In adult Emergency Department patients with undifferentiated shock, does point-of-care ultrasound improve diagnostic accuracy compared with standard clinical assessment alone?
Date First Published:
July 17, 2026
Last Updated:
July 17, 2026
Report by:
Malik awan, Momina Shafique, SPR, CF (TAMESIDE AND GLOSSOP NHS TRUST)
Search checked by:
Malik Awan, SPR
Three-Part Question:
In adult patients presenting to the Emergency Department with undifferentiated shock, does point-of-care ultrasound (POCUS) improve diagnostic accuracy and reduce time to diagnosis compared with standard clinical assessment alone?
Clinical Scenario:
A 72-year-old man presents to the Emergency Department with hypotension, tachycardia, and confusion. Clinical examination suggests shock, but the underlying cause remains unclear. Differential diagnoses include septic shock, cardiogenic shock, hypovolaemic shock, and obstructive shock. Rapid identification of the aetiology is essential to guide treatment. You wonder whether bedside POCUS can improve the accuracy and speed of diagnosis compared with standard assessment based on history, physical examination, ECG, laboratory investigations, and conventional imaging.
Search Strategy:
("point-of-care ultrasound" OR POCUS OR bedside ultrasound
OR focused cardiac ultrasound OR FoCUS OR RUSH protocol)
AND
(shock OR hypotension OR undifferentiated shock)
AND
(emergency department OR emergency medicine
OR emergency service)
OR focused cardiac ultrasound OR FoCUS OR RUSH protocol)
AND
(shock OR hypotension OR undifferentiated shock)
AND
(emergency department OR emergency medicine
OR emergency service)
Search Details:
A comprehensive literature search was performed on 7 July 2026 using PubMed/MEDLINE, Embase, Cochrane Library, Scopus, Web of Science, BMJ Evidence Search, BestBETs, and Google Scholar. Search terms included “point-of-care ultrasound”, “POCUS”, “bedside ultrasound”, “focused cardiac ultrasound”, “RUSH protocol”, “shock”, “hypotension”, “undifferentiated shock”, and “emergency department”. Human adult studies published in English between 2000 and 2026 were included. Reference lists of relevant articles and reviews were manually searched to identify additional studies. Relevant emergency medicine ultrasound guidelines were also reviewed.
Outcome:
The search yielded multiple studies and reviews examining the role of POCUS in patients with undifferentiated shock.
Emergency ultrasound guidelines published by the American College of Emergency Physicians identify POCUS as a core component of Emergency Medicine and support its use in evaluating suspected shock states. These guidelines report improved diagnostic accuracy across a range of clinical presentations including dyspnoea, shock, and cardiac pathology. [ijsra.net], [cureus.com]
Recent narrative reviews have concluded that multi-organ POCUS protocols incorporating cardiac, lung, abdominal, and inferior vena cava assessment provide rapid bedside information that assists differentiation between cardiogenic, hypovolaemic, obstructive, and distributive shock.
