Introduction
Acute dyspnea is a common complaint in emergency departments and is caused by different conditions including heart failure, pneumonia and chronic obstructive lung disease.1,2 Patients admitted with acute dyspnea as the primary complaint have high mortality rates, with one and 30-day mortality rates at 3.6% and 13.0%, respectively.3 It is therefore crucial to pay special attention to this patient population.
Patients admitted with acute dyspnea are often monitored through a combination of physical examination (e.g. vital signs, symptom scores and lung auscultation) and medical tests (e.g. chest X-ray, blood samples and arterial blood gas).4-7 Because these methods lack sensitivity and specificity, other approaches are warranted.4,5
Point-of-care ultrasound is a fast and simple bedside tool used in both the diagnostic and secondary evaluation of patients with acute dyspnea. Focused ultrasound of the lungs (FLUS) can be used to diagnose interstitial syndrome (lung diseases affecting the lung interstitium, such as lung edema), lung consolidation, pneumothorax or pleural effusion.8,9 Interstitial syndrome can be evaluated and quantified via ultrasound through dynamic artifacts called B-lines.9 In addition, ultrasound of the inferior vena cava (IVC), either alone or as part of echocardiography or focused cardiac ultrasound (FoCUS), can be used to evaluate volume status and as a diagnostic tool for identification of congestive heart failure in patients presenting with undifferentiated dyspnea.10-12
Both FLUS13-15 and IVC ultrasound16-20 have been used in some studies to monitor and guide therapy for patients with acute dyspnea, but these studies are heterogenic, both clinically and methodologically. Additionally, both ultrasound modalities have been used in patients with diagnosed or suspected heart failure and not in patients with undifferentiated dyspnea caused by other conditions. Only a few inconclusive studies have been conducted that use FLUS in combination with IVC ultrasound to monitor patients with acute dyspnea.21,22
Monitoring patients with acute dyspnea is essential to optimize and guide therapy, decrease length of stay in hospital and long-term mortality, and improve morbidity.
A preliminary search has been conducted on PROSPERO, PubMed, the Cochrane Database of Systematic Reviews and the JBI Database of Systematic Reviews and Implementation Reports to find reviews on the review topic, but no current or ongoing systematic reviews were identified.
The objective of this review is therefore to evaluate the effectiveness of using serial FLUS and/or IVC ultrasound, compared to standard care, for monitoring patients with acute dyspnea.
Review question
What is the effect of monitoring patients with acute dyspnea with serial FLUS and IVC ultrasound, compared to standard care, on length of stay, readmission and mortality?
Inclusion criteria
Participants
Studies that focus on adults who are 18 years or older and admitted to hospital with acute dyspnea as the primary symptom will be considered for inclusion.
Intervention
This review will include studies that examine monitoring of patients with serial/repeated ultrasound two or more times via FLUS, IVC ultrasound or both.
Comparator
The intervention will be compared to standard care of another group of patients monitored through other examinations, for example, vital signs, symtom scores, lung auscultation, blood samples and arterial blood gas.
Outcomes
This review will consider studies that include the following outcomes: length of stay, readmission, mortality, diameter of the IVC, percentage collapsibility of IVC correlated to vital signs and symptoms, and number of B-lines correlated to vital signs and symptoms.
Types of studies
Controlled trials (randomized and non-randomized), observational studies (cohort, case-control), case reports and conference abstracts based on these types of studies will be included for screening. Other systematic reviews will be excluded. Both published articles and unpublished trials will be included.
The review will include articles written in English, Danish, Swedish, Norwegian and German. Furthermore, articles published before 2003 will be excluded from the search, as preliminary searches did not reveal any relevant articles prior to that year.
Methods
The proposed systematic review will be conducted in accordance with JBI methodology23 and the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines.24,25
Search strategy
The search strategy was developed in conjunction with a professional librarian at the University Library of Southern Denmark. Both controlled vocabulary (e.g. MeSH in PubMed and Emtree in Embase) as well as free text and keyword searches will be conducted. For the free-text search, different spelling and synonyms will be used. The basic search is composed of a combination of the fundamental items from the research question: dyspnea AND ultrasound AND monitoring. The general search string is provided in Appendix I, and the specific search strings, which will be used in the different databases, are provided in Appendix II. The reference lists of the included full-text studies will be examined to find additional studies that were not identified through the search of the electronic bibliographic databases. Some chosen databases have an inbuilt function to find related/similar articles. This function will be used with the full-text articles from the original search of these databases to find any additional relevant articles. Furthermore, included full-text articles will be examined using backward searching in the citations databases Scopus and Web of Science.
