Begin with a well-focused research question, which you may often have to create from a clinical scenario.
In patients undergoing cardiac surgery, is amiodarone more effective than beta blockers in preventing arrhythmias such as atrial fibrillations?
What are the main terms in this question?
cardiac surgery / amidarone / beta blockers / arrythmias
Cardiac surgery, as well as heart surgery, maps to both thoracic surgery and cardiac surgical procedures--which is too broad. Go to the MeSH Database or check details and pick out cardiac surgical procedures to search on
Synonyms, words that mean the same thing or are closely related to your main search terms, can help expand your search appropriately.
cardiac surgery | amiodarone | beta blockers | arrhythmias |
heart surgery | drug therapy | adrenergic beta-antagonists | atrial fibrillation |
thoracic surgery |
benzofurans | beta blockers | tachycardia |
cardiac surgery | bradycardia |
Boolean operators such as AND & OR are used to connect synonyms & concepts.
Here is the search string that can be used to search the database:
(cardiac surgery OR heart surgery) AND (amiodarone OR adrenergic beta-antagonists OR beta blockers) AND (arrhythmias)
Sometimes, you'll need to search for a phrase rather than a word. If you use quotation marks around the the phrase, you could run into problems. Using quotation marks can mean that no part of that phrase will map to an indexing term, so you may miss important articles. On the other hand, sometimes quotation marks can help your search, especially if there is no relevant indexing term for a concept.
For example, in PubMed, dietary intake doesn't map to a MeSH term; instead, dietary is searched as a keyword, & mapped to diet & intake is mapped as a separate keyword & MeSH term. This results in thousands of inappropriate results. When "dietary intake" is searched as a phrase, you get a smaller number of highly relevant results.
Quotation marks can also be used to search phrases as keywords, even when a MeSH term exists. For example, in PubMed, vegan maps to the MeSH term Diet, Vegtarian. In addition to using vegan as a keyword, you can also use "plant-based diet" as a keyword phrase.