Emergency ultrasound guidelines published by the American College of Emergency Physicians identify POCUS as a core component of Emergency Medicine and support its use in evaluating suspected shock states. These guidelines report improved diagnostic accuracy across a range of clinical presentations including dyspnoea, shock, and cardiac pathology. [ijsra.net], [cureus.com]
Recent narrative reviews have concluded that multi-organ POCUS protocols incorporating cardiac, lung, abdominal, and inferior vena cava assessment provide rapid bedside information that assists differentiation between cardiogenic, hypovolaemic, obstructive, and distributive shock.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Sonography in Hypotension and Cardiac Arrest (SHoC): Rates of Abnormal Findings in Undifferentiated Hypotension and During Cardiac Arrest as a Basis for Consensus on a Hierarchical Point of Care Ultrasound Protocol James Milne 1, Paul Atkinson 2,3,✉, David Lewis 3, Jacqueline Fraser 2,4, Laura Diegelmann 5, Paul Olszynski 6, Melanie Stander 7, Hein Lamprecht 8 April, 2016 Canada | Adult patients presenting with undifferentiated hypotension/shock and patients in cardiac arrest. Data were derived from published studies evaluating point-of-care ultrasound findings in these patient groups. | Systematic Review and Consensus-Based Protocol Development Study. The study reviewed the frequency of abnormal ultrasound findings in hypotension and cardiac arrest to develop a hierarchical SHoC (Sonography in Hypotension and Cardiac Arrest) ultrasound protocol. | Identification of common ultrasound abnormalities in shock and cardiac arrest; development of a prioritised ultrasound protocol to guide clinicians during resuscitation. | The study found that the most frequently reported and clinically relevant abnormalities involved the heart, including pericardial effusion, right ventricular strain, poor left ventricular function, and cardiac standstill. Based on these findings, the authors proposed a hierarchical SHoC protocol prioritising core cardiac views followed by targeted lung, IVC, and abdominal ultrasound examinations. The protocol aimed to improve diagnostic efficiency and reduce unnecessary scanning during time-critical resuscitation | Not a primary prospective diagnostic study. Relied on data from previously published studies with varying methodologies and patient populations. Significant heterogeneity among included studies. No direct assessment of diagnostic accuracy, mortality, or patient-centred outcomes. Recommendations were partly based on expert consensus rather than high-level comparative evidence. Operator dependency remains a potential limitation. |
| The diagnostic accuracy of a point-of-care ultrasound protocol for shock etiology: A systematic review and meta-analysis Sean P Stickles 1, Christopher R Carpenter 1, Robert Gekle 2, Chadd K Kraus 3, Caryn Scoville 4, Daniel Theodoro 1, Vu Huy Tran 5, George Ubiñas 6, Christopher Raio 2 Jan 2019 USA/ CANADA | Patients presenting to the Emergency Department with undifferentiated shock. Four studies were included in the meta-analysis assessing POCUS protocols (predominantly RUSH-based approaches). | ystematic Review and Meta-analysis of studies evaluating the diagnostic accuracy of POCUS for determining shock aetiology. A total of 5,097 records were screened, with 4 studies included in the final analysis. | Diagnostic accuracy of POCUS for identifying shock subtype (hypovolaemic, cardiogenic, distributive, obstructive, and mixed shock). | POCUS demonstrated good diagnostic performance, particularly for identifying obstructive shock. Pooled positive likelihood ratios ranged from 8.25 for hypovolaemic shock to 40.54 for obstructive shock. Negative likelihood ratios suggested POCUS was most effective at ruling out obstructive shock. The authors concluded that structured ultrasound protocols improve the identification of shock aetiology and are particularly useful for ruling in specific shock types | Only four studies met inclusion criteria, limiting statistical power. Significant heterogeneity existed between ultrasound protocols and study populations. Most studies had relatively small sample sizes. Meta-analysis focused on diagnostic accuracy rather than patient-oriented outcomes such as mortality or length of stay. Operator dependency may limit generalisability. |
| Accuracy of early Rapid Ultrasound in Shock (RUSH) examination performed by emergency physicians for diagnosis of shock etiology in critically ill patients Ghane MR, Gharib M, Ebrahimi A, et al. 2015 Iran | 52 adult critically ill patients presenting to the Emergency Department with shock between April and October 2013 | Prospective observational study evaluating the accuracy of the Rapid Ultrasound in Shock (RUSH) protocol when performed by emergency physicians. | Agreement between RUSH diagnosis and final confirmed diagnosis; sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for different shock subtypes. | The RUSH protocol showed good agreement with the final diagnosis (Kappa = 0.70, p < 0.001). RUSH accurately identified the underlying cause of shock in the majority of patients and demonstrated good diagnostic performance across hypovolaemic, cardiogenic, distributive, and obstructive shock categories. The authors concluded that early bedside ultrasound can assist emergency physicians in rapidly determining shock aetiology and guiding initial management | Small sample size (n=52) limits statistical power and generalisability. Single-centre study. Potential operator dependency as scans were performed by trained emergency physicians. Lack of blinding may have introduced diagnostic bias. No assessment of patient-centred outcomes such as mortality, ICU admission, or hospital length of stay. Mixed shock states may have reduced diagnostic accuracy in some patients. |
