You should look for scholarly or peer-reviewed sources to assist you in determining the best course of action for your patient.
In PubMed Central or Medline Plus or TRIP or STAT!Ref or any of the other nursing-focused resources, you can refine your results by limiting your search to full-text sources only and by narrowing the publication dates. These databases use something called (MeSH), which are Medical Subject Headings controlled and produced by the National Library of Medicine, that are used for indexing, cataloging, and searching of biomedical and health-related information. So once you have identified the relevant MeSH, you can use that language to search across all of the above-referenced databases.
It's important to understand the difference between Medline and PubMed. Medline is part of PubMed; when you search PubMed you are searching all of Medline, but if you only search Medline you will miss some material that is only in PubMed. The TRIP Database is a clinical search engine, which searches PubMed in addition to a variety of other sources, including clinician-submitted images, videos, patient information leaflets, educational courses, and news.
Levels of evidence (sometimes called hierarchy of evidence) are assigned to studies based on the methodological quality of their design, validity, and applicability to patient care. The diagram below illustrates this hierarchy.
Use PubMed's Medical Subject Headings (MeSH) to identify the medical terminology for the patient's problem, and find potential courses of treatment from the articles and studies retrieved.
Have you found an article that is right on point? Check out the bibliography of sources to which that author cited (end of the article). In this way, you will find more relevant sources. This is sometimes called citation tracing.
Once you have created your search string in PubMed, you can copy and paste it for searching in other databases.
Qualitative Research Methods for Nurses by 
Doing a Literature Review in Nursing, Health and Social Care by