Disclaimer: The Rapid Response Service is an information service for those involved in planning and providing health care in Canada. Rapid responses are based on a limited literature search and are not comprehensive, systematic reviews. The intent is to provide a list of sources of the best evidence on the topic that CADTH could identify using all reasonable efforts within the time allowed. Rapid responses should be considered along with other types of information and health care considerations. The information included in this response is not intended to replace professional medical advice, nor should it be construed as a recommendation for or against the use of a particular health technology. Readers are also cautioned that a lack of good quality evidence does not necessarily mean a lack of effectiveness particularly in the case of new and emerging health technologies, for which little information can be found, but which may in future prove to be effective. While CADTH has taken care in the preparation of the report to ensure that its contents are accurate, complete and up to date, CADTH does not make any guarantee to that effect. CADTH is not liable for any loss or damages resulting from use of the information in the report. Copyright: This report contains CADTH copyright material and may contain material in which a third party owns copyright. This report may be used for the purposes of research or private study only. It may not be copied, posted on a web site, redistributed by email or stored on an electronic system without the prior written permission of CADTH or applicable copyright owner. Links: This report may contain links to other information available on the websites of third parties on the Internet. CADTH does not have control over the content of such sites. Use of third party sites is governed by the owners’ own terms and conditions.
TITLE: Portable Ultrasound Devices in the Pre-Hospital Setting: A Review of Clinical and Cost-Effectiveness and Guidelines
DATE: 29 May 2015 CONTEXT AND POLICY ISSUES Emergency physicians often rely on technology such as portable ultrasound (US) to assist in decision making when treating patients in critical condition.1 Portable US devices, also referred to as point-of-care US (POCUS), mobile US, bedside US, and encompassing specific procedures such as focused-assessment with sonography for trauma (FAST), comprise a range of technologies including handheld devices, conventional mobile bedside devices and other devices with mobility. Examples include PRIMEDIC HandyScan, V-scan (GE Healthcare), and SonoSite devices.1 Portable US devices are lauded for being lightweight, small, and durable, and for providing high quality, high-resolution imaging at a lower cost than conventional US.2,3 Their application in emergency medicine is widespread as the operation of US is non-invasive, inexpensive and not associated with radiation exposure.1 Portable US is primarily used for diagnostic purposes, but therapeutic uses (e.g., US guided pericardiocentesis) have been documented.3 They have shown value in the context of limited resources and expertise such as rural or remote settings where treatment may be improved by transmitting images to central sites.4 Another out-of-hospital context that portable US has shown potential for is the pre-hospital setting. Proposed benefits of using portable US in the pre-hospital setting include support in determining the appropriate method of transportation and patient destination (i.e., level of facility), prevention of unnecessary field interventions (e.g., needle thoracostomy for patients with suspected pneumothorax), provision of necessary time-sensitive pharmaceutical treatments (e.g., as may be required by patients with congestive heart failure), and increased efficiency of care of the critically ill.3,5 In North America, portable US use has been reported for FAST, pulseless electrical activity arrest, cardiac tamponade, to detect aortic aneurysm, examine for pneumothorax, use for vascular access, assess volume status, or to identify fractures.6 Diagnostic accuracy, reliability, and feasibility of portable US has been well demonstrated in the out-of-hospital setting. 7-10
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Despite the proposed utility of these devices, only 4.1% of emergency medical services directors surveyed in Canada and the United States (30% response rate) reported using portable US in the pre-hospital setting.6 Of the respondents, 21.7% stated that they would consider implementing the technology.6 Major barriers to adoption include cost, training requirements, and lack of evidence for improvement in patient-related outcomes (e.g., morbidity and mortality).6 In light of the perceived potential clinical benefit of pre-hospital US but the lack of direct evidence and presence of other factors, such as cost, impeding their use, the purpose of this review is to review the relationship between the use of portable US in the pre-hospital setting and definitive patient outcomes and resource implications, as well as guidance regarding their use. RESEARCH QUESTIONS 1. What is the clinical effectiveness of portable ultrasound (US) devices for patients in the
pre-hospital setting?
2. What is the cost-effectiveness of portable US devices for patients in the pre-hospital setting?
3. What are the evidence-based guidelines associated with the use of portable US devices for patients in the pre-hospital setting?