Information sources
The following electronic databases will be searched: PubMed, Cochrane, Embase, Scopus, Web of Science and Google Scholar. Gray literature will be sought in OpenGrey and ProQuest. Ongoing trials on the subject will be sought in Clinical Trials (ClinicalTrials.gov) and International Clinical Trials Registry Platform (ICTRP) and authors will be contacted for preliminary results.
Study selection
Studies from each of the databases will be uploaded to the reference tool EndNote V8.2 (Clarivate Analytics, PA, USA) and checked for duplicates. References will then be transferred to Covidence (Covidence, Melbourne, Australia), an Internet-based software program, used to screen and extract data. The references will be double-checked for duplicates using this program.
Two independent reviewers (MDA and NJ) will screen the titles and abstracts yielded by the search against the inclusion criteria. The selected articles will then undergo full-text screening by the same two reviewers. Disagreements will be resolved through discussion or with a third reviewer (CBL) and reasons for exclusion will be recorded. The selections process will be illustrated in a PRISMA flowchart25 in the final systematic review.
Assessment of methodological quality
Different study designs will be included in this study, and therefore the studies will be evaluated according to the study design type. Eligible studies will be critically appraised by two independent reviewers (MDA and NJ) using the standardized critical appraisal tools provided by JBI.23 No studies will be excluded on the grounds of the methodological quality. Instead, limitations in the included studies will be reported. The quality of the included studies will be presented in narrative form and in a table in the final systematic review.
Data extraction
The data from the included studies will be extracted using the inbuilt function in Covidence. The data will be extracted independently by two reviewers (MDA and NJ) from each eligible study. Any disagreements that arise between the reviewers will be resolved through discussion and in the case of continued discrepancy, with a third reviewer (CBJ). Authors of papers will be contacted to request missing or additional data, where required.
Data will include: general information (i.e. authors, year), methods (i.e. study design, single or multi center, inclusion and exclusion criteria, population [age, gender], sample size, intervention [ultrasound scanning protocol]), and results (i.e. outcomes).
The extracted data will be represented in a table in the results section of the systematic review.
Data synthesis
Quantitative data from the included studies will, where possible, be pooled with statistical meta-analysis using RevMan V5.3 (Copenhagen: The Nordic Cochrane Centre, Cochrane). Effect sizes will be expressed as either odds ratio (for dichotomous data) or weighted mean differences (for continuous data), and 95% confidence intervals will be calculated for analysis. Heterogeneity will be assessed statistically using the standard Chi-squared and I2 tests. Statistical analyses will be performed using the random effects or fixed effects model, based on the flow chart and guidance provided by Tufanaru et al.26 Subgroup analyses will be conducted where there are sufficient data to investigate diagnosis (e.g. heart failure, chronic obstructive disease, and pulmonary embolism) and type of intervention (FLUS, ultrasound of the IVC or both). Sensitivity analyses will be conducted to test decisions made regarding, for example, study design, type of intervention and outcomes; however, it is recognized that many issues suitable for sensitivity analysis are only identified during the review process. Where statistical pooling is not possible, the findings will be presented in narrative form including tables and figures to aid in data presentation, where appropriate.
A funnel plot will be generated with RevMan V5.3 to assess publication bias if there are 10 or more studies included in a meta-analysis. Statistical tests for funnel plot asymmetry (Egger test, Begg test, Harbord test) will be performed, where appropriate.
Assessing certainty in the findings
An overall assessment of the robustness of evidence will be provided using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach27 and presented in a Summary of Findings (SoF) with the following information if applicable: PICO (participants, intervention, comparator, outcomes), results (participants and studies, absolute and relative risk), ranking of the quality of evidence (based on the risk of bias, inconsistency, indirectness, imprecision, publication bias), comments and footnotes. The outcomes in the table will be: length of stay, readmission(s), mortality and improvement of dyspnea. The SoF will be created using GRADEpro (McMaster University, ON, Canada).
Acknowledgments
The authors would like to acknowledge Anne Faber Hansen, research librarian, the University Library of Southern Denmark, who provided guidance in designing the search strategy.
Appendix I: General search strategy
The basic search which will be used on the different electronic databases. Spelling variations, synonyms and abbreviations have been taking into account. A controlled vocabulary is used in databases providing this service.
