Pre-hospital and emergency department point-of-care ultrasound in cardiovascular emergencies: a scoping review

Introduction

Cardiovascular emergencies demand rapid diagnostic clarity, as outcomes hinge on timely, correct intervention to change the therapeutic trajectory. Point-of-care ultrasound (POCUS) has evolved into an essential bedside modality providing real-time, high-yield information that can answer critical diagnostic questions without the delays associated with formal imaging departments (1). Technological advances, including portable handheld platforms and wireless probes, have expanded POCUS use into pre-hospital settings, including ambulances and helicopters, as well as in resuscitation bays (2).

Despite its widespread adoption, the literature on POCUS has often developed along separate tracks for pre-hospital care and the emergency department (ED). Recent advances, such as miniaturised transducers, artificial intelligence (AI)-assisted interpretation, and standardised training curricula, have transformed POCUS into a core diagnostic technology across emergency care (3). Reviews frequently focus on a single indication or environment, and studies are frequently siloed in reporting, which obscures how diagnostic accuracy, workflow integration, and patient outcomes truly differ between settings (4). This fragmentation is problematic because context shapes performance: pre-hospital environments impose constraints on operator experience, governance, device choice, and time; whereas EDs offer greater environmental control, supervision, and immediate access to downstream diagnostics and interventions (5,6).

This scoping review provides an integrated comparative synthesis of POCUS for six major cardiovascular emergencies—cardiac arrest, cardiac tamponade, acute heart failure, shock, pneumothorax, and aortic dissection—across both pre-hospital and ED settings (7).

Our objectives are: (I) to compare diagnostic performance, workflow impact, and patient-centred outcomes between pre-hospital and ED applications; (II) to evaluate the influence of operator background, training, device technology, and governance structures; and (III) to identify reproducible implementation models and evidence gaps. By directly juxtaposing pre-hospital and ED data, this review seeks to move beyond descriptive summaries and provide a comparative framework that clarifies where POCUS yields tangible clinical advantage and where its benefits remain primarily operational to between proven process improvements (e.g., faster diagnosis, altered triage) and the more elusive patient-centred outcome benefits (e.g., survival, functional recovery). This distinction is critical, as recent evidence demonstrate that process gains do not automatically confer outcome benefits. Understanding where and why this translation fails is essential for designing effective implementation strategies (8). We present this article in accordance with the PRISMA-ScR reporting checklist (available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-1-646/rc).

Methods

A structured scoping review design was implemented. Adult studies (≥18 years) were eligible when POCUS was performed pre-hospital [ground emergency medical services (EMS), aeromedical/helicopter EMS] or in EDs for cardiac arrest, pneumothorax, acute heart failure/dyspnoea, shock, tamponade, or aortic dissection. We included prospective cohorts, randomised controlled trials (RCTs), retrospective cohorts, feasibility studies and case series if they reported at least one of: diagnostic accuracy (sensitivity, specificity, predictive values); process measures (time to diagnosis or intervention; adequacy of views within prescribed pauses; scan duration; proportion completed); management effects (procedure decisions, destination change, triage modification, resuscitation termination); or outcomes (e.g., admission, survival to discharge, short-term mortality).

Literature searches were executed in PubMed, Ovid MEDLINE, Cochrane Library, and Google Scholar from database inception through August 2025. The upper boundary was chosen to reflect current device capabilities (handhelds widely available), contemporary resuscitation algorithms, and modern EMS/ED workflows. We combined exploded subject headings (“Ultrasonography”; “Point-of-Care Systems”; “Emergency Medical Services”; “Emergency Service, Hospital”; condition-specific headings for “Heart Arrest”, “Pneumothorax”, “Heart Failure”, “Shock”, “Hypotension”, “Cardiac Tamponade”, “Aortic Dissection”) with free-text synonyms (“POCUS”; “pre-hospital”/“prehospital”; “ambulance”; “HEMS”; “aeromedical”; “ED”; disease names). Reference lists of included articles and key reviews were manually screened to identify additional studies. Two reviewers independently screened titles and abstracts for relevance, followed by full-text review of potentially eligible studies. Disagreements were resolved through discussion and consensus.

Substantial clinical and methodological heterogeneity precluded meta-analysis. Variability in study design (feasibility pilots to RCTs), populations (out-of-hospital vs. in-hospital arrests; traumatic vs. non-traumatic dyspnoea), and definitions (e.g., cardiac standstill, clinically significant pneumothorax) precluded meaningful pooling. Findings were synthesised narratively with emphasis on diagnostic accuracy, workflow effects, and clinical impact across settings. The summary of the search strategy detailed above can be found in Table 1.

Because the included literature spans a wide range of study designs, including randomised trials, prospective observational studies, retrospective cohorts, feasibility studies, and case reports, the strength of evidence varies across conditions and settings. In synthesising the findings, greater weight was given to higher-quality designs such as randomised trials and prospective multicentre studies, while smaller feasibility studies and case reports were interpreted primarily as exploratory or hypothesis-generating. Evidence strength is therefore indicated contextually throughout the Results when interpreting diagnostic performance, workflow effects, and outcome data.