KEY FINDINGS Low-quality evidence from two systematic reviews and one non-randomized study suggests that pre-hospital portable US use for a variety of clinical applications may improve the patient care process and influence treatment and patient management decisions. However, there is no conclusive evidence to support a beneficial effect on patient-related clinical outcomes such as morbidity or mortality. No evidence regarding the cost-effectiveness of these devices or evidence-based guidelines regarding their use were identified; therefore, the resource implications of adopting this technology, as well as their recommended use, are unclear. METHODS Literature Search Methods A limited literature search was conducted on key resources including PubMed, The Cochrane Library, University of York Centre for Reviews and Dissemination (CRD) databases, Canadian and major international health technology agencies, as well as a focused Internet search. No filters were applied to limit the retrieval by study type. Where possible, retrieval was limited to the human population. The search was also limited to English language documents published between January 1, 2010 and May 1, 2015. Rapid Response reports are organized so that the evidence for each research question is presented separately. Selection Criteria and Methods One reviewer screened citations and selected studies. In the first level of screening, titles and abstracts were reviewed and potentially relevant articles were retrieved and assessed for
Portable Ultrasound Devices in the Pre-Hospital Setting 3
inclusion. The final selection of full-text articles was based on the inclusion criteria presented in Table 1.
Table 1: Selection Criteria
Population Patients in the pre-hospital setting (e.g., ambulance under the care of a paramedic or emergency physician)
Intervention Portable ultrasound devices (US) (other terms include point of care US, bedside US, focused-assessment with sonography for trauma [FAST])
Comparator No US No comparator
Outcomes Q1: Clinical effectiveness (e.g., impact on condition/disease progression, benefits, safety [patient harms]) Q2: Cost-effectiveness Q3: Guidelines
Study Designs Health technology assessments, systematic reviews, meta-analyses, randomized controlled trials, non-randomized studies, economic evaluations, evidence-based guidelines.
Exclusion Criteria Studies were excluded if they did not meet the selection criteria outlined in Table 1, they were duplicate publications, or were published prior to 2010. Systematic reviews and meta-analyses were excluded if there was incomplete reporting of methodology or if they were superseded by a more recent, rigorous, or updated review. Randomized controlled trials (RCTs) and non-randomized studies were excluded if they were described in an included systematic review. Critical Appraisal of Individual Studies Key methodological aspects relevant to each study design were appraised. The included systematic reviews were critically appraised using AMSTAR criteria.11 Methods used when conducting the literature search, study selection, quality assessment, data extraction, and for summarizing the data were assessed. Non-randomized studies were assessed using the Downs and Black checklist.12 Appropriateness and external validity of cohorts, blinding, recruitment time-frames, losses to follow-up, consideration of confounders, and completeness of reporting were assessed. Summary scores were not calculated for the included studies; rather, strengths and limitations of each included study were described narratively. SUMMARY OF EVIDENCE Details of study characteristics, critical appraisal, and study findings are located in Appendices 2, 3, and 4, respectively. Quantity of Research Available A total of 444 citations were identified in the literature search. Following screening of titles and abstracts, 424 citations were excluded and 20 potentially relevant reports from the electronic search were retrieved for full-text review. One potentially relevant publication was retrieved from the grey literature search. Of these potentially relevant articles, 14 publications were excluded
Portable Ultrasound Devices in the Pre-Hospital Setting 4