Block 1: Ultrasound
Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR "Vena cava inferior" OR VCI OR Echocardiography
AND
Block 2: Dyspnea/heart failure
Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR "Shortness of breath" OR SOB OR Breathless OR Breathlessness OR "Heart failure" OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion
AND
Block 3: Monitoring
Monitoring OR Monitor OR Serial OR repeated OR repeating
The complete search string to "copy-paste" into the search field:
(Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR "Vena cava inferior" OR VCI OR Echocardiography) AND (Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR "Shortness of breath" OR SOB OR Breathless OR Breathlessness OR "Heart failure" OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion) AND (Monitoring OR Monitor OR Serial OR repeated OR repeating)
Appendix II: Search strategies
PubMed
Limits: Human, from the year 2003
((Ultrasound[Title/Abstract] OR Ultrasonography[Title/Abstract] OR Ultrasonic[Title/Abstract] OR Sonographic[Title/Abstract] OR Sonography[Title/Abstract] OR POCUS[Title/Abstract] OR LUS[Title/Abstract] OR FLUS[Title/Abstract] OR CaTUS[Title/Abstract] OR FoCUS[Title/Abstract] OR "inferior vena cava"[Title/Abstract] OR IVC[Title/Abstract] OR "Vena cava inferior"[Title/Abstract] OR VCI[Title/Abstract] OR Echocardiography[Title/Abstract] OR "ultrasonography"[MeSH Terms] OR "echocardiography"[MeSH Terms]) AND (Dyspnea[Title/Abstract] OR Dyspnoea[Title/Abstract] OR Dyspneic[Title/Abstract] OR Dyspnoeic[Title/Abstract] OR "Shortness of breath"[Title/Abstract] OR SOB[Title/Abstract] OR Breathless[Title/Abstract] OR Breathlessness[Title/Abstract] OR Dyspnea[MeSH] OR Dyspnea, paroxysmal[MeSH] OR "Heart failure"[Title/Abstract] OR HF[Title/Abstract] OR AHF[Title/Abstract] OR ADHF[Title/Abstract] OR Decompensation[Title/Abstract] OR Decompensated[Title/Abstract] OR Congested[Title/Abstract] OR Congestion[Title/Abstract] OR Heart failure[MeSH]) AND (Monitoring[Title/Abstract] OR Monitor[Title/Abstract] OR Serial[Title/Abstract] OR repeated[Title/Abstract] OR repeating[Title/Abstract] OR "monitoring, physiologic"[MeSH Terms])) AND (("2003/01/01"[PDat]: "2018/12/31"[PDat]) AND Humans[Mesh])
Embase
Limits: Human, from the year 2003
((Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR IVC OR VCI OR Echocardiography).ti OR inferior vena cava/ OR ultrasonography/ OR echocardiography/) AND ((Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR SOB OR Breathless OR Breathlessness OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion).ti OR Dyspnea/ OR paroxysmal dyspnea/ OR Heart failure/) AND ((Monitoring OR Monitor OR Serial OR repeated OR repeating).ti OR monitoring/)
Web of Science
Limits: Articles, from the year 2003
TS=(Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR "vena cava inferior" OR VCI OR Echocardiography) AND TS=(Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR "shortness of breath" OR SOB OR Breathless OR Breathlessness OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion OR "Heart failure") AND TS=(Monitoring OR Monitor OR Serial OR repeated OR repeating)
Scopus
Limits: From the year 2003, article, conference paper, conference review, subject area medicine. The platform further limited the search in terms of a reduced number of letters to fill in the search bar.
(Ultraso* OR Sonograph* OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR Echocardiography) AND (Dyspn* OR "heart failure" OR HF OR AHF OR ADHF OR Decompensat* OR congest*) AND (monitor* OR serial OR repeat*)
Cochrane
Limits: Trials, from the year 2003
(Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR "Vena cava inferior" OR VCI OR Echocardiography OR [mh ultrasonography] OR [mh echocardiography]) AND (Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR "Shortness of breath" OR SOB OR Breathless OR Breathlessness OR [mh Dyspnea] OR [mh Dyspnea, paroxysmal] OR "Heart failure" OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion OR [mh Heart failure]) AND (Monitoring OR Monitor OR Serial OR repeated OR repeating OR [mh monitoring, physiologic])
Google Scholar
Limits: Title search only (otherwise > 18000 citations), the year from 2003. The platform further limited the search in terms of a reduced number of letters to fill in the search bar.