Results

Cardiac arrest

Across settings, ultrasound during resuscitation supplies two categories of information: (I) a binary or graded assessment of cardiac activity as a prognostic marker; and (II) identification of reversible causes such as tamponade or right-sided strain suggesting pulmonary embolism. In the field, a single disciplined window carries prognostic weight. In a prospective series of 42 out-of-hospital arrests, operators visualised the heart in every case (9). Three-quarters (n=32) showed a standstill, and only a single patient among them survived to admission. In contrast, four of ten with motion on POCUS survived to admission, yielding a positive predictive value of 97% for death when a standstill was seen at any point (9). Crucially, the operators were emergency physicians without formal POCUS credentials, demonstrating that, for the narrow question “is there motion?”, a subxiphoid or parasternal long-axis snapshot is attainable when embedded within the rhythm-check envelope. A single feasibility study [paramedic ultrasound in cardiac arrest (PUCA)] provides the counterpoint, though its findings should be interpreted as hypothesis-generating given the small sample size and single-site design. Over 2 years, seven paramedics attempted imaging during the ten-second pulse check; although adequacy was roughly 80% on first attempts, only 44% of scans were completed within ten seconds, and the median pause drifted to seventeen seconds, largely from communication and choreography failures rather than image acquisition difficulty (10). A subsequent protocolised pathway changed the equation: after a focused 4-hour curriculum and a formal pre-hospital echo protocol, image adequacy, defined as visualisation of the heart sufficient to determine presence or absence of cardiac activity rose to 85%, and interpretation accuracy, defined as correct identification of cardiac standstill or activity compared with expert over-read of recorded clips, rose to 87%. Additionally, management changed in more than a quarter of cases, and ten-second checks were preserved in 95% (10). These metrics represent post-training performance within the study and were assessed through internal expert review of stored images; baseline performance prior to protocol implementation was not systematically reported. This provides evidence that micro-workflow discipline converts feasibility into safe practice.

In the ED, larger datasets deepen and qualify the picture. Multicentre experience shows that sonographic cardiac activity during pulseless electrical activity (PEA)/asystole is associated with higher return of spontaneous circulation (ROSC), admission, and even discharge survival, and secondary analyses distinguishing organised from disorganised motion sharpen prognostic utility and direct interventions (11). High-quality evidence was identified from a 2025 meta-analysis of eighteen studies in PEA which affirmed high sensitivity of “activity present” for ROSC and admission, and a weaker but present association with survival to discharge (12). Multiple observational studies consistently caution against using POCUS alone to terminate resuscitation, reinforcing ultrasound as a prognostic adjunct rather than an autonomous termination tool (13). Across both venues, audits converge on the same behavioural hazard: unless ultrasound is embedded in a rehearsed algorithm with a single pre-selected view and a hard stop, pulse checks lengthen—eroding the very survival determinant ultrasound is intended to support (14).

The cross-setting distinction is therefore one of purpose and risk. In the field, POCUS functions as a trajectory tool guiding continuation or termination, destination selection and pre-alerts. In the ED, POCUS acts as an accelerator and disambiguator, reclassifying PEA physiology and uncovering treatable states. Figure 1 presents an illustrative comparison of conventional and POCUS-integrated diagnostic pathways in cardiovascular emergencies across pre-hospital and ED settings. Survival-to-discharge remains inconsistent in both settings; the enduring precept is that seconds spent on imaging must never be purchased at the expense of compressions.

Figure 1 Illustrative comparison of conventional and POCUS-integrated diagnostic pathways in cardiovascular emergencies.

The key message is that safety hinges on choreography. While several EMS and ED audits link POCUS to longer pauses when poorly integrated, controlled studies now show ultrasound-assisted pulse checks can be as fast or faster than manual checks when teams pre-select a single view, time-box to 10 seconds, and verbalise role assignments (14). This reconciles historical delays with a governance solution: ultrasound can shrink pulse-check time when embedded in a disciplined micro-workflow.

Pneumothorax

Thoracic POCUS is where environmental control and protocolisation have the greatest impact. Multiple prospective cohort studies consistently demonstrate that ED ultrasound achieves very high sensitivity and near-perfect specificity, consistently outperforming chest radiography. In trauma cohorts, sensitivity was 87% percent with 100% specificity for pneumothoraces at or above clinically relevant size thresholds, whereas standard chest X-ray (CXR) reached only 53% sensitivity (15). Moreover, POCUS identified many computed tomography (CT)-confirmed cases that were missed on radiography. In acute dyspnoea, a before-after study comparing a POCUS-first approach to conventional diagnostic pathways (which typically relied on chest radiography and laboratory testing) found front-loading lung ultrasound reduced time to correct diagnosis from roughly 3 hours to under 30 minutes (16), and the bedside lung ultrasound in emergency (BLUE) protocol demonstrated that a complete, clinically meaningful examination can be performed in under 3 minutes by trained operators (17). Pooled analyses show earlier targeted treatment and reduced intensive care unit (ICU) length of stay which are clinically valuable process improvements, yet mortality and 30-day readmissions remain unchanged. This dissociation between process gains and patient-centred outcomes underscores a critical distinction: POCUS functions as a process accelerator, but its conversion into survival benefits depends on the wider system’s capacity to leverage that accelerated timeline for definitive therapy.