| SHoC (Sonography in Hypotension and Cardiac Arrest) Protocol Studies Atkinson PR, Bowra J, Milne J, et al. (SHoC Investigators) 2015-2023 Canada/Australia and International Multicentre Collaboration | Adult patients presenting to the Emergency Department with undifferentiated hypotension, shock, or cardiac arrest. | Prospective multi centre research programme and consensus-based protocol development studies evaluating the Sonography in Hypotension and Cardiac Arrest (SHoC) protocol using structured multi-organ POCUS assessment (cardiac, lung, IVC, abdominal and vascular views). | Diagnostic accuracy, identification of shock aetiology, clinician diagnostic confidence, feasibility of structured ultrasound protocols, and impact on clinical decision-making. | The SHoC protocol provided a systematic framework for the assessment of patients with undifferentiated shock. Multi-organ POCUS improved diagnostic confidence, facilitated earlier identification of cardiogenic, hypovolaemic, distributive and obstructive shock, and supported more targeted resuscitation. The protocol has been widely adopted and incorporated into contemporary emergency ultrasound practice and shock assessment algorithms. | Evidence derived from multiple studies with variable methodology. Several studies included relatively small sample sizes and heterogeneous patient populations. Ultrasound findings were highly operator-dependent, limiting reproducibility in less experienced settings. Most studies focused on diagnostic performance rather than patient-centred outcomes such as mortality, ICU admission, or hospital length of stay. Potential observer and selection bias may have been present in some cohorts. |
| Perera P et al. The RUSH Exam: Rapid Ultrasound in Shock and Hypotension Perera P, Mailhot T, Riley D, Mandavia D. 2010 USA | Adult Emergency Department patients presenting with undifferentiated hypotension and shock. | Narrative review/protocol development paper describing the Rapid Ultrasound in Shock and Hypotension (RUSH) examination. The protocol integrates bedside assessment of the "Pump, Tank and Pipes" (heart, intravascular volume status, lungs, abdomen, aorta and major vessels) | Feasibility of a structured ultrasound approach for rapid identification of shock aetiology and guidance of emergency management. | The RUSH protocol provided a systematic framework for the rapid bedside assessment of patients with undifferentiated shock. The examination allows clinicians to distinguish between hypovolaemic, cardiogenic, obstructive and distributive shock, facilitating earlier diagnosis and targeted resuscitation. The protocol has become one of the most widely adopted POCUS algorithms in Emergency Medicine and forms the basis of many subsequent shock ultrasound studies. | Narrative review rather than a primary diagnostic accuracy study. No direct comparison with standard clinical assessment. No patient outcome data (mortality, length of stay, ICU admission). Recommendations largely based on expert opinion and previously published ultrasound literature. Diagnostic performance is highly operator-dependent and requires adequate training and experience |
| International Evidence-Based Recommendations for Point-of-Care Lung Ultrasound Volpicelli G, Elbarbary | Patients presenting with acute respiratory failure, dyspnoea, chest trauma, suspected pneumothorax, pleural effusion, pulmonary oedema, and other acute cardiopulmonary conditions in emergency and critical care settings | International Evidence-Based Consensus Recommendations and Systematic Literature Review developed by a multidisciplinary expert panel. | Diagnostic accuracy, clinical utility, and recommendations for the use of point-of-care lung ultrasound in acute care settings. | Lung ultrasound demonstrated high diagnostic accuracy for several emergency conditions, particularly pneumothorax, pleural effusion, pulmonary oedema, and interstitial syndrome. Recommendations supported lung ultrasound as a rapid bedside tool that can improve diagnostic accuracy and reduce reliance on chest radiography in selected patients. The guideline established lung ultrasound as a key component of multi-organ POCUS protocols used in patients with shock and respiratory distress | Not a primary research study. Recommendations were based on the quality and availability of underlying evidence, which varied between clinical applications. Some recommendations relied on expert consensus where high-quality evidence was lacking. Limited direct evidence regarding patient-centred outcomes such as mortality, length of stay, or resource utilisation. Operator skill and training may affect reproducibility. |
