Conducting a literature search using PubMed.

hello my name is Elizabeth Salzer I'm a librarian at the Medical College of Wisconsin this tutorial will demonstrate how to conduct a literature search in PubMed the learning objectives of this tutorial are learning the steps of literature searching understanding mesh terms which are medical subject headings learning about database searching techniques conducting a search in PubMed and learning how to get access to the medical literature I will use the search topic of intubating pediatric head injury patients in the pre-hospital setting throughout this video the search process is made up of the following steps breaking down the search into the main concepts gathering keywords for each concept searching the concepts separately in PubMed and then combining the search concepts together in an advanced search and then filtering the results to include the most relevant ones let's start with step one of breaking up the search question into the main concepts I have identified the following concepts in the search topic intubating pediatric head injury and the pre-hospital setting the next step in the search process is to gather keywords for each concept when I start gathering keywords I often start out on the internet with Google if the results on the first page are not helpful there are ways to limit the results in Google to find more scholarly information for instance you can limit to websites that end in gov which is a government website edu which indicates a school or university website or org which is the domain for organizations limiting to gov is a great way to narrow down to more relevant results this captures information from state local and national government websites as well as sites like NASA PubMed and the Census and other government agencies which produce research and data Wikipedia is also among the first stops for me I used the site to get background information and to find links for references and external websites finally Google Scholar is a place to search scholarly materials like books articles and patents I will demonstrate searches in all of these locations using the term intubation a Google search of intubation finds this blurb from Wikipedia moving down the results list I see keywords such as airway management tracheal intubation and endotracheal intubation let's see what happens when I add gov to my search all of the results come from websites that end in gov and in this list I see PubMed the national guideline Clearinghouse in clinical trials gov these are all great resources in the Wikipedia article for tracheal intubation I find other keywords including ventilation scrolling down to the notes and references section I see the sources that were cited in this article sources include text books journal articles and Conference proceedings moving on to Google Scholar a search for intubation brings up many results you will notice that the top results in Google Scholar are often older articles such as this one from 1991 one factor for how the results are displayed is how many times the article was cited articles that are cited more often are considered to have a higher value and therefore they appear at the top of the results you can click the cited by link to find related articles that built off information from this one searching tracheal intubation brings up a completely different list of results this is because Google is searching the exact terms that are in the search box keep in mind that when you search Google and Google Scholar you are only finding results that use the search terms that you typed in for concepts that have many synonyms it's hard to do a comprehensive search on the Internet after identifying key words to describe our concepts the next step is to move to PubMed to find relevant mesh terms mesh stands for medical subject headings and it is a set of controlled vocabulary terms used by the National Library of Medicine in PubMed articles are assigned mesh terms by subject specialists who read over the articles and determine the subject contents applying mesh terms ensures the articles on the same subject are grouped together regardless of the vocabulary used by the author mesh descriptors are arranged in a tree structure that allows you to search at different levels of specificity I'm going to demonstrate how to look up the mesh term for the topic pediatric patient in PubMed switch from searching PubMed to mesh I'll start out with the term pediatric King through the list I see that many of the entries refer to the medical specialty of Pediatrics not the age of a patient let's try searching child the first result says that child is a person aged 6 to 12 years of age this seems on point in a mesh entry you'll typically see the entry name and a description of what the term encompasses and under this is the tree of hierarchy that I mentioned earlier a narrower term for child is child comma preschool and a broader term is age groups let's see what other age groups there are mesh terms for rolling down the page to the mesh hierarchy tree I see that there are a few narrower age groups child adolescent and infant are all age groups that relate to a pediatric aged patient when we search PubMed I'll be sure to include all of these terms in order to find articles that pertain to this patient population before we move on to conducting our search in PubMed it's important to know some basic search techniques these techniques apply to many databases not just PubMed first of all many databases allow the use of truncation truncation is the addition of the symbol usually an asterisk at the end of a word stem to find variants of the root word and this is very useful for finding synonyms in this example putting an asterisk after intubate will retrieve the words intubation intubating and intubate the next technique is the use of quotation marks this keeps terms together in the