and more effective, such as a studied 90-minute combined didactic and procedural training session for prehospital care nurses and paramedics that improved POCUS-based identification and management of pneumothorax in 94.7% of cases.4
With ongoing advances in clinical care, training, and device technology, EMS is now better-positioned to widely integrate out-of-hospital POCUS procedures. Part of this pivotal development will be inclusion of initiatives to expand the scope of practice in each state, progressively develop standardization in future educational programs, and establish robust quality improvement programs with expert oversight.
In addition, while certain important clinical indications for POCUS have already been identified, further research to document the versatility of its utility and the resulting impact on patient outcomes will help to encourage broader adoption.
References
1. Karfunkle B, Chan HK, Fisher B, et al. Prehospital Ultrasound: Nationwide Incidence from the NEMSIS Database. Prehosp Emerg Care. 2024;28(3):515-530.
2. Von Foerster N, Radomski MA, Martin-Gill C. Prehospital Ultrasound: A Narrative Review. Prehosp Emerg Care. 2024;28(1):1-13.
3. Taylor J, McLaughlin K, McRae A, et al. Use of prehospital ultrasound in North America: a survey of emergency medical services medical directors. BMC Emerg Med. 2014;14:6. doi:10.1186/1471-227X-14-6
4. Dewar ZE, Ko S, Rogers C, et al. Prehospital portable ultrasound for safe and accurate prehospital needle thoracostomy: a pilot educational study. Ultrasound J. 2022;14(1):23. doi:10.1186/s13089-022-00270-w
5. Amaral CB, Ralston DC, Becker TK. Prehospital point-of-care ultrasound: a transformative technology. SAGE Open Med. 2020;8:2050312120932706. doi:10.1177/2050312120932706
6. Hilbert-Carius P, Struck MF, Rudolph M, et al. Point-of-care ultrasound (POCUS) practices in the helicopter emergency medical services in Europe: results of an online survey. Scand J Trauma Resusc Emerg Med. 2021;29(1):124. doi:10.1186/s13049-021-00933-y
7. National Association of State EMS Officials. National EMS Scope of Practice Model 2019: Including Change Notices 1.0 and 2.0. Report No. DOT HS 813 151. Washington, DC: National Highway Traffic Safety Administration; 2021.
8. Hsieh A, Baker MB, Phalen JM, et al. Handheld Point-of-care ultrasound: safety considerations for creating guidelines. J Intensive Care Med. 2022;37(9):1146-1151.
9. Micheller D, Peterson WJ, Cover M, et al. Defining a theory-driven ultrasound curriculum for prehospital providers. Air Med J. 2019;38(4):285-288.
Resident Eagle profiles the work of top EMS physicians and medical directors from the Metropolitan EMS Medical Directors Global Alliance (the "Eagles"), who primarily represent the largest U.S. cities and jurisdictions. For information on the Gathering of Eagles conferences, see useagles.org.