Pre-hospital findings look less uniform until context is applied. A single aeromedical cohort study (n≈300) reported markedly lower sensitivity (19%) but +99% percent specificity, though this finding requires confirmation given the unique environmental challenges and potential selection bias as (18) clinically unimportant collections and scans were performed in a technically hostile environment. Ground-based and on-scene scans achieve high sensitivity, but aeromedical conditions erode sensitivity, supporting a pragmatic stance: a negative in-flight scan cannot confidently exclude a small pneumothorax, whereas a positive scan is highly actionable (19).

In contrast, focused non-traumatic dyspnoea cohorts show different strengths. The most comprehensive synthesis to date—a 2025 systematic review and meta-analysis—concluded that lung ultrasound is highly feasible in pre-hospital POCUS for non-traumatic dyspnoea, with typical scan times under 5 minutes. Though this conclusion rests on a small number of contributing studies with heterogeneous methodology. They reported excellent accuracy in detecting pneumothoraces across the two contributing studies. Critically, it also changed referrals in about half of patients and transport vectors in a quarter, while altering therapy in roughly one-tenth to one-half, depending on cohort; outcome effects were neutral in the few studies with follow-up (20).

The coherent comparative interpretation is that ED POCUS functions as a superior diagnostic test that also improves flow, while pre-hospital POCUS functions as a triage adjunct that conserves safety by preventing wrong procedures and wrong destinations within a minute-scale scan.

Acute heart failure and undifferentiated dyspnoea

Acute heart failure best illustrates how POCUS answers different questions at different points on the time axis. A meta-analysis of diagnostic accuracy studies (predominantly prospective cohorts) demonstrated that when integrated with clinical assessment, ED ultrasound is substantially more sensitive than chest radiography for diagnosing acute heart failure in older dyspnoeic adults (92.5% vs. 63.5%), with acceptable trade-offs in specificity (21). This comparison evaluates ultrasound against chest radiography, which remains the most common initial imaging study in this population, rather than against formal echocardiography, a distinct modality with different diagnostic goals. Studies comparing POCUS-enhanced pathways to usual care (typically involving delayed or selective imaging) demonstrate that front-loading ultrasound reduces time to correct diagnosis and often shortens ED length of stay, which are meaningful process improvements that enhance departmental efficiency and patient throughput (22). Right-heart assessment improves risk stratification for safer, earlier dispositions (23). However, these process measures should be distinguished from patient-centred outcomes; the same meta-analysis demonstrating reduced length of stay found no corresponding mortality benefit, indicating that faster diagnosis and discharge, while valuable, do not automatically translate into improved survival (22).

In the field, feasibility and discriminative value emerge when we examine how quickly teams can obtain meaningful lung information and what they do with it. In German EMS experience, pleural effusion was detected with striking accuracy in congestive heart failure, while accuracy for acute coronary syndrome (ACS) and chronic obstructive pulmonary disease (COPD) was far lower, underscoring that ultrasound must be indication-specific pre-hospital; average scan durations clustered around two to three minutes, compatible with transport timelines (8). Pilot feasibility work suggests that B-line-based assessments may provide a high negative predictive value (≈94%) for detecting cardiogenic pulmonary oedema when incorporated into clinical evaluation. However, lung ultrasound alone cannot diagnose or exclude heart failure, which is a heterogeneous syndrome in which pulmonary congestion may be absent in certain presentations, including right-sided or acute-on-chronic heart failure. These findings therefore support lung ultrasound as an adjunct to clinical assessment rather than a standalone diagnostic or exclusion tool (24).

The largest prospective pre-hospital cohort to date (n=214) demonstrated a modest incremental gain at scale: adding field POCUS raised sensitivity for acute heart failure from 58% to 65% and improved overall discrimination [area under the curve (AUC) 0.72 to 0.79] (25). These modest numbers matter because they occur earlier in the pathway. The 2025 meta-analysis of pre-hospital non-traumatic dyspnoea strengthens this signal, reporting moderate-to-excellent feasibility for lung ultrasound, typical scan times under 5 minutes, and consistent effects on referral and transport, even as outcomes remained unchanged in the small subset with follow-up (20). This aligns with our interpretation that field ultrasound shifts care earlier without guaranteeing a survival benefit in isolation. In comparative terms, ED POCUS functions primarily as an accuracy and throughput engine, improving diagnostic certainty and departmental flow, while pre-hospital POCUS serves as a triage enhancer, modifying transport decisions and resource activation. Both represent valuable process improvements when used as adjuncts to shift care in the right direction. However, it is essential to recognise that neither, in isolation, guarantees improved patient-centred outcomes such as survival or reduced hospital admission. This distinction is not merely semantic; it clarifies that the value proposition for POCUS implementation may legitimately rest on process efficiency and resource optimisation, even in the absence of demonstrated mortality benefit.