exact order this is helpful for searching exact titles or terms like emergency medicine try searching PubMed with and without the quotes around emergency medicine and you'll find different results another search technique is the use of parentheses parentheses are used in the same manner that they would be used in math equations and they allow for ordering sets of terms in this example putting parentheses around child or adolescents ask the database to search these terms together first and then add that to intubate finally boolean operators are used to connect and define the relationships between your search terms when searching electronic databases you can use boolean operators to either narrow or broaden your search results the three boolean operators are and or and not most databases require that these terms are entered in capital letters for the database to recognize them as boolean operators use and to narrow your search by combining together two separate topics putting and between child and head injury ask the database to find articles that contain both of these concepts notice the quotation marks around head injury to keep this together as a phrase and the asterisk after child to find variants on this word such as child or children use the boolean operator or to broaden your search and this is often used with synonyms child pediatric infant or adolescents are all ways of described the topic of a pediatric patient so putting or between these terms last the database to find articles that contain any or all of these terms finally not is a boolean operator and it excludes terms from your search results I use this with caution since an offhand mention of a term could mean that a relevant article is excluded from your search results an example of using not would be intubation not gastrointestinal with this search I would hope to find articles that focus on intubation through the trachea I've taken some time to collect keywords and mesh terms for all of our topics remember for each topic I did a broad search on the internet using Google Wikipedia and Google Scholar browsing through the webpages and papers gave me some good ideas on terminology and I found the mesh terms in PubMed I put together my search strategies using the advanced search techniques that I just explained let's take a look at what I found for the first topic of intubating I found the mesh term intubation when searching through the Internet I also found variations on intubating including intubation into Bader's and intubate the search string that I'll use to describe this topic will be intubation or a truncated version of intubate for the topic of head injury I identified the mesh term cranial cerebral trauma I also identified narrower mesh terms of head injuries closed and brain concussion if I'm finding too many results using the mesh term cranial cerebral trauma I can change this to one of the narrower mesh terms searching the Internet I also found terms like head injury and concussion so for this search strategy I'll use cranial cerebral trauma or head injury notice that head injury and cranial cerebral trauma both have quotation marks around them and this is to keep these words together I may decide to use the word concussion in my search but I can add that at a later time for the topic of the pediatric aged patient I identified the mesh terms of child infant and adolescent for all of these terms truncation will come in handy to find the plural variations of these words for instance if I truncate child I'll find child or children and if I truncate adolescents I'll find adolescent adolescent or adolescents plural so for this search strategy I will use child truncated or infant truncated or pediatric truncated or adolescents truncated and for our final topic of pre-hospital setting if I identified the mesh term emergency medical services looking throughout the literature I also saw that pre hospital or EMS are other words to describe this topic so for this strategy I'm going to use emergency medical services with quotations or pre-hospital or EMS this is my first pass at formulating this search after I look over my search results I may choose to add or remove terms in order to find different results now that we have learned some advanced searching techniques and have identified a list of keywords and mesh terms for each topic let's run a search in PubMed I'm going to demonstrate using the advanced search page in PubMed and we'll search each topic separately before combining them together in onesearch start at PubMed and click advanced search we'll start with the first topic of intubation so here we're searching intubation or the truncated version of intubate there are over 69 thousand results in our list but this is okay because we'll narrow down the results once we start combining together our topics let's see how PubMed interpreted this search scrolling down the page on the right side of the screen you can see the search details here we see that intubation was searched as a mesh term as well as in all fields in all fields includes the title the journal title author and abstract fields as well as the mesh terms and you can also see the different variations of the truncated version of intubate click on advanced to go back to the advanced search builder we'll enter in our second topic of head injury we've identified the mesh terms cranial cerebral trauma or head injury at this point I can choose to include the word concussion I'll remove the parentheses around this term and add concussion in with the boolean operator of or you'll see that we've retrieved a few more results using this third term in the search history on the advanced search page we can see the modified search that we did where the term concussion was added to the phrases cranial cerebral trauma or head injury let's move on to the third topic of a pediatric patient we've identified the terms child