for irrelevant outcomes (e.g., diagnostic accuracy or feasibility)8,13-24 or interventions,25 three studies were excluded based on publication type (e.g., review article26,27 or trial protocol28) and one study was excluded as it was contained within an included systematic review.29 Three publications30-32 met the inclusion criteria and were included in this report. Appendix 1 describes the PRISMA flowchart of the study selection. Summary of Study Characteristics Detailed study characteristics are described in Tables A1 and A2 of Appendix 2. Study Design Two systematic reviews31,32 and one non-randomized study (retrospective chart review)30 were identified regarding the clinical effectiveness of portable US devices for patients in the pre-hospital setting. There was some overlap in included studies among the two systematic reviews31,32. Four observational studies9,33-35 were common to both reviews. The newer review contained six additional unique studies10,19,21,29,36,37 and the older review included ten additional unique studies.38-42,42-46 Both systematic reviews were designed to retrieve evidence on the clinical effectiveness of portable US use in the pre-hospital setting and did not identify any randomized controlled trials for review but included primarily prospective observational studies, as well as case reports and case series.31,32 All of the studies within both reviews were non-randomized and non-blinded. The Rudolph et al. review32 contained studies published between 2004 and 2012 (search timeframe 1992 to July 2012), and the Jørgensen et al.31 review contained studies published between 2000 and 2008 (search timeframe 1996 to November 2008). No relevant literature was identified regarding the cost-effectiveness of portable US devices for patients in the pre-hospital setting. In addition, no evidence-based guidelines associated with the use of portable US devices for patients in the pre-hospital setting were identified. Country of Origin The systematic reviews were carried out by research groups in Denmark.31,32 Country of origin for individual studies housed within the systematic reviews was not reported. The single non-randomized study was conducted in The Netherlands.30 Study Setting The systematic review by Rudolph et al.32 included studies conducted in urban, suburban and rural pre-hospital settings. The systematic review by Jørgensen et al. included studies conducted in unspecified pre-hospital settings. Specific setting descriptors were not reported. The non-randomized study30 included cases where US was conducted in helicopter ambulance or at the site of incident (e.g., trauma location, location of emergency call). Patient Population The systematic review by Rudolph et al.32 included studies that included patients in cardiac arrest and circulatory failure; with acute dyspnea, suspected stroke, suspected ruptured abdominal aortic aneurism, pneumothorax, pelvic infections, pregnancy related symptoms, renal
Portable Ultrasound Devices in the Pre-Hospital Setting 5
colic, and gallstones; and receiving US for central venous access. The systematic review by Jørgensen et al.31 included studies that included trauma patients undergoing echocardiography, FAST, invasive procedures (e.g., pericardiocentesis), or receiving US for central venous access. The non-randomized study30 included patients receiving chest examinations such as patients undergoing CPR and trauma patients. Interventions and Comparators Both systematic reviews31,32 assessed portable US devices (brands not specified) used for a variety of clinical applications and operated in the pre-hospital setting by personnel ranging from novices with no experience using US to experienced physician specialists with a background in US. The non-randomized study30 specifically looked at portable chest US (MicroMaxx, SonoSite Inc., Bothwell, WA) in the pre-hospital setting performed by physicians or paramedics. Outcomes The included reviews31,32 and study30 were designed to assess various patient related outcomes related to administration of pre-hospital portable US including patient survival,31,32 change of on-scene treatment or eventual treatment approach,30-32 change in patient transfer location,30-32 change in hospital response,32 change in primary diagnosis ,31 and patient care time delays.31 Summary of Critical Appraisal Appendix 3 provides detailed summary of critical appraisal points. Systematic Reviews Both systematic reviews31,32 were reasonably well conducted. The review by Rudolph et al.32 registered their protocol with PROSPERO whereas the a priori nature of the objectives set for the Jørgensen et al.31 review was unclear. Both studies included duplicate study selection. Rudolph et al.32 also included duplicate extraction while the number of reviewers involved in data extraction in the Jørgensen et al. review was unclear.31 Both reviews included a comprehensive literature search but in both cases the methods of grey literature searching and restrictions based on publication type or language were unclear. A list of included and excluded studies including reasons for exclusion was provided for both reviews. Quality assessments were completed for both reviews (though quality was only discussed generally and disaggregated results were not presented in the Jørgensen et al. review)31 and were considered in the formulation of conclusions. Review authors provided a rationale for foregoing pooling of results in both cases.31,32 As no pooling of