Shock and undifferentiated hypotension

“Shock” is a basket of pathophysiologies, and the literature reflects that heterogeneity. Pre-hospital scanning remains a story of actionable signals and governance trade-offs. In series where hypotension and shock are the leading indications, roughly one third of patients demonstrate abnormal findings such as collapsed inferior vena cava (IVC) suggesting profound hypovolaemia, gross left ventricular (LV) systolic impairment, right ventricular dilatation consistent with pressure overload, or intra-abdominal free fluid, each of which plausibly modifies fluid and vasopressor plans or destination (7). Implementation work has moved beyond feasibility to programmes that embed an extended focused assessment with sonography for trauma (FAST) into EMS with structured teaching, archiving and continuous feedback. Importantly, sensitivity for life-threatening injuries is around 50% and rises to about 75% in haemodynamically compromised patients, with high specificity (26). Scene times tend to increase when scanning is performed, a reminder that every minute must be justified by the clarity it buys for triage and activation (26,27).

Multiple large observational studies comparing POCUS-augmented assessment to clinical evaluation alone have consistently shown that POCUS reduces diagnostic uncertainty increases the proportion of early definitive diagnoses in the ED, which are important process measures that reflect improved diagnostic efficiency (28). These studies compare POCUS against clinical assessment without ultrasound, not against formal echocardiography, which is typically unavailable in the initial resuscitation phase. However, observational data could not establish a direct translational link between these diagnostic improvements and better patient outcomes.

Critically, the distinction between process and outcome is most starkly illustrated the international Shock-Optimized Care-Emergency Department (SHOC-ED) trial, which compared a structured POCUS pathway against standard care (clinical assessment without protocolised ultrasound) for undifferentiated hypotension. Despite compelling observational data suggesting benefit, SHOC-ED found no difference in 30-day or in-hospital mortality when comparing a structured POCUS pathway against standard care. There was no superiority in diagnostic accuracy at 60 minutes for a structured POCUS pathway compared with standard care for undifferentiated hypotension, arguing for ultrasound as a multiplier of clinical judgment rather than a replacement (29). This high-quality evidence demonstrates that the process improvements suggested by observational studies (reduced uncertainty, faster diagnosis) do not automatically confer patient-centred outcome benefits. Subsequent syntheses emphasise that protocol content [e.g., early cardiac and right ventricle (RV) assessment, IVC context, lung sliding/B-lines, FAST] is consistent. Whether process gains translate into improved survival depends on patient characteristics, operator expertise, and the healthcare system’s capacity to act on earlier diagnostic information (7). The SHOC-ED findings serve as an essential corrective: POCUS enhances clinical judgment but does not replace the need for effective therapeutic interventions, and faster diagnosis only improves survival when it enables faster effective treatment. Programmes that restrict pre-hospital shock POCUS to a few high-yield binary reads (gross LV function, RV size, IVC tiny/plethoric, free fluid yes/no) seem to balance information gain best with time.

Pre-hospital shock POCUS adds value by collapsing diagnostic ambiguity into a working diagnosis that guides transport and early therapy, a process improvement with face validity but unproven outcome benefit. ED shock POCUS similarly adds value when it accelerates diagnostic convergence without delaying definitive interventions. However, the SHOC-ED trial counsels humility: these process improvements, however intuitively beneficial, have not yet been shown to improve survival. The value proposition for POCUS in shock may therefore rest on improved resource utilisation, reduced diagnostic testing, and enhanced clinician confidence, legitimate endpoints that should be explicitly distinguished from, rather than conflated with, patient-centred outcomes.

Cardiac tamponade and pericardial effusion

Cardiac tamponade is a quintessential POCUS diagnosis as it presents with a distinctive sonographic pattern and requires urgent procedural input. Retrospective data forms the current highest available evidence for this rare condition, and suggest an association between early POCUS and faster intervention, though these findings are susceptible to confounding and should be interpreted cautiously. Hoch et al. reviewed 257 encounters and found that patients assessed early with POCUS underwent drainage at a mean of 21.6 hours, compared with 34.6 hours for those without early ultrasound, and that 28-day mortality fell from 26% to 9.7% (30). This comparison reflects POCUS against standard care pathways where ultrasound was not routinely employed early in assessment. Tamponade may represent a condition where process gains more readily translate into outcome benefits, given the direct relationship between timely decompression and survival. However, as a retrospective study, these findings are susceptible to confounding because patients receiving early POCUS may have differed in unmeasured ways from those who did not hence higher-quality designs are required before assuming causality.

Pre-hospital evidence is limited to case reports and small series, the lowest level of evidence, which can demonstrate feasibility but cannot establish efficacy or generalisable outcome benefits. While it is plausible that recognition of a large effusion in the field could alter destination choice, prompt earlier activation of surgical teams, and reduce time to definitive intervention, robust outcome data confirming this benefit are lacking. The comparative conclusion is that both pre-hospital and ED POCUS compress diagnostic time, with ED POCUS showing a direct correlation with outcomes and pre-hospital POCUS being more inferential but potentially lifesaving (31).

Aortic dissection

Aortic dissection is another diagnosis where time is of the essence, with mortality increasing by the hour. A multicentre prospective observational study of the sonographic protocol for the emergent evaluation of aortic dissections (SPEED) POCUS protocol demonstrated high sensitivity exceeding 90% and specificities around 90% in a high-risk cohort, with 100% sensitivity in type A aortic dissection (TAAD). This represents the best available evidence for this application (6). Prospective pilots comparing POCUS to CT angiography (the definitive diagnostic standard) have shown that POCUS reduced door-to-diagnosis times by about 70 minutes compared with CT angiography (32).

