Clinical practice guidelines (CPG) are statements to assist a practitioner to make decisions about appropriate health care in certain clinical circumstances.
The Institute of Medicine (IOM) defines clinical practice guidelines as "statements that include recommendations, intended to optimize patient care, that are informed by a systematic review of evidence and an assessment of the benefits and harms of alternative care options" (https://www.nhlbi.nih.gov/node/80397).
CPGs can be found in databases like CINAHL and PubMed but are also found in specific databases and through specialized search tools for guidelines listed below.
You may also want to consider a web search for the organization that would issue the guideline. For example, the American Diabetes Association would issue guidelines for diabetes.
More information about CPGs can be found on the library's Johns Hopkins EBP guide under level IV evidence.