results was conducted, publication bias was not assessed and was not discussed within either review. With the exception of insufficiently rigorous grey literature searches and some lack of clarity surrounding methods in the case of the Jørgensen et al. review there were no major concerns with conduct of the reviews. Non-Randomized Studies There were inconsistencies in the quality of reporting for the single non-randomized study.30 While the objectives, intervention, and outcomes were well described and presented, explanation of patient inclusion criteria, confounders, adverse events, and follow-up data was limited. External validity was good, based on the large sample size, wide inclusion criteria, and real-life setting. Internal validity was limited as there was no blinding of study subjects and
Portable Ultrasound Devices in the Pre-Hospital Setting 6
outcome assessors, no direct comparisons between individuals who received US versus those who did not, and no randomization of study subjects to US. As such, individual studies suffered from selection and performance bias. No causal conclusions could be made about the clinical effectiveness of portable US for pre-hospital assessment due to the limitations of the study design. Summary of Findings Appendix 4 provides detailed outcome data and author’s conclusions. What is the clinical effectiveness of portable ultrasound devices for patients in the pre-hospital setting? Both systematic reviews31,32 reported that there is a lack of high-quality evidence regarding whether the use of pre-hospital US improves clinical outcomes of trauma patients. Most evidence for individual outcomes came from single studies with a high risk of bias. Several outcome themes were common to multiple studies. Overall, there was limited evidence from non-randomized studies and case reports that portable US in the pre-hospital setting may improve diagnostic accuracy and confidence,9,19,29,33 provide valuable diagnostic information leading to reduced time to treatment and more appropriate patient triage,19,19,38 and improve patient management and treatment approaches,10,29,33,40 which could potentially lead to improved clinical outcomes. The Rudolph et al. review32 retrieved evidence from three studies to suggest that the use of pre-hospital portable US for various purposes — including detection of peritoneal, pleural, or pericardial effusion; detection of vascular lesions; gastric tube placement; chest examination for patients with acute dyspnea; and trauma, hepatobiliary, transabdominal, transvaginal, renal, and abdominal aortic assessment — is associated with improved diagnostic accuracy or confidence in diagnosis in the majority of cases, with a smaller proportion of cases showing no change and even fewer showing reduced accuracy.9,19,29,33 Both reviews31,32 summarized findings to suggest that the use of portable US for clinical applications including gastric tube placement and transcranial assessment, may save time in the overall care pathway (i.e., from arrival of medical personnel to treatment decision or discharge).19,38 Both reviews31,32 reported findings from studies that support a role for pre-hospital portable US in influencing change in medical management or destination of patient for clinical applications including peri-rescuscitation of severely hypotensive, dyspnoeic, or tachypnoeic patients; chest examination for patients with acute dyspnea; patients requiring trauma, hepatobiliary, transabdominal, transvaginal, renal, and abdominal aortic assessment; and combat trauma patients.10,29,33,40 In addition, they both31,32 presented findings from studies that reported that pre-hospital portable US may lead to change in therapeutic course or improved treatment approaches, in some cases resulting in improved patient safety for clinical applications including gastric tube placement and pre-hospital chest examination for patients with acute dyspnea.18,29 One review reported that there was no evidence of harm associated with using these devices.32 The results from the non-randomized study30 support the evidence from the reviews suggesting that pre-hospital portable US is associated with changes in treatment decisions (including a reduction in inappropriate interventions) and choice of hospital destination for trauma patients and patients requiring CPR undergoing chest US examination.
Portable Ultrasound Devices in the Pre-Hospital Setting 7
What is the cost-effectiveness of portable ultrasound devices for patients in the pre-hospital setting?
No relevant evidence was identified regarding the cost-effectiveness of portable US devices for
patients in the pre-hospital setting; therefore, no summary can be provided.
What are the evidence-based guidelines associated with the use of portable ultrasound devices
for patients in the pre-hospital setting?