However, mortality was not improved highlighting a critical dissociation between process and outcome. This is likely because definitive surgical capacity and disease severity are dominant determinants of survival; accelerating diagnosis by 70 minutes confers little benefit if surgical teams are not immediately available or if the patient’s condition is already irreversibly compromised. This example powerfully illustrates that process gains only translate into outcome benefits when the healthcare system can absorb and act upon accelerated information. Pre-hospital evidence is limited to case reports. Ripoll-Gallardo and colleagues reported that on-scene recognition of a TAAD enabled direct transfer to a cardiothoracic centre, formal echocardiography within 1 hour, and surgery within 2 hours, with favourable outcomes (33). Aeromedical teams have described similar cases in which dissection-related effusions were detected in-flight, accelerating definitive care (34).

The comparative synthesis is that ED POCUS functions as a high-performance screening and acceleration tool that reduces diagnostic delay. At the same time, pre-hospital POCUS provides earlier suspicion and critical triage, even if the evidence remains anecdotal. In both contexts, the shared theme is the compression of time to definitive management.

A comparative summary of diagnostic accuracy, workflow metrics and clinical impact across both environments is presented in Table 2. The numerical ranges presented are derived from heterogeneous sources including RCTs, prospective and retrospective observational studies, feasibility studies, and case series as cited in the main text. These figures are approximate, context-dependent, and should be interpreted as illustrative rather than definitive pooled estimates. Values vary considerably based on patient population, operator experience, clinical setting, and study methodology. Readers should refer to the main text for detailed discussion of evidence quality for each condition and setting.

Discussion

Across conditions, POCUS provides consistent diagnostic and operational benefits in both settings, though the nature of those benefits differs. ED POCUS is generally more accurate, especially for acute heart failure and pneumothorax, and consistently compresses time to correct diagnosis and treatment which are valuable process measures that enhance clinical efficiency (35). Pre-hospital POCUS provides decisive triage and trajectory information, influencing termination, destination and referral decisions even when sensitivity is imperfect (5). However, a central finding of this review is that these process improvements do not consistently translate into improved patient-centred outcomes such as survival or functional recovery. The SHOC-ED trial provides the clearest evidence that faster diagnosis, in isolation, does not guarantee better outcomes (29). This dissociation arises because ultrasound is diagnostic rather than therapeutic; hence, the impact depends on the system’s ability to translate minutes saved into timely definitive care (22). Acknowledging this distinction is essential: POCUS implementation may be justified by process efficiency, resource optimisation, and clinician confidence, even where mortality benefits remain unproven. Training structures, governance frameworks, and device characteristics that influence performance are summarised in Table 3.

Training and governance are the fulcrum. Pre-hospital programmes succeed when they pair a defined scope with focused choreography. This is exemplified by a short, focused curriculum, a single prespecified window in arrest, loud, time-boxed call-outs, and a formal rule for when to skip the scan (36). In the ED, structured curricula can materially improve novice performance. The 2025 IMPULSE study shows that a brief, structured POCUS programme for residents managing acute respiratory or circulatory failure enabled juniors to use ultrasound as a primary diagnostic tool, with diagnostic accuracy comparable to that of experienced physicians and faster time to correct management (37). This bears evidence that curriculum design, archiving and feedback are as important as scan counts. Training should be short, focused, and protocol-tethered in EMS (single-arrest view; binary lung sliding; LV/RV gross function; IVC tiny/plethoric; FAST free fluid) and curriculum-based, with archiving in EDs.

Competency studies in rural EMS suggest that limited targeted training suffices for correct application (38). Early tele-ultrasound results indicate the feasibility of remote expert guidance, hinting at a safety net for low-volume services (39).

Credentialing should adopt a clearly structured process, starting with initial certification tied to a defined logbook and supervised scans, routine image archiving with peer over-read, regular audit of adequacy and interpretation, and revalidation keyed to performance metrics, rather than being solely time-based (40). Governance work from 2025 EMS implementation studies emphasises that continuous feedback loops and archiving are not optional add-ons but the substrate sustaining quality in real-world operations (41). Clinical performance appears to depend more on governance structures than on device class alone. Programmes that archive every scan, mandate peer over-read, and run feedback loops sustain adequacy and interpretation accuracy; those without archiving regress to anecdote.

EMS-hospital networks have demonstrated feasible cloud archiving and quality assurance (QA) with physician-paramedic models. In contrast, hospital enterprises publish roadmaps that formalise programme, clinical, information, and technology governance with credentialing and revalidation.

Device decisions increasingly favour handhelds for pre-hospital and triage contexts. Modern handhelds deliver sufficient image quality for focused questions, boot instantly, and are easier to disinfect and carry. Their risks are governance risks: without archiving, there is no feedback; without feedback, skills plateau and drift. Programmes that pair handhelds with routine cloud archiving and QA report diagnostic performance similar to carts for focused views (42). In EDs, carts still matter for advanced Doppler and quantified haemodynamics, but a “handheld-first for triage; cart-plus for equivocal or advanced questions” model appears efficient. Device class should match the question and context. Handhelds now achieve diagnostic accuracy comparable to carts for many focused ED/EMS applications, with minor sensitivity gaps offset by instant boot, portability, and lower cost. Independent head-to-head evaluations show similar specificity (≈91–92%) and clinically acceptable sensitivity for focused questions (43). At the same time, technical reviews note brand-level differences in image quality that rarely alter management-level decisions.