allintitle: Ultrasound OR Sonographic POCUS OR LUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR Echocardiography AND Dyspnea OR "heart failure" OR decompensated OR decompensation OR congestion OR congested AND monitoring OR serial OR repeated
OpenGrey
(Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR "Vena cava inferior" OR VCI OR Echocardiography) AND (Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR "Shortness of breath" OR SOB OR Breathless OR Breathlessness OR "Heart failure" OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion) AND (Monitoring OR Monitor OR Serial OR repeated OR repeating)
ProQuest
((Ultrasound OR Ultrasonography OR Ultrasonic OR Sonographic OR Sonography OR POCUS OR LUS OR FLUS OR CaTUS OR FoCUS OR "inferior vena cava" OR IVC OR "Vena cava inferior" OR VCI OR Echocardiography) AND (Dyspnea OR Dyspnoea OR Dyspneic OR Dyspnoeic OR "Shortness of breath" OR SOB OR Breathless OR Breathlessness OR "Heart failure" OR HF OR AHF OR ADHF OR Decompensation OR Decompensated OR Congested OR Congestion) AND (Monitoring OR Monitor OR Serial OR repeated OR repeating)) AND stype.exact ("Conference Papers & Proceedings" OR "Other Sources" OR "Standards & Practice Guidelines" OR "Government & Official Publications" OR "Reports" OR "Working Papers" OR "Blogs, Podcasts, & Websites" OR "Scholarly Journals" OR "Dissertations & Theses" OR "Pamphlets & Ephemeral Works") AND at.exact ("Book Chapter" OR "Letter To The Editor" OR "Pamphlet/Ephemera" OR "Dissertation/Thesis" OR "Government & Official Document" OR "Working Paper/Pre-Print" OR "Blog" OR "Correction/Retraction" OR "Editorial" OR "Conference Paper" OR "Book" OR "Correspondence" OR "Speech/Lecture" OR "Conference" OR "Audio/Video Clip" OR "Evidence Based Healthcare" OR "Website/Webcast" OR "News" OR "Report" OR "Review" OR "Case Study" OR "Conference Proceeding" OR "General Information" OR "Article") AND (fdb(10000255 10000155 1007617 10000115 10000205 1007584 1008749 1006520 1007108 1007885 1007913 1009046 1009063 1009064 10000204 1008742) NOT fdb (1007107 10000260 10000253 10000238 10000025 1007899 10000234 1000283 1006481 10000008 1000001 1007588 1008753 1007583 1008748 10000265 1009240 10000250 1007106 10000262 1007587 1008752 1007200 1007903 10000233 1007898 1007555 1007902 10000023 10000026 10000264 1005683 1007156 1007429 10000245 1007161 1007883 1007884 1007886 1007887 1007888 1007889 1007582 1007900 1008747 10000254 1005684 1007586 1008751 10000244 1007901 10000231 1007133 1009060 10000180 10000236 1000277 1007585 1007897 1008750 10000017 10000243 1007025 1007455 1007527 1007917 10000263 1007409 1007480 1007911 1007912 1007914 1007915 1007916 10000249 1005641 1006984 1007139 1007485 1009049 1009059) AND at.exact (("Article" OR "Report" OR "Case Study" OR "Dissertation/Thesis" OR "Conference" OR "Working Paper/Pre-Print" OR "Instructional Material/Guideline" OR "Conference Proceeding" OR "Evidence Based Healthcare" OR "Blog") NOT ("Feature" OR "General Information" OR "News" OR "Commentary" OR "Editorial" OR "Correspondence" OR "Undefined" OR "Literature Review" OR "Speech/Lecture" OR "Statistics/Data Report" OR "Biography" OR "Interview" OR "Business Case" OR "Front Matter" OR "Table Of Contents" OR "Book" OR "Country Report" OR "Front Page/Cover Story" OR "Industry Report")) AND subt.exact (("humans" OR "studies" OR "female" OR "male" OR "middle aged" OR "aged" OR "mortality") AND ("adult" OR "heart failure" OR "cardiovascular disease" OR "risk factors" OR "heart attacks" OR "treatment outcome" OR "patients" OR "hospitals" OR "hypertension" OR "aged, 80 & over" OR "adolescent" OR "blood pressure" OR "prospective studies" OR "heart" OR "diabetes" OR "prognosis" OR "follow-up studies" OR "cardiology" OR "retrospective studies" OR "echocardiography" OR "electrocardiography" OR "time factors" OR "drug therapy" OR "index medicus" OR "quality of life" OR "public health" OR "heart rate" OR "cardiovascular diseases" OR "coronary vessels" OR "clinical trials" OR "myocardial infarction" OR "medical imaging" OR "heart diseases" OR "united states" OR "age" OR "cardiac arrhythmia" OR "biological markers" OR "severity of illness index" OR "older people") NOT ("electrical engineering" OR "statistical data" OR "animals" OR "child" OR "rodents" OR "young adult" OR "risk assessment" OR "proteins" OR "pregnancy" OR "mice" OR "questionnaires" OR "magnetic resonance imaging" OR "child, preschool" OR "gene expression" OR "infant" OR "infant, newborn" OR "nursing" OR "tomography, x-ray computed" OR "economics"))) AND pd (2003-2018)
References