No relevant evidence-based guidelines associated with the use of portable US devices for patients in the pre-hospital setting were identified; therefore, no summary can be provided. Limitations The relevance of the retrieved publications30-32 is limited by the lack of availability of direct evidence regarding patient related clinical outcomes. All of the outcomes measured suggest a potential clinical benefit for patients but relate to improvements in the patient care process rather than direct clinical outcomes. The overall quality of the reviews31,32 was good with minor underreporting issues present in the Jørgensen et al.31 review. Since the studies were of insufficient quality to be pooled, results must be interpreted in the context of the individual study data presented. Due to study design limitations, including limited internal validity and consideration of relevant confounders (e.g., expertise of personnel operating US, patient condition, study setting), the non-randomized study30 could only provide descriptive data on the topic. External validity of the evidence is somewhat limited as outcome data was not universally available for all clinical populations or US purposes. Therefore, the results must be interpreted in the context of the individual study population, setting, and US application from which they were derived. It was not possible to comment on the cost-effectiveness of portable US or evidence-based guidelines for their use as no relevant evidence was identified. CONCLUSIONS AND IMPLICATIONS FOR DECISION OR POLICY MAKING The clinical effectiveness of portable US in the pre-hospital setting was evaluated by two systematic reviews,31,32 and one non-randomized study.30 Overall, there was insufficient evidence directly evaluating the clinical benefits of US in terms of direct patient outcomes, suggesting a need for further research on this topic. Within all of the evidence retrieved, calls were made for further well-designed research that measures direct patient outcomes (e.g., morbidity and mortality). This is akin to an earlier report that portable US lands within the top five research priorities in pre-hospital care in Europe.47 While no evidence was identified regarding direct clinical patient outcomes, the overall trend in the presented literature suggested that the use of portable US in the pre-hospital setting has a positive impact on aspects of the patient care process, including aiding in diagnosis, patient triage, and treatment decisions with no apparent evidence of harm. The influence of factors such as expertise of the US administrator, patient condition, and specific pre-hospital setting (e.g., helicopter, land ambulance, site of injury) on patient care outcomes was not explored. As such, it is unclear whether the benefits to the patient care process observed depend on the
Portable Ultrasound Devices in the Pre-Hospital Setting 8
context under which US is performed. Further, no cost-effectiveness evidence or evidence-based guidelines were identified; therefore, no conclusions can be made about resource implications, and recommended use of this technology is unclear. In conclusion, despite evidence to support the feasibility, accuracy, and reliability of these devices, evidence to support their role in enhancing pre-hospital care, diagnosis, and treatment, and commentary in support of potential benefits, there is no high-quality empirical evidence to support a role for these devices in improving direct patient outcomes. PREPARED BY: Canadian Agency for Drugs and Technologies in Health Tel: 1-866-898-8439 www.cadth.ca
http://www.cadth.ca/
Portable Ultrasound Devices in the Pre-Hospital Setting 9
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44. Melanson SW, McCarthy J, Stromski CJ, Kostenbader J, Heller M. Aeromedical trauma sonography by flight crews with a miniature ultrasound unit. Prehosp Emerg Care. 2001 Oct;5(4):399-402.
45. Polk JD, Fallon WF, Jr., Kovach B, Mancuso C, Stephens M, Malangoni MA. The "Airmedical F.A.S.T." for trauma patients--the initial report of a novel application for sonography. Aviat Space Environ Med. 2001 May;72(5):432-6.
46. Polk JD, Fallon WF, Jr. The use of focused assessment with sonography for trauma (FAST) by a prehospital air medical team in the trauma arrest patient. Prehosp Emerg Care. 2000 Jan;4(1):82-4.
47. Fevang E, Lockey D, Thompson J, Lossius HM, Torpo Research Collaboration. The top five research priorities in physician-provided pre-hospital critical care: a consensus report from a European research collaboration. Scand J Trauma Resusc Emerg Med [Internet]. 2011 [cited 2015 May 22];19:57. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3204240
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1726750http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3204240
Portable Ultrasound Devices in the Pre-Hospital Setting 13
APPENDIX 1: Selection of Included Studies
424 citations excluded
20 potentially relevant articles retrieved for scrutiny (full text, if
available)
1 potentially relevant report retrieved from other sources (grey
literature, hand search)
21 potentially relevant reports