The evidence carries structural limitations. Selection bias is frequent, with many pre-hospital series enrolling only the sickest or most logistically tractable patients, whilst ED cohorts often reflect convenience sampling during staffed hours. Measurement bias arises from subjective thresholds (e.g., what counts as a standstill vs. disorganised twitching; “clinically significant” pneumothorax) and non-blinded interpretation. Confounding is also present when, for example, patients with visible cardiac motion are more likely to receive more aggressive and prolonged resuscitation, inflating associations with ROSC and admission, as well as those with clear effusions reaching procedures faster for reasons not solely attributable to ultrasound. Attrition and missingness hamper comparisons of outcomes, particularly in pre-hospital registries with incomplete follow-up. Reporting bias favours positive feasibility and time-to-event results, whereas neutral mortality studies, such as the aforementioned SHOC-ED study, remain relatively rare (44). This review has attempted to explicitly distinguish between these outcome categories, but the underlying evidence base remains disproportionately focused on process measures. Generalisability is bounded by operator mix and system capacity. The strongest pre-hospital programmes tend to be physician-led helicopter emergency medical services (HEMS) or paramedic services with robust governance; therefore, replication without these structures may not reproduce safety or adequacy metrics. In EDs, gains in time and accuracy will only be translated into survival when surgical, interventional, and critical care capacity can absorb accelerated diagnoses.

The 2025 dyspnoea meta-analysis reinforces this: pre-hospital lung ultrasound is feasible, fast, and triage-changing, but prognosis did not shift in the small subset with outcomes, which serves as a reminder that ultrasound saves minutes and that systems must turn those minutes into fewer complications and deaths (20).

A concrete agenda follows. In the pre-hospital setting, multicentre stepped-wedge or cluster RCTs of narrow, protocolised POCUS packages for arrest (single cardiac view), dyspnoea (anterior/lateral sliding and B-line read), and shock (binary LV function, RV size, IVC tiny/plethoric, FAST free fluid), tied to pre-specified destination rules, activation bundles, archiving and independent QA, are needed (2). Primary endpoints should include time to correct destination, avoidance of inappropriate procedures (e.g., non-indicated thoracostomy), and composite safety.

In addition, secondary endpoints can track admission patterns, ICU LOS and survival. In the ED, rather than new accuracy trials, we need pathway trials that test whether earlier POCUS-mediated recognition in tamponade, pneumothorax and dissection yields fewer peri-procedural complications, shorter door-to-definitive therapy, and better functional outcomes in the short- and mid-term (45). Training trials, inspired by the prospective, single-arm, multi-centre, safety and feasibility study IMPULSE, should randomise teams to structured curricula with archiving and feedback versus usual training and quantify gains in adequacy and diagnostic timeliness at the programme level (37). Finally, the integration of AI-assisted interpretation and tele-ultrasound represents the next frontier for standardisation and equity of access (3).

A limitation of this review is the heterogeneity in study design and evidentiary strength across conditions and settings. For some applications, such as pre-hospital detection of cardiac tamponade and aortic dissection, the literature is largely limited to observational studies and feasibility reports, which restricts the strength of conclusions that can be drawn. By contrast, conditions such as undifferentiated shock and acute dyspnoea are supported by higher-quality evidence, including RCT and meta-analyses, allowing more confident interpretation of outcome findings.

Conclusions

POCUS is a fast, information-dense adjunct whose value depends on context. In EDs, it provides high diagnostic accuracy and accelerates care, reducing diagnostic delay and length of stay. In the field, it offers early, actionable information that shapes triage, transport and, at times, termination. Across both settings, mortality benefits remain unproven, but process improvements and decision support are consistent. The path forward lies in standardised training and governance, robust archiving and QA, and pragmatic trials that measure not just speed and accuracy but outcomes that matter to patients.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the PRISMA-ScR reporting checklist. Available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-1-646/rc