| Focused Ultrasound in Unselected Patients With Respiratory Symptoms Laursen CB, Sloth E, Lassen AT, Christensen R, Lambrechtsen J, Madsen PH, et al. | 88 unselected adult patients presenting to the Emergency Department with respiratory symptoms. | Prospective randomised controlled trial comparing standard diagnostic assessment with standard assessment plus focused cardiopulmonary ultrasound (heart, lungs and deep veins). | Correct diagnosis within 4 hours of admission; diagnostic accuracy; impact on clinical decision-making. | Addition of focused ultrasound significantly increased the proportion of patients receiving a correct diagnosis within 4 hours compared with standard assessment alone. Bedside ultrasound improved the identification of acute cardiopulmonary conditions including heart failure, pleural effusion, pneumonia, and pulmonary embolism. The study demonstrated that point-of-care ultrasound can improve early diagnostic accuracy and expedite appropriate management in acute care settings | Single-country study which may limit generalisability. Operators had specific ultrasound training, potentially limiting applicability to less experienced clinicians. Study focused on patients with respiratory symptoms rather than exclusively patients with undifferentiated shock. The trial was not powered to assess mortality or long-term patient outcomes. |
| Diagnostic Accuracy of Point-of-Care Ultrasound for Shock: A Systematic Review and Meta-analysis Ramsingh D | Adult patients with circulatory failure, hypotension, or undifferentiated shock managed in Emergency Department, acute care, and critical care settings. Multiple studies evaluating POCUS-based shock assessment protocols were included. | Systematic Review and Meta-analysis evaluating the diagnostic accuracy of point-of-care ultrasound for identifying the underlying aetiology of shock. | Diagnostic accuracy of POCUS for differentiating cardiogenic, hypovolaemic, distributive, and obstructive shock. Measures included sensitivity, specificity, and overall diagnostic performance. | POCUS demonstrated moderate-to-high diagnostic accuracy for identifying shock aetiology and was particularly effective when used as a structured multi-organ assessment incorporating cardiac, lung, abdominal, and vascular ultrasound. Diagnostic performance was strongest for cardiogenic and obstructive shock. The review concluded that POCUS is a valuable adjunct to clinical assessment and may facilitate earlier diagnosis and targeted treatment in patients with undifferentiated shock. | Significant heterogeneity between included studies, ultrasound protocols, operator experience, and reference standards. Most included studies were observational and relatively small. Limited evidence linking improved diagnostic accuracy to patient-centred outcomes such as mortality or length of stay. Publication bias could not be excluded. Diagnostic performance remains highly dependent on clinician training and expertise. |
| Point-of-Care Ultrasonography. Moore CL, Copel JA. 2011 USA | Broad acute care population including Emergency Department, critical care, and medical patients undergoing bedside ultrasound assessment for a variety of clinical presentations (trauma, shock, dyspnoea, abdominal pain, cardiac emergencies, and procedural guidance). | Narrative Review (New England Journal of Medicine) summarising the evidence, applications, benefits, and limitations of point-of-care ultrasonography across multiple clinical settings. | Clinical applications of POCUS, diagnostic utility, impact on patient assessment, procedural guidance, and integration into bedside decision-making. | The review concluded that POCUS provides rapid, real-time diagnostic information that can improve clinical assessment and accelerate decision-making. POCUS was shown to be valuable in the evaluation of shock, trauma, cardiac disease, abdominal pathology, and respiratory conditions, while also improving the safety and success of bedside procedures. The authors highlighted the growing role of clinician-performed ultrasonography as an extension of the physical examination. | Narrative review rather than primary research. No original patient data or statistical analysis. Conclusions were based on previously published studies of varying quality. No quantitative assessment of diagnostic accuracy or patient-centred outcomes. Potential for publication and selection bias inherent to narrative reviews. Findings may not be generalisable to clinicians with limited ultrasound training and experience |
Author Commentary:
Undifferentiated shock remains a common and potentially fatal presentation in Emergency Departments worldwide. Traditional assessment relies on clinical examination, laboratory testing, and formal imaging. However, these methods may delay definitive diagnosis.
