Adding Additional Terms to Search History
Once you have identified additional keywords and MeSH terms, and added them to your PICO chart, go into the PubMed Advanced Search and add each new term to your search history one by one.
Remember: when adding MeSH Terms, make sure to change the search field to MeSH Terms.
Combining terms with "OR" within each column
For each column in the PICO chart that had new terms added to it, redo the search by combining your old search with the new terms. See below for an example using the "P" column. You would also need to do something similar for the "I" column, as that had terms added to it as well.
Combining terms with "AND" between the P, I, C, and O columns
After you have added the new terms to your search, you can combine the P, I, C, & O column searches using "AND"
By adding additional terms, our final result has grown from 25 in the initial search to 69.
Remember: Research is an ongoing process. As you look at your results, you may want to continue to develop your search by adding more keywords and MeSH terms to your PICO chart, and then adding those new terms to your search.
For some questions, alternatives to the PICO format might be a better fit. See the next section for other question formats.