Peer Review File: Available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-1-646/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://cdt.amegroups.com/article/view/10.21037/cdt-2025-1-646/coif). M.J. serves as an unpaid editorial board member of Cardiovascular Diagnosis and Therapy from July 2025 to June 2027. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Lau YH, See KC. Point-of-care ultrasound for critically-ill patients: A mini-review of key diagnostic features and protocols. World J Crit Care Med 2022;11:70-84. [Crossref] [PubMed]
2. Hellenthal KEM, Porschen C, Wnent J, et al. Evolving role of point-of-care ultrasound in prehospital emergency care: a narrative review. Scand J Trauma Resusc Emerg Med 2025;33:126. [Crossref] [PubMed]
3. Kim S, Fischetti C, Guy M, et al. Artificial Intelligence (AI) Applications for Point of Care Ultrasound (POCUS) in Low-Resource Settings: A Scoping Review. Diagnostics (Basel) 2024;14:1669. [Crossref] [PubMed]
4. Haskings EM, Eissa M, Allard RV, et al. Point-of-care ultrasound use in emergencies: what every anaesthetist should know. Anaesthesia 2023;78:105-18. [Crossref] [PubMed]
5. Bøtker MT, Jacobsen L, Rudolph SS, et al. The role of point of care ultrasound in prehospital critical care: a systematic review. Scand J Trauma Resusc Emerg Med 2018;26:51. [Crossref] [PubMed]
6. Gibbons RC, Smith D, Feig R, et al. The sonographic protocol for the emergent evaluation of aortic dissections (SPEED protocol): A multicenter, prospective, observational study. Acad Emerg Med 2024;31:112-8. [Crossref] [PubMed]
7. Kok B, Wolthuis D, Bosch F, et al. POCUS in dyspnea, nontraumatic hypotension, and shock; a systematic review of existing evidence. Eur J Intern Med 2022;106:9-38. [Crossref] [PubMed]
8. Kowalczyk D, Piotrowski WJ, Rosiak O, et al. Concise, Practical Review on Transthoracic Lung Ultrasound in Prehospital Diagnosis of Dyspnea in Adults. Medicina (Kaunas) 2023;59:224. [Crossref] [PubMed]
9. Albaroudi O, Albaroudi B, Haddad M, et al. Can absence of cardiac activity on point-of-care echocardiography predict death in out-of-hospital cardiac arrest? A systematic review and meta-analysis. Ultrasound J 2024;16:10.
10. Reed MJ, Gibson L, Dewar A, et al. Introduction of paramedic led Echo in Life Support into the pre-hospital environment: The PUCA study. Resuscitation 2017;112:65-9. [Crossref] [PubMed]
11. Flower L, Olusanya O, Madhivathanan PR. The use of critical care echocardiography in peri-arrest and cardiac arrest scenarios: Pros, cons and what the future holds. J Intensive Care Soc 2021;22:230-40. [Crossref] [PubMed]
12. Jian SZ, Cheng TH, Yen CC. Prognostic accuracy of point-of-care ultrasound in patients with pulseless electrical activity: a systematic review and meta-analysis. Scand J Trauma Resusc Emerg Med 2025;33:27. [Crossref] [PubMed]
13. Gaspari R, Weekes A, Adhikari S, et al. Emergency department point-of-care ultrasound in out-of-hospital and in-hospital cardiac arrest: a systematic review. Resuscitation 2016;109:1-12.
14. Wik L, Kramer-Johansen J, Myklebust H, et al. Quality of cardiopulmonary resuscitation during out-of-hospital cardiac arrest. JAMA 2005;293:299-304. [Crossref] [PubMed]
15. Kirkpatrick AW, Sirois M, Laupland KB, et al. Hand-held thoracic sonography for detecting post-traumatic pneumothoraces: the Extended Focused Assessment with Sonography for Trauma (EFAST). J Trauma 2004;57:288-95. [Crossref] [PubMed]
16. Ciumanghel I, Barbuta E, Ciumanghel AI, et al. Point-of-care lung ultrasound - a rapid and reliable diagnostic tool for emergency physicians treating patients with acute dyspnea in high-volume emergency departments. Emerg Radiol 2025;32:329-38. [Crossref] [PubMed]
17. Lichtenstein DA, Mezière GA. Relevance of lung ultrasound in the diagnosis of acute respiratory failure: the BLUE protocol. Chest 2008;134:117-25. [Crossref] [PubMed]
18. Press GM, Miller SK, Hassan IA, et al. Prospective evaluation of prehospital trauma ultrasound during aeromedical transport. J Emerg Med 2014;47:638-45. [Crossref] [PubMed]
19. Quick JA, Uhlich RM, Ahmad S, et al. In-flight ultrasound identification of pneumothorax. Emerg Radiol 2016;23:3-7. [Crossref] [PubMed]
20. Taheri O, Samain J, Mauny F, et al. Contribution of point-of-care ultrasound in the prehospital management of patients with non-trauma acute dyspnea: a systematic review and meta-analysis. Eur J Emerg Med 2025;32:87-99. [Crossref] [PubMed]
21. Martindale JL, Wakai A, Collins SP, et al. Diagnosing Acute Heart Failure in the Emergency Department: A Systematic Review and Meta-analysis. Acad Emerg Med 2016;23:223-42. [Crossref] [PubMed]
22. Szabó GV, Szigetváry C, Szabó L, et al. Point-of-care ultrasound improves clinical outcomes in patients with acute onset dyspnea: a systematic review and meta-analysis. Intern Emerg Med 2023;18:639-53. [Crossref] [PubMed]