infant pediatric or adolescents and you'll find over 3,000,000 result for these terms the last topic that we need to search is emergency medical services or the pre-hospital setting emergency medical services was the mesh term associated with this topic we've also added the keywords of pre-hospital or EMS with the search we've retrieved over 40,000 results now that all the pieces have been searched separately we can put them together with ands by adding all of the pieces to the search builder notice the and between each line and when we put everything together we get a total of 45 results we can decide if we need to broaden the search by either removing some of the andddd parts or we can broaden up our terminology in PubMed we can apply filters to our to our search results one helpful filter is language type to see this filter click show additional filters select language and click show you'll see that languages appear as a possible filter we can click English to filter our results to include only articles that are written in English another helpful filter is article type if you are specifically looking for research or review articles you can use this filter to specify that let's take a look at one of the articles at the top of the page I see the citation information for this article including the journal name the article title and the author's on the right side of the page I see a full text link and this goes to the publishers website we also see the abstract and scrolling down you'll see the mesh terms applied to this article it's often helpful to look over the mesh terms and see the words that are used to describe this article you may get ideas on other terms to include in your search also on the right side of the page you'll see that this article was cited by for PubMed Central articles what is PubMed Central you might ask PubMed Central is a database of open access or free to view articles many of the articles in PubMed Central came about through research funding provided by NIH grants researchers who receive grants from the National Institute of Health are obligated to make their findings of the research freely accessible and they do that by putting their manuscripts in PubMed Central if you don't have access to a library that subscribes to many research databases or publications one place to find three peer-reviewed literature is in pubmed central in most searches in PubMed on the right side of the page you'll see if any of the search results are in PubMed Central and in the search two of the articles in the results list are published in PubMed Central clicking on this link here will take you to the full-text of those articles if we're interested in finding more articles we can change up our search term so let's try broadening our search results by just looking at emergency medical services intubation and pediatric patients going back to the advanced search page I can select these three topics and add them to the search builder notice that there are many more results in this list and also notice that the English language filter is still on and on the right side of the page you'll find that 33 free full-text articles are available in PubMed Central another thing to mention is that some of the articles in this list refer to patients in the emergency department the mesh term emergency medical services refers to both the in hospital and out of hospital setting at this point you'll need to filter out the in hospital results by hand if you want to focus specifically on the pre-hospital setting if there are articles in your results list that you want to keep track of you can create a my NCBI account and save documents to a collection select the articles that you want to save and click send to collections at this point you'll be prompted to either sign into NCBI directly or register for an account you can create any number of collections in my NCBI and this is a good way to keep track of articles and to organize them for specific research papers after the initial search has been done I look over the results that I pulled scan the abstracts and determine if I should add or subtract any terms from my search I ask myself if there's anything I feel that I'm missing and I try to find words to describe that also after you find a very relevant article look through the bibliography to see what sources were cited this is a good way of finding other relevant literature the search process is a dynamic one and your search terms will change as you encounter information the last step that I will address is getting access to the literature I mentioned PubMed Central already this is a repository of open access articles if you are located in an area with the college or university library you might be able to get access to their subscriptions at the Medical College of Wisconsin our library is open to the public in anyone who uses our computers can get access to our journal subscriptions I recommend calling around your area to see what kind of access is available to you also many hospitals have library staff who facilitate document delivery and they might be able to retrieve articles for you for free or at a low cost public libraries can also assist with this thank you for taking the time to view this tutorial about conducting an advanced search in PubMed if you have any questions about using PubMed there are many resources available the National Library of Medicine has a free online training center for PubMed and the national network of libraries of medicine have trainings and tutorials available as well additionally googling PubMed training will bring up guides and tutorials posted by librarians from around the world and if you can find the medical librarian near you we are here to help

Channel: Medical College of Wisconsin Libraries

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Length: 20min 51sec (1251 seconds)

Published: Thu Dec 31 2015