18 reports excluded: -irrelevant intervention (1) -irrelevant outcomes (13) -other (review articles, editorials) (3) -included in systematic review (1)
3 reports included in review
444 citations identified from electronic literature search and
screened
Portable Ultrasound Devices in the Pre-Hospital Setting 14
APPENDIX 2: Characteristics of Included Publications
Table A1: Characteristics of Included Systematic Reviews and Meta-Analyses First Author, Publication
Year, Country
Types and numbers of primary studies
included
Population Characteristics
Setting(s), US Administrator(s)
Intervention, Comparator
Clinical Outcomes
Rudolph32
, 2014, Denmark
Total, n = 10
Non-randomized studies, n = 9
“Other/unsure” (case report), n = 1
Non-trauma patients in the pre-hospital setting, n = 1068
Urban, suburban, rural Range of expertise from US novices to physician specialists with extensive US knowledge and skills
Pre-hospital US used to investigate or for:
cardiac arrest
circulatory failure
acute dyspnea
suspected stroke
Abdominal aortic aneurism
pneumothorax
pelvic infections
pregnancy related symptoms
renal colic
gallstones
central venous access,
No comparator
Survival
Change of on-scene treatment
Change in decision of where to transfer patients
Change in hospital response based on pre-hospital US
Jørgensen,31
2010, Denmark
Total, n = 14
Case reports, n = 3;
Non-randomized studies, n = 11
Patients in the prehospital setting, n = 885
Pre-hospital settings, no specifics given Range of US novices (e.g., air crew members) to specialist physicians with US knowledge
Prehospital US used for
echocardiogram
FAST
invasive procedures (e.g., pericardiocentesis)
central venous access
No comparator
Survival
Time to hospital
Change in primary diagnosis
Change in therapy
Early diagnosis
Potential for change of admittance
Time delay FAST = focused-assessment with sonography for trauma; US = ultrasound
Portable Ultrasound Devices in the Pre-Hospital Setting 15
Table A2: Characteristics of Included Clinical Studies First Author,
Publication Year, Country, Study
Name
Study Design Patient Characteristics Setting(s), US Administrator(s)
Intervention, Comparator Clinical Outcomes
Ketelaars,30
2013, The Netherlands
Retrospective chart review
Patients aged 0 to 95 Total: n = 281 (n = 326 US examinations of the chest)
n = 31 patients receiving CPR (n = 39 US examinations of patients receiving CPR)
n = 250 trauma patients (n = 287 US examinations of trauma patients)
Helicopter ambulance or site of incident, Physicians or paramedics
Portable US examinations of the chest by Helicopter Emergency Medical Services, No comparator
Change in treatment decisions
CPR = cardiopulmonary resuscitation; PREP = Polytrauma Rapid Echo-Evaluation Program (Programme Rapide d’Échographie d’un Polytraumatisé); RCT = randomized controlled trial; US = ultrasound
Portable Ultrasound Devices in the Pre-Hospital Setting 16
APPENDIX 3: Critical Appraisal of Included Publications
Table A3: Strengths and Limitations of Systematic Reviews and Meta-Analyses using AMSTAR11
Strengths Limitations
Rudolph32
Protocol registered with PROSPERO prior to conduct of the review
Two reviewers were involved in independent screening and data extraction
A comprehensive literature search using two databases was performed
List of included and excluded studies (including reasons for exclusion) provided
Characteristics of included studies reported
Risk of bias assessed using the SIGN 50 checklist for assessment of risk of bias of observational studies
Risk of bias and heterogeneity among studies mentioned in study conclusions
Choice to not perform meta-analyses was based on thorough assessment of heterogeneity
Conflict of interest declared
Grey literature search methods unclear
Restrictions to search based on language or publication type unclear
Publication bias assessment not conducted due to absence of pooling
Jørgensen31
Clear objectives were set
Duplicate study selection
A comprehensive literature search using two databases was performed
List of included and excluded studies (including reasons for exclusion) provided
Characteristics of included studies reported
Quality was assessed in terms of concealment of allocation, compliance of treatment, number of withdrawals and dropouts, comparability o groups, and proportion analyzed according to randomization
Risk of bias and heterogeneity among studies mentioned in study conclusions
Choice to not perform meta-analyses was based on thorough assessment of heterogeneity
Financial support disclosed
A priori nature of objectives unclear
Unclear data extraction process
Individual study results not reported disaggregated
Grey literature search methods unclear
Restrictions to search based on language or publication type unclear
Quality assessment results were not presented disaggregated, only narratively
Publication bias assessment not conducted due to absence of pooling
Portable Ultrasound Devices in the Pre-Hospital Setting 17
Table A4: Strengths and Limitations of Non-Randomized Studies using Downs and Black12
Strengths Limitations
Ketelaars30 Reporting
Clearly described objective
Outcomes to be extracted described in methods section
Intervention clearly described
Outcome data clearly described
Only descriptive quantitative outcomes presented; therefore, no random variability measures provided