23. Platz E, Merz AA, Jhund PS, et al. Dynamic changes and prognostic value of pulmonary congestion by lung ultrasound in acute and chronic heart failure: a systematic review. Eur J Heart Fail 2017;19:1154-63. [Crossref] [PubMed]
24. Rahmani E, Farrokhi M, Farrokhi M, et al. Accuracy of Lung Ultrasonography for Diagnosis of Heart Failure; a Systematic Review and Meta-analysis. Arch Acad Emerg Med 2025;13:e33. [Crossref] [PubMed]
25. Gundersen EA, Juhl-Olsen P, Bach A, et al. PrehospitaL Ultrasound in Undifferentiated DyspnEa (PreLUDE): a prospective, clinical, observational study. Scand J Trauma Resusc Emerg Med 2023;31:6. [Crossref] [PubMed]
26. Naeem S, Aziz S, Hirst T, et al. Implementation of prehospital point-of-care ultrasound using a novel continuous feedback approach in a UK helicopter emergency medical service. Scand J Trauma Resusc Emerg Med 2025;33:21. [Crossref] [PubMed]
27. Gamberini L, Scquizzato T, Tartaglione M, et al. Diagnostic accuracy for hemoperitoneum, influence on prehospital times and time-to-definitive treatment of prehospital FAST: A systematic review and individual participant data meta-analysis. Injury 2023;S0020-1383(23)00280-2.
28. Yoshida T, Yoshida T, Noma H, et al. Diagnostic accuracy of point-of-care ultrasound for shock: a systematic review and meta-analysis. Crit Care 2023;27:200. [Crossref] [PubMed]
29. Atkinson PR, Milne J, Diegelmann L, et al. Does Point-of-Care Ultrasonography Improve Clinical Outcomes in Emergency Department Patients With Undifferentiated Hypotension? An International Randomized Controlled Trial From the SHoC-ED Investigators. Ann Emerg Med 2018;72:478-89.
30. Hoch VC, Abdel-Hamid M, Liu J, et al. ED point-of-care ultrasonography is associated with earlier drainage of pericardial effusion: A retrospective cohort study. Am J Emerg Med 2022;60:156-63. [Crossref] [PubMed]
31. Rosario J, Mangal R, Houck J, et al. Pericardial effusion with tamponade: bedside ultrasonography saves another life. Int J Emerg Med 2020;13:3. [Crossref] [PubMed]
32. Morello F, Bima P, Castelli M, et al. Diagnosis of acute aortic syndromes with ultrasound and d-dimer: the PROFUNDUS study. Eur J Intern Med 2024;128:94-103. [Crossref] [PubMed]
33. Ripoll-Gallardo A, Cabrini M, Cairo M, et al. A Case Report of Prehospital Point-Of-Care Ultrasound in Acute Aortic Dissection: Reinforcing the Out-of-Hospital Chain of Survival. Prehosp Emerg Care 2026;30:570-5. [Crossref] [PubMed]
34. Zanatta M, Scorpiniti M, Cianci V. Early identification of aortic dissection with pre-hospital ultrasound: a case report. EJMC 2018;2:83-6.
35. Chiu L, Jairam MP, Chow R, et al. Meta-Analysis of Point-of-Care Lung Ultrasonography Versus Chest Radiography in Adults With Symptoms of Acute Decompensated Heart Failure. Am J Cardiol 2022;174:89-95. [Crossref] [PubMed]
36. Zanatta M, Benato P, Cianci V. Pre-hospital ultrasound: current indications and future perspectives. Int J Crit Care Emerg Me. 2016;2:019.
37. Bieler S, von Düring S, Tagan D, et al. Impact of a Point-of-Care Ultrasound Training Program on the Management of Patients With Acute Respiratory or Circulatory Failure by In-Training Emergency Department Residents (IMPULSE): Before-and-After Implementation Study. JMIRx Med 2025;6:e53276. [Crossref] [PubMed]
38. Heegaard W, Hildebrandt D, Spear D, et al. Prehospital ultrasound by paramedics: results of field trial. Acad Emerg Med 2010;17:624-30. [Crossref] [PubMed]
39. Salerno A, Tupchong K, Verceles AC, et al. Point-of-Care Teleultrasound: A Systematic Review. Telemed J E Health 2020;26:1314-21. [Crossref] [PubMed]
40. Chu A, Yee J. Cardiac Tamponade. J Educ Teach Emerg Med 2020;5:S84-S107. [Crossref] [PubMed]
41. Warren J, Toy J. Current Practices in Prehospital Ultrasound: A Systematic Evaluation of Prehospital Protocols Within the United States. Prehosp Emerg Care 2025; Epub ahead of print. [Crossref]
42. Warren J, Tamhankar O, Toy J, et al. Use of Ultrasound in the Prehospital Setting: A Scoping Review. J Am Coll Emerg Physicians Open 2025;6:100086. [Crossref] [PubMed]
43. Kayarian F, Patel D, O'Brien JR, et al. Artificial intelligence and point-of-care ultrasound: Benefits, limitations, and implications for the future. Am J Emerg Med 2024;80:119-22. [Crossref] [PubMed]
44. Atkinson P, Bowra J, Milne J, et al. International Federation for Emergency Medicine Consensus Statement: Sonography in hypotension and cardiac arrest (SHoC): An international consensus on the use of point of care ultrasound for undifferentiated hypotension and during cardiac arrest. CJEM 2017;19:459-70. [Crossref] [PubMed]
45. American College of Emergency Physicians Clinical Policies Subcommittee (Writing Committee) on Nontraumatic Thoracic Aortic Dissection. Critical Issues in the Evaluation and Management of Adult Patients With Suspected Acute Nontraumatic Thoracic Aortic Dissection. Ann Emerg Med 2025;86:e12-e26. [Crossref] [PubMed]