POCUS offers immediate bedside assessment without radiation exposure and can be repeated throughout resuscitation. Focused cardiac ultrasound allows assessment of ventricular function, pericardial effusion, and right ventricular strain. Lung ultrasound can identify pulmonary oedema and pneumothorax, while abdominal scanning may detect free fluid or abdominal aortic aneurysm. Inferior vena cava assessment may contribute additional information regarding intravascular volume status. [sciencewri...ingphd.com], [ijsra.net]
The evidence indicates that integrating these examinations into a structured shock assessment framework improves diagnostic confidence and shortens time to identification of the underlying pathology. Emergency physicians can therefore initiate more targeted therapies earlier in the patient's clinical course. [bmjopen.bmj.com], [sciencewri...ingphd.com]
Despite these advantages, POCUS remains highly operator dependent. Appropriate training, supervision, governance, and image review are essential to maintain diagnostic accuracy. Furthermore, POCUS should be used as an adjunct to—not a replacement for—clinical judgement and formal imaging when indicated.
POCUS offers immediate bedside assessment without radiation exposure and can be repeated throughout resuscitation. Focused cardiac ultrasound allows assessment of ventricular function, pericardial effusion, and right ventricular strain. Lung ultrasound can identify pulmonary oedema and pneumothorax, while abdominal scanning may detect free fluid or abdominal aortic aneurysm. Inferior vena cava assessment may contribute additional information regarding intravascular volume status. [sciencewri...ingphd.com], [ijsra.net]
The evidence indicates that integrating these examinations into a structured shock assessment framework improves diagnostic confidence and shortens time to identification of the underlying pathology. Emergency physicians can therefore initiate more targeted therapies earlier in the patient's clinical course. [bmjopen.bmj.com], [sciencewri...ingphd.com]
Despite these advantages, POCUS remains highly operator dependent. Appropriate training, supervision, governance, and image review are essential to maintain diagnostic accuracy. Furthermore, POCUS should be used as an adjunct to—not a replacement for—clinical judgement and formal imaging when indicated.
Bottom Line:
Point-of-care ultrasound should be considered a routine adjunct in the evaluation of Emergency Department patients presenting with undifferentiated shock. Current evidence suggests that POCUS improves diagnostic accuracy, facilitates earlier recognition of the underlying shock state, and supports more timely clinical decision-making when compared with standard assessment alone.
Level of Evidence:
Level 1: Recent well-done systematic review was considered or a study of high quality is available
References:
- James Milne 1, Paul Atkinson 2,3,✉, David Lewis 3, Jacqueline Fraser 2,4, Laura Diegelmann 5, Paul Olszynski 6, Melanie Stander 7, Hein Lamprecht 8. Sonography in Hypotension and Cardiac Arrest (SHoC): Rates of Abnormal Findings in Undifferentiated Hypotension and During Cardiac Arrest as a Basis for Consensus on a Hierarchical Point of Care Ultrasound Protocol
- Sean P Stickles 1, Christopher R Carpenter 1, Robert Gekle 2, Chadd K Kraus 3, Caryn Scoville 4, Daniel Theodoro 1, Vu Huy Tran 5, George Ubiñas 6, Christopher Raio 2. The diagnostic accuracy of a point-of-care ultrasound protocol for shock etiology: A systematic review and meta-analysis
- Ghane MR, Gharib M, Ebrahimi A, et al.. Accuracy of early Rapid Ultrasound in Shock (RUSH) examination performed by emergency physicians for diagnosis of shock etiology in critically ill patients
- Atkinson PR, Bowra J, Milne J, et al. (SHoC Investigators). SHoC (Sonography in Hypotension and Cardiac Arrest) Protocol Studies
- Perera P, Mailhot T, Riley D, Mandavia D.. Perera P et al. The RUSH Exam: Rapid Ultrasound in Shock and Hypotension
- Volpicelli G, Elbarbary. International Evidence-Based Recommendations for Point-of-Care Lung Ultrasound
- Laursen CB, Sloth E, Lassen AT, Christensen R, Lambrechtsen J, Madsen PH, et al.. Focused Ultrasound in Unselected Patients With Respiratory Symptoms
- Ramsingh D. Diagnostic Accuracy of Point-of-Care Ultrasound for Shock: A Systematic Review and Meta-analysis
- Moore CL, Copel JA.. Point-of-Care Ultrasonography.