External Validity
Study subjects represented the entire population of relevant patients in the region of interest
Staff, patient treatment settings, and overall setting were representative of a real-life scenario
Internal Validity
All patients recruited from the same population
Reporting
Limited patient inclusion criteria not well described
No principal confounders related to the outcomes of interest were identified
Adverse events sparsely reported
No follow-up data due to study design
No comparisons made for relevant outcomes; therefore, no probability values reported
External Validity
Subjects selected based on chart data therefore differences based on willingness to participate unclear
Internal Validity
No blinding of study subjects or outcome assessors
No randomization of study subjects to intervention
Portable Ultrasound Devices in the Pre-Hospital Setting 18
APPENDIX 4: Main Study Findings and Author’s Conclusions
Table A5: Summary of Findings of Included Systematic Reviews
Main Study Findings Author’s Conclusions
Rudolph32 Survival
Three studies10,36,37
identified patients in whom pre-hospital portable US had a potential impact on outcomes related survival after out of hospital cardiac arrest
No direct evidence on survival rates associated with the use of pre-hospital portable US was available
Change in diagnosis
One study reported that pre-hospital US improved diagnostic accuracy in 67% of cases, decreased it in 8% and did not alter it in 25%
9
One study reported that 68% of emergency physicians found that prehospital sonography improved diagnosis
29
and found that the technology was most useful in patients with CHF, COPD and pericardial effusion, and least useful in acute coronary syndrome
o Therapeutic course was changed in 25% of patients based on US findings
29
One study reported that investigators felt transcranial doppler US in the pre-hospital setting improved confidence in diagnosis and saved time in 36% of cases.
19
In one study US findings had a significant impact on diagnosis in 7% of patients
33
o Diagnostic certainty improved in 68%, was not affected in 24% and decreased in 8% after examination
Change in treatment and referral
Three studies reported a change in treatment and referral o One study reported that US findings contributed
to changed medical management in 89% of patients undergoing CPR, and changed the hospital referral in a number of patients
10
o One study reported that therapeutic consequences were drawn in 25% of patients undergoing pre-hospital US
29
o One study reported altered disposition in 7 patients, including foregoing of 4 potentially lethal decisions
33
Harm
No evidence of harms associated with the use of pre-hospital portable US reported by any of the included studies
The current available literature, which includes non-randomized studies and case-reports with high risk of bias, does not allow for conclusions to be drawn regarding whether pre-hospital US improves patient outcomes
The general trend in the available literature suggests that US is a “helpful tool in pre-hospital decision-making” and that it may positively impact diagnosis, treatment and referral and is unlikely to cause harm
Further research is needed on the clinical effectiveness and safety of pre-hospital US
Jørgensen31 One study
38 reported that pre-hospital transcranial US
streamlined further treatment
One study35
reported that pre-hospital US improved patient safety and treatment
Some evidence of earlier diagnosis, and potential for change in admittance and treatment with the use of US
Portable Ultrasound Devices in the Pre-Hospital Setting 19
Table A5: Summary of Findings of Included Systematic Reviews
Main Study Findings Author’s Conclusions
One study40
reported that pre-hospital US aided in triage of a combat trauma patient
One study33
reported that pre-hospital US used in trauma patients and for hepatobiliary, transabdominal, transvaginal, renal, and abdominal examination can alter disposition and treatment
Data regarding the use of US in the pre-hospital setting too limited and of insufficient quality to definitively answer objectives of review such as whether its use improves treatment of the trauma patient
Further high-quality investigations involving measurement of patient related outcomes are needed
CPR = cardiopulmonary resuscitation; US = ultrasound
Table A6: Summary of Findings of Included Non-Randomized Studies
Main Study Findings Author’s Conclusions
Ketelaars30
Treatment decisions changed in 60 cases (21%) due to information obtained by the US examination
In 9 of 60 patients the physician decided to stop treatment based on US imaging of the heart
In 6 patients intravascular fluid strategy changed
In 24 patients chest tubes were inserted, in 13 cases US examination changed decision to insert tube
In 10 cases the destination hospital changed (e.g,. lower level hospital versus level 1 trauma center)
Information obtained by administering pre-hospital US aided in foregoing unnecessary invasive interventions and directing patients to the appropriate type of hospital
Further prospective data is needed to provide evidence regarding the value of pre-hospital